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  • 1.
    Al-Hashimi, Osamah
    et al.
    Babylon Water Directorate, Babylon 51001, Iraq; School of Civil Engineering and Built Environment, Liverpool John Moores University, Liverpool L3 3AF, UK.
    Hashim, Khalid
    School of Civil Engineering and Built Environment, Liverpool John Moores University, Liverpool L3 3AF, UK; Department of Environmental Engineering, College of Engineering, University of Babylon, Babylon 51001, Iraq.
    Loffill, Edward
    School of Civil Engineering and Built Environment, Liverpool John Moores University, Liverpool L3 3AF, UK.
    Marolt Čebašek, Tina
    School of Civil Engineering and Built Environment, Liverpool John Moores University, Liverpool L3 3AF, UK.
    Nakouti, Ismini
    Built Environment and Sustainable Technology Research Institute, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK.
    Faisal, Ayad A. H.
    Department of Environmental Engineering, College of Engineering, University of Baghdad, Baghdad 10001, Iraq.
    Al-Ansari, Nadhir
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    A Comprehensive Review for Groundwater Contamination and Remediation: Occurrence, Migration and Adsorption Modelling2021In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 26, no 19, p. 5913-5913Article in journal (Refereed)
    Abstract [en]

    The provision of safe water for people is a human right; historically, a major number of people depend on groundwater as a source of water for their needs, such as agricultural, industrial or human activities. Water resources have recently been affected by organic and/or inorganic contaminants as a result of population growth and increased anthropogenic activity, soil leaching and pollution. Water resource remediation has become a serious environmental concern, since it has a direct impact on many aspects of people’s lives. For decades, the pump-and-treat method has been considered the predominant treatment process for the remediation of contaminated groundwater with organic and inorganic contaminants. On the other side, this technique missed sustainability and the new concept of using renewable energy. Permeable reactive barriers (PRBs) have been implemented as an alternative to conventional pump-and-treat systems for remediating polluted groundwater because of their effectiveness and ease of implementation. In this paper, a review of the importance of groundwater, contamination and biological, physical as well as chemical remediation techniques have been discussed. In this review, the principles of the permeable reactive barrier’s use as a remediation technique have been introduced along with commonly used reactive materials and the recent applications of the permeable reactive barrier in the remediation of different contaminants, such as heavy metals, chlorinated solvents and pesticides. This paper also discusses the characteristics of reactive media and contaminants’ uptake mechanisms. Finally, remediation isotherms, the breakthrough curves and kinetic sorption models are also being presented. It has been found that groundwater could be contaminated by different pollutants and must be remediated to fit human, agricultural and industrial needs. The PRB technique is an efficient treatment process that is an inexpensive alternative for the pump-and-treat procedure and represents a promising technique to treat groundwater pollution. 

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  • 2.
    Baran, Tomasz
    et al.
    SajTom Light Future, Wężerów 37/1, 32-090 Wężerów, Poland.
    Visibile, Alberto
    Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivägen 10, 41296 Gothenburg, Sweden.
    Busch, Michael
    Department of Chemistry and Material Science, School of Chemical Engineering, Aalto University, Kemistintie 1, 02150 Espoo, Finland.
    He, Xiufang
    Dipartimento di Chimica, Università degli Studi di Milano, Via Golgi 19, 20133 Milano, Italy.
    Wojtyla, Szymon
    SajTom Light Future, Wężerów 37/1, 32-090 Wężerów, Poland.
    Rondinini, Sandra
    Dipartimento di Chimica, Università degli Studi di Milano, Via Golgi 19, 20133 Milano, Italy.
    Minguzzi, Alessandro
    Dipartimento di Chimica, Università degli Studi di Milano, Via Golgi 19, 20133 Milano, Italy.
    Vertova, Alberto
    Dipartimento di Chimica, Università degli Studi di Milano, Via Golgi 19, 20133 Milano, Italy.
    Copper Oxide-Based Photocatalysts and Photocathodes: Fundamentals and Recent Advances2021In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 26, no 23, article id 7271Article in journal (Refereed)
  • 3.
    Das, Oisik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Capezza, Antonio J
    Department of Fibre and Polymer Technology, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden. Department of Plant Breeding, Faculty of Landscape Planning, Horticulture and Crop Production Sciences, Swedish University of Agricultural Sciences, 23053 Alnarp, Sweden.
    Mårtensson, Julia
    Department of Fibre and Polymer Technology, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
    Dong, Yu
    School of Civil and Mechanical Engineering, Curtin University, Perth WA 6845, Australia.
    Neisiany, Rasoul Esmaeely
    Department of Materials and Polymer Engineering, Faculty of Engineering, Hakim Sabzevari University, Sabzevar 9617976487, Iran.
    Pelcastre, Leonardo
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Jiang, Lin
    School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
    Xu, Qiang
    School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
    Olsson, Richard T.
    Department of Fibre and Polymer Technology, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
    Hedenqvist, Mikael S
    Department of Fibre and Polymer Technology, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
    The Effect of Carbon Black on the Properties of Plasticised Wheat Gluten Biopolymer2020In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 25, no 10, article id 2279Article in journal (Refereed)
    Abstract [en]

    Wheat gluten biopolymers generally become excessively rigid when processed without plasticisers, while the use of plasticisers, on the other hand, can deteriorate their mechanical properties. As such, this study investigated the effect of carbon black (CB) as a filler into glycerol-plasticised gluten to prepare gluten/CB biocomposites in order to eliminate the aforementioned drawback. Thus, biocomposites were manufactured using compression moulding followed by the determination of their mechanical, morphological, and chemical properties. The filler content of 4 wt% was found to be optimal for achieving increased tensile strength by 24%, and tensile modulus by 268% along with the toughness retention based on energy at break when compared with those of glycerol-plasticised gluten. When reaching the filler content up to 6 wt%, the tensile properties were found to be worsened, which can be ascribed to excessive agglomeration of carbon black at the high content levels within gluten matrices. Based on infrared spectroscopy, the results demonstrate an increased amount of β-sheets, suggesting the formation of more aggregated protein networks induced by increasing the filler contents. However, the addition of fillers did not improve fire and water resistance in such bionanocomposites owing to the high blend ratio of plasticiser to gluten.

