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Patel, A., Matsakas, L., Rova, U. & Christakopoulos, P. (2019). A perspective on biotechnological applications of thermophilic microalgae and cyanobacteria. Bioresource Technology, 278, 424-434
Open this publication in new window or tab >>A perspective on biotechnological applications of thermophilic microalgae and cyanobacteria
2019 (English)In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 278, p. 424-434Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Thermophilic microorganisms, Microalgae, Cyanobacteria, Biotechnological applications, Biofuels, Biologically active compounds, Pigments
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-73043 (URN)10.1016/j.biortech.2019.01.063 (DOI)000457852400049 ()30685131 (PubMedID)2-s2.0-85060269950 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-02-27 (johcin)

Available from: 2019-02-27 Created: 2019-02-27 Last updated: 2019-02-27Bibliographically approved
Kalogiannis, K. G., Matsakas, L., Lappas, A. A., Rova, U. & Christakopoulos, P. (2019). Aromatics from Beechwood Organosolv Lignin through Thermal and Catalytic Pyrolysis. Energies, 12(9), Article ID 1606.
Open this publication in new window or tab >>Aromatics from Beechwood Organosolv Lignin through Thermal and Catalytic Pyrolysis
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2019 (English)In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 12, no 9, article id 1606Article in journal (Refereed) Published
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

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
beechwood, organosolv delignification, lignin pyrolysis, ZSM-5, phenols, aromatic hydrocarbons
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-74900 (URN)10.3390/en12091606 (DOI)000469761700022 ()2-s2.0-85066273519 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-06-24 (johcin)

Available from: 2019-06-24 Created: 2019-06-24 Last updated: 2019-06-24Bibliographically approved
Patel, A., Matsakas, L., Hruzova, K., Rova, U. & Christakopoulos, P. (2019). Biosynthesis of Nutraceutical Fatty Acids by the Oleaginous Marine Microalgae Phaeodactylum tricornutum Utilizing Hydrolysates from Organosolv-Pretreated Birch and Spruce Biomass. Marine Drugs, 17(12), Article ID 119.
Open this publication in new window or tab >>Biosynthesis of Nutraceutical Fatty Acids by the Oleaginous Marine Microalgae Phaeodactylum tricornutum Utilizing Hydrolysates from Organosolv-Pretreated Birch and Spruce Biomass
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2019 (English)In: Marine Drugs, ISSN 1660-3397, E-ISSN 1660-3397, Vol. 17, no 12, article id 119Article in journal (Refereed) Published
Abstract [en]

Polyunsaturated fatty acids (PUFAs) are essential for human function, however they have to be provided through the diet. As their production from fish oil is environmentally unsustainable, there is demand for new sources of PUFAs. The aim of the present work was to establish the microalgal platform to produce nutraceutical-value PUFAs from forest biomass. To this end, the growth of Phaeodactylum tricornutum on birch and spruce hydrolysates was compared to autotrophic cultivation and glucose synthetic media. Total lipid generated by P. tricornutum grown mixotrophically on glucose, birch, and spruce hydrolysates was 1.21, 1.26, and 1.29 g/L, respectively. The highest eicosapentaenoic acid (EPA) production (256 mg/L) and productivity (19.69 mg/L/d) were observed on spruce hydrolysates. These values were considerably higher than those obtained from the cultivation without glucose (79.80 mg/L and 6.14 mg/L/d, respectively) and also from the photoautotrophic cultivation (26.86 mg/L and 2.44 mg/L/d, respectively). To the best of our knowledge, this is the first report describing the use of forest biomass as raw material for EPA and docosapentaenoic acid (DHA) production.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
polyunsaturated fatty acids, EPA, DHA, marine algae, Phaeodactylum tricornutum, forest biomass
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-73136 (URN)10.3390/md17020119 (DOI)000460795500047 ()30781416 (PubMedID)2-s2.0-85061857091 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-03-07 (johcin)

Available from: 2019-03-07 Created: 2019-03-07 Last updated: 2019-04-24Bibliographically approved
Charisteidis, I., Lazaridis, P., Fotopoulos, A., Pachatouridou, E., Matsakas, L., Rova, U., . . . Triantafyllidis, K. (2019). Catalytic Fast Pyrolysis of Lignin Isolated by Hybrid Organosolv—Steam Explosion Pretreatment of Hardwood and Softwood Biomass for the Production of Phenolics and Aromatics. Catalysts, 9(11), Article ID 935.
Open this publication in new window or tab >>Catalytic Fast Pyrolysis of Lignin Isolated by Hybrid Organosolv—Steam Explosion Pretreatment of Hardwood and Softwood Biomass for the Production of Phenolics and Aromatics
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2019 (English)In: Catalysts, E-ISSN 2073-4344, Vol. 9, no 11, article id 935Article in journal (Refereed) Published
Abstract [en]

