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  • 1.
    Hruzova, Katerina
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Patel, Alok
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Masák, Jan
    Department of Biotechnology, University of Chemistry and Technology Prague, Prague, Czech Republic.
    Maťátková, Olga
    Department of Biotechnology, University of Chemistry and Technology Prague, Prague, Czech Republic.
    Rova, Ulrika
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Christakopoulos, Paul
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Matsakas, Leonidas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    A novel approach for the production of green biosurfactant from Pseudomonas aeruginosa using renewable forest biomass2020In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 711, article id 135099Article in journal (Refereed)
    Abstract [en]

    The rising demand for surfactants by the pharmaceuticals and cosmetic industries has generated vast amounts of petroleum-based synthetic surfactants, which are often toxic and non-degradable. Owing to their low toxicity, stability in extreme conditions, and biodegradability, biosurfactants could represent a sustainable alternative. The present study aimed to maximize the production of rhamnolipids (RL) from Pseudomonas aeruginosa by optimizing glucose concentration, temperature, and C/N and C/P ratios. After 96 h of cultivation at 37 °C, the final RL concentration was 4.18 ± 0.19 g/L with a final yield of 0.214 ± 0.010 g/gglucose when pure glucose was used as a carbon source. At present, the main obstacle towards commercialization of RL production is economic sustainability, due to the high cost of downstream processes and media components. For this reason, a renewable source such as wood hydrolysates (from birch and spruce woodchips) was examined here as a possible source of glucose for RL production. Both hydrolysates proved to be adequate, resulting in 2.34 ± 0.17 and 2.31 ± 0.10 g/L of RL, respectively, and corresponding yields of 0.081 ± 0.006 and 0.089 ± 0.004 g/gsugar after 96 h. These results demonstrate the potential of using renewable biomass for the production of biosurfactants and, to the best of our knowledge, they constitute the first report on the use of wood hydrolysates for RL production.

  • 2.
    Patel, Alok
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Karageorgou, Dimitra
    Laboratory of Biotechnology, Department of Biological Applications and Technologies, University of Ioannina, Ioannina 45110, Greece.
    Rova, Emma
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Katapodis, Petros
    Laboratory of Biotechnology, Department of Biological Applications and Technologies, University of Ioannina, Ioannina 45110, Greece.
    Rova, Ulrika
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Christakopoulos, Paul
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Matsakas, Leonidas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    An Overview of Potential Oleaginous Microorganisms and Their Role in Biodiesel and Omega-3 Fatty Acid-Based Industries2020In: Microorganisms, ISSN 2076-2607, Vol. 8, no 3, article id 434Article, review/survey (Refereed)
    Abstract [en]

    Microorganisms are known to be natural oil producers in their cellular compartments. Microorganisms that accumulate more than 20% w/w of lipids on a cell dry weight basis are considered as oleaginous microorganisms. These are capable of synthesizing vast majority of fatty acids from short hydrocarbonated chain (C6) to long hydrocarbonated chain (C36), which may be saturated (SFA), monounsaturated (MUFA), or polyunsaturated fatty acids (PUFA), depending on the presence and number of double bonds in hydrocarbonated chains. Depending on the fatty acid profile, the oils obtained from oleaginous microorganisms are utilized as feedstock for either biodiesel production or as nutraceuticals. Mainly microalgae, bacteria, and yeasts are involved in the production of biodiesel, whereas thraustochytrids, fungi, and some of the microalgae are well known to be producers of very long-chain PUFA (omega-3 fatty acids). In this review article, the type of oleaginous microorganisms and their expertise in the field of biodiesel or omega-3 fatty acids, advances in metabolic engineering tools for enhanced lipid accumulation, upstream and downstream processing of lipids, including purification of biodiesel and concentration of omega-3 fatty acids are reviewed.

  • 3.
    Patel, Alok
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Rova, Ulrika
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Christakopoulos, Paul
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Matsakas, Leonidas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Assessment of Fatty Acids Profile and Omega-3 Polyunsaturated Fatty Acid Production by the Oleaginous Marine Thraustochytrid Aurantiochytrium sp. T66 Cultivated on Volatile Fatty Acids2020In: Biomolecules, E-ISSN 2218-273X, Vol. 10, no 5, article id 694Article in journal (Refereed)
    Abstract [en]

    Thraustochytrids are considered natural producers of omega-3 fatty acids as they can synthesize up to 70% docosahexaenoic acids (DHA) of total lipids. However, commercial and sustainable production of microbial DHA is limited by elevated cost of carbon substrates for thraustochytrids cultivation. This problem can be addressed by utilizing low-cost renewable substrates. In the present study, growth, lipid accumulation and fatty acid profiles of the marine thraustochytrid Aurantiochytrium sp. T66 (ATCC-PRA-276) cultivated on volatile fatty acids (C1, formic acid; C2, acetic acid; C3, propionic acid; C4, butyric acid; C5, valeric acid and C6, caproic acid) and glucose as control were evaluated for the first time. This strain showed an inability to utilize C3, C5 and C6 as a substrate when provided at >2 g/L, while efficiently utilizing C2 and C4 up to 40 g/L. The highest cell dry weight (12.35 g/L) and total lipid concentration (6.59 g/L) were attained when this strain was cultivated on 40 g/L of butyric acid, followed by cultivation on glucose (11.87 g/L and 5.34 g/L, respectively) and acetic acid (8.70 g/L and 3.43 g/L, respectively). With 40 g/L butyric acid, the maximum docosahexaenoic acid content was 2.81 g/L, corresponding to 42.63% w/w of total lipids and a yield of 0.23 g/gcell dry weight (CDW). This marine oleaginous microorganism showed an elevated potential for polyunsaturated fatty acids production at higher acetic and butyric acid concentrations than previously reported. Moreover, fluorescence microscopy revealed that growth on butyric acid caused cell size to increase to 45 µm, one of the largest values reported for oleaginous microorganisms, as well as the presence of numerous tiny lipid droplets.

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  • 4.
    Nazir, Uzma
    et al.
    Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan.
    Akhter, Zareen
    Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan.
    Janjua, Naveed Kausar
    Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan.
    Asghar, Muhammad Adeel
    Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan.
    Kanwal, Sehrish
    Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan.
    Butt, Tehmeena Maryum
    Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan.
    Sani, Asma
    Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan.
    Liaqat, Faroha
    Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan.
    Hussain, Rizwan
    Laboratory for Advanced Materials Processing (LAMP), NCP, Islamabad, Pakistan.
    Shah, Faiz Ullah
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Biferrocenyl Schiff bases as efficient corrosion inhibitors for an aluminium alloy in HCl solution: a combined experimental and theoretical study2020In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 10, no 13, p. 7585-7599Article in journal (Refereed)
    Abstract [en]

    The corrosion inhibitive capabilities of some ferrocene-based Schiff bases on aluminium alloy AA2219-T6 in acidic medium were investigated using Tafel polarization, electrochemical impedance spectroscopy (EIS), weight loss measurement, FT-IR spectroscopy and scanning electron microscopic (SEM) techniques. The influence of molecular configuration on the corrosion inhibition behavior has been explored by quantum chemical calculation. Ferrocenyl Schiff bases 4,4′-((((ethane-1,2-diylbis(oxy))bis(4,1-phenylene))bis(methaneylylidene))bis(azaneylylidene))bisferrocene (Fcua), 4,4′-((((ethane-1,2-diylbis(oxy))bis(2-methoxy-1,4-phenylene))bis(methaneylylidene))bis(azaneylylidene))bisferrocene (Fcub) and 4,4′-((((ethane-1,2-diylbis(oxy))bis(2-ethoxy-1,4-phenylene))bis(methaneylylidene))bis(azaneylylidene))bisferrocene (Fcuc) have been synthesized and characterized by FT-IR, 1H and 13C NMR spectroscopic studies. These compounds showed a substantial corrosion inhibition against aluminium alloy in 0.1 M of HCl at 298 K. Fcub and Fcuc showed better anticorrosion efficiency as compared with Fcua due to the electron donating methoxy and ethoxy group substitutions, respectively. Polarization curves also indicated that the studied biferrocenyl Schiff bases were mixed type anticorrosive materials. The inhibition of the aluminium alloy surface by biferrocenyl Schiff bases was evidenced through scanning electron microscopy (SEM) studies. Semi-empirical quantum mechanical studies revealed a correlation between corrosion inhibition efficiency and structural functionalities.

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  • 5.
    Shah, Faiz Ullah
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Khan, Inayat Ali
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Johansson, Patrik
    Department of Physics, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
    Comparing the Thermal and Electrochemical Stabilities of Two Structurally Similar Ionic Liquids2020In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 25, no 10, article id 2388Article in journal (Refereed)
    Abstract [en]

    Here we focus on the thermal and variable temperature electrochemical stabilities of two ionic liquids (ILs) having a common tributyloctyl phosphonium cation [P4,4,4,8]+ and two different orthoborate anions: bis(mandelato)borate [BMB] and bis(salicylato)borate [BScB]. The thermo-gravimetric analysis data suggest that [P4,4,4,8][BScB] is thermally more stable than [P4,4,4,8][BMB] in both nitrogen atmosphere and air, while the impedance spectroscopy reveals that [P4,4,4,8][BScB] has higher ionic conductivity than [P4,4,4,8][BMB] over the whole studied temperature range. In contrast, the electrochemical studies confirm that [P4,4,4,8][BMB] is more stable and exhibits a wider electrochemical stability window (ESW) on a glassy carbon electrode surface as compared to [P4,4,4,8][BScB]. A continuous decrease in the ESWs of both ILs is observed as a function of operation temperature.

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  • 6.
    Patel, Alok
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Liefeldt, Stephan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Rova, Ulrika
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Christakopoulos, Paul
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Matsakas, Leonidas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Co-production of DHA and squalene by thraustochytrid from forest biomass2020In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 10, article id 1992Article in journal (Refereed)
    Abstract [en]

    Omega-3 fatty acids, and specifically docosahexaenoic acid (DHA), are important and essential nutrients for human health. Thraustochytrids are recognised as commercial strains for nutraceuticals production, they are group of marine oleaginous microorganisms capable of co-synthesis of DHA and other valuable carotenoids in their cellular compartment. The present study sought to optimize DHA and squalene production by the thraustochytrid Schizochytrium limacinum SR21. The highest biomass yield (0.46 g/gsubstrate) and lipid productivity (0.239 g/gsubstrate) were observed with 60 g/L of glucose, following cultivation in a bioreactor, with the DHA content to be 67.76% w/wtotal lipids. To reduce costs, cheaper feedstocks and simultaneous production of various value-added products for pharmaceutical or energy use should be attempted. To this end, we replaced pure glucose with organosolv-pretreated spruce hydrolysate and assessed the simultaneous production of DHA and squalene from S. limacinum SR21. After the 72 h of cultivation period in bioreactor, the maximum DHA content was observed to 66.72% w/wtotal lipids that was corresponded to 10.15 g/L of DHA concentration. While the highest DHA productivity was 3.38 ± 0.27 g/L/d and squalene reached a total of 933.72 ± 6.53 mg/L (16.34 ± 1.81 mg/gCDW). In summary, we show that the co-production of DHA and squalene makes S. limacinum SR21 appropriate strain for commercial-scale production of nutraceuticals.

