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Dekkera bruxellensis - a competitive yeast for ethanol production from conventional and non-conventional substrates

Blomqvist, Johanna (2011). Dekkera bruxellensis - a competitive yeast for ethanol production from conventional and non-conventional substrates. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2011:88
ISBN 978-91-576-7632-0
[Doctoral thesis]

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Abstract

In the ethanol industry and research community, Saccharomyces cerevisiae is regarded as the most competitive fermentation yeast and therefore industrial yeast populations are rarely studied. This thesis investigates yeast and lactic acid bacteria (LAB) populations in a Swedish ethanol plant. Interestingly, the yeast population was dominated by Dekkera bruxellensis and not by the inoculated S. cerevisiae. High numbers of lactic acid bacteria (LAB) were also found, with Lactobacillus vini dominating. Since there was no indication of a reduction in productivity, we regarded D. bruxellensis together with L. vini as a production consortium.

In test fermentations, the industrial D. bruxellensis strains had similar or higher ethanol yield than two industrial S. cerevisiae strains. Glycerol yield was lower and biomass yield higher, indicating more energy-efficient metabolism of D. bruxellensis.

To test the ability of our isolates to produce ethanol from lignocellulosic substrate, we cultured D. bruxellensis in aspen sawdust hydrolysate. D. bruxellensis was slightly more sensitive to the hydrolysate than S. cerevisiae in batch culture, but was able to adapt to the inhibitors, achieving an ethanol production comparable to S. cerevisiae.

Five years after the first isolation, the ethanol plant made substantial process changes. Renewed investigations showed that D. bruxellensis and L. vini were still the dominant microbial population.

In continuous competition experiments, D. bruxellensis was only able to outcompete S. cerevisiae during glucose limitation. This suggests that in glucose-limited conditions, D. bruxellensis is more competitive due to its more energy-efficient metabolism, probably together with a higher affinity for glucose uptake in such conditions. Although D. bruxellensis is indeed facultatively anaerobic, it has a higher nutritional demand under anaerobic conditions than S. cerevisiae. This is probably due to a redox imbalance caused by low glycerol production.

The results show that D. bruxellensis is a competitive yeast owing to its energy-efficient metabolism in glucose-limited conditions. It can act as production yeast for ethanol production from both first- and second-generation substrates under conditions of optimal aeration and nutrient supply.

Authors/Creators:Blomqvist, Johanna
Title:Dekkera bruxellensis - a competitive yeast for ethanol production from conventional and non-conventional substrates
Series/Journal:Acta Universitatis agriculturae Sueciae (1652-6880)
Year of publishing :2011
Volume:2011:88
Number of Pages:59
Papers/manuscripts:
NumberReferences
I.Passoth V, Blomqvist J and Schnürer J (2007). Dekkera bruxellensis and Lactobacillus vini form a stable ethanol-producing consortium in a commercial alcohol production process. Appl Environ Microbiol 73, 4354- 4356.
II.Blomqvist J, Eberhard T, Schnürer J and Passoth V (2010). Fermentation characteristics of Dekkera bruxellensis strains. Appl Microbiol Biotechnol 87, 1487-1497.
III.Blomqvist J, South E, Tiukova I, Momeni MH, Hansson H, Ståhlberg J, Horn SH, Schnürer J and Passoth V (2011). Fermentation of lignocellulosic hydrolysates by the alternative industrial ethanol yeast Dekkera bruxellensis. Lett Appl Microbiol 53, 73-78.
IV.Blomqvist J, Nordstedt P and Passoth V. Yeast-yeast and yeast-lactic acid bacteria interactions in industrial ethanol fermentation (manuscript).
V.Blomqvist J, Sànchez-Nogué V, Gorwa-Grauslund M and Passoth V. Physiological requirements for growth and competitiveness of Dekkera bruxellensis under oxygen limited or anaerobic conditions (submitted manuscript).
Place of Publication:Uppsala
Publisher:Dept. of Microbiology, Swedish University of Agricultural Sciences
ISBN for printed version:978-91-576-7632-0
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:X Agricola extesions > X30 Life sciences
Subjects:(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Microbiology (Microbiology in the medical area to be 30109)
(A) Swedish standard research categories 2011 > 2 Engineering and Technology > 209 Industrial Biotechnology > Bioenergy
Agrovoc terms:brewer's yeast, yeasts, saccharomyces cerevisiae, ethanol, alcoholic fermentation, anaerobiosis, lactobacillus, lactic acid bacteria
Keywords:Dekkera bruxellensis, Saccharomyces cerevisiae, fermentation, lignocellulosic hydrolysate, continuous cultivation, competition, anaerobic growth
URN:NBN:urn:nbn:se:slu:epsilon-e-242
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-242
ID Code:8404
Department:(NL, NJ) > Dept. of Microbiology (until 161231)
Deposited By: Johanna Blomqvist
Deposited On:01 Nov 2011 09:03
Metadata Last Modified:02 Dec 2014 10:47

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