Lignin, one of the three main structural biopolymers of lignocellulosic biomass, is the most abundant natural source of aromatics with a great valorization potential towards the production of fuels, chemicals, and polymers. Although kraft lignin and lignosulphonates, as byproducts of the pulp/paper industry, are available in vast amounts, other types of lignins, such as the organosolv or the hydrolysis lignin, are becoming increasingly important, as they are side-streams of new biorefinery processes aiming at the (bio)catalytic valorization of biomass sugars. Within this context, in this work, we studied the thermal (non-catalytic) and catalytic fast pyrolysis of softwood (spruce) and hardwood (birch) lignins, isolated by a hybrid organosolv–steam explosion biomass pretreatment method in order to investigate the effect of lignin origin/composition on product yields and lignin bio-oil composition. The catalysts studied were conventional microporous ZSM-5 (Zeolite Socony Mobil–5) zeolites and hierarchical ZSM-5 zeolites with intracrystal mesopores (i.e., 9 and 45 nm) or nano-sized ZSM-5 with a high external surface. All ZSM-5 zeolites were active in converting the initially produced via thermal pyrolysis alkoxy-phenols (i.e., of guaiacyl and syringyl/guaiacyl type for spruce and birch lignin, respectively) towards BTX (benzene, toluene, xylene) aromatics, alkyl-phenols and polycyclic aromatic hydrocarbons (PAHs, mainly naphthalenes), with the mesoporous ZSM-5 exhibiting higher dealkoxylation reactivity and being significantly more selective towards mono-aromatics compared to the conventional ZSM-5, for both spruce and birch lignin.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
spruce and birch wood lignin, hybrid organosolv—steam explosion pretreatment, catalytic fast pyrolysis, model compounds, bio-oil, phenolics and aromatics, microporous and hierarchical ZSM-5 zeolite
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-76789 (URN)10.3390/catal9110935 (DOI)2-s2.0-85074766498 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-11-20 (johcin)

Available from: 2019-11-20 Created: 2019-11-20 Last updated: 2019-11-20Bibliographically approved
Cerullo, G., Varriale, S., Bozonnet, S., Antonopoulou, I., Christakopoulos, P., Rova, U., . . . Faraco, V. (2019). Directed evolution of the type C feruloyl esterase from Fusarium oxysporum FoFaeC and molecular docking analysis of its improved variants. New Biotechnology, 51, 14-20
Open this publication in new window or tab >>Directed evolution of the type C feruloyl esterase from Fusarium oxysporum FoFaeC and molecular docking analysis of its improved variants
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2019 (English)In: New Biotechnology, ISSN 1871-6784, E-ISSN 1876-4347, Vol. 51, p. 14-20Article in journal (Refereed) Published
Abstract [en]

The need to develop competitive and eco-friendly processes in the cosmetic industry leads to the search for new enzymes with improved properties for industrial bioconversions in this sector. In the present study, a complete methodology to generate, express and screen diversity for the type C feruloyl esterase from Fusarium oxysporium FoFaeC was set up in a high-throughput fashion. A library of around 30,000 random mutants of FoFaeC was generated by error prone PCR of fofaec cDNA and expressed in Yarrowia lipolytica. Screening for enzymatic activity towards the substrates 5-bromo-4-chloroindol-3-yl and 4-nitrocatechol-1-yl ferulates allowed the selection of 96 enzyme variants endowed with improved enzymatic activity that were then characterized for thermo- and solvent- tolerance. The five best mutants in terms of higher activity, thermo- and solvent- tolerance were selected for analysis of substrate specificity. Variant L432I was shown to be able to hydrolyze all the tested substrates, except methyl sinapate, with higher activity than wild type FoFaeC towards methyl p-coumarate, methyl ferulate and methyl caffeate. Moreover, the E455D variant was found to maintain completely its hydrolytic activity after two hour incubation at 55 °C, whereas the L284Q/V405I variant showed both higher thermo- and solvent- tolerance than wild type FoFaeC. Small molecule docking simulations were applied to the five novel selected variants in order to examine the binding pattern of substrates used for enzyme characterization of wild type FoFaeC and the evolved variants.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Directed evolution, Feruloyl esterase, Fusarium oxysporum, High-throughput screening, Library
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-72926 (URN)10.1016/j.nbt.2019.01.008 (DOI)000461362500003 ()2-s2.0-85061183564 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-02-18 (svasva)

