To provide an esterase, to provide a gene DNA which encodes the esterase, to provide a recombinant vector which has the gene DNA, to provide a transformant which has the recombinant vector, to provide the esterase which is collected from a culture obtained by culturing the transformant, to provide a method for producing the esterase by collecting the esterase from the culture obtained by culturing the transformant, and to provide a method for producing an optically active substance using the same.

The esterase, the gene DNA which encodes the esterase, the recombinant vector which has the gene DNA, the transformant which has the recombinant vector, and the esterase which is collected from the culture obtained by culturing the transformant are provided, respectively. The esterase is produced by collecting the esterase from the culture obtained by culturing the transformant. Further, an optically active carboxylic acid or an enantiomeric ester thereof is produced by contacting the culture thus produced, or a processed product of the culture, with a carboxylic acid ester.