R-(-)-2-(3(prm1)-Benzoylphenyl)propionic acid [R-(-)-ketoprofen] was produced from racemic 2-(3(prm1)-benzoylphenyl)propionamide (keto-amide) by the isolated bacterial strain Comamonas acidovorans KPO-2771-4. Sodium fumarate as the carbon source and 2-azacyclononanone or isobutyronitrile as the enhancer in the culture medium were effective for bacterial growth and the enhancement of R-(-)-ketoprofen-producing activity. R-(-)-Ketoprofen produced from the keto-amide by resting cells was present in 99% enantiomeric exess. C. acidovorans KPO-2771-4 has an R-enantioselective amidase for keto-amide because the purified amidase from the bacterium hydrolyzed keto-amide, producing optically pure R-ketoprofen and ammonia.