The formation and substrate specificity of bacterial lactonases capable of enantioselective resolution of racemic lactones

Abstract

The substrate specificities of ϵ-caprolactone hydrolase from Acinetobacter NCIMB 9871 and δ-valerolactone hydrolase from Pseudomonas NCIMB 9872 were investigated. Both lactonases showed activity toward six- and seven-membered ring lactones. δ-Valerolactone hydrolase exhibited enantioselectivity in its activity. It showed a preference for the R enantiomer of δ-decanolactone and δ-nonalactone whereas ϵ-caprolactone hydrolase showed little enantioselectivity toward the lactone substrates tested. The δ-valerolactone hydrolase from Pseudomonas NCIMB 9872 may be useful for the resolution of racemic lactones, and hence may serve as an alternative route to chiral lactone synthesis.