  • 4.
    Fredsgaard, Malthe
    et al.
    AAU Energy, Aalborg University, Esbjerg, Denmark.
    Kaniki, Samba Evelyne Kabemba
    AAU Energy, Aalborg University, Esbjerg, Denmark.
    Antonopoulou, Io
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Chaturvedi, Tanmay
    AAU Energy, Aalborg University, Esbjerg, Denmark.
    Thomsen, Mette Hedegaard
    AAU Energy, Aalborg University, Esbjerg, Denmark.
    Phenolic Compounds in Salicornia spp. and Their Potential Therapeutic Effects on H1N1, HBV, HCV, and HIV: A Review2023In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 28, no 14, article id 5312Article, review/survey (Refereed)
    Abstract [en]

    Despite public health risk mitigation measures and regulation efforts by many countries, regions, and sectors, viral outbreaks remind the world of our vulnerability to biological hazards and the importance of mitigation actions. The saltwater-tolerant plants in the Salicornia genus belonging to the Amaranthaceae family are widely recognized and researched as producers of clinically applicable phytochemicals. The plants in the Salicornia genus contain flavonoids, flavonoid glycosides, and hydroxycinnamic acids, including caffeic acid, ferulic acid, chlorogenic acid, apigenin, kaempferol, quercetin, isorhamnetin, myricetin, isoquercitrin, and myricitrin, which have all been shown to support the antiviral, virucidal, and symptom-suppressing activities. Their potential pharmacological usefulness as therapeutic medicine against viral infections has been suggested in many studies, where recent studies suggest these phenolic compounds may have pharmacological potential as therapeutic medicine against viral infections. This study reviews the antiviral effects, the mechanisms of action, and the potential as antiviral agents of the aforementioned phenolic compounds found in Salicornia spp. against an influenza A strain (H1N1), hepatitis B and C (HBV/HCV), and human immunodeficiency virus 1 (HIV-1), as no other literature has described these effects from the Salicornia genus at the time of publication. This review has the potential to have a significant societal impact by proposing the development of new antiviral nutraceuticals and pharmaceuticals derived from phenolic-rich formulations found in the edible Salicornia spp. These formulations could be utilized as a novel strategy by which to combat viral pandemics caused by H1N1, HBV, HCV, and HIV-1. The findings of this review indicate that isoquercitrin, myricetin, and myricitrin from Salicornia spp. have the potential to exhibit high efficiency in inhibiting viral infections. Myricetin exhibits inhibition of H1N1 plaque formation and reverse transcriptase, as well as integrase integration and cleavage. Isoquercitrin shows excellent neuraminidase inhibition. Myricitrin inhibits HIV-1 in infected cells. Extracts of biomass in the Salicornia genus could contribute to the development of more effective and efficient measures against viral infections and, ultimately, improve public health.

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  • 5.
    Ginesy, Mireille
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Enman, Josefine
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Rusanova-Naydenova, Daniela
    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.
    Simultaneous Quantification of L-Arginine and Monosaccharides during Fermentation: An Advanced Chromatography Approach2019In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 24, no 4, article id 802Article in journal (Refereed)
    Abstract [en]

    Increasing demand for L-arginine by the food and pharmaceutical industries has sparked the search for sustainable ways of producing it. Microbial fermentation offers a suitable alternative; however, monitoring of arginine production and carbon source uptake during fermentation, requires simple and reliable quantitative methods compatible with the fermentation medium. Two methods for the simultaneous quantification of arginine and glucose or xylose are described here: high-performance anion-exchange chromatography coupled to integrated pulsed amperometric detection (HPAEC-IPAD) and reversed-phase ultra-high-performance liquid chromatography combined with charged aerosol detection (RP-UHPLC-CAD). Both were thoroughly validated in a lysogeny broth, a minimal medium, and a complex medium containing corn steep liquor. HPAEC-IPAD displayed an excellent specificity, accuracy, and precision for arginine, glucose, and xylose in minimal medium and lysogeny broth, whereas specificity and accuracy for arginine were somewhat lower in medium containing corn steep liquor. RP-UHPLC-CAD exhibited high accuracy and precision, and enabled successful monitoring of arginine and glucose or xylose in all media. The present study describes the first successful application of the above chromatographic methods for the determination and monitoring of L-arginine amounts during its fermentative production by a genetically modified Escherichia coli strain cultivated in various growth media.

  • 6.
    Hassan, Waqed
    et al.
    Department of Civil Engineering, College of Engineering, University of Kerbala, Kerbala 56001, Iraq.
    Faisal, Ayad
    Environmental Engineering, College of Engineering, University of Baghdad, Baghdad 10001, Iraq.
    Abed, Enas
    Department of Civil Engineering, College of Engineering, University of Kerbala, Kerbala 56001, Iraq.
    Al-Ansari, Nadhir
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Saleh, Bahaa
    Mechanical Engineering Department, College of Engineering, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia.
    New Composite Sorbent for Removal of Sulfate Ions from Simulated and Real Groundwater in the Batch and Continuous Tests2021In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 26, no 14, article id 4356Article in journal (Refereed)
    Abstract [en]

    The evaluation of groundwater quality in the Dammam formation, Faddak farm, Karbala Governorate, Iraq proved that the sulfate (SO42−) concentrations have high values; so, this water is not suitable for livestock, poultry and irrigation purposes. For reclamation of this water, manufacturing of new sorbent for permeable reactive barrier was required through precipitation of Mg and Fe hydroxides nanoparticles on the activated carbon (AC) surface with best Mg/Fe molar ratio of 7.5/2.5. Mixture of 50% coated AC and 50% scrap iron was applied to eliminate SO42− from contaminated water with efficiency of 59% and maximum capacity of adsorption equals to 9.5 mg/g for a time period of 1 h, sorbent dosage 40 g/L, and initial pH = 5 at 50 mg/L initial SO42− concentration and 200 rpm shaking speed. Characterization analyses certified that the plantation of Mg and Fe nanoparticles onto AC was achieved. Continuous tests showed that the longevity of composite sorbent is increased with thicker bed and lower influent concentration and flow rate. Computer solution (COMSOL) software was well simulated for continuous measurements. The reclamation of real contaminated groundwater was achieved in column set-up with efficiency of 70% when flow rate was 5 mL/min, bed depth was 50 cm and inlet SO42− concentration was 2301 mg/L.