  • 7.
    Aryal, Nabin
    et al.
    Biological and Chemical Engineering, Aarhus University, Aarhus N, Denmark.
    Ghimire, Nirmal
    Department of Process, Energy and Environmental Technology, University of South-Eastern Norway, Porsgrunn, Norway.
    Bajracharya, Suman
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Coupling of microbial electrosynthesis with anaerobic digestion for waste valorization2020In: Advances in Bioenergy, Elsevier, 2020Chapter in book (Other academic)
    Abstract [en]

    Anaerobic digestion (AD) has been widely applied bioprocess to produce the biogas for fuels from organic waste degradation. AD has been integrated with other processes for increasing the digestion efficiency and waste valorization. The integration of AD with other bioprocess optimizes the production of targeted product and reduces the waste. Recently, microbial electrosynthesis (MES) was coupled with AD for the biomethane production, chemical synthesis and resource recovery. MES coupling to AD also gives an opportunity for value-added chemical generation and hence provides additional economic gains of integrated system. In MES, the remaining carbon dioxide (CO2) in biogas is reduced to methane by methanogens utilizing in situ produced hydrogen at cathode, thereby enriching methane content. Furthermore, electroactive microbes could directly accept the electron from cathode to reduce the CO2 to methane and chemicals. Therefore, CO2 fraction in the biogas could be utilized for the further chemical synthesis such as acetate, butyrate. In this chapter, advances on AD technology and MES coupling with AD are thoroughly discussed for the production of fuels and chemicals. The outputs of recent laboratory scale experiments are summarized and discussed. Furthermore, mechanism of CO2 reduction is elaborated with methane and chemical production.

  • 8.
    Zerva, Anastasia
    et al.
    InduBioCat Group, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 5 Iroon Polytechniou Str., Zografou Campus, 15780 Athens, Greece.
    Pentari, Christina
    InduBioCat Group, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 5 Iroon Polytechniou Str., Zografou Campus, 15780 Athens, Greece.
    Topakas, Evangelos
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. InduBioCat Group, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 5 Iroon Polytechniou Str., Zografou Campus, 15780 Athens, Greece.
    Crosslinked Enzyme Aggregates (CLEAs) of Laccases from Pleurotus citrinopileatus Induced in Olive Oil Mill Wastewater (OOMW)2020In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 25, no 9, article id 2221Article in journal (Refereed)
    Abstract [en]

    The enzymatic factory of ligninolytic fungi has proven to be a powerful tool in applications regarding the degradation of various types of pollutants. The degradative potential of fungi is mainly due to the production of different types of oxidases, of which laccases is one of the most prominent enzymatic activities. In the present work, crude laccases from the supernatant of Pleurotus citrinopileatus cultures grown in olive oil mill wastewater (OOMW) were immobilized in crosslinked enzyme aggregates (CLEAs), aiming at the development of biocatalysts suitable for the enzymatic treatment of OOMW. The preparation of laccase CLEAs was optimized, resulting in a maximum of 72% residual activity. The resulting CLEAs were shown to be more stable in the presence of solvents and at elevated temperatures compared to the soluble laccase preparation. The removal of the phenolic component of OOMW catalyzed by laccase-CLEAs exceeded 35%, while they were found to retain their activity for at least three cycles of repetitive use. The described CLEAs can be applied for the pretreatment of OOMW, prior to its use for valorization processes, and thus, facilitate its complete biodegradation towards a consolidated process in the context of circular economy.

  • 9.
    Rodina, Tatyana A.
    et al.
    Institute of Geology and Nature Management, Far Eastern Branch of the Russian Academy of Sciences, 675000 Blagoveschensk, Amur Region, Russia.
    Loseva, Olga V.
    Institute of Geology and Nature Management, Far Eastern Branch of the Russian Academy of Sciences, 675000 Blagoveschensk, Amur Region, Russia.
    Smolentsev, Anton I.
    Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia. Novosibirsk State University, 630090 Novosibirsk, Russia.
    Antzutkin, Oleg N.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Department of Physics, Warwick University, Coventry CV4 7AL, UK.
    Ivanov, Alexander V.
    Institute of Geology and Nature Management, Far Eastern Branch of the Russian Academy of Sciences, 675000 Blagoveschensk, Amur Region, Russia.
    Crystal structure, solid-state 13C and 15N NMR characterisation, chemisorption activity and thermal behaviour of new mercury(II) dipropyldithiocarbamate: Binuclear, pseudo-binuclear and heteronuclear complexes of [Hg2(PrDtc)4], [Hg(PrDtc)2]2 and [Au(PrDtc)2]2[Hg2Cl6]2020In: Inorganica Chimica Acta, ISSN 0020-1693, E-ISSN 1873-3255, Vol. 508, article id 119630Article in journal (Refereed)
    Abstract [en]

    Two polymorphs of a new mercury(II) N,N-dipropyldithiocarbamate represented by centrosymmetric binuclear and pseudo-binuclear molecules, [Hg2(PrDtc)4] (1) and [Hg(PrDtc)2]2 (2), have been isolated, identified using heteronuclear (13C, 15N) CP-MAS NMR and structurally characterised by single-crystal X-ray diffraction analysis. There are two pairs of inequivalent PrDtc ligands playing either terminal chelating or tridentate bridging structural functions in the former compound; while the latter complex comprises two pairs of structurally inequivalent chelating PrDtc ligands. The reaction of freshly precipitated mercury(II) N,N-dipropyldithiocarbamate (HgPrDtc) with a [AuCl4]−/2 M HCl solution results in the formation of the ionic complex [Au(PrDtc)2]2[Hg2Cl6] (3). There are two inequivalent centrosymmetric cations, [Au(PrDtc)2]+ (‘A’ and ‘B’), and a binuclear centrosymmetric anion, [Hg2Cl6]2− in the structure of 3. In the cationic part of the complex, each of the gold(III) cations has two pairs of the relatively weak inequivalent secondary Au···S bonds with two neighbours, therefore forming linear supramolecular cationic chains (⋯‘A’⋯‘B’⋯‘A’⋯‘B’⋯)n. To study the thermal behaviour of the compounds, simultaneous thermal analysis was also performed. The formation of HgS and reduced elemental gold was established during the thermolysis of 1/2 and 3, respectively.

  • 10.
    Nabavi, Mohammad Sadegh
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Defects in Zeolite Catalysts and Membranes2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    ZSM-5 is one of the most well-known zeolites. It has been synthesized for many different applications, including as catalyst for catalytic reactions and as a membrane in separation processes.  The main goal of this thesis is to investigate and characterize the defects in crystal and film growth of ZSM-5 for modification purposes.

    Primarily, ZSM-5 crystals with carefully controlled thickness were synthesized in fluoride and hydroxide media. These synthesized catalysts were then characterized and the two synthesis routes were compared with each other in terms of stability. Then, in the synthesized catalysts, the role of defects during reaction was investigated. Furthermore, the growth of ZSM-5 nanocrystals and subsequent film formation was investigated to better understand how particles formed in synthesis solution (a hydrolyzed mixture of H2O-TEOS-TPAOH), followed by how these crystals interact to form a zeolite film. Finally, pre- and post-production modification of ZSM-5 and PHI membranes was investigated. Since, the roughness surface of the support could play a crucial role in having an even film, it was done as a pre-treatment technique for membrane synthesis. Additionally, a technique was developed in an attempt to plug the defects of grain boundaries to increase the membrane performance.

     

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  • 11.
    Nikolaivits, Efstratios
    et al.
    Industrial Biotechnology & Biocatalysis Group, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 15780 Athens, Greece.
    Agrafiotis, Andreas
    Industrial Biotechnology & Biocatalysis Group, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 15780 Athens, Greece.
    Baira, Eirini
    Division of Pharmacognosy and Chemistry of Natural Products, Department of Pharmacy, National and Kapodistrian University of Athens, 15771 Athens, Greece.
    Le Goff, Géraldine
    Institut de Chimie des Substances Naturelles, ICSN, CNRS, 91198 Gif sur Yvette, France.
    Tsafantakis, Nikolaos
    Division of Pharmacognosy and Chemistry of Natural Products, Department of Pharmacy, National and Kapodistrian University of Athens, 15771 Athens, Greece.
    Chavanich, Suchana A.
    Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
    Benayahu, Yehuda
    School of Zoology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel.
    Ouazzani, Jamal
    Institut de Chimie des Substances Naturelles, ICSN, CNRS, 91198 Gif sur Yvette, France.
    Fokialakis, Nikolas
    Division of Pharmacognosy and Chemistry of Natural Products, Department of Pharmacy, National and Kapodistrian University of Athens, 15771 Athens, Greece.
    Topakas, Evangelos
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Industrial Biotechnology & Biocatalysis Group, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 15780 Athens, Greece.
    Degradation Mechanism of 2,4-Dichlorophenol by Fungi Isolated from Marine Invertebrates2020In: International Journal of Molecular Sciences, ISSN 1422-0067, E-ISSN 1422-0067, Vol. 21, no 9, article id 3317Article in journal (Refereed)
    Abstract [en]

    2,4-Dichlorophenol (2,4-DCP) is a ubiquitous environmental pollutant categorized as a priority pollutant by the United States (US) Environmental Protection Agency, posing adverse health effects on humans and wildlife. Bioremediation is proposed as an eco-friendly, cost-effective alternative to traditional physicochemical remediation techniques. In the present study, fungal strains were isolated from marine invertebrates and tested for their ability to biotransform 2,4-DCP at a concentration of 1 mM. The most competent strains were studied further for the expression of catechol dioxygenase activities and the produced metabolites. One strain, identified as Tritirachium sp., expressed high levels of extracellular catechol 1,2-dioxygenase activity. The same strain also produced a dechlorinated cleavage product of the starting compound, indicating the assimilation of the xenobiotic by the fungus. This work also enriches the knowledge about the mechanisms employed by marine-derived fungi in order to defend themselves against chlorinated xenobiotics.

