<P>An efficient multienzyme system for the preparative synthesis of <SMALL>D</SMALL>-xylonate, a chemical with versatile industrial applications, is described. The multienzyme system is based on <SMALL>D</SMALL>-xylose oxidation catalyzed by the xylose dehydrogenase from <I>Calulobacter crescentus</I> and the use of catalytic amounts of NAD<SUP>+</SUP>. The cofactor is regenerated in situ by coupling the reduction of acetaldehyde into ethanol catalyzed by alcohol dehydrogenase from <I>Clostridium kluyveri</I>. Excellent conversions (>95%) were obtained in a process that allows easy product isolation by simple evaporation of the volatile buffer and byproducts.</P><BR>[FIG OMISSION]</BR>