Verification of the Role of PCP 4-monooxygenase in Chlorine Elimination from Pentachlorophenol by Flavobacterium Sp. Strain ATCC 39723

The bacterial enzyme PCP 4-monooxygenase from Flavobacterium sp. strain ATCC 39723 catalyzes the oxygenolytic removal of the first chlorine from pentachlorophenol. PCP 4-monooxygenase is an FAD binding, NADPH requiring oxygenase, with similar functional domains as other bacterial flavoprotein monooxygenases specific for phenolic substrates. However, the definitive proof for the singular role of an oxygenolytic elimination of the primary chlorine from pentachlorophenol by Flavobacterium sp. has awaited the development of a genetic system whereby targeted mutagenesis via allelic exchange could be carried out with the corresponding gene from PCP 4-monooxygenase, pcpB. We report the development of a genetic system for Flavobacterium sp. strain ATCC 39723, and its application in targeted mutagenesis of the pcpB allele for elimination of PCP 4-monooxygenase activity.