  • 12.
    Zaeva, Anna S.
    et al.
    Institute of Geology and Nature Management, Far Eastern Branch of the Russian Academy of Sciences,Blagoveschensk, Amur Region, Russia.
    Ivanov, Maxim A.
    Institute of Geology and Nature Management, Far Eastern Branch of the Russian Academy of Sciences,Blagoveschensk, Amur Region, Russia.
    Gerasimenko, Andrey V.
    Institute of Chemistry, Far Eastern Branch of the Russian Academy of Sciences,Vladivostok, Russia.
    Ivanov, Alexander V.
    Institute of Geology and Nature Management, Far Eastern Branch of the Russian Academy of Sciences, Blagoveschensk, Amur Region, Russia.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Department of Physics, Warwick University, Coventry, UK.
    Dialkyldithiocarbamate platinum(II) complexes of [Pt(S2CNR2)2] (R = iso-C3H7iso-C4H9): Preparation, 13C CP-MAS NMR, molecular structure, supramolecular self-assembly and thermal behaviour2020In: Polyhedron, ISSN 0277-5387, E-ISSN 1873-3719, Vol. 175, article id 114166Article in journal (Refereed)
    Abstract [en]

    Two new dialkyldithiocarbamato platinum(II) complexes of [Pt(S2CNR)2], R = iso-C3H7 (1) and iso-C4H9 (2), have been prepared and characterised using 13C CP-MAS NMR. The crystal and molecular structures of the isolated compounds were established by single-crystal X-ray diffraction. The unit cell of 1 contains four centrosymmetric discrete molecules of [Pt{S2CN(iso-C3H7)2}2], of which the pairs are structurally inequivalent to each other (hereafter denoted as molecules 1a and 1b). At the supramolecular level, due to numerous intermolecular C–H···S hydrogen bonds, the 1a molecules form linear polymeric ribbons, whose interaction with the 1b molecules results in a two-dimensional polymeric network. In the structure of 2, the construction of supramolecular zigzag chains by non-centrosymmetric molecules of [Pt{S2CN(iso-C4H9)2}2] is determined by intermolecular C–H···Pt anagostic interactions. The thermal behaviour of crystalline compounds 1 and 2 was studied by simultaneous thermal analysis (STA), a combination of the TG and DSC techniques, under an argon atmosphere. In both cases, platinum(II) sulphide (PtS) was identified as the main end-product upon thermal decomposition of the complexes at 600 °C.

  • 13.
    Filippov, Andrei
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Bulat, Munavirov
    System and Component Design, KTH Royal Institute of Technology, Stockholm, Sweden.
    Sergei, Glavatskih
    System and Component Design, KTH Royal Institute of Technology, Stockholm, Sweden. Department of Electromechanical, Systems and Metal Engineering, Ghent University, Ghent, Belgium. School of Chemistry, University of New South Wales, Sydney, Australia.
    Shah, Faiz Ullah
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Department of Physics, Warwick University, Coventry, United Kingdom.
    Diffusion of Ions in Phosphonium Orthoborate Ionic Liquids Studied by 1H and 11B Pulsed Field Gradient NMR2020In: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 8, article id 119Article in journal (Refereed)
    Abstract [en]

    Non-halogenated boron-based ionic liquids (ILs) composed of phosphonium cations and chelated orthoborate anions have high hydrolytic stability, low melting point and exceptional properties for various applications. This study is focused on ILs with the same type of cation, trihexyltetradecylphosphonium ([P6,6,6,14]+), and two orthoborate anions, such as bis(salicylato)borate ([BScB]−) and bis(oxalato)borate ([BOB]−). We compare the results of this study with our previous studies on ILs with bis(mandelato)borate ([BMB]−) and a variety of different cations (tetraalkylphosphonium, dialkylpyrrolidinium and dialkylimidazolium). The ion dynamics and phase behavior of these ILs is studied using 1H and 11B pulsed-field-gradient (PFG) NMR. PFG NMR is demonstrated to be a useful tool to elucidate the dynamics of ions in this class of phosphonium orthoborate ILs. In particular, the applicability of 11B PFG NMR for studying anions without 1H, such as [BOB]−, and the limitations of this technique to measure self-diffusion of ions in ILs are demonstrated and discussed in detail for the first time.

  • 14.
    Mushtaq, Irrum
    et al.
    Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan.
    Mushtaq, Iram
    Department of Biochemistry, Quaid-i-Azam University, Islamabad, Pakistan.
    Akhter, Zareen
    Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan.
    Murtaza, Iram
    Department of Biochemistry, Quaid-i-Azam University, Islamabad, Pakistan.
    Qamar, Samina
    Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan.
    Ayub, Sidra
    Department of Biochemistry, Quaid-i-Azam University, Islamabad, Pakistan.
    Mirza, Bushra
    Department of Biochemistry, Quaid-i-Azam University, Islamabad, Pakistan.
    Butt, Tehmeena Maryum
    Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan.
    Janjua, Naveed Kausar
    Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan.
    Shah, Faiz Ullah
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Zaman, Farasat
    Department of Women's and Children's Health, Karolinska Institutet and Pediatric Endocrinology Unit, Karolinska University Hospital, Solna, Sweden.
    Engineering electroactive and biocompatible tetra(aniline)-based terpolymers with tunable intrinsic antioxidant properties in vivo2020In: Materials science & engineering. C, biomimetic materials, sensors and systems, ISSN 0928-4931, E-ISSN 1873-0191, Vol. 108, article id 110456Article in journal (Refereed)
    Abstract [en]

    Under different pathological conditions, high levels of reactive oxygen species (ROS) cause substantial damage to multiple organs. To counter these ROS levels in multiple organs, we have engineered highly potent novel terpolymers. We found that combination of FDA-approved polyethylene glycol, fumaric acid moieties and electroactive tetra(aniline) by varying the content of tetra(aniline) results into a novel drug composition with biologically active tunable intrinsic antioxidant properties. To test tunable intrinsic antioxidative properties of these engineered novel terpolymers, we used alloxan to induce diabetes in rats where ROS generation is known to be higher. The systemic administration of terpolymers to the diabetic rats showed strong electroactive antioxidant behavior which normalized ROS levels, enzymatic antioxidants including superoxide dismutase, catalase, but also reduced glutathione. As a proof-of-principle, we here show TANI based novel drug composition of terpolymers with tunable intrinsic antioxidant effects confirmed in multiple organs.

  • 15.
    Patel, Alok
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Matsakas, Leonidas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Sartaj, Km
    Molecular Microbiology Laboratory, Biotechnology Department, Indian Institute of Technology (IIT-R), Roorkee, India.
    Chandra, Rajesh
    Bioenergy Research Laboratory, Department of Polymer & Process Engineering, Indian Institute of Technology Roorkee (Saharanpur Campus), Saharanpur, India.
    Extraction of lipids from algae using supercritical carbon dioxide2020In: Green Sustainable Process for Chemical and Environmental Engineering and Science: Supercritical Carbon Dioxide as Green Solvent / [ed] Inamuddin, Abdullah M. Asiri, and Arun M. Isloor, Elsevier, 2020, p. 17-39Chapter in book (Other academic)
    Abstract [en]

    Microalgal oils are considered an important source of industrially valuable oleochemicals with significant applications ranging from the energy to pharmaceutical sectors. Industrial production of microalgal oil is emerging rapidly; however, the high cost associated with downstream processes may constrain this process. Oils are accumulated intracellularly in oleaginous microalgae in the form of lipid droplets, which in turn require cell wall disruption followed by extraction in order to recover them. Disruption of the microalgal cell is very challenging owing to its distinctive features like high water content, hard cell wall, presence of algaenan, and sporopollenin like biopolymers that in turn create hurdles in efficient extraction of lipids. Various conventional pretreatment methods have been explored to rupture the cellular integrity of microalgal cells to enhance lipid extraction, and each method has certain advantages and disadvantages. Supercritical fluid extraction is the oldest technique for the extraction of valuable compounds from microalgae and is considered an alternative to conventional solvent extraction methods. It has several advantageous features such as being free from organic solvents (and their disposal), environment-friendly, and operating at a mild range of temperature (40–80°C). CO2 is considered to be an ideal supercritical fluid due to its non-toxic, non-flammable, and lipophilic nature. In this chapter, use of supercritical carbon dioxide extraction of lipids from microalgae is discussed and compared with other available lipid extraction methods.

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  • 16.
    Karimi, Somayeh
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Catalysis and Nanostructured Materials Research Laboratory, College of Engineering, School of Chemical Engineering, University of Tehran, Tehran, Iran.
    Mortazavi, Yadollah
    Catalysis and Nanostructured Materials Research Laboratory, College of Engineering, School of Chemical Engineering, University of Tehran, Tehran, Iran.
    Khodadadi, Abbas Ali
    Catalysis and Nanostructured Materials Research Laboratory, College of Engineering, School of Chemical Engineering, University of Tehran, Tehran, Iran.
    Holmgren, Allan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Korelskiy, Danil
    Materials Technology and Chemistry, Alfa Laval Tumba AB, Tumba, Sweden.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Functionalization of silica membranes for CO2 separation2020In: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 235, article id 116207Article in journal (Refereed)
    Abstract [en]

    Five organic CO2-philic functional groups were incorporated in silica matrixes for preparation of functionalized silica membranes to explore the CO2 separation performance. Chemical groups including acetate, trifluoromethyl, methacrylate, urea and vinyl groups were anchored in the silica network using the co-condensation method.

    The information from 29Si solid-state NMR and FTIR analyses indicates the successful formation of a covalent bond between functional groups and the silica network. The thickness of the functionalized silica layers was measured by SEM and the thermal stability of the organic groups was determined by thermogravimetric analysis (TGA).

    The gas permeance and mixed gas selectivity of CO2/N2 was measured in the temperature range of 253–373 K with a feed pressure of 9 bar. A maximum selectivity of as high as 10 was observed for a trifluoromethyl functionalized silica membrane with a CO2 permeance of 5.5 × 10−7 mol s−1 m−2 Pa−1. Permporometry measurements indicated that the contribution of flow through micropores to the total flow for all the functionalized silica membranes varied between 62 and 82%. All membranes were CO2 selective.

     

  • 17.
    Wei, Jiayuan
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Geng, Shiyu
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Fibre and Particle Engineering, University of Oulu, Finland. Mechanical and Industrial Engineering (MIE), University of Toronto, Toronto, Canada.
    Lightweight, flexible, and multifunctional anisotropic nanocellulose-based aerogels for CO2 adsorption2020In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 27, no 5, p. 2695-2707Article in journal (Refereed)
    Abstract [en]

    CO2 adsorption is a promising strategy to reduce costs and energy use for CO2 separation. In this study, we developed CO2 adsorbents based on lightweight and flexible cellulose nanofiber aerogels with monolithic structures prepared via freeze-casting, and cellulose acetate or acetylated cellulose nanocrystals (a-CNCs) were introduced into the aerogels as functional materials using an impregnation method to provide CO2 affinity. The microstructure of the adsorbent was examined using scanning electron microscopy, and compression tests were performed to analyze the mechanical properties of the adsorbents. The CO2 adsorption behavior was studied by recording the adsorption isotherms and performing column breakthrough experiments. The samples showed excellent mechanical performance and had a CO2 adsorption capacity of up to 1.14 mmol/g at 101 kPa and 273 K. Compared to the adsorbent which contains cellulose acetate, the one impregnated with a-CNCs had better CO2 adsorption capacity and axial mechanical properties owing to the building of a nanoscale scaffold on the surface of the adsorbent. Although the CO2 adsorption capacity could be improved further, this paper reports a potential CO2 adsorbent that uses all cellulose-based materials, which is beneficial for the environment from both resource and function perspectives. Moreover, the interesting impregnation process provides a new method to attach functional materials to aerogels, which have potential for use in many other applications.

