초록
<P>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 <I>Saccharomyces cerevisiae</I> 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 <I>GCY1</I> and <I>DAK1</I>, 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 <I>mhpF</I> gene, encoding acetylating NAD<SUP>+</SUP>-dependent acetaldehyde dehydrogenase from <I>Escherichia coli</I>, 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.</P><P><B>Electronic supplementary material</B></P><P>The online version of this article (doi:10.1007/s10295-013-1311-5) contains supplementary material, which is available to authorized users.</P>