Available from: 2019-02-18 Created: 2019-02-18 Last updated: 2019-04-12Bibliographically approved
Matsakas, L., Raghavendran, V., Yakimenko, O., Persson, G., Olsson, E., Rova, U., . . . Christakopoulos, P. (2019). Lignin-first biomass fractionation using a hybrid organosolv: Steam explosion pretreatment technology improves the saccharification and fermentability of spruce biomass. Bioresource Technology, 273, 521-528
Open this publication in new window or tab >>Lignin-first biomass fractionation using a hybrid organosolv: Steam explosion pretreatment technology improves the saccharification and fermentability of spruce biomass
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2019 (English)In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 273, p. 521-528Article in journal (Refereed) Published
Abstract [en]

For a transition to a sustainable society, fuels, chemicals, and materials should be produced from renewable resources. Lignocellulosic biomass constitutes an abundant and renewable feedstock; however, its successful application in a biorefinery requires efficient fractionation into its components; cellulose, hemicellulose and lignin. Here, we demonstrate that a newly established hybrid organosolv – steam explosion pretreatment can effectively fractionate spruce biomass to yield pretreated solids with high cellulose (72% w/w) and low lignin (delignification up to 79.4% w/w) content. The cellulose-rich pretreated solids present high saccharification yields (up to 61% w/w) making them ideal for subsequent bioconversion processes. Moreover, under high-gravity conditions (22% w/w) we obtained an ethanol titer of 61.7 g/L, the highest so far reported for spruce biomass. Finally, the obtained high-purity lignin is suitable for various advanced applications. In conclusion, hybrid organosolv pretreatment could offer a closed-loop biorefinery while simultaneously adding value to all biomass components.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Softwood, Organosolv explosion, High gravity fermentation, Fractionation, Biorefinery
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-71766 (URN)10.1016/j.biortech.2018.11.055 (DOI)000453742100064 ()30471644 (PubMedID)2-s2.0-85056772752 (Scopus ID)
Funder
Swedish Energy Agency, 2015-006989
Note

Validerad;2018;Nivå 2;2018-11-27 (johcin)

Available from: 2018-11-27 Created: 2018-11-27 Last updated: 2019-03-27Bibliographically approved
Patel, A., Antonopoulou, I., Enman, J., Rova, U., Christakopoulos, P. & Matsakas, L. (2019). Lipids detection and quantification in oleaginous microorganisms: an overview of the current state of the art. BMC Chemical Engineering, 1, Article ID 13.
Open this publication in new window or tab >>Lipids detection and quantification in oleaginous microorganisms: an overview of the current state of the art
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2019 (English)In: BMC Chemical Engineering, ISSN 2524-4175, Vol. 1, article id 13Article in journal (Refereed) Published
Abstract [en]

Oleaginous microorganisms are among the most promising feedstocks for the production of lipids for biofuels and oleochemicals. Lipids are synthesized in intracellular compartments in the form of lipid droplets. Therefore, their qualitative and quantitative analysis requires an initial pretreatment step that allows their extraction. Lipid extraction techniques vary with the type of microorganism but, in general, the presence of an outer membrane or cell wall limits their recovery. This review discusses the various types of oleaginous microorganisms, their lipid accumulating capabilities, lipid extraction techniques, and the pretreatment of cellular biomass for enhanced lipid recovery. Conventional methods for lipid quantification include gravimetric and chromatographic approaches; whereas non-conventional methods are based on infrared, Raman, nuclear magnetic resonance, and fluorescence spectroscopic analysis. Recent advances in these methods, their limitations, and fields of application are discussed, with the aim of providing a guide for selecting the best method or combination of methods for lipid quantification.

Place, publisher, year, edition, pages
BioMed Central, 2019
Keywords
Oleaginous microorganisms, Microbial lipids, Lipid extraction, Lipid quantification, Conventional methods, High-throughput analysis
National Category
Chemical Process Engineering Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-75376 (URN)10.1186/s42480-019-0013-9 (DOI)
Available from: 2019-07-30 Created: 2019-07-30 Last updated: 2019-08-14Bibliographically approved
Lage, S., Kudahettige, N. P., Ferro, L., Matsakas, L., Funk, C., Rova, U. & Gentili, F. G. (2019). Microalgae Cultivation for the Biotransformation of Birch Wood Hydrolysate and Dairy Effluent. Catalysts, 9(2), Article ID 150.
Open this publication in new window or tab >>Microalgae Cultivation for the Biotransformation of Birch Wood Hydrolysate and Dairy Effluent
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2019 (English)In: Catalysts, ISSN 2073-4344, Vol. 9, no 2, article id 150Article in journal (Refereed) Published
Abstract [en]

