Efficient conversion of 1,2-butanediol to (R)-2-hydroxybutyric acid using whole cells of Gluconobacter oxydans.

(R)-2-Hydroxybutyric acid ((R)-2-HBA) is an important building block for azinothricin family of antitumour antibiotics and biodegradable poly(2-hydroxybutyric acid). However, optically active (R)-2-HBA could not be produced through microbial fermentation or chemical synthesis. Several biocatalytic methods have been reported for the production of (R)-2-HBA. Those processes used expensive and scarce substrates and would not be suitable for practical application. In this work, Gluconobacter oxydans DSM 2003 was confirmed to have the ability to produce (R)-2-HBA from 1,2-butanediol, a non-toxic and inexpensive compound that had a great potential for biotechnological processes. Under the optimal conditions, the biocatalytic process produced (R)-2-HBA at a high concentration (18.5 g l(-1)) and a high enantiomeric excess (99.7%). The biocatalysis process introduced in this study may provide a technically and economically interesting route for production of (R)-2-HBA.