  • 18.
    Patel, Alok
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Rova, Ulrika
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Christakopoulos, Paul
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Matsakas, Leonidas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Mining of squalene as a value-added byproduct from DHA producing marine thraustochytrid cultivated on food waste hydrolysate2020In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026Article in journal (Refereed)
    Abstract [en]

    The commercial production of docosahexaenoic acid (DHA) from oleaginous microorganisms is getting more attention due to several advantages over fish oils. The processing cost became a major bottleneck for commercialization of DHA from microorganisms. The most of cost shares in the feedstock to cultivate the microorganisms and downstream processing. The cost of feedstock can be compensated with the utilization of substrate from waste stream whereas production of value-added chemicals boosts the economic viability of nutraceutical production. In the present study, the docosahexaenoic acid (DHA)-producing marine protist Aurantiochytrium sp. T66 was cultivated on post-consumption food waste hydrolysate for the mining of squalene. After 120 h of cultivation, cell dry weight was 14.7 g/L, of which 6.34 g/L (43.13%; w/w) were lipids. DHA accounted for 2.15 g/L (34.05%) of total extracted lipids or 0.15 g/gCDW. Maximum squalene concentration and yield were 1.05 g/L and 69.31 mg/gCDW, respectively. Hence, utilization of food waste represents an excellent low-cost strategy for cultivating marine oleaginous thraustochytrids and produce squalene as a byproduct of DHA.

  • 19.
    Geng, Shiyu
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Wei, Jiayuan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Jonasson, Simon
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Fibre and Particle Engineering, University of Oulu. Mechanical & Industrial Engineering (MIE), University of Toronto.
    Multifunctional Carbon Aerogels with Hierarchical Anisotropic Structure Derived from Lignin and Cellulose Nanofibers for CO2 Capture and Energy Storage2020In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 12, no 6, p. 7432-7441Article in journal (Refereed)
    Abstract [en]

    In current times, CO2 capture and light-weight energy storage are receiving significant attention and will be vital functions in next-generation materials. Porous carbonaceous materials have great potential in these areas, whereas most of the developed carbon materials still have significant limitations, such as non-renewable resources, complex and costly processing or the absence of tailorable structure. In this study, a new strategy is developed for using the currently under-utilized lignin and cellulose nanofibers, which can be extracted from renewable resources to produce high-performance multifunctional carbon aerogels with a tailorable, anisotropic pore structure. Both the macro- and microstructure of the carbon aerogels can be simultaneously controlled by discreetly tuning the weight ratio of lignin to cellulose nanofibers in the carbon aerogel precursors, which considerably influences their final porosity and surface area. The designed carbon aerogels demonstrate excellent performance in both CO2 capture and capacitive energy storage, and the best results exhibit a CO2 adsorption capacity of 5.23 mmol g-1 at 273 K and 100 kPa, and a specific electrical double layer capacitance of 124 F g-1 at a current density of 0.2 A g-1, indicating that they have great future potential in the relevant applications.

  • 20.
    Shaikhullina, Milyausha
    et al.
    Institute of Physics, Kazan Federal University, 420008 Kazan, Russia.
    Khaliullina, Aliya
    Institute of Physics, Kazan Federal University, 420008 Kazan, Russia. Medical and Biological Physics, Kazan Medical University, 420012 Kazan, Russia.
    Gimatdinov, Rustam
    Medical and Biological Physics, Kazan Medical University, 420012 Kazan, Russia.
    Butakov, Anatoly
    Radiophysics and Electronics, Chelyabinsk State University, Chelyabinsk 454001, Russia.
    Chernov, Vladimir
    Radiophysics and Electronics, Chelyabinsk State University, Chelyabinsk 454001, Russia.
    Filippov, Andrei
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Medical and Biological Physics, Kazan Medical University, 420012 Kazan, Russia.
    NMR relaxation and self-diffusion in aqueous micellar gels of pluronic F-1272020In: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166, Vol. 306, article id 112898Article in journal (Refereed)
    Abstract [en]

    We studied the transverse NMR relaxation of protons of different chemical groups and diffusion of molecules in an aqueous pluronic F-127 system. The system was studied at concentrations of 15, 21 and 28 wt% and in the temperature range of 293–333 K. The dynamic peculiarities in different phases were analyzed based on the NMR relaxation and diffusion data. Our study demonstrated a correlation between phase states, T2 relaxation times of “solid-like” and “liquid” protons of selected chemical groups of polypropylene oxide (PPO) and polyethylene oxide (PEO) blocks, and diffusion coefficients. Transverse NMR relaxation established that the presence of a “solid-like” component of CH3 protons of PEO blocks is observed only at temperatures and concentrations corresponding to the rigid-gel phase, due to entanglements between micellar coronas. At all temperatures and concentrations, some CH3 protons of PPO blocks and some CH2 protons of PEO blocks show “liquid-like” transverse NMR relaxation. Under the conditions corresponding to formation of the rigid-gel phase of the pluronic, relaxation of the “liquid-like” protons additionally accelerates due to entanglements of micellar coronas. Transition of the system to the rigid-gel phase is accompanied by decrease of diffusion coefficients by a factor of 10–104 relative to the diffusivity of free-moving pluronic micelles in the sol phase. Diffusion measurements show that there are pre-transition phenomena, which are characteristic for temperatures and concentrations near sol-gel phase boundaries.

  • 21.
    Najjarzadeh, Nasim
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Krige, Adolf
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Pamidi, Taraka Rama Krishna
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Johansson, Örjan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Enman, Josefine
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Matsakas, Leonidas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Rova, Ulrika
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Christakopoulos, Paul
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Numerical modeling and verification of a sonobioreactor and its application on two model microorganisms2020In: PLoS ONE, E-ISSN 1932-6203, Vol. 15, no 3, article id e0229738Article in journal (Refereed)
    Abstract [en]

    Ultrasound has many uses, such as in medical imaging, monitoring of crystallization, characterization of emulsions and suspensions, and disruption of cell membranes in the food industry. It can also affect microbial cells by promoting or slowing their growth and increasing the production of some metabolites. However, the exact mechanism explaining the effect of ultrasound has not been identified yet. Most equipment employed to study the effect of ultrasound on microorganisms has been designed for other applications and then only slightly modified. This results in limited control over ultrasound frequency and input power, or pressure distribution in the reactor. The present study aimed to obtain a well-defined reactor by simulating the pressure distribution of a sonobioreactor. Specifically, we optimized a sonotrode to match the bottle frequency and compared it to measured results to verify the accuracy of the simulation. The measured pressure distribution spectrum presented the same overall trend as the simulated spectrum. However, the peaks were much less intense, likely due to non-linear events such as the collapse of cavitation bubbles. To test the application of the sonobioreactor in biological systems, two biotechnologically interesting microorganisms were assessed: an electroactive bacterium, Geobacter sulfurreducens, and a lignocellulose-degrading fungus, Fusarium oxysporum. Sonication resulted in increased malate production by Gsulfurreducens, but no major effect on growth. In comparison, morphology and growth of Foxysporum were more sensitive to ultrasound intensity. Despite considerable morphological changes at 4 W input power, the growth rate was not adversely affected; however, at 12 W, growth was nearly halted. The above findings indicate that the novel sonobioreactor provides an effective tool for studying the impact of ultrasound on microorganisms.

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  • 22.
    Zhou, Ming
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Khokarale, Santosh Govind
    Department of Chemistry, Chemical-Biological Centre (KBC), Umeå University, Umeå, Sweden.
    Balsamo, Marco
    Dipartimento di Scienze Chimiche, Università degli Studi di Napoli Federico II, Napoli, Italy.
    Mikkola, Jyri-Pekka
    Department of Chemistry, Chemical-Biological Centre (KBC), Umeå University, Umeå, Sweden. Industrial Chemistry & Reaction Engineering, Johan Gadollin Process Chemistry Centre, Åbo Akademi University, Åbo-Turku, Finland.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Oligoamine ionic liquids supported on mesoporous microspheres for CO2 separation with good sorption kinetics and low cost2020In: Journal of CO2 Utilization, ISSN 2212-9820, E-ISSN 2212-9839, Vol. 39, article id 101186Article in journal (Refereed)
    Abstract [en]

    Ionic liquids display good CO2 absorption capacity but poor absorption kinetics and high costs. In the present work, we show that these problems can be solved by impregnating the new low cost ionic liquid pentaethylenehexammonium chloride [PEHA][Cl] and the corresponding amine precursor on a low cost mesoporous microsphere support. Nitrogen adsorption/ desorption, high-resolution SEM and thermogravimetric analysis were employed to analyze the structural and thermal properties of the prepared sorbents. The CO2 adsorption and desorption performance was studied by column experiments and mathematical models were fitted to the data. The results showed that sorbents displayed excellent sorption kinetics and capacity, comparable to the best reports in the literature. In addition, the sorbents could be regenerated and displayed high thermal stability. Finally, the costs of the sorbents developed in the present work is much lower than previously reported sorbents. Therefore this novel supported IL system could be promising for industrial CO2 removal and recovery applications.

  • 23.
    Naz, Sadia
    et al.
    Institute of Chemistry, University of the Punjab, Lahore, Pakistan.
    Uroos, Maliha
    Institute of Chemistry, University of the Punjab, Lahore, Pakistan.
    Asim, Azmat Mehmood
    Institute of Chemistry, University of the Punjab, Lahore, Pakistan.
    Muhammad, Nawshad
    Interdisciplinary Research Centre in Biomedical Materials (IRCBM), COMSATS University Islamabad, Lahore, Pakistan.
    Shah, Faiz Ullah
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    One-Pot Deconstruction and Conversion of Lignocellulose Into Reducing Sugars by Pyridinium-Based Ionic Liquid–Metal Salt System2020In: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 8, article id 236Article in journal (Refereed)
    Abstract [en]

    Constantly decreasing fossil resources and exceeding energy demands are the most alarming concerns now-a-days. The only way out is to develop efficient, safe and economic biomass processing protocols that can lead towards biofuels and fine chemicals. This research is one of such consequences involving the deconstruction and conversion of wheat straw carbohydrate constituents into reducing sugars via one-pot reaction promoted by Lewis acidic pyridinium based ionic liquids (PyILs) mixed with different metal salts (MCl). Various parameters such as the type of metal salt, loading amount of metal salt, time, temperature, particle size of biomass and water content which affect the deconstruction of wheat straw have been evaluated and optimized. Among the studied IL and metal salt systems, the best results were obtained with [BMPy]+CoCl3‒. The dinitrosalicylic acid (DNS) assay was used to determine the percentage of total reducing sugars (TRS) generated during treatment of wheat straw. The deconstructed wheat straw was characterized with various analytical tools i.e. FTIR, SEM and XRD analyses. The ionic liquid‒metal salt system was recycled for subsequent treatment of wheat straw. Statistical parameters were calculated from analysis of variance (ANOVA) at 0.05 level of confidence.

