초록
<P>Acetoin is widely used in food and cosmetic industry as taste and fragrance enhancer. For acetoin production in this study, <I>Saccharomyces cerevisiae</I> JHY605 was used as a host strain, where the production of ethanol and glycerol was largely eliminated by deleting five alcohol dehydrogenase genes (<I>ADH1</I>, <I>ADH2</I>, <I>ADH3</I>, <I>ADH4</I>, and <I>ADH5</I>) and two glycerol 3-phosphate dehydrogenase genes (<I>GPD1</I> and <I>GPD2</I>). To improve acetoin production, acetoin biosynthetic genes from <I>Bacillus subtilis</I> encoding α-acetolactate synthase (AlsS) and α-acetolactate decarboxylase (AlsD) were overexpressed, and <I>BDH1</I> encoding butanediol dehydrogenase, which converts acetoin to 2,3-butanediol, was deleted. Furthermore, by NAD<SUP>+</SUP> regeneration through overexpression of water-forming NADH oxidase (NoxE) from <I>Lactococcus lactis</I>, the cofactor imbalance generated during the acetoin production from glucose was successfully relieved. As a result, in fed-batch fermentation, the engineered strain JHY617-SDN produced 100.1 g/L acetoin with a yield of 0.44 g/g glucose.</P>