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Antonopoulou, I., Spanopoulos, A. & Matsakas, L. (2020). Single cell oil and ethanol production by the oleaginous yeast Trichosporon fermentans utilizing dried sweet sorghum stalks. Renewable energy, 146, 1609-1617
Open this publication in new window or tab >>Single cell oil and ethanol production by the oleaginous yeast Trichosporon fermentans utilizing dried sweet sorghum stalks
2020 (English)In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 146, p. 1609-1617Article in journal (Refereed) Published
Abstract [en]

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

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Trichosporon fermentans CBS 439.83, Crabtree effect, Ethanol, Sweet sorghum, Enzymatic saccharification, Microbial lipids
National Category
Chemical Engineering Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-75377 (URN)10.1016/j.renene.2019.07.107 (DOI)
Note

Validerad;2019;Nivå 2;2019-08-14 (johcin)

Available from: 2019-07-30 Created: 2019-07-30 Last updated: 2019-08-14Bibliographically approved
Patel, A. & Matsakas, L. (2019). A comparative study on de novo and ex novo lipid fermentation by oleaginous yeast using glucose and sonicated waste cooking oil. Ultrasonics sonochemistry, 52, 364-374
Open this publication in new window or tab >>A comparative study on de novo and ex novo lipid fermentation by oleaginous yeast using glucose and sonicated waste cooking oil
2019 (English)In: Ultrasonics sonochemistry, ISSN 1350-4177, E-ISSN 1873-2828, Vol. 52, p. 364-374Article in journal (Refereed) Published
Abstract [en]

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

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Oleaginous yeast, Sonicated waste cooking oil, De novo lipid accumulation, Ex novo lipid accumulation, LipidsFatty acid methyl esters
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-72671 (URN)10.1016/j.ultsonch.2018.12.010 (DOI)000467509200041 ()2-s2.0-85058415972 (Scopus ID)
Note

Validerad;Nivå 2;2019-05-27 (oliekm)

Available from: 2019-01-24 Created: 2019-01-24 Last updated: 2019-06-05Bibliographically approved
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
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
Mu, L., Wu, J., Matsakas, L., Chen, M., Rova, U., Christakopoulos, P., . . . Shi, Y. (2019). Two important factors of selecting lignin as efficient lubricating additives in poly (ethylene glycol): Hydrogen bond and molecular weight. International Journal of Biological Macromolecules, 129, 564-570
Open this publication in new window or tab >>Two important factors of selecting lignin as efficient lubricating additives in poly (ethylene glycol): Hydrogen bond and molecular weight
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2019 (English)In: International Journal of Biological Macromolecules, ISSN 0141-8130, E-ISSN 1879-0003, Vol. 129, p. 564-570Article in journal (Refereed) Published
Abstract [en]

Lignin, one of the most abundant natural polymers, has been successfully used as an effective lubricant additive with high value. The chemical structure of lignin is very diverse and strongly affected by both the source of lignin (i.e. plant species) and the lignin extraction process. In this work, a series of lignin from different biomass sources (hard or soft wood) and extraction process (organosolv with or without acid catalyst) has been successfully incorporated into poly(ethylene glycol) (PEG) and fortified lubricating properties were achieved. The effects of different lignin on the rheological, thermal and tribological properties of the lignin/EG lubricants were systematically investigated by different characterization techniques. Lignin in PEG significantly improves the lubricating property, where a wear reduction of 93.8% was observed. The thermal and lubrication properties of the PEG lubricants filled with different kinds of lignin are tightly related to the synergistic state of hydrogen bonding and molecular weight distribution. Lignin with broader molecular weight distribution and higher hydroxyl content shows better adhesion on metal surfaces and strengthened lubricating film, which could be used as the efficient lubricating additives. This work provides a criterion for selecting appropriate lignin as the efficient lubricant additive and accelerates the application of lignin.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Lignin, Lubrication, Poly (ethylene glycol), Hydrogen bonding, Molecular weight
National Category
Bioprocess Technology Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements; Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-72899 (URN)10.1016/j.ijbiomac.2019.01.175 (DOI)000466621200058 ()2-s2.0-85061540788 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-02-20 (svasva)

Available from: 2019-02-14 Created: 2019-02-14 Last updated: 2019-06-18Bibliographically approved
Patel, A., Sartaj, K., Pruthi, P., Pruthi, V. & Matsakas, L. (2019). Utilization of Clarified Butter Sediment Waste as a Feedstock for Cost-Effective Production of Biodiesel. Foods, 8(7), Article ID 234.
Open this publication in new window or tab >>Utilization of Clarified Butter Sediment Waste as a Feedstock for Cost-Effective Production of Biodiesel
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2019 (English)In: Foods, E-ISSN 2304-8158, Vol. 8, no 7, article id 234Article in journal (Refereed) Published
Abstract [en]

The rising demand and cost of fossil fuels (diesel and gasoline), together with the need for sustainable, alternative, and renewable energy sources have increased the interest for biomass-based fuels such as biodiesel. Among renewable sources of biofuels, biodiesel is particularly attractive as it can be used in conventional diesel engines without any modification. Oleaginous yeasts are excellent oil producers that can grow easily on various types of hydrophilic and hydrophobic waste streams that are used as feedstock for single cell oils and subsequently biodiesel production. In this study, cultivation of Rhodosporidium kratochvilovae on a hydrophobic waste (clarified butter sediment waste medium (CBM)) resulted in considerably high lipid accumulation (70.74% w/w). Maximum cell dry weight and total lipid production were 15.52 g/L and 10.98 g/L, respectively, following cultivation in CBM for 144 h. Neutral lipids were found to accumulate in the lipid bodies of cells, as visualized by BODIPY staining and fluorescence microscopy. Cells grown in CBM showed large and dispersed lipid droplets in the intracellular compartment. The fatty acid profile of biodiesel obtained after transesterification was analyzed by gas chromatography-mass spectrometry (GC–MS), while its quality was determined to comply with ASTM 6751 and EN 14214 international standards. Hence, clarified sediment waste can be exploited as a cost-effective renewable feedstock for biodiesel production. 

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
clarified butter sediment waste, hydrophobic substrates, oleaginous yeast, lipids, biodiesel, fatty acid methyl esters
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-75277 (URN)10.3390/foods8070234 (DOI)31261933 (PubMedID)
Note

Validerad;2019;Nivå 2;2019-07-10 (johcin)

Available from: 2019-07-10 Created: 2019-07-10 Last updated: 2019-07-10Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-3687-6173

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