Degradation of D,L-2-chloropropionic Acid by Bacterial Dehalogenases that Shows Stereospecificity and its Partial Enzymatic Characteristics

Abstract

A Pseudomonas sp. strain S3, which can utilise a halogenated compound of D., L-2CP as sole carbon and energy source, catalyses the hydrolytic dehalogenation of both D-and L-isomers of 2-chloropropionic acid. Two kinds of dehalogenase enzymes were isolated from cells of Pseudomonas sp. strain S3. A thermostable L-specific dehalogenase (DehL) and non-thermostable D-specific dehalogenase (DehD) can be obtained when cells grown only in the presence of D., L-2CP. These inducible enzymes were then further characterised. The maximum activity of D-specific dehalogenase (DehD) enzyme on D-2CP was found at pH 9.5 at 35°C, whereas the L-specific dehalogenase is thermostable and retained its full activity upon heating at 55°C for 15 min. The pH and temperature optima for dehalogenation of L-2CP were 7.5 and 50°C. respectively.