Degradation of 3-chloropropionic acid (3CP) by Pseudomonas sp. B6P isolated from a rice paddy field

Abstract

A bacterium that degrades 3-chloropropionic acid (3CP) was isolated from local paddy (rice) agricultural soil by enrichment culture. Taxonomic analysis identified the strain as Pseudomonas sp. Strain-mediated degradation of 3CP released chloride ions into the growth medium, and the degradation of ∼100% of 20 mM 3CP was monitored by high performance liquid chromatography (HPLC). The putative Pseudomonas sp. dehalogenase that released the chloride ions from 3CP was induced by growth of the bacterium in the presence of 3CP as the sole carbon source. The dehalogenase showed activity against a specific type of halogenated aliphatic acids, and the highest activity was obtained with 3CP. However, the enzyme could only remove halogen atoms from 3-carbon alkanoic acids if the halogen was at the β- but not the α-position. In crude bacterial extracts, the dehalogenase activity with 3CP was maximum at 30 °C, over a broad pH range (pH 7.5 optimum) and had an apparent Kms of 0.25 ± 0.04 mM and 0.67 ± 0.17 mM for 3CP and 2,3-dichloropropionic acid, respectively.