Enantioselective oxidation of racemic 1,2-propanediol to D-(−)-lactic acid by Gluconobacter oxydans

Gluconobacter oxydans DSM 2003 was firstly used in the production of (R)-2-hydroxy-propionic acid through microbial oxidation of racemic 1,2-propanediol. The biotransformation was processed with high enantiomeric excess (>99) and near theoretical yield (48 of racemic 1,2-propanediol) when the substrate concentration was lower than 20 g/L. When the substrate concentration was increased, maintaining the pH at 6.0 helped to improve the enantioselectivity