초록
<P><B>ABSTRACT</B></P><P>Ethylene glycol (EG) is an important chemical used as antifreeze and a raw material in polyester synthesis. The EG biosynthetic pathway from <SMALL>D</SMALL>-xylose with <SMALL>D</SMALL>-xylonate as key intermediate has some advantages, but showed low EG production. Here, we reconstructed and optimized this pathway in <I>Escherichia coli</I>. In view of the greater intracellular prevalence of NADH, an aldehyde reductase FucO using NADH was employed to convert glycoaldehyde into EG, in replacement of NADPH-dependent reductase YqhD. To suppress the accumulation of by-products acetate and glycolate, two genes <I>arcA</I> and <I>aldA</I> were knocked out. The resultant strain Q2843 produced 72 g/L EG under fed-batch fermentation conditions, with the yield of 0.40 g/g <SMALL>D</SMALL>-xylose and EG productivity of 1.38 g/L/h. The use of NADH-dependent enzyme FucO and by-product elimination significantly improved the performance of EG producing strain, which represented the highest titer, yield and productivity of EG reported so far.</P>