Engineering of the glycerol decomposition pathway and cofactor regulation in an industrial yeast improves ethanol production

Glycerol is a major by-product of industrial ethanol production and its formation consumes up to 4 % of the sugar substrate. This study modified the glycerol decomposition pathway of an industrial strain of Saccharomyces cerevisiae to optimize the consumption of substrate and yield of ethanol. This study is the first to couple glycerol degradation with ethanol formation, to the best of our knowledge. The recombinant strain overexpressing GCY1 and DAK1, encoding glycerol dehydrogenase and dihydroxyacetone kinase, respectively, in glycerol degradation pathway, exhibited a moderate increase in ethanol yield (2.9 %) and decrease in glycerol yield (24.9 %) compared to the wild type with the initial glucose concentration of 15 % under anaerobic conditions. However, when the mhpF gene, encoding acetylating NAD(+)-dependent acetaldehyde dehydrogenase from Escherichia coli, was co-expressed in the aforementioned recombinant strain, a further increase in ethanol yield by 5.5 % and decrease in glycerol yield by 48 % were observed for the resultant recombinant strain GDMS1 when acetic acid was added into the medium prior to inoculation compared to the wild type. The process outlined in this study which enhances glycerol consumption and cofactor regulation in an industrial yeast is a promising metabolic engineering strategy to increase ethanol production by reducing the formation of glycerol.

NATURVETENSKAP Biologi Biokemi och molekylärbiologi hsv//swe
NATURAL SCIENCES Biological Sciences Biochemistry and Molecular Biology hsv//eng
saccharomyces-cerevisiae
glucose
Ethanol production
metabolism
nadh kinase
cultures
Cofactor NADH
Glycerol
Industrial yeast
Recombinant strain

Tang, Y.Jiangnan University (author)
Guo, Zhongpeng,1983Chalmers tekniska högskola,Chalmers University of Technology(Swepub:cth)guoz (author)
Shi, G. Y.Jiangnan University (author)
Jiangnan UniversityChalmers tekniska högskola (creator_code:org_t)

In:Journal of Industrial Microbiology and Biotechnology: Oxford University Press (OUP)40:10, s. 1153-11601367-54351476-5535

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NATURAL SCIENCES: NATURAL SCIENCES; and Biological Scien ...; and Biochemistry and ...

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