Formation of d(-)-1,2-propanediol and d(-)-lactate from glucose by Clostridium sphenoides under phosphate limitation

Clostridium sphenoides was grown on glucose in a phosphate-limited medium. Below 80 M phosphate two new products were formed in addition to ethanol, acetate, H₂ and CO₂: d(-)-1,2-propanediol and d(-)-lactate. These compounds were apparently synthesized via the methylglyoxal by-pass. The activity of the enzymes involvedmethylglyoxal synthase, methylglyoxal reductase, 1,2-propanediol dehydrogenase and glyoxalase-could be demonstrated in cell extracts of C. sphenoides. The formation of 1,2-propanediol from methylglyoxal proceeded via lactaldehyde. The enzyme methylgloxal synthase was inhibited by phosphate.Clostridium glycolicum, C. nexile, C. cellobioparum, C. oroticum and C. indolis did not produce propanediol under the condition of phosphate limitation. The latter two species, however, formed d(-)-lactate.Dedicated to Prof. Dr. G. Drews on the occasion of his 60th birthday