  • 24.
    Chalima, Angelina
    et al.
    Industrial Biotechnology & Biocatalysis Group, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, Zografou Campus, Athens, Greece.
    Taxeidis, George
    Industrial Biotechnology & Biocatalysis Group, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, Zografou Campus, Athens, Greece.
    Topakas, Evangelos
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Industrial Biotechnology & Biocatalysis Group, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, Zografou Campus, Athens, Greece.
    Optimization of the production of docosahexaenoic fatty acid by the heterotrophic microalga Crypthecodinium cohnii utilizing a dark fermentation effluent2020In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 152, p. 102-109Article in journal (Refereed)
    Abstract [en]

    Dark fermentation is an anaerobic digestion process of biowaste, used to produce hydrogen as a fuel, which however releases high amounts of polluting volatile fatty acids in the environment. In order for the process to become more competitive, the acids stream can be utilized through conversion to high added-value docosahexaenoic acid by the microalga Crypthecodinium cohnii. Docosahexaenoic acid is one of the two main omega-3 fatty acids, necessary for human nutrition. The purpose of this work was to optimize the production of omega-3 fatty acids by the cells, utilizing the organic content of a dark fermentation effluent. For that purpose, the effect of different fermentation conditions was examined, such as incubation temperature, nitrogen source and concentration, the addition of chemical modulators, as well as the feeding composition. The volatile fatty acid content of the effluent was totally depleted in a fed-batch culture of the microalga, while the cells accumulated DHA in a percentage of 35.6% of total lipids, when fed with yeast extract or 34.2% when fed with ammonium sulfate. Taking into consideration the economic feasibility of the culture conditions proposed it was concluded that the use of yeast extract could be substituted by the much economic ammonium sulfate.

  • 25.
    Hruzova, Katerina
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Matsakas, Leonidas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Sand, Anders
    Boliden Mineral AB, SE-776 98 Garpenberg, Sweden.
    Rova, Ulrika
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Christakopoulos, Paul
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Organosolv lignin hydrophobic micro- and nanoparticles as a low-carbon footprint biodegradable flotation collector in mineral flotation2020In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 306, article id 123235Article in journal (Refereed)
    Abstract [en]

    Flotation is a key step during mineral separation. Xanthates are the most commonly used collectors for recovering Cu, Ni, and Zn from sulphide ores. However, xanthates are fossil-based and toxic for the environment. The aim of this study was to evaluate the use of lignin nanoparticles and microparticles as sustainable and environmentally friendly collectors. Lignin particles demonstrated good selectivity toward Cu (chalcopyrite), with total recoveries exceeding 80% and grades of up to 8.6% w/w from a Cu-Ni ore in rougher flotation tests. When floating Zn-Pb-Cu ore, lignin nanoparticles could reduce the use of xanthates by 50%. Moreover, they outperformed xanthates alone, achieving total recoveries of up to 91%, 85%, and 98% for Cu, Pb, and Zn, respectively. These results prove the potential of lignin as a flotation collector.

  • 26.
    Kanwal, Sehrish
    et al.
    Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan.
    Ali, Naveed Zafar
    Federal Institute for Materials Research and Testing (BAM), Richard-Willstaetter-Strasse 11, Berlin 12489, Germany. Laboratory for Advanced Materials & Processing (LAMP) National Centre for Physics, Quaid-i-Azam University Campus, Islamabad, Pakistan.
    Hussain, Rizwan
    Laboratory for Advanced Materials & Processing (LAMP) National Centre for Physics, Quaid-i-Azam University Campus, Islamabad, Pakistan.
    Shah, Faiz Ullah
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Akhter, Zareen
    Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan.
    Poly-thiourea formaldehyde based anticorrosion marine coatings on type 304 stainless steel2020In: Journal of Materials Research and Technology, ISSN 2238-7854, Vol. 9, no 2, p. 2146-2153Article in journal (Refereed)
    Abstract [en]

    In the present study, hexamethylene diisocyanate (HMDI) encapsulated poly-thiourea formaldehyde (PTF) (10 wt%) coating was developed in an epoxy-polyamine matrix and their anticorrosion studies on Type SS304 stainless steel substrate have been conducted using electrochemistry techniques. The compact and hydrophobic shell wall of PTF proved to be a potent shell wall material for HMDI encapsulation. The effect of temperature and pH values was found to be decisive factor in the synthesis of microcapsules. The PTF microcapsules were synthesized in acidic condition with a pH value of 3. Over 90% of the core fraction is retained in water after 21 days immersion. However, core content decreased with increasing temperature. The capsules were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy(SEM), thermogravimetric analysis (TGA) and Electrochemical Impedance spectroscopy (EIS). Scanning electron microscopic analysis depicts the uniform morphology of coating with a particle size in the range of 1.08 μm–22.06 μm. The vibrational band at 2271 cm−1 attributed to NCO signal further endorses the successful encapsulation of HMDI into the PTF capsules. Electrochemical testing on steel specifies the appreciable anticorrosion performance of the synthesized poly thiourea formaldehyde (PTF) coating against artificial sea water.

  • 27.
    Matsakas, Leonidas
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Gerber, Milena
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Yu, Liang
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Rova, Ulrika
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Christakopoulos, Paul
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Preparation of low carbon impact lignin nanoparticles with controllable size by using different strategies for particles recovery2020In: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 147, article id 112243Article in journal (Refereed)
    Abstract [en]

    Lignin still remains an underutilized plentiful resource whose conversion to high-added value products is a cornerstone towards establishing a viable biomass biorefinery. Bio-materials in the form of nanoparticles represent promising high-value products with numerous downstream applications. The aim of the current work was to develop a method that would allow controlling the size of (birch and spruce) lignin nano- and micro-particles for their subsequent recovery into a solid product. We tested different two-step and one-step isolation processes and demonstrated that particle size could be easily controlled to meet different ranges (<100 nm, <500 nm, and>1 μm). In general, two-step isolation methods, i.e. a step of decrease of solvent concentration followed by isolation of lignin particles, were better for the isolation of well-defined spherical particles. In particular, the rate at which ethanol concentration was decreased played a significant role in determining the size of lignin particles. Moreover, when lignin concentration was increased from 1 % to 5 % and 10 % (w/v), particle size and homogeneity decreased slightly, but productivity augmented. The present study demonstrates that different isolation methods can be applied to obtain renewable, customarily sized, lignin spherical micro- and nano-particles.

  • 28.
    Li, Jie
    et al.
    State Key Laboratory of Materials-Oriented Chemical Engineering and College of Chemical Engineering, Nanjing Tech University, Nanjing, PR China.
    Jiang, Leilei
    State Key Laboratory of Materials-Oriented Chemical Engineering and College of Chemical Engineering, Nanjing Tech University, Nanjing, PR China.
    Yu, Liang
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Zhang, Lixiong
    State Key Laboratory of Materials-Oriented Chemical Engineering and College of Chemical Engineering, Nanjing Tech University, Nanjing, PR China.
    Preparation of Silica@Silica Core–Shell Microspheres Using an Aqueous Two-Phase System in a Novel Microchannel Device2020In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 36, no 2, p. 576-584Article in journal (Refereed)
    Abstract [en]

    In the present work, a novel microchannel device was developed and used for the preparation of core–shell microspheres combining with a dextran/poly(ethylene glycol) diacrylate (DEX/PEGDA) aqueous two-phase system. Silica@silica core–shell microspheres were prepared as a model material. Silica@silica core–shell microspheres with different sizes of cores and thicknesses of shells were prepared by using different flowrate ratios of DEX/silica and PEGDA/silica aqueous solutions. The content of colloidal silica and the calcination temperature have a significant effect on the texture properties of the prepared core–shell microspheres. The surface area decreased from 199 to 177 m2/g with an increase in the colloidal silica content from 30 to 60 wt %. For a specific colloidal silica content (50 wt %), with the increase in calcination temperature from room temperature to 650 °C, the total pore volume went through a maximum of 0.7 cm3 g–1 with a surface area of 178 m2 g–1 and pore size of 7.32 nm at 450 °C. Due to the accumulation of metal nanoparticles in DEX, different metal nanoparticles (Ni and Pd) were successfully introduced into the core of the core–shell microspheres for the preparation of silica/metal nanoparticles@silica core–shell microsphere catalysts. The catalysts showed similar catalytic performance as the metal nanoparticles for hydrogenation of 4-nitrophenol with a conversion higher than 95%. However, the core–shell microsphere catalyst is much easier to recover. The reuse experiments indicated that the core–shell catalyst has high stability.

  • 29.
    Paulsen Thoresen, Petter
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Matsakas, Leonidas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Rova, Ulrika
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Christakopoulos, Paul
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Recent advances in organosolv fractionation: Towards biomass fractionation technology of the future2020In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 306, article id 123189Article, review/survey (Refereed)
    Abstract [en]

    Organosolv treatment is among the most promising strategies for valorising lignocellulosic biomass and could facilitate the transition towards enhanced utilization of renewable feedstocks. However, issues such as inefficient solvent recycle and fractionation has to be overcome. The present review aims to address these issues and discuss the role of the components present during organosolv treatment and their influence on the overall process. Thus, the review focuses not only on how the choice of solvent and catalyst affects lignocellulosic fractionation, but also on how the choice of treatment liquor influences the possibility for solvent recycling and product isolation. Several organic solvents have been investigated in combination with water and acid/base catalysts; however, the lack of a holistic approach often compromises the performance of the different operational units. Thus, an economically viable organosolv process should optimize biomass fractionation, product isolation, and solvent recycling.

  • 30.
    Filippov, Andrei
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Kazan State Medical University, Kazan, Russia.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Department of Physics, Warwick University, Coventry, UK.
    Gimatdinov, Rustam
    Kazan State Medical University, Kazan, Russia.
    Gnezdilovd, Oleg I.
    Kazan Federal University, Kazan, Russia.
    Self-diffusion in ionic liquids with nitrate anion: Effects of confinement between glass plates and static magnetic field2020In: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166Article in journal (Refereed)
    Abstract [en]

    Alkylammonium nitrate protic ionic liquids (ILs), when placed between flat polar borosilicate glass plates, have demonstrated enhanced diffusivity and the gradual decrease of diffusivity after exposure to an external static magnetic field (Filippov et al., 2018). This phenomenon has been explained by phase transformations taking place in the ILs. In this study, we observed similar processes occurring in systems prepared with ethylammonium nitrate confined between quartz plates. A higher content of silicon oxide in the plates does not significantly alter the phenomenon previously found in the system prepared with borosilicate glass plates. For the first time, we have observed similar effects of confinement and magnetic field on the aprotic IL, 1‑ethyl‑3‑methylimidazolium nitrate. Substitution of the ethylammonium cation with a 1‑ethyl‑3‑methylimidazolium cation slows down the kinetics and increases magnitude of the processes occurring in the IL exposed to a magnetic field. We suggested that the main factor determining these effects is the presence and modification of the hydrogen-bonding network in the studied protic and aprotic ILs. The process of inverse phase transformation for the confined ethylammonium nitrate after removing the sample from the magnetic field was observed and analysed.