In order to investigate environmentally sustainable sources of organic carbon and nutrients, four Nordic green microalgal strains, Chlorella sorokiniana, Chlorella saccharophila, Chlorella vulgaris, and Coelastrella sp., were grown on a wood (Silver birch, Betula pendula) hydrolysate and dairy effluent mixture. The biomass and lipid production were analysed under mixotrophic, as well as two-stage mixotrophic/heterotrophic regimes. Of all of the species, Coelastrella sp. produced the most total lipids per dry weight (~40%) in the mixture of birch hydrolysate and dairy effluent without requiring nutrient (nitrogen, phosphorus, and potassium-NPK) supplementation. Overall, in the absence of NPK, the two-stage mixotrophic/heterotrophic cultivation enhanced the lipid concentration, but reduced the amount of biomass. Culturing microalgae in integrated waste streams under mixotrophic growth regimes is a promising approach for sustainable biofuel production, especially in regions with large seasonal variation in daylight, like northern Sweden. To the best of our knowledge, this is the first report of using a mixture of wood hydrolysate and dairy effluent for the growth and lipid production of microalgae in the literature.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
Birch hydrolysate, Chlorella, Coelastrella, Dairy wastewater, Fatty acid methyl esters, Green algae, Heterotrophic, Lipids, Mixotrophic
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-73233 (URN)10.3390/catal9020150 (DOI)000460702200044 ()2-s2.0-85062564536 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-03-18 (svasva)

Available from: 2019-03-18 Created: 2019-03-18 Last updated: 2019-04-12Bibliographically approved
Krige, A., Sjöblom, M., Ramser, K., Christakopoulos, P. & Rova, U. (2019). On-line Raman spectroscopic study of cytochromes’ redox state of biofilms in microbial fuel cells. Molecules, 24(3), Article ID 646.
Open this publication in new window or tab >>On-line Raman spectroscopic study of cytochromes’ redox state of biofilms in microbial fuel cells
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2019 (English)In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 24, no 3, article id 646Article in journal (Refereed) Published
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. 

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
Cytochrome-C, Geobacter sulfurreducens, Microbial fuel cell, Omc, Raman spectroscopy
National Category
Bioprocess Technology Applied Mechanics
Research subject
Biochemical Process Engineering; Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-73003 (URN)10.3390/molecules24030646 (DOI)000458934000270 ()30759821 (PubMedID)2-s2.0-85061525740 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-02-26 (svasva)

Available from: 2019-02-26 Created: 2019-02-26 Last updated: 2019-05-14Bibliographically approved
Antonopoulou, I., Iancu, L., Jütten, P., Piechot, A., Rova, U. & Christakopoulos, P. (2019). Screening of novel feruloyl esterases from Talaromyces wortmannii for the development of efficient and sustainable syntheses of feruloyl derivatives. Enzyme and microbial technology, 120, 124-135
Open this publication in new window or tab >>Screening of novel feruloyl esterases from Talaromyces wortmannii for the development of efficient and sustainable syntheses of feruloyl derivatives
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2019 (English)In: Enzyme and microbial technology, ISSN 0141-0229, E-ISSN 1879-0909, Vol. 120, p. 124-135Article in journal (Refereed) Published
Abstract [en]

The feruloyl esterases Fae125, Fae7262 and Fae68 from Talaromyces wortmannii were screened in 10 different solvent: buffer systems in terms of residual hydrolytic activity and of the ability for the transesterification of vinyl ferulate with prenol or L-arabinose. Among the tested enzymes, the acetyl xylan-related Fae125 belonging to the phylogenetic subfamily 5 showed highest yield and selectivity for both products in alkane: buffer systems (n-hexane or n-octane). Response surface methodology, based on a 5-level and 6-factor central composite design, revealed that the substrate molar ratio and the water content were the most significant variables for the bioconversion yield and selectivity. The effect of agitation, the possibility of DMSO addition and the increase of donor concentration were investigated. After optimization, competitive transesterification yields were obtained for prenyl ferulate (87.5-92.6%) and L-arabinose ferulate (56.2-61.7%) at reduced reaction times (≤ 24 h) resulting in good productivities (> 1 g/L/h, >300 kg product/kg FAE). The enzyme could be recycled for six consecutive cycles retaining 66.6% of the synthetic activity and 100% of the selectivity.

Place, publisher, year, edition, pages
Elsevier, 2019
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-70723 (URN)10.1016/j.enzmictec.2018.08.007 (DOI)000452576500016 ()30396393 (PubMedID)2-s2.0-85053620494 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-11-08 (johcin)

Available from: 2018-09-03 Created: 2018-09-03 Last updated: 2019-02-01Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0001-7500-2367

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