MUTATIONAL ANALYSIS OF PCPA AND ITS ROLE IN PENTACHLOROPHENOL DEGRADATION BY SPHINGOMONAS (FLAVOBACTERIUM) CHLOROPHENOLICA ATCC-39723

Sphingomonas (Flavobacterium) chlorophenolica ATCC 39723 degrades pent achlorophenol (PCP) through a catabolic pathway encoded by multiple ge nes. One gene required for PCP degradation is pcpA, which encodes info rmation for a 30-kDa polypeptide, PcpA, found in the periplasm of the bacterium. The biological role of PcpA has remained unknown. We disrup ted pcpA by replacing it with a defective copy through homologous reco mbination. The pcpA recombinant, mutant strains accumulated 2,6-dichlo rohydroquinone (2,6-DiCH) as a metabolite of PCP. This work confirms t hat pcpA is essential for degradation of PCP by S. chlorophenolica ATC C 39723 and suggests that it encodes a protein involved in hydrolytic dehalogenation of 2,6-DiCH, an already established primary metabolite of the PCP catabolic pathway.