초록
<P>2-Butanol and its chemical precursor butanone (methyl ethyl ketone – MEK) are chemicals with potential uses as biofuels and biocommodity chemicals. In order to produce 2-butanol, we have demonstrated the utility of using a TEV-protease based expression system to achieve equimolar expression of the individual subunits of the two protein complexes involved in the B<SUB>12</SUB>-dependent dehydratase step (from the pdu-operon of <I>Lactobacillus reuterii</I>), which catalyze the conversion of <I>meso</I>-2,3-butanediol to butanone. We have furthermore identified a NADH dependent secondary alcohol dehydrogenase (Sadh from <I>Gordonia</I> sp.) able to catalyze the subsequent conversion of butanone to 2-butanol. A final concentration of 4±0.2 mg/L 2-butanol and 2±0.1 mg/L of butanone was found. A key factor for the production of 2-butanol was the availability of NADH, which was achieved by growing cells lacking the <I>GPD1</I> and <I>GPD2</I> isogenes under anaerobic conditions.</P>