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  • 7.
    Imran, Muhammad
    et al.
    Department of Mathematical Sciences, United Arab Emirates University, Al Ain P. O. Box 15551, United Arab Emirates.
    Khan, Abdul Rauf
    Department of Mathematics, Faculty of Science, Ghazi University, Dera Ghazi Khan 32200, Pakistan.
    Husin, Mohamad Nazri
    Special Interest Group on Modelling, Data Analytics (SIGMDA) Faculty of Ocean Engineering Technology, Informatics Universiti Malaysia Terengganu, Kuala Nerus 21030, Terengganu, Malaysia.
    Tchier, Fairouz
    Mathematics Department, College of Science, King Saud University, P.O. Box 22452, Riyadh 11495, Saudi Arabia.
    Ghani, Muhammad Usman
    Institute of Mathematics, Khawaja Fareed University of Engineering & Information Technology, Abu Dhabi Road, Rahim Yar Khan 64200, Pakistan.
    Hussain, Shahid
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Computation of Entropy Measures for Metal-Organic Frameworks2023In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 28, no 12, article id 4726Article in journal (Refereed)
    Abstract [en]

    Entropy is a thermodynamic function used in chemistry to determine the disorder and irregularities of molecules in a specific system or process. It does this by calculating the possible configurations for each molecule. It is applicable to numerous issues in biology, inorganic and organic chemistry, and other relevant fields. Metal-organic frameworks (MOFs) are a family of molecules that have piqued the curiosity of scientists in recent years. They are extensively researched due to their prospective applications and the increasing amount of information about them. Scientists are constantly discovering novel MOFs, which results in an increasing number of representations every year. Furthermore, new applications for MOFs continue to arise, illustrating the materials' adaptability. This article investigates the characterisation of the metal-organic framework of iron(III) tetra-p-tolyl porphyrin (FeTPyP) and CoBHT (CO) lattice. By constructing these structures with degree-based indices such as the K-Banhatti, redefined Zagreb, and the atom-bond sum connectivity indices, we also employ the information function to compute entropies.

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  • 8.
    Kalogiannis, Konstantinos G
    et al.
    Chemical Process and Energy Resources Institute (CPERI), Centre for Research and Technology Hellas (CERTH), 6th km Harilaou-Thermi Rd, 57001 Thessaloniki, Greece.
    Matsakas, Leonidas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Aspden, James
    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), 6th km Harilaou-Thermi Rd, 57001 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.
    Acid Assisted Organosolv Delignification of Beechwood and Pulp Conversion towards High Concentrated Cellulosic Ethanol via High Gravity Enzymatic Hydrolysis and Fermentation2018In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 23, no 7, article id 1647Article in journal (Refereed)
    Abstract [en]

    Background: Future biorefineries will focus on converting low value waste streams to chemical products that are derived from petroleum or refined sugars. Feedstock pretreatment in a simple, cost effective, agnostic manner is a major challenge.

    Methods: In this work, beechwood sawdust was delignified via an organosolv process, assisted by homogeneous inorganic acid catalysis. Mixtures of water and several organic solvents were evaluated for their performance. Specifically, ethanol (EtOH), acetone (AC), and methyl- isobutyl- ketone (MIBK) were tested with or without the use of homogeneous acid catalysis employing sulfuric, phosphoric, and oxalic acids under relatively mild temperature of 175 °C for one hour.

    Results: Delignification degrees (DD) higher than 90% were achieved, where both AC and EtOH proved to be suitable solvents for this process. Both oxalic and especially phosphoric acid proved to be good alternative catalysts for replacing sulfuric acid. High gravity simultaneous saccharification and fermentation with an enzyme loading of 8.4 mg/gsolids at 20 wt.% initial solids content reached an ethanol yield of 8.0 w/v%.

    Conclusions: Efficient delignification combining common volatile solvents and mild acid catalysis allowed for the production of ethanol at high concentration in an efficient manner

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  • 9.
    Karnaouri, Anthi C
    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.
    Effect of Different Pretreatment Methods on Birch Outer Bark: New Biorefinery Routes2016In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 21, no 4, article id 427Article in journal (Refereed)
    Abstract [en]

    A comparative study among different pretreatment methods used for the fractionation of the birch outer bark components, including steam explosion, hydrothermal and organosolv treatments based on the use of ethanol/water media, is reported. The residual solid fractions have been characterized by ATR-FTIR, 13C-solid-state NMR and morphological alterations afterpretreatment were detected by scanning electron microscopy. The general chemical composition of the untreated and treated bark including determination of extractives, suberin, lignin and monosaccharides was also studied. Composition of the residual solid fraction and relative proportions of different components, as a function of the processing conditions, could be established. Organosolv treatment produces a suberin-rich solid fraction, while duringhydrothermal and steam explosion treatment cleavage of polysaccharide bonds occurs. This work will provide a deeper fundamental knowledge of the bark chemical composition, thus increasing the utilization efficiency of birch outer bark and may create possibilities to up-scale the fractionation processes.