  • 31.
    Khan, Inayat Ali
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Catalysis and Nanomaterials Lab 27, Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan.
    Khan, Luqman
    Catalysis and Nanomaterials Lab 27, Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan.
    Khan, Syed Ishtiaq
    Catalysis and Nanomaterials Lab 27, Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan.
    Badshah, Amin
    Catalysis and Nanomaterials Lab 27, Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan.
    Shape-control synthesis of PdCu nanoparticles with excellent catalytic activities for direct alcohol fuel cells application2020In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 349, article id 136381Article in journal (Refereed)
    Abstract [en]

    In this article, we described a simple method of PdCu nanoparticles (NPs) synthesis in different morphologies at 120 °C using polyvinylpyrrolidone (PVP) capping agent and ethylene glycol (EG) solvent. Form instrumental characterization it is find out that PdCu NPs are prepared in different morphologies by varying the Pd:Cu weight percent (wt.%) ratios. Nanospheres (NS) are obtained in the absence of Cu, sphere-like NPs having Pd3Cu1 composition are obtained at 3:1 wt.% ratio, cubic NPs having Pd1Cu1 composition are obtained at 1:1 wt.% ratio and cube-like NPs having Pd1Cu3 composition are obtained at 1:3 wt.% ratio. The metals wt.% ratio not only controlled the morphology, but also affected the catalytic activity toward methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR) in alkaline media. The PdCu catalyst, in 1:1 wt.% ratio, have demonstrated high specific and mass activities toward MOR (18.07 mA cm−2 and 11.15 A mgPd−1) and EOR (10.24 mA cm−2 and 6.32 A mgPd−1) in alkaline media. Excellent catalytic activity and long-term stability of Pd1Cu1 toward both MOR and EOR is attributed to its stable cubic morphology, composition and synergetic effect, high electrochemical active surface area (ECSA) and PdO reduction at more negative potential. In comparison to the literature, the cubic-PdCu is one of the best electorcatalyst toward MOR and EOR. The cubic-PdCu NPs as anode have potential application in direct alcohol fuel cells owing to their excellent electrochemical performance, stability and cost effectiveness.

  • 32.
    Antonopoulou, Io
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Spanopoulos, Athanasios
    Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 5 Iroon Polytechniou Str, Zografou Campus, Athens, Greece.
    Matsakas, Leonidas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Single cell oil and ethanol production by the oleaginous yeast Trichosporon fermentans utilizing dried sweet sorghum stalks2020In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 146, p. 1609-1617Article in journal (Refereed)
    Abstract [en]

    The ability of the oleaginous yeast Trichosporon fermentans to efficiently produce lipids when cultivated in dried sweet sorghum was evaluated. First, lipid production was evaluated in synthetic media mimicking the composition of sweet sorghum stalks and optimized based on the nitrogen source and C: N ratio. Under optimum conditions, the lipid production reached 3.66 g/L with 21.91% w/w lipid content by using a mixture of sucrose, glucose and fructose and peptone at C: N ratio 160. Cultivation on pre-saccharified sweet sorghum stalks offered 1.97 g/L, while it was found that sweet sorghum stalks can support yeast growth and lipid production without the need for external nitrogen source addition. At an attempt to increase the carbon source concentration for optimizing lipid production, the Crabtree effect was observed in T. fermentans. To this end, the yeast was evaluated for its potential to produce ethanol under anaerobic conditions in synthetic media and sweet sorghum. The ethanol concentration at 100 g/L glucose was 40.31 g/L, while utilizing sweet sorghum by adding a distinct saccharification step and external nitrogen source offered ethanol concentration equal to 23.5 g/L. To the authors’ knowledge, this is the first time that the Crabtree effect is observed in T. fermentans.

  • 33.
    Grahn, Mattias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Faisal, Abrar
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Department of Chemical Engineering, COMSATS University Islamabad, Lahore Campus, Lahore, Pakistan.
    Öhrman, Olov G.W
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. RISE ETC - Energy Technology Center, SE-941 28 Piteå, Sweden.
    Zhou, Ming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Signorile, Matteo
    Department of Chemistry, NIS and INSTM Reference Centre, Università di Torino, Torino, Italy.
    Crocellà, Valentina
    Department of Chemistry, NIS and INSTM Reference Centre, Università di Torino, Torino, Italy.
    Nabavi, Mohammad Sadegh
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Small ZSM-5 crystals with low defect density as an effective catalyst for conversion of methanol to hydrocarbons2020In: Catalysis Today, ISSN 0920-5861, E-ISSN 1873-4308, Vol. 345, p. 136-146Article in journal (Refereed)
    Abstract [en]

    This work presents the synthesis of nearly defect-free ZSM-5 nanosized crystals, prepared in fluoride medium by seeding with silicalite-1. This material was carefully characterized and its catalytic performances in the methanol to hydrocarbons (MTH) reaction were assessed. Such fluoride-based material was compared to a reference ZSM-5, produced through a conventional alkaline synthesis but from the same seeding. Despite both the materials show closely identical morphology and they have a comparable acid site population, the catalyst prepared using the fluoride route showed significantly longer lifetime in MTH compared to the catalyst prepared using conventional synthesis at high pH. The slower deactivation for the samples prepared using the fluoride route was ascribed, thanks to a thorough in situ IR spectroscopy study, to its lower density of internal defects. According to the UV-Raman characterization of coke on the spent catalyst, the fluoride-based ZSM-5 catalyst produces less molecular coke species, most probably because of the absence of enlarged cavities/channels as due to the presence of internal defects. On the basis of these observations, the deactivation mechanism in the ZSM-5 synthesized by fluoride medium could be mostly related to the deposition of an external layer of bulk coke, whereas in the alkali-synthesized catalyst an additional effect from molecular coke accumulating within the porous network accelerates the deactivation process.

  • 34.
    Larsson, Anna-Carin
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Patra, Anuttam
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Studies on environmentally friendly flame retardants for cellulosebased materials2020Report (Other (popular science, discussion, etc.))
  • 35.
    Dimarogona, Maria
    et al.
    Institute of Chemical Biology, National Hellenic Research Foundation, Athens, Greece. School of Chemical Engineering, National Technical University of Athens, Greece.
    Topakas, Evangelos
    School of Chemical Engineering, National Technical University of Athens, Greece.
    Christakopoulos, Paul
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Chrysina, Evangelia D.
    Institute of Chemical Biology, National Hellenic Research Foundation, Athens, Greece.
    The crystal structure of a Fusarium oxysporum feruloyl esterase that belongs to the tannase family2020In: FEBS Letters, ISSN 0014-5793, E-ISSN 1873-3468Article in journal (Refereed)
    Abstract [en]

    Feruloyl esterases are enzymes of industrial interest that catalyse the hydrolysis of the ester bond between hydroxycinnamic acids such as ferulic acid and sugars present in the plant cell wall. Although there are several structures of biochemically characterized feruloyl esterases available, the structural determinants of their substrate specificity are not yet fully understood. Here, we present the crystal structure of a feruloyl esterase from Fusarium oxysporum (FoFaeC) at 2.3 Å resolution. Similar to the two other tannase‐like feruloyl esterases, FoFaeC features a large lid domain covering the active site with potential regulatory role and a disulphide bond that brings together the serine and histidine of the catalytic triad. Differences are mainly observed in the metal coordination site and the substrate binding pocket.

  • 36.
    Fan, Pengpeng
    et al.
    Herbert Gleiter Institute of Nanoscience, Department of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, P. R. China.
    Qiu, Xiuhua
    Herbert Gleiter Institute of Nanoscience, Department of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, P. R. China.
    Shah, Faiz Ullah
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Ji, Qingmin
    Herbert Gleiter Institute of Nanoscience, Department of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, P. R. China.
    An, Rong
    Herbert Gleiter Institute of Nanoscience, Department of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, P. R. China. Center for Nanotechnology (CeNTech), Institute of Physics, Westfälische Wilhelms-Universität Münster, Münster, Germany.
    The effect of nanoscale friction of mesoporous carbon supported ionic liquids on the mass transfer of CO2 adsorption2020In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 22, no 3, p. 1097-1106Article in journal (Refereed)
    Abstract [en]

    Supported ionic liquids (ILs) are attractive alternatives for CO2 capture and the thickness of supported IL films plays a critical role in the CO2 mass transfer rate. However, the dependence of CO2 uptake on the IL film thickness differs as the system varies. In this work, atomic force microscopy (AFM) is employed to probe the ‘nanofriction coefficient’ to characterize the mobility of ILs at the solid interface, in which, the smaller the nanofriction coefficient, the faster are the ionic mobility and CO2 mass transfer. A monotonic and almost linear relationship for supported IL films is obtained between the resistance of CO2 mass transfer (1/k) and the nanofriction coefficient (μ), avoiding the controversy over the effect of supported IL film thickness on CO2 adsorption. The enhanced mass transfer of CO2 adsorption at IL-solid interfaces is observed at smaller resistance 1/k and friction coefficient μ. The low-friction driven local mobility (diffusion) of ILs at solid interfaces is enhanced, promoting the exchange mixing of the ILs adsorbing CO2 with the ‘blank-clean’ ions of the ILs, and thus accelerating the CO2 mass transfer. The proposed correlation links the nanoscale friction with the mass transfer of CO2 adsorption, providing a fresh view on the design of ultra-low frictional supported ILs for enhanced CO2 capture and separation processes.

  • 37.
    Barai, Manas
    et al.
    Department of Chemistry, Vidyasagar University, Midnapore, West Bengal, India.
    Mandal, Manas Kumar
    Department of Chemistry, Vidyasagar University, Midnapore, West Bengal, India.
    Sultana, Habiba
    Department of Chemistry, Vidyasagar University, Midnapore, West Bengal, India.
    Manna, Emili
    Centre for Life Sciences, Vidyasagar University, Midnapore, West Bengal, India.
    Das, Sourav
    Centre for Surface Science, Department of Chemistry, Jadavpur University, Kolkata, West Bengal, India.
    Nag, Kaushik
    Department of Biochemistry, Memorial University of Newfoundland, St. John's, Canada.
    Ghosh, Soumen
    Centre for Surface Science, Department of Chemistry, Jadavpur University, Kolkata, West Bengal, India.
    Patra, Anuttam
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Panda, Amiya Kumar
    Department of Chemistry, Vidyasagar University, Midnapore, West Bengal, India.
    Theoretical Approaches on the Synergistic Interaction between Double-Headed Anionic Amino Acid-Based Surfactants and Hexadecyltrimethylammonium Bromide2020In: Journal of Surfactants and Detergents (JSD), ISSN 1097-3958, E-ISSN 1558-9293Article in journal (Refereed)
    Abstract [en]

    Theoretical investigations on the micellization of mixtures of (i) amino acid-based anionic surfactants [AAS: N-dodecyl derivatives of aminomalonate, −aspartate, and -glutamate] and (ii) hexadecyltrimethylammonium bromide (HTAB), were carried out at different mole ratios. Variation in the theoretical values of critical micelle concentration (CMC), mole fraction of surfactants in the micellar phase (X), at the interface (Xσ), interaction parameters at the bulk/interface (βR/βσ), ideality/nonideality of the mixing processes, and activity coefficients (f) were evaluated using Rubingh, Rosen, Motomora, and Sarmoria-Puvvada-Blankschtein models. CMC values significantly deviate from the theroretically calculated values, indicating associative interaction. With increasing mole fraction of AAS (αAAS), the magnitude of the (βR/βσ) values gradually decreased, considered to attributable to hydrophobic interactions. With increasing αAAS, the micellar mole fraction of HTAB (X2) decreased insignificantly and X2 values were higher than those compared to AAS for all combinations, due to the dominance of HTAB in micelles. Micellar mole fraction at the ideal state of AAS ((Formula presented.)) differed from micellar mole fraction of AAS (X1), indicating nonideality in the mixed micellization process. Gibbs free energy of micellization (∆Gm) values are more negative than the free energy of micellization for ideal mixing ((Formula presented.)), indicating the micellization process is spontaneous. With increasing αAAS, the enthalpy of micellization (ΔHm) and entropy of micellization (ΔSm) values gradually increased, which indicates micellization is exothermic. The different physicochemical parameters of the mixed micelles are correlated with the variation in the spacer length between the two carboxylate groups of AAS. © 2020 AOCS

