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Vörös, Dimitrij
Publications (3 of 3) Show all publications
Matsakas, L., Giannakou, M. & Vörös, D. (2017). Effect of synthetic and natural media on lipid production from Fusarium oxysporum. Electronic Journal of Biotechnology, 30, 95-102
Open this publication in new window or tab >>Effect of synthetic and natural media on lipid production from Fusarium oxysporum
2017 (English)In: Electronic Journal of Biotechnology, ISSN 0717-3458, E-ISSN 0717-3458, Vol. 30, p. 95-102Article in journal (Refereed) Published
Abstract [en]

Background

Dependence on fossil resources, for the production of fuels and energy, has resulted in environmental and financial problems, which require our immediate action in order to reverse the situation. Use of renewable sources for the production of fuels and energy is an important alternative with biodiesel remains as one of the promising options. Aim of this work is to evaluate the fungus Fusarium oxysporum for its potentials to accumulate microbial lipids when grown on synthetic media and saccharified sweet sorghum stalks.

Results

The effect of different carbon sources, nitrogen sources and C/N ratio on the lipid production was initially examined, which resulted in a lipid concentration of 4.4 g/L, with lipid content of 42.6% w/w. Sweet sorghum stalks were able to support growth and lipid production of the fungus, both as carbon source and as nitrogen source. It was also shown that saccharification of the dried stalks is an important step to increase lipid production. Removal of the remaining stalk solids enabled the lipid production during cultivation in increased initial solids of up to 16 w/w. This resulted in a lipid production of 3.81 g/L.

Conclusions

It was demonstrated that F. oxysporum can be used as an efficient oleaginous microorganism, with sweet sorghum serving as an excellent raw material for the cultivation of the fungus. The lipids obtained during this work were also found to have a fatty acid profile with good potentials to be used for biodiesel production.

Place, publisher, year, edition, pages
Elsevier, 2017
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-66028 (URN)10.1016/j.ejbt.2017.10.003 (DOI)000416721500016 ()2-s2.0-85034096464 (Scopus ID)
Note

Validerad;2017;Nivå 2;2017-12-05 (rokbeg)

Available from: 2017-10-10 Created: 2017-10-10 Last updated: 2017-12-14Bibliographically approved
Matsakas, L., Nitsos, C., Vörös, D., Rova, U. & Christakopoulos, P. (2017). High-Titer Methane from Organosolv-Pretreated Spruce and Birch. Energies, 10(3), Article ID 263.
Open this publication in new window or tab >>High-Titer Methane from Organosolv-Pretreated Spruce and Birch
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2017 (English)In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 10, no 3, article id 263Article in journal (Refereed) Published
Abstract [en]

The negative impact of fossil fuels and the increased demand for renewable energy sources has led to the use of novel raw material sources. Lignocellulosic biomass could serve as a possible raw material for anaerobic digestion and production of biogas. This work is aimed at using forest biomass, both softwood (spruce) and hardwood (birch), as a raw material for anaerobic digestion. We examined the effect of different operational conditions for the organosolv pretreatment (ethanol content, duration of treatment, and addition of acid catalyst) on the methane yield. In addition, we investigated the effect of addition of cellulolytic enzymes during the digestion. We found that inclusion of an acid catalyst during organosolv pretreatment improved the yields from spruce, but it did not affect the yields from birch. Shorter duration of treatment was advantageous with both materials. Methane yields from spruce were higher with lower ethanol content whereas higher ethanol content was more beneficial for birch. The highest yields obtained were 185 mL CH4/g VS from spruce and 259.9 mL CH4/g VS from birch. Addition of cellulolytic enzymes improved these yields to 266.6 mL CH4/g VS and 284.2 mL CH4/g VS, respectively.

Place, publisher, year, edition, pages
MDPI, 2017
Keywords
biogas, methane, lignocellulosic biomass, organosolv pretreatment, anaerobic digestion, birch, spruce
National Category
Bioenergy Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-62838 (URN)10.3390/en10030263 (DOI)000398736700003 ()2-s2.0-85017581416 (Scopus ID)
Funder
Bio4Energy
Note

Validerad; 2017; Nivå 2; 2017-04-03 (andbra)

Available from: 2017-04-01 Created: 2017-04-01 Last updated: 2019-09-12Bibliographically approved
Nitsos, C., Stoklosa, R. J., Karnaouri, A. C., Vörös, D., Lange, H., Hodge, D., . . . Christakopoulos, P. (2016). Isolation and Characterization of Organosolv and Alkaline Lignins from Hardwood and Softwood Biomass. ACS Sustainable Chemistry and Engineering, 4(10), 5181-5193
Open this publication in new window or tab >>Isolation and Characterization of Organosolv and Alkaline Lignins from Hardwood and Softwood Biomass
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2016 (English)In: ACS Sustainable Chemistry and Engineering, ISSN 2168-0485, Vol. 4, no 10, p. 5181-5193Article in journal (Refereed) Published
Abstract [en]

Isolation of lignins from hardwood and softwood biomass samples, containing 26.1% and 28.1% lignin, respectively, has been performed with the use of alkaline and organosolv pretreatment methods. The effect of catalyst loading, ethanol content, particle size, and pretreatment time on the yields and properties of the isolated lignins were investigated. Alkaline lignins had higher carbohydrate content - up to 30% - and exhibited higher molecular weights in the range of 3000 Da, with a maximum phenolic hydroxyl content of 1 mmol g-1 for birch and 2 mmol g-1 for spruce. Organosolv lignins, on the other hand, showed high purity - 93% or higher - despite the more extensive biomass dissolution into the pretreatment medium; they also exhibited a lower range of molecular weights between 600 and 1600 Da depending on the source and pretreatment conditions. Due to the lower molecular weight, phenolic hydroxyl content was also increased, reaching as high as 4 mmol g-1 with a simultaneous decrease in aliphatic hydroxyl content as low as 0.6 mmol g-1. Efficient lignin dissolution of 62% for spruce and 69% for birch, achieved at optimal pretreatment conditions, was combined with extensive hemicellulose removal

National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-60086 (URN)10.1021/acssuschemeng.6b01205 (DOI)000384791500009 ()2-s2.0-84989952894 (Scopus ID)
Note

Validerad; 2016; Nivå 2; 2016-11-01 (andbra)

Available from: 2016-11-02 Created: 2016-11-01 Last updated: 2018-07-10Bibliographically approved
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