  • 10.
    Kim, Nam Kyeun
    et al.
    Centre for Advanced Composite Materials, Department of Mechanical Engineering, The University of Auckland, Auckland, 1142, New Zealand.
    Das, Oisik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Special issue “recent advances in flame-retardant polymers and composites”2021In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 26, no 20, article id 6167Article in journal (Other academic)
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  • 11.
    Krige, Adolf
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Sjöblom, Magnus
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Ramser, Kerstin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Christakopoulos, Paul
    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.
    On-line Raman spectroscopic study of cytochromes’ redox state of biofilms in microbial fuel cells2019In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 24, no 3, article id 646Article in journal (Refereed)
    Abstract [en]

    Bio-electrochemical systems such as microbial fuel cells and microbial electrosynthesis cells depend on efficient electron transfer between the microorganisms and the electrodes. Understanding the mechanisms and dynamics of the electron transfer is important in order to design more efficient reactors, as well as modifying microorganisms for enhanced electricity production. Geobacter are well known for their ability to form thick biofilms and transfer electrons to the surfaces of electrodes. Currently, there are not many “on-line” systems for monitoring the activity of the biofilm and the electron transfer process without harming the biofilm. Raman microscopy was shown to be capable of providing biochemical information, i.e., the redox state of C-type cytochromes, which is integral to external electron transfer, without harming the biofilm. In the current study, a custom 3D printed flow-through cuvette was used in order to analyze the oxidation state of the C-type cytochromes of suspended cultures of three Geobacter sulfurreducens strains (PCA, KN400 and ∆pilA). It was found that the oxidation state is a good indicator of the metabolic state of the cells. Furthermore, an anaerobic fluidic system enabling in situ Raman measurements was designed and applied successfully to monitor and characterize G. sulfurreducens biofilms during electricity generation, for both a wild strain, PCA, and a mutant, ∆S. The cytochrome redox state, monitored by the Raman peak areas, could be modulated by applying different poise voltages to the electrodes. This also correlated with the modulation of current transferred from the cytochromes to the electrode. The Raman peak area changed in a predictable and reversible manner, indicating that the system could be used for analyzing the oxidation state of the proteins responsible for the electron transfer process and the kinetics thereof in-situ. 

  • 12.
    Matsakas, Leonidas
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Karnaouri, Anthi C
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Cwirzen, Andrzej
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire 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.
    Formation of Lignin Nanoparticles by Combining Organosolv Pretreatment of Birch Biomass and Homogenization Processes2018In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 23, no 7, article id 1822Article in journal (Refereed)
    Abstract [en]

    Valorization of lignocellulosic biomass into a biorefinery scheme requires the use of all biomass components; in this, the lignin fraction is often underutilized. Conversion of lignin to nanoparticles is an attractive solution. Here, we investigated the effect of different lignin isolation processes and a post-treatment homogenization step on particle formation. Lignin was isolated from birch chips by using two organosolv processes, traditional organosolv (OS) and hybrid organosolv-steam explosion (HOS-SE) at various ethanol contents. For post-treatment, lignin was homogenized at 500 bar using different ethanol:water ratios. Isolation of lignin with OS resulted in unshaped lignin particles, whereas after HOS-SE, lignin micro-particles were formed directly. Addition of an acidic catalyst during HOS-SE had a negative impact on the particle formation, and the optimal ethanol content was 50⁻60% v/v. Homogenization had a positive effect as it transformed initially unshaped lignin into spherical nanoparticles and reduced the size of the micro-particles isolated by HOS-SE. Ethanol content during homogenization affected the size of the particles, with the optimal results obtained at 75% v/v. We demonstrate that organosolv lignin can be used as an excellent starting material for nanoparticle preparation, with a simple method without the need for extensive chemical modification. It was also demonstrated that tuning of the operational parameters results in nanoparticles of smaller size and with better size homogeneity.

  • 13.
    Monção, Maxwel
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hrůzová, Kateřina
    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.
    Matsakas, Leonidas
    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 Fractionation of Birch Sawdust: Establishing a Lignin-First Biorefinery2021In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 26, no 21, p. 6754-6754Article in journal (Refereed)
    Abstract [en]

    The use of residual biomass for bioconversions makes it possible to decrease the output of fossil-based chemicals and pursue a greener economy. While the use of lignocellulosic material as sustainable feedstock has been tried at pilot scale, industrial production is not yet economically feasible, requiring further technology and feedstock optimization. The aim of this study was to examine the feasibility of replacing woodchips with residual sawdust in biorefinery applications. Woodchips can be used in value-added processes such as paper pulp production, whereas sawdust is currently used mainly for combustion. The main advantages of sawdust are its large supply and a particle size sufficiently small for the pretreatment process. Whereas, the main challenge is the higher complexity of the lignocellulosic biomass, as it can contain small amounts of bark and cambium. Here, we studied the fractionation of birch sawdust by organosolv pretreatment at two different temperatures and for two different durations. We evaluated the efficiency of fractionation into the three main fractions: lignin, cellulose, and hemicellulose. The cellulose content in pretreated biomass was as high as 69.2%, which was nearly double the amount in untreated biomass. The obtained lignin was of high purity, with a maximum 4.5% of contaminating sugars. Subsequent evaluation of the susceptibility of pretreated solids to enzymatic saccharification revealed glucose yields ranging from 75% to 90% after 48 h but reaching 100.0% under the best conditions. In summary, birch sawdust can be successfully utilized as a feedstock for organosolv fractionation and replace woodchips to simplify and lower the costs of biorefinery processes.