  • 38.
    Filippov, Andrei
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Kazan State Medical University, Kazan, Russia.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Department of Physics, Warwick University, Coventry, U.K.
    Shah, Faiz Ullah
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Understanding the Interaction of Boric Acid and CO2 with Ionic Liquids in Aqueous Medium by Multinuclear NMR Spectroscopy2020In: ACS Sustainable Chemistry & Engineering, E-ISSN 2168-0485, Vol. 8, no 1, p. 552-560Article in journal (Refereed)
    Abstract [en]

    Boric acid is known to enhance the kinetics of CO2 absorption by some active aqueous solutions. However, the mechanism of interaction of boric acid with CO2 in the presence of active molecules is not yet fully understood. In this work, the interaction and dynamics of ions in aqueous solutions of functionalized choline-based ionic liquids [N1,1,5,2OH][Threo] and [N1,1,5,2OH][Tau] in the presence of boric acid and CO2 was thoroughly investigated using a multinuclear NMR approach: 13C and 11B NMR spectroscopy, 11B NMR transverse relaxation, and 1H and 11B NMR diffusometry. 13C and 11B NMR spectroscopy revealed the formation of borate-based complexes as a result of a reaction between boric acid and the anions of the ILs at ionic liquid/boric acid molar ratios larger than ca. 0.15. The formation of these complexes and their dynamics were further investigated using 11B relaxation and 1H and 11B pulse-field-gradient (PFG) NMR. Plausible reaction mechanisms of boric acid with the anions of the ILs, formation of the borate complexes, and dissociation of these complexes facilitated by CO2 molecules are suggested.

  • 39.
    Karnaouri, Anthi
    et al.
    Industrial Biotechnology & Biocatalysis Group, School of Chemical Engineering, National Technical University of Athens.
    Chalima, Angelina
    Industrial Biotechnology & Biocatalysis Group, School of Chemical Engineering, National Technical University of Athens.
    Kalogiannis, Konstantinos G.
    Chemical Process and Energy Resources Institute (CPERI), CERTH.
    Varamogianni-Mamatsi, Despoina
    Industrial Biotechnology & Biocatalysis Group, School of Chemical Engineering, National Technical University of Athens.
    Lappas, Angelos
    Chemical Process and Energy Resources Institute (CPERI), CERTH.
    Topakas, Evangelos
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Industrial Biotechnology & Biocatalysis Group, School of Chemical Engineering, National Technical University of Athens.
    Utilization of lignocellulosic biomass towards the production of omega-3 fatty acids by the heterotrophic marine microalga Crypthecodinium cohnii2020In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 303, article id 122899Article in journal (Refereed)
    Abstract [en]

    Omega-3 fatty acids have become a commodity of high nutritional and commercial value; intensive fishing and its environmental and social cost has led researchers to seeking alternative more sustainable ways of producing them. Heterotrophic microalgae such as Crypthecodinium cohnii, a marine dinoflagellate, have the ability to utilize various substrates and accumulate high amounts of docosahexaenoic acid (DHA). In this work, a mild oxidative organosolv pretreatment of beechwood pulps was employed that allowed up to 95% of lignin removal in a single stage, thus yielding a cellulose-rich solid fraction. The enzymatic hydrolysates were evaluated for their ability to support the growth and lipid accumulation of C. cohnii in batch and fed-batch cultures; the results verified the successful microalgae growth, while DHA reached up to 43.5% of the cell’s total lipids. The proposed bioprocess demonstrated the utilization of non-edible biomass towards high added value food supplements in a sustainable and efficient manner.

  • 40.
    Patel, Alok
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Matsakas, Leonidas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    A comparative study on de novo and ex novo lipid fermentation by oleaginous yeast using glucose and sonicated waste cooking oil2019In: Ultrasonics sonochemistry, ISSN 1350-4177, E-ISSN 1873-2828, Vol. 52, p. 364-374Article in journal (Refereed)
    Abstract [en]

    There are only a few reports available about the assimilation of hydrophobic substrates by microorganisms, however, it is well known that oleaginous microorganisms are capable of utilizing both hydrophilic and hydrophobic substrates and accumulate lipids via two different pathways namely de novo and ex novo lipid synthesis, respectively. In the present study, an oleaginous yeast, Cryptococcus curvatus, was investigated for its potentials to utilize a waste substrate of hydrophobic nature (waste cooking oil – WCO) and compared with its ability to utilize a hydrophilic carbon source (glucose). To facilitate the utilization of WCO by C. curvatus, the broth was sonicated to form a stable oil-in-water emulsion without adding any emulsifier, which was then compared with WCO samples without any ultrasound treatment (unsonicated) for the yeast cultivation. Ultrasonication reduces the size of hydrophobic substrates and improves their miscibility in an aqueous broth making them easily assimilated by oleaginous yeast. Under de novo lipid fermentation, the yeast synthesized 9.93 ± 0.84 g/L of cell dry weight and 5.23 ± 0.49 g/L lipids (lipid content of 52.66 ± 0.93% w/w) when cultivated on 40 g/L of glucose (C/N ratio of 40). The amount of cell dry weight, lipid concentration, and lipid content were considerably higher during the ex novo lipid synthesis. More specifically, the highest lipid content achieved was 70.13 ± 1.65% w/w with a corresponding dry cell weight and lipid concentration of 18.62 ± 0.76 g/L and 13.06 ± 0.92 g/L respectively, when grown on 20 g/L sonicated WCO. The highest lipid concentration, however, was observed when the yeast was cultivated on 40 g/L sonicated WCO. Under these conditions, 20.34 g/L lipids were produced with a lipid content of 57.05% w/w. On the other hand, lipid production with unsonicated WCO was significant lower, reaching 11.16 ± 1.02 g/L (69.14 ± 1.34% w/w of lipid content) and 12.21 ± 1.34 g/L (47.39 ± 1.67% w/w of lipid content) for 20 g/L and 40 g/L of WCO, respectively. This underpins the significance of the sonication treatment, especially at elevated WCO concentrations, to improve the accessibility of the yeast to the WCO. Sonication treatment that was used in this study assisted the utilization of WCO without the need to add emulsifiers, thus reducing the need for chemicals and in turn has a positive impact on the production costs. The microbial lipids produced presented a different fatty acid composition compared to the WCO, making them more suitable for biodiesel production as suggested by the theoretical estimation of the biodiesel properties.

  • 41.
    Katsimpouras, Constantinos
    et al.
    Industrial Biotechnology & Biocatalysis Group, School of Chemical Engineering, National Technical University of Athens, 9 Iroon Polytechniou Str., Zografou Campus, Athens, Greece.
    Dedes, Grigorios
    Industrial Biotechnology & Biocatalysis Group, School of Chemical Engineering, National Technical University of Athens, 9 Iroon Polytechniou Str., Zografou Campus, Athens, Greece.
    Thomaidis, Nikolaos S.
    Laboratory of Analytical Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimioupolis Zografou, Athens, Greece.
    Topakas, Evangelos
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Industrial Biotechnology & Biocatalysis Group, School of Chemical Engineering, National Technical University of Athens, 9 Iroon Polytechniou Str., Zografou Campus, Athens, Greece.
    A novel fungal GH30 xylanase with xylobiohydrolase auxiliary activity2019In: Biotechnology for Biofuels, ISSN 1754-6834, E-ISSN 1754-6834, Vol. 12, article id 120Article in journal (Refereed)
    Abstract [en]

    Background:

    The main representatives of hemicellulose are xylans, usually decorated β-1,4-linked d-xylose polymers, which are hydrolyzed by xylanases. The efficient utilization and complete hydrolysis of xylans necessitate the understanding of the mode of action of xylan degrading enzymes. The glycoside hydrolase family 30 (GH30) xylanases comprise a less studied group of such enzymes, and differences regarding the substrate recognition have been reported between fungal and bacterial GH30 xylanases. Besides their role in the utilization of lignocellulosic biomass for bioenergy, such enzymes could be used for the tailored production of prebiotic xylooligosaccharides (XOS) due to their substrate specificity.

    Results:

    The expression of a putative GH30_7 xylanase from the fungus Thermothelomyces thermophila (synonyms Myceliophthora thermophila, Sporotrichum thermophile) in Pichia pastoris resulted in the production and isolation of a novel xylanase with unique catalytic properties. The novel enzyme designated TtXyn30A, exhibited an endo- mode of action similar to that of bacterial GH30 xylanases that require 4-O-methyl-d-glucuronic acid (MeGlcA) decorations, in contrast to most characterized fungal ones. However, TtXyn30A also exhibited an exo-acting catalytic behavior by releasing the disaccharide xylobiose from the non-reducing end of XOS. The hydrolysis products from beechwood glucuronoxylan were MeGlcA substituted XOS, and xylobiose. The major uronic XOS (UXOS) were the aldotriuronic and aldotetrauronic acid after longer incubation indicating the ability of TtXyn30A to cleave linear parts of xylan and UXOS as well.

    Conclusions:

    Hereby, we reported the heterologous production and biochemical characterization of a novel fungal GH30 xylanase exhibiting endo- and exo-xylanase activity. To date, considering its novel catalytic properties, TtXyn30A shows differences with most characterized fungal and bacterial GH30 xylanases. The discovered xylobiohydrolase mode of action offers new insights into fungal enzymatic systems that are employed for the utilization of lignocellulosic biomass. The recombinant xylanase could be used for the production of X2 and UXOS from glucuronoxylan, which in turn would be utilized as prebiotics carrying manifold health benefits.

  • 42.
    Yu, Liang
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Holmgren, Allan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    A novel method for fabrication of high-flux zeolite membranes on supports with arbitrary geometry2019In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 7, no 17, p. 10325-10330Article in journal (Refereed)
    Abstract [en]

    A novel procedure for the preparation of high-flux zeolite membranes was developed. This method relies on rendering the support hydrophobic, and thereby protected from the synthesis mixture and invasion of the support pores, while the cationic polymer on the surface still allowed deposition of zeolite seeds. Both high-flux MFI and CHA zeolite films were grown on both discs and tubular supports, which illustrates the applicability of the method to arbitrary membrane geometries. Typically, MFI disc membranes showed a very high CO2permeance of 85 × 10−7 mol m−2 s−1 Pa−1 and a CO2/H2 separation selectivity of 56 at 278 K and CHA disc membranes showed a very high CO2 permeance of 79 × 10−7 mol m−2 s−1 Pa−1 and a CO2/CH4 separation selectivity of 76 at 249 K. As the method is applicable to supports with complex geometries, it is suitable for preparation of membranes for industrial applications.

