Identification of the novel operon catalyzing the dechlorination of pentachlorophenol in the Gram-positive bacterium sp. strain PD653.

While genes are well known in Gram-negative bacteria to code for the enzymes responsible for pentachlorophenol (CHClO; PCP) degradation, little is known about PCP-degrading genes in Gram-positive bacteria. Here we describe a novel gene operon possibly responsible for catalyzing the degradation of PCP in the Gram-positive bacterium sp. strain PD653, which is capable of mineralizing hexachlorobenzene (CCl; HCB) PCP. Transcriptome analysis based on RNA-Seq revealed overexpressed genes in strain PD653 following exposure to HCB. Based on annotation, three open reading frames (ORFs) were selected as biodegrading enzyme candidates. Recombinant cells expressing candidate genes degraded approximately 9.4 µmol L PCP in 2 hr. Therefore, we designated these genes as . Interestingly, PCP-degrading activity was recorded when was coexpressed with or , and the function of HcbB3 was expected to be similar to chlorophenol 4-monooxygenase (TftD).