  • 14.
    Mu, Liwen
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements. Intelligent Composites Laboratory, Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, USA.
    Wu, Jian
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Matsakas, Leonidas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Chen, Minjiao
    Luleå University of Technology.
    Vahidi, Alireza
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Grahn, Mattias
    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.
    Zhu, Jiahua
    Intelligent Composites Laboratory, Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, USA.
    Shi, Yijun
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Lignin from Hardwood and Softwood Biomass as a Lubricating Additive to Ethylene Glycol2018In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 23, no 3, article id 537Article in journal (Refereed)
    Abstract [en]

    Ethylene glycol (EG)-based lubricant was prepared with dissolved organosolv lignin from birch wood (BL) and softwood (SL) biomass. The effects of different lignin types on the rheological, thermal, and tribological properties of the lignin/EG lubricants were comprehensively investigated by various characterization techniques. Dissolving organosolv lignin in EG results in outstanding lubricating properties. Specifically, the wear volume of the disc by EG-44BL is only 8.9% of that lubricated by pure EG. The enhanced anti-wear property of the EG/lignin system could be attributed to the formation of a robust lubrication film and the strong adhesion of the lubricant on the contacting metal surface due to the presence of a dense hydrogen bonding (H-bonding) network. The lubricating performance of EG-BL outperforms EG-SL, which could be attributed to the denser H-bonding sites in BL and its broader molecular weight distribution. The disc wear loss of EG-44BL is only 45.7% of that lubricated by EG-44SL. Overall, H-bonding is the major contributor to the different tribological properties of BL and SL in EG-based lubricants.

  • 15.
    Najjarzadeh, Nasim
    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.
    Effect of Oligosaccharide Degree of Polymerization on the Induction of Xylan-Degrading Enzymes by Fusarium oxysporum f. sp. Lycopersici2020In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 25, no 24, article id 5849Article in journal (Refereed)
    Abstract [en]

    Xylan is one of the most abundant carbohydrates on Earth. Complete degradation of xylan is achieved by the collaborative action of endo-β-1,4-xylanases and β-d-xylosidases and a number of accessories enzymes. In filamentous fungi, the xylanolytic system is controlled through induction and repression. However, the exact mechanism remains unclear. Substrates containing xylan promote the induction of xylanases, which release xylooligosaccharides. These, in turn, induce expression of xylanase-encoding genes. Here, we aimed to determine which xylan degradation products acted as inducers, and whether the size of the released oligomer correlated with its induction strength. To this end, we compared xylanase production by different inducers, such as sophorose, lactose, cellooligosaccharides, and xylooligosaccharides in Fusarium oxysporum f. sp. lycopersici. Results indicate that xylooligosaccharides are more effective than other substrates at inducing endoxylanase and β-xylosidases. Moreover, we report a correlation between the degree of xylooligosaccharide polymerization and induction efficiency of each enzyme. Specifically, xylotetraose is the best inducer of endoxylanase, xylohexaose of extracellular β-xylosidase, and xylobiose of cell-bound β-xylosidase.

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  • 16.
    Narang, Kritika
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Akhtar, Farid
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Freeze Granulated Zeolites X and A for Biogas Upgrading2020In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 25, no 6, article id 1378Article in journal (Refereed)
    Abstract [en]

    Biogas is a potential renewable energy resource that can reduce the current energy dependency on fossil fuels. The major limitation of utilizing biogas fully in the various applications is the presence of a significant volume fraction of carbon dioxide in biogas. Here, we used adsorption-driven CO2 separation using the most prominent adsorbents, NaX (faujasite) and CaA (Linde Type A) zeolites. The NaX and CaA zeolites were structured into hierarchically porous granules using a low-cost freeze granulation technique to achieve better mass transfer kinetics. The freeze granulation processing parameters and the rheological properties of suspensions were optimized to obtain homogenous granules of NaX and CaA zeolites 2–3 mm in diameter with macroporosity of 77.9% and 68.6%, respectively. The NaX and CaA granules kept their individual morphologies, crystallinities with a CO2 uptake of 5.8 mmol/g and 4 mmol/g, respectively. The CO2 separation performance and the kinetic behavior were estimated by breakthrough experiments, where the NaX zeolite showed a 16% higher CO2 uptake rate than CaA granules with a high mass transfer coefficient, 1.3 m/s, compared to commercial granules, suggesting that freeze-granulated zeolites could be used to improve adsorption kinetics and reduce cycle time for biogas upgrading in the adsorption swing technology.

  • 17.
    Nyberg, Erik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Schneidhofer, Christoph
    AC2T Research GmbH, AT-2700 Wiener Neustadt, Austria.
    Pisarova, Lucia
    AC2T Research GmbH, AT-2700 Wiener Neustadt, Austria.
    Dörr, Nicole
    AC2T Research GmbH, AT-2700 Wiener Neustadt, Austria.
    Minami, Ichiro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Ionic Liquids as Performance Ingredients in Space Lubricants2021In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 26, no 4, article id 1013Article in journal (Refereed)
    Abstract [en]

    Low vapor pressure and several other outstanding properties make room-temperature ionic liquids attractive candidates as lubricants for machine elements in space applications. Ensuring sufficient liquid lubricant supply under space conditions is challenging, and consequently, such tribological systems may operate in boundary lubrication conditions. Under such circumstances, effective lubrication requires the formation of adsorbed or chemically reacted boundary films to prevent excessive friction and wear. In this work, we evaluated hydrocarbon-mimicking ionic liquids, designated P-SiSO, as performance ingredients in multiply alkylated cyclopentane (MAC). The tribological properties under vacuum or various atmospheres (air, nitrogen, carbon dioxide) were measured and analyzed. Thermal vacuum outgassing and electric conductivity were meas- ured to evaluate ‘MAC & P-SiSO’ compatibility to the space environment, including the secondary effects of radiation. Heritage space lubricants—MAC and perfluoroalkyl polyethers (PFPE)—were employed as references. The results corroborate the beneficial lubricating performance of incorporating P-SiSO in MAC, under vacuum as well as under various atmospheres, and demonstrates the feasibility for use as a multifunctional additive in hydrocarbon base oils, for use in space exploration applications.