  • 43.
    Patel, Alok
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Molecular Microbiology Laboratory, Biotechnology Department, Indian Institute of Technology Roorkee (IIT-R), Roorkee.
    Arora, Neha
    Molecular Microbiology Laboratory, Biotechnology Department, Indian Institute of Technology Roorkee (IIT-R), Roorkee.
    Pruthi, Vikas
    Molecular Microbiology Laboratory, Biotechnology Department, Indian Institute of Technology Roorkee (IIT-R), Roorkee.
    Pruthi, Parul A.
    Molecular Microbiology Laboratory, Biotechnology Department, Indian Institute of Technology Roorkee (IIT-R), Roorkee.
    A novel rapid ultrasonication-microwave treatment for total lipid extraction from wet oleaginous yeast biomass for sustainable biodiesel production2019In: Ultrasonics sonochemistry, ISSN 1350-4177, E-ISSN 1873-2828, Vol. 51, p. 504-516Article in journal (Refereed)
    Abstract [en]

    Oleaginous yeasts have emerged as a sustainable source of renewable oils for liquid biofuels. However, biodiesel production from them has few constraints with respect to their cell disruption and lipid extraction techniques. The lipid extraction from oleaginous yeasts commonly includes dewatering and drying of cell biomass, which requires energy and time. The aim of this work was to establish a process for the lipid extraction techniques from wet biomass applying acid catalyzed hot water, microwave, rapid ultrasonication-microwave treatment together with conventional Bligh and Dyer method. In the wake of testing all procedures, it was revealed that rapid ultrasonication-microwave treatment has great potential to give high lipid content (70.86 % w/w) on the cell dry weight basis. The lipid profile after treatment showed the presence of appropriate quantities of saturated (10.39 ± 0.15%), monounsaturated (76.55 ± 0.19%) and polyunsaturated fatty acids (11.49 ± 0.23%) which further improves biodiesel quality compared to the rest of methods. To the best of our knowledge, this is the first report of using rapid ultrasonication-microwave treatment for the lipid extraction from wet oleaginous yeast biomass in the literature.

  • 44.
    Zerva, Anastasia
    et al.
    Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, Athens, Greece.
    Koutroufini, Efthymia
    Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, Athens, Greece.
    Kostopoulou, Ioanna
    Laboratory of Organic Chemistry, School of Chemical Engineering, National Technical University of Athens, Athens, Greece.
    Detsi, Anastasia
    Laboratory of Organic Chemistry, School of Chemical Engineering, National Technical University of Athens, Athens, Greece.
    Topakas, Evangelos
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    A novel thermophilic laccase-like multicopper oxidase from Thermothelomyces thermophila and its application in the oxidative cyclization of 2′,3,4-trihydroxychalcone2019In: New Biotechnology, ISSN 1871-6784, E-ISSN 1876-4347, Vol. 49, p. 10-18Article in journal (Refereed)
    Abstract [en]

    Laccase-like multicopper oxidases (LMCOs) are a heterogeneous group of oxidases, acting mainly on phenolic compounds and which are widespread among many microorganisms, including Basidiomycetes and Ascomycetes. Here, we report the cloning, heterologous expression, purification and characterization of a novel LMCO from the thermophilic fungus Thermothelomyces thermophila. The 1953 bp lmco gene sequence comprises of 3 exons interrupted by 2 introns and according to the LccED database the translated sequence belongs to superfamily 6 of multicopper oxidases. After removal of the introns, the gene was transformed into Pichia pastoris, under the control of the alcohol oxidase (AOX1) promoter. The heterologous enzyme was purified with an apparent molecular weight of 80 kDa. TtLMCO1 displayed optimum activity at pH 4 and 50 °C and appeared thermostable up to 50 °C. A variety of phenolic compounds were oxidized by TtLMCO1, including standard laccase substrates such as ABTS and 2,6 dimethoxyphenol. The UV/Vis spectrum of purified TtLMCO1 indicates that it belongs to yellow laccase-like oxidases. The enzyme was used for the bioconversion of 2′,3,4-trihydroxychalcone to 3′,4′-dihydroxy-aurone, a bioactive aurone recently shown to possess inhibitory activity against several isoforms of the histone deacetylase complex (HDAC). Overall, the thermophilic yellow LMCO TtLMCO1 presents a number of superior properties with potential use in industrial biocatalysis.

  • 45.
    Patel, Alok
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Matsakas, Leonidas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Rova, Ulrika
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Christakopoulos, Paul
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    A perspective on biotechnological applications of thermophilic microalgae and cyanobacteria2019In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 278, p. 424-434Article in journal (Refereed)
    Abstract [en]

    The importance of expanding our knowledge on microorganisms derived from extreme environments stems from the development of novel and sustainable technologies for our health, food, and environment. Microalgae and cyanobacteria represent a group of diverse microorganisms that inhabit a wide range of environments, are capable of oxygenic photosynthesis, and form a thick microbial mat even at extreme environments. Studies of thermophilic microorganisms have shown a considerable biotechnological potential due to their optimum growth and metabolisms at high temperatures (≥50 °C), which is supported by their thermostable enzymes. Microalgal and cyanobacterial communities present in high-temperature ecosystems account for a large part of the total ecosystem biomass and productivity, and can be exploited to generate several value-added products of agricultural, pharmaceutical, nutraceutical, and industrial relevance. This review provides an overview on the current status of biotechnological applications of thermophilic microalgae and cyanobacteria, with an outlook on the challenges and future prospects.

  • 46.
    Hua, Jing
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Björling, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Grahn, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Larsson, Roland
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Shi, Yijun
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    A smart friction control strategy enabled by CO2 absorption and desorption2019In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, no 1, article id 13262Article in journal (Refereed)
    Abstract [en]

    Intelligent control of friction is an attractive but challenging topic and it has rarely been investigated for full size engineering applications. In this work, it is instigated if it would be possible to adjust friction by controlling viscosity in a lubricated contact. By exploiting the ability to adjust the viscosity of the switchable ionic liquids, 1,8-Diazabicyclo (5.4.0) undec-7-ene (DBU)/ glycerol mixture via the addition of CO2, the friction could be controlled in the elastohydrodynamic lubrication (EHL) regime. The friction decreased with increasing the amount of CO2 to the lubricant and increased after partial releasing CO2. As CO2 was absorbed by the liquid, the viscosity of the liquid increased which resulted in that the film thickness increased. At the same time the pressure-viscosity coefficient decreased with the addition of CO2. When CO2 was released again the friction increased and it was thus possible to control friction by adding or removing CO2.

  • 47.
    Nobandegani, Mojtaba
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Yu, Liang
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Mayne, Benjamin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering. Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Adsorption and transport of CO2 and CH4 in CHA zeolite2019Conference paper (Refereed)
    Download full text (pdf)
    Adsorption CHA
  • 48.
    Nobandegani, Mojtaba Sinaei
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Yu, Liang
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Mayne, Benjamin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Adsorption and transport of CO2 and CH4 in CHA zeolite2019Conference paper (Other academic)
    Download full text (pdf)
    fulltext
  • 49.
    Kalogiannis, Konstantinos G.
    et al.
    Chemical Process and Energy Resources Institute (CPERI), Centre for Research and Technology Hellas (CERTH), Thessaloniki, Greece.
    Matsakas, Leonidas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Lappas, Angelos A.
    Chemical Process and Energy Resources Institute (CPERI), Centre for Research and Technology Hellas (CERTH), Thessaloniki, Greece.
    Rova, Ulrika
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Christakopoulos, Paul
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Aromatics from Beechwood Organosolv Lignin through Thermal and Catalytic Pyrolysis2019In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 12, no 9, article id 1606Article in journal (Refereed)
    Abstract [en]

    Biomass fractionation, as an alternative to biomass pretreatment, has gained increasing research attention over the past few years as it provides separate streams of cellulose, hemicellulose, and lignin. These streams can be used separately and can provide a solution for improving the economics of emerging biorefinery technologies. The sugar streams are commonly used in microbial conversions, whereas during recent years lignin has been recognized as a valuable compound as it is the only renewable and abundant source of aromatic chemicals. Successfully converting lignin into valuable chemicals and products is key in achieving both environmental and economic sustainability of future biorefineries. In this work, lignin retrieved from beechwood sawdust delignification pretreatment via an organosolv process was depolymerized with thermal and catalytic pyrolysis. ZSM-5 commercial catalyst was used in situ to upgrade the lignin bio-oil vapors. Lignins retrieved from different modes of organosolv pretreatment were tested in order to evaluate the effect that upstream pretreatment has on the lignin fraction. Both thermal and catalytic pyrolysis yielded oils rich in phenols and aromatic hydrocarbons. Use of ZSM-5 catalyst assisted in overall deoxygenation of the bio-oils and enhanced aromatic hydrocarbons production. The oxygen content of the bio-oils was reduced at the expense of their yield. Organosolv lignins were successfully depolymerized towards phenols and aromatic hydrocarbons via thermal and catalytic pyrolysis. Hence, lignin pyrolysis can be an effective manner for lignin upgrading towards high added value products

  • 50.
    Yan, Baili
    et al.
    Nanjing Tech University, Nanjing, China.
    Yu, Shuang
    Zeng, Changfeng
    Nanjing Tech University, Nanjing, China.
    Yu, Liang
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Luleå University of Technology.
    Wang, Chongqing
    Nanjing Tech University, Nanjing, China.
    Zhang, Lixiong
    Nanjing Tech University, Nanjing, China.
    Binderless zeolite NaX microspheres with enhanced CO2 adsorption selectivity2019In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 278, p. 267-274Article in journal (Refereed)
    Abstract [en]

    Zeolite NaX@NaA core-shell microspheres were prepared via a post-treatment secondary growth of zeolite NaA films on outer surface of binderless zeolite NaX microspheres. The obtained core-shell microspheres were composed of intergrown octahedral NaX particles inside, with particles size of ca. 500–750 nm, and continuous zeolite NaA films on the outer surface with the thickness of about 2 μm. Higher CO2 separation performance was observed for the core-shell microspheres comparing to the parental binderless zeolite NaX microspheres. The ideal separation factors of zeolite NaX@NaA core-shell microspheres for CO2/CH4 and CO2/N2 were 13 and 47, and the adsorption selectivities for the corresponding binary mixtures were 308 and 923, significantly higher than the binderless zeolite NaX microspheres of 9 and 19 as well as 264 and 735, respectively. After K+ ion exchanging, the core-shell zeolite microspheres have even higher adsorption selectivities of 326 and 1109 for CO2/CH4 and CO2/N2 binary mixtures. The crushing strength of the binderless zeolite NaX microspheres was increased from 0.46 MPa to 3.42 MPa after the secondary growth. In addition, the growth of zeolite A film was resultant from interzeolite conversion and the interzeolite conversion was investigated by the conversion of zeolite NaX to NaA crystals in NaA membrane synthesis gel.