New acetoin reductases from Bacillus stearothermophilus: meso- and 2R,3R-butanediol as fermentation products

▶ Products from sucrose fermentation with Bacillus stearotermophilus. ▶ Metabolic pathway to the fermentation products. ▶ R-Acetoin is produced following the “catabolic pathway”. ▶ R-Acetoin is the precursor of meso- and 2R,3R-butanediol and two new acetoin reductases (i.e., S-ACR and R-ACR) are separated. ▶ The acetoin reductases are potentially useful for the biocatalytic approach to the synthesis of S- and R-stereospecific optically active α-hydroxyketones and vic-diols.