Enzymatic dehalogenation of 2,2-dichloropropionic acid by locally isolated methylobacterium sp. HJ1

Abstract

Synthetic halogenated organic compounds are found widely throughout the biosphere due to modern industrial and agricultural processes. Various soils microorganisms are able to utilize halogenated alkanoic acids as a sole carbon source. An active dehalogenase enzyme was demonstrated in the crude extracts of partially purified enzyme from Methylobacterium sp. HJ1. The ability of the enzyme to catalyze the dehalogenation of various halogen-substituted organic acids was investigated and the highest activity was found with 2,2-dichloropropionic acid with maximum activity in phosphate buffer pH 6.8. The partially purified enzyme was unaffected by Co+, Mg+ or Mn+ ions or glutathione. The enzyme removed chlorides ions present on a number of 2-carbon alkanoic acids if the halogen was on the a but not on the ß-position. The putative product of dehalogenation was pyruvate using a standard assay system and at the same time 2,2-dichloropropionic acid depletion was detected in growth medium by High Performance Liquid Chromatography (HPLC).