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  • 18.
    Papaspyridi, Lefki-Maria
    et al.
    National Technical University of Athens.
    Aligiannis, Nektarios
    University of Athens.
    Topakas, Evangelos
    National Technical University of Athens.
    Christakopoulos, Paul
    Skaltsounis, Alexandros-Leandros
    University of Athens.
    Fokialakis, Nikolas
    University of Athens.
    Submerged fermentation of the edible mushroom Pleurotus ostreatus in a batch stirred tank bioreactor as a promising alternative for the effective production of bioactive metabolites2012In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 17, no 3, p. 2714-2724Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to investigate the potential of the submerged fermentation procedure in the production of bioactive metabolites of the common edible mushroom Pleurotus ostreatus. The biomass of the mushroom strain was produced by submerged fermentation in a batch stirred tank bioreactor and extracted by solvents of increasing polarity. The dichloromethane and methanol extract were fractioned by different techniques including Adsorption Chromatography and Fast Centrifugal Partition Chromatography (FCPC). The structures of pure compounds were elucidated with 1D/2D NMR-spectroscopic analyses, and chemical correlations combined with GC/MS and LC/MS experiments. Nineteen metabolites (e.g., fatty acids, phenolic metabolites, nucleotides and alkaloids) were isolated. Beyond the production of known metabolites, we report herein the production also of trans-3,4-dihydro-3,4,8-trihydroxynapthalen-1(2H)-one, indolo-3-carboxylic acid, 3-formylpyrrole and 4-hydroxybenzoic acid, that have pharmaceutical interest and are isolated for the first time from Pleurotus strains.This work indicates the great potential of the established bioprocess for the production of P. ostreatus mycelia with enhanced metabolic profile.

  • 19.
    Patel, Alok
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Mikes, Fabio
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Bühler, Saskja
    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.
    Valorization of Brewers’ Spent Grain for the Production of Lipids by Oleaginous Yeast2018In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 23, no 12, article id 3052Article in journal (Refereed)
    Abstract [en]

    Brewers’ spent grain (BSG) accounts for 85% of the total amount of by-products generated by the brewing industries. BSG is a lignocellulosic biomass that is rich in proteins, lipids, minerals, and vitamins. In the present study, BSG was subjected to pretreatment by two different methods (microwave assisted alkaline pretreatment and organosolv) and was evaluated for the liberation of glucose and xylose during enzymatic saccharification trials. The highest amount of glucose (46.45 ± 1.43 g/L) and xylose (25.15 ± 1.36 g/L) were observed after enzymatic saccharification of the organosolv pretreated BSG. The glucose and xylose yield for the microwave assisted alkaline pretreated BSG were 34.86 ± 1.27 g/L and 16.54 ± 2.1 g/L, respectively. The hydrolysates from the organosolv pretreated BSG were used as substrate for the cultivation of the oleaginous yeast Rhodosporidium toruloides, aiming to produce microbial lipids. The yeast synthesized as high as 18.44 ± 0.96 g/L of cell dry weight and 10.41 ± 0.34 g/L lipids (lipid content of 56.45 ± 0.76%) when cultivated on BSG hydrolysate with a C/N ratio of 500. The cell dry weight, total lipid concentration and lipid content were higher compared to the results obtained when grown on synthetic media containing glucose, xylose or mixture of glucose and xylose. To the best of our knowledge, this is the first report using hydrolysates of organosolv pretreated BSG for the growth and lipid production of oleaginous yeast in literature. The lipid profile of this oleaginous yeast showed similar fatty acid contents to vegetable oils, which can result in good biodiesel properties of the produced biodiesel

  • 20.
    Patel, Alok
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Mikes, Fabio
    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 Current Pretreatment Methods Used to Improve Lipid Extraction from Oleaginous Microorganisms2018In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 23, no 7, article id 1562Article in journal (Refereed)
    Abstract [en]

    Microbial oils, obtained from oleaginous microorganisms are an emerging source of commercially valuable chemicals ranging from pharmaceuticals to the petroleum industry. In petroleum biorefineries, the microbial biomass has become a sustainable source of renewable biofuels. Biodiesel is mainly produced from oils obtained from oleaginous microorganisms involving various upstream and downstream processes, such as cultivation, harvesting, lipid extraction, and transesterification. Among them, lipid extraction is a crucial step for the process and it represents an important bottleneck for the commercial scale production of biodiesel. Lipids are synthesized in the cellular compartment of oleaginous microorganisms in the form of lipid droplets, so it is necessary to disrupt the cells prior to lipid extraction in order to improve the extraction yields. Various mechanical, chemical and physicochemical pretreatment methods are employed to disintegrate the cellular membrane of oleaginous microorganisms. The objective of the present review article is to evaluate the various pretreatment methods for efficient lipid extraction from the oleaginous cellular biomass available to date, as well as to discuss their advantages and disadvantages, including their effect on the lipid yield. The discussed mechanical pretreatment methods are oil expeller, bead milling, ultrasonication, microwave, high-speed and high-pressure homogenizer, laser, autoclaving, pulsed electric field, and non-mechanical methods, such as enzymatic treatment, including various emerging cell disruption techniques.

