Elimination of glycerol and replacement with alternative products in ethanol fermentation by Saccharomyces cerevisiae

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dc.contributor.authorJain, V. K.en_ZA
dc.contributor.authorDivol, Benoiten_ZA
dc.contributor.authorPrior, B. A.en_ZA
dc.contributor.authorBauer, Florianen_ZA
dc.date.accessioned2011-10-13T16:58:41Z
dc.date.available2011-10-13T16:58:41Z
dc.date.issued2011
dc.description.abstractGlycerol is a major by-product of ethanol fermentation by Saccharomyces cerevisiae and typically 2-3% of the sugar fermented is converted to glycerol. Replacing the NAD+-regenerating glycerol pathway in S. cerevisiae with alternative NADH reoxidation pathways may be useful to produce metabolites of biotechnological relevance. Under fermentative conditions yeast reoxidizes excess NADH through glycerol production which involves NADH-dependent glycerol-3-phosphate dehydrogenases (Gpd1p and Gpd2p). Deletion of these two genes limits fermentative activity under anaerobic conditions due to accumulation of NADH. We investigated the possibility of converting this excess NADH to NAD+ by transforming a double mutant (gpd1δgpd2δ) with alternative oxidoreductase genes that might restore the redox balance and produce either sorbitol or propane-1,2-diol. All of the modifications improved fermentative ability and/or growth of the double mutant strain in a self-generated anaerobic high sugar medium. However, these strain properties were not restored to the level of the parental wild-type strain. The results indicate an apparent partial NAD+ regeneration ability and formation of significant amounts of the commodity chemicals like sorbitol or propane-1,2-diol. The ethanol yields were maintained between 46 and 48% of the sugar mixture. Other factors apart from the maintenance of the redox balance appeared to influence the growth and production of the alternative products by the genetically manipulated strains. © 2010 Society for Industrial Microbiology.
dc.description.versionArticle
dc.identifier.citationJournal of Industrial Microbiology and Biotechnology
dc.identifier.citation38
dc.identifier.citation9
dc.identifier.citationhttp://www.scopus.com/inward/record.url?eid=2-s2.0-80052473597&partnerID=40&md5=4256afd80a95ccb1e1944b04155e1aa4
dc.identifier.issn13675435
dc.identifier.other10.1007/s10295-010-0928-x
dc.identifier.urihttp://hdl.handle.net/10019.1/16818
dc.subjectEthanol
dc.subjectGlycerol
dc.subjectPropane-1,2-diol
dc.subjectRedox imbalance
dc.subjectSorbitol
dc.subjectYeast
dc.subjectalcohol
dc.subjectaldehyde reductase
dc.subjectglycerol
dc.subjectglycerol dehydrogenase
dc.subjectmethylglyoxal
dc.subjectnicotinamide adenine dinucleotide
dc.subjectoxidoreductase
dc.subjectpropylene glycol
dc.subjectreduced nicotinamide adenine dinucleotide
dc.subjectsorbitol
dc.subjectsugar
dc.subjectanaerobic capacity
dc.subjectarticle
dc.subjectcontrolled study
dc.subjectethanol fermentation
dc.subjectfermentation
dc.subjectfungal strain
dc.subjectfungus growth
dc.subjectgene
dc.subjectgene deletion
dc.subjectgene expression
dc.subjectgene mutation
dc.subjectgenetic code
dc.subjectnonhuman
dc.subjectoxidation reduction reaction
dc.subjectprotein expression
dc.subjectSaccharomyces cerevisiae
dc.subjectwild type
dc.subjectSaccharomyces cerevisiae
dc.titleElimination of glycerol and replacement with alternative products in ethanol fermentation by Saccharomyces cerevisiae
dc.typeArticle
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