초록
<P><B>Abstract</B></P><P><I>S</I>‐acetoin (<I>S</I>‐AC) is an important four‐carbon chiral compound that has unique industrial applications in the asymmetric synthesis of valuable chiral specialty chemicals. However, previous studies showed that the usually low yield and optical purity of <I>S</I>‐AC as well as the very high substrate cost have hindered the application of this compound. In the current work, a gene encoding diacetyl reductase (DAR) from a <I>Paenibacillus polymyxa</I> strain ZJ‐9 was cloned and expressed in <I>Escherichia coli</I>. Whole cells of the recombinant <I>E.？coli</I> were used to produce <I>S</I>‐AC from diacetyl (DA). Under optimal conditions, <I>S</I>‐AC with high optical purity (purity >99·9%) was obtained with a yield of 13·5？±？0·24 and 39·4？±？0·38？g？l<SUP>−1</SUP> under batch and fed‐batch culture conditions, respectively. This process featured the biotransformation of DA into <I>S</I>‐AC using whole cells of engineered <I>E.？coli</I>. The result is a considerable increase in the yield and optical purity of <I>S</I>‐AC, which in turn facilitated the practical application of the compound.</P><P><B>Significance and Impact of the Study</B></P><P>This study demonstrated a highly efficient new method to produce <I>S</I>‐acetoin with higher than 99·9% optical purity from diacetyl using whole cells of engineered <I>Escherichia coli</I>. It will therefore decrease the production cost of <I>S</I>‐acetoin and highlight its application in asymmetric synthesis of highly valuable chiral compounds.</P>