  • 21.
    Patel, Mitul Kumar
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Schwendemann, Daniel
    Institute for Material Engineering and Plastics Processing, University of Applied Sciences Eastern Switzerland, CH-8640 Rapperswil, Switzerland.
    Spigno, Giorgia
    Department for Sustainable Food Process (DiSTAS), Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy.
    Geng, Shiyu
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Berglund, Linn
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Mechanical & Industrial Engineering, University of Toronto, Toronto, ON M5S 3BS, Canada.
    Functional Nanocomposite Films of Poly(Lactic Acid) with Well-Dispersed Chitin Nanocrystals Achieved Using a Dispersing Agent and Liquid-Assisted Extrusion Process2021In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 26, no 15, article id 4557Article in journal (Refereed)
    Abstract [en]

    The development of bio-based nanocomposites is of high scientific and industrial interest, since they offer excellent advantages in creating functional materials. However, dispersion and distribution of the nanomaterials inside the polymer matrix is a key challenge to achieve high-performance functional nanocomposites. In this context, for better dispersion, biobased triethyl citrate (TEC) as a dispersing agent in a liquid-assisted extrusion process was used to prepare the nanocomposites of poly (lactic acid) (PLA) and chitin nanocrystals (ChNCs). The aim was to identify the effect of the TEC content on the dispersion of ChNCs in the PLA matrix and the manufacturing of a functional nanocomposite. The nanocomposite film’s optical properties; microstructure; migration of the additive and nanocomposites’ thermal, mechanical and rheological properties, all influenced by the ChNC dispersion, were studied. The microscopy study confirmed that the dispersion of the ChNCs was improved with the increasing TEC content, and the best dispersion was found in the nanocomposite prepared with 15 wt% TEC. Additionally, the nanocomposite with the highest TEC content (15 wt%) resembled the mechanical properties of commonly used polymers like polyethylene and polypropylene. The addition of ChNCs in PLA-TEC15 enhanced the melt viscosity, as well as melt strength, of the polymer and demonstrated antibacterial activity.

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  • 22.
    Rezvani Ghomi, Erfan
    et al.
    Center for Nanofibers and Nanotechnology, Department of Mechanical Engineering, Faculty of Engineering, National University of Singapore, Singapore 117576, Singapore.
    Khosravi, Fatemeh
    Center for Nanofibers and Nanotechnology, Department of Mechanical Engineering, Faculty of Engineering, National University of Singapore, Singapore 117576, Singapore.
    Mossayebi, Zahra
    Center for Nanofibers and Nanotechnology, Department of Mechanical Engineering, Faculty of Engineering, National University of Singapore, Singapore 117576, Singapore.
    Saedi Ardahaei, Ali
    Department of Polymer Engineering, Faculty of Engineering, Golestan University, P.O. Box 491888369, Gorgan 1575949138, Iran.
    Morshedi Dehaghi, Fatemeh
    Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran 1591634311, Iran.
    Khorasani, Masoud
    Department of Chemistry, Materials and Chemical Engineering “G. Natta”, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, Italy.
    Esmaeely Neisiany, Rasoul
    Department of Materials and Polymer Engineering, Faculty of Engineering, Hakim Sabzevari University, Sabzevar 9617976487, Iran.
    Das, Oisik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Marani, Atiye
    Baspar Sadaf Nab Sepahan, between 23 and 24 Streets, Mahmoodabad Industrial Town, Isfahan 8161199774, Iran.
    Afriyie Mensah, Rhoda
    School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
    Jiang, Lin
    School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
    Xu, Qiang
    School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
    Försth, Michael
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Berto, Filippo
    Department of Mechanical and Industrial Engineering, Norwegian University of Science and Technology NTNU, S.P. Andersens Veg 3, 7031 Trondheim, Norway.
    Ramakrishna, Seeram
    Center for Nanofibers and Nanotechnology, Department of Mechanical Engineering, Faculty of Engineering, National University of Singapore, Singapore 117576, Singapore.
    The Flame Retardancy of Polyethylene Composites: From Fundamental Concepts to Nanocomposites2020In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 25, no 21, article id 5157Article, review/survey (Refereed)
    Abstract [en]

    Polyethylene (PE) is one the most used plastics worldwide for a wide range of applications due to its good mechanical and chemical resistance, low density, cost efficiency, ease of processability, non-reactivity, low toxicity, good electric insulation, and good functionality. However, its high flammability and rapid flame spread pose dangers for certain applications. Therefore, different flame-retardant (FR) additives are incorporated into PE to increase its flame retardancy. In this review article, research papers from the past 10 years on the flame retardancy of PE systems are comprehensively reviewed and classified based on the additive sources. The FR additives are classified in well-known FR families, including phosphorous, melamine, nitrogen, inorganic hydroxides, boron, and silicon. The mechanism of fire retardance in each family is pinpointed. In addition to the efficiency of each FR in increasing the flame retardancy, its impact on the mechanical properties of the PE system is also discussed. Most of the FRs can decrease the heat release rate (HRR) of the PE products and simultaneously maintains the mechanical properties in appropriate ratios. Based on the literature, inorganic hydroxide seems to be used more in PE systems compared to other families. Finally, the role of nanotechnology for more efficient FR-PE systems is discussed and recommendations are given on implementing strategies that could help incorporate flame retardancy in the circular economy model.

  • 23.
    Sain, S.
    et al.
    Swedish Centre for Resource Recovery, University of Borås, Borås, SE‐501 90, Sweden.
    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.
    Oman, T.
    Materials and Production, RISE Research Institutes of Sweden, Öjebyn, SE‐943 33, Sweden.
    Skrifvars, M.
    Swedish Centre for Resource Recovery, University of Borås, Borås, SE‐501 90, Sweden.
    Spruce bark‐extracted lignin and tannin‐based bioresin‐adhesives: Effect of curing temperatures on the thermal properties of the resins2021In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 26, no 12, article id 3523Article in journal (Refereed)
    Abstract [en]

    In this study, formaldehyde‐free bioresin adhesives were synthesised from lignin and tannin, which were obtained from softwood bark. The extraction was done via organosolv treatment and hot water extraction, respectively. A non‐volatile, non‐toxic aldehyde, glyoxal, was used as a substitute for formaldehyde in order to modify the chemical structure of both the lignin and tannin. The glyoxal modification reaction was confirmed by ATR–FTIR spectroscopy. Three different resin formulations were prepared using modified lignin along with the modified tannin. The thermal properties of the modified lignin, tannin, and the bioresins were assessed by DSC and TGA. When the bioresins were cured at a high temperature (200 ℃) by compression moulding, they exhibited higher thermal stability as well as an enhanced degree of cross‐linking compared to the low temperature‐cured bioresins. The thermal properties of the resins were strongly affected by the compositions of the resins as well as the curing temperatures. 

  • 24.
    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 1431-5157, 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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  • 25.
    Sunner, Hampus
    et al.
    Chalmers University of Technology, Department of Chemical and Biological Engineering, Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology.
    Charavgi, Maria-Despoina
    National Technical University of Athens, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens.
    Olsson, Lisbeth
    Technical University of Denmark, Chalmers University of Technology, Department of Chemical and Biological Engineering.
    Topakas, Evangelos
    National Technical University of Athens, School of Chemical Engineering, National Technical University of Athens, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens.
    Christakopoulos, Paul
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Glucuronoyl Esterase Screening and Characterization Assays Utilizing Commercially Available Benzyl Glucuronic Acid Ester2015In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 20, no 10, p. 17807-17Article in journal (Refereed)
    Abstract [en]

    Research on glucuronoyl esterases (GEs) has been hampered by the lack of enzyme assays based on easily obtainable substrates. While benzyl d-glucuronic acid ester (BnGlcA) is a commercially available substrate that can be used for GE assays, several considerations regarding substrate instability, limited solubility and low apparent affinities should be made. In this work we discuss the factors that are important when using BnGlcA for assaying GE activity and show how these can be applied when designing BnGlcA-based GE assays for different applications: a thin-layer chromatography assay for qualitative activity detection, a coupled-enzyme spectrophotometric assay that can be used for high-throughput screening or general activity determinations and a HPLC-based detection method allowing kinetic determinations. The three-level experimental procedure not merely facilitates routine, fast and simple biochemical characterizations but it can also give rise to the discovery of different GEs through an extensive screening of heterologous Genomic and Metagenomic expression libraries.

  • 26.
    Vafiadi, Christina
    et al.
    National Technical University of Athens.
    Topakas, Evangelos
    National Technical University of Athens.
    Bakx, Edwin J.
    Wageningen University.
    Schols, Henk A.
    Wageningen University.
    Christakopoulos, Paul
    Structural characterisation by ESI-MS of feruloylated arabino-oligosaccharides synthesised by chemoenzymatic esterification2007In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 12, no 7, p. 1367-1375Article in journal (Refereed)
    Abstract [en]

    The chemoenzymatic synthesis of feruloylated arabino-oligosaccharides has been achieved, using a feruloyl esterase type C from Sporotrichum thermophile (StFaeC).The structure of the feruloylated products was confirmed by ESI-MSn.

  • 27.
    Zerva, Anastasia
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Antonopoulou, Io
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Enman, Josefine
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Iancu, Laura
    DuPont Industrial Biosciences, Wageningen, The Netherlands.
    Jütten, Peter
    Taros Chemicals GmbH & Co. KG, Dortmund, Germany.
    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.
    Optimization of Transesterification Reactions with CLEA-Immobilized Feruloyl Esterases from Thermothelomyces thermophila and Talaromyces wortmannii2018In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 23, no 9, article id 2403Article in journal (Refereed)
    Abstract [en]

    Feruloyl esterases (FAEs, E.C. 3.1.1.73) are biotechnologically important enzymes with several applications in ferulic acid production from biomass, but also in synthesis of hydroxycinnamic acid derivatives. The use of such biocatalysts in commercial processes can become feasible by their immobilization, providing the advantages of isolation and recycling. In this work, eight feruloyl esterases, immobilized in cross-linked enzyme aggregates (CLEAs) were tested in regard to their transesterification performance, towards the production of prenyl ferulate (PFA) and arabinose ferulate (AFA). After solvent screening, comparison with the activity of respective soluble enzymes, and operational stability tests, FAE125 was selected as the most promising biocatalyst. A central composite design revealed the optimum conditions for each transesterification product, in terms of water content, time, and substrate ratio for both products, and temperature and enzyme load additionally for prenyl ferulate. The optimum product yields obtained were 83.7% for PFA and 58.1% for AFA. FAE125 CLEAs are stable in the optimum conditions of transesterification reactions, maintaining 70% residual activity after five consecutive reactions. Overall, FAE125 CLEAs seem to be able to perform as a robust biocatalyst, offering satisfactory yields and stability, and thus showing significant potential for industrial applications.

  • 28.
    Zerva, Anastasia
    et al.
    Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens.
    Manos, Nikolaos
    Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens.
    Vouyiouka, Stamatina
    National Technical University of Athens, Laboratory of Polymer Technology, School of Chemical Engineering, National Technical University of Athens.
    Christakopoulos, Paul
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Topakas, Evangelos
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Bioconversion of Biomass-Derived Phenols Catalyzed by Myceliophthora thermophila Laccase2016In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 21, no 5, article id 550Article in journal (Refereed)
    Abstract [en]

    Biomass-derived phenols have recently arisen as an attractive alternative for building blocks to be used in synthetic applications, due to their widespread availability as an abundant renewable resource. In the present paper, commercial laccase from the thermophilic fungus Myceliophthora thermophila was used to bioconvert phenol monomers, namely catechol, pyrogallol and gallic acid in water. The resulting products from catechol and gallic acid were polymers that were partially characterized in respect to their optical and thermal properties, and their average molecular weight was estimated via solution viscosity measurements and GPC. FT-IR and 1H-NMR data suggest that phenol monomers are connected with ether or C–C bonds depending on the starting monomer, while the achieved molecular weight of polycatechol is found higher than the corresponding poly(gallic acid). On the other hand, under the same condition, pyrogallol was dimerized in a pure red crystalline compound and its structure was confirmed by 1H-NMR as purpurogallin. The herein studied green synthesis of enzymatically synthesized phenol polymers or biological active compounds could be exploited as an alternative synthetic route targeting a variety of applications.

  • 29.
    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 1431-5157, 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.

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