A Novel Bacterium That Degrades Aroclor-1254 and Its bphC Gene Encodes an Extradiol Aromatic Ring Cleavage Dioxygenase (EARCD)

The congener-specific degradation pattern of polychlorinated biphenyls (PCBs) in Aroclor 1254 was investigated using a novel bacterial strain, Stenotrophomonas sp. JSG1, and it was accelerated by the surfactant, β-cyclodextrin. In addition, 4-chorobenzoic acid (CBA) degradation was also confirmed by the estimation of CBA depletion rate, microbial growth, and release of free chloride ion in mineral medium. Metal ions such as Ni 2+ , Hg 2+ Ba 2+ , Cu 2+ , and NaCl (>4 %) were found greatly influencing the PCB degradation. However, Ca 2+ , Mg 2+ , Fe 2+ , and Mn 2+ have not shown any impact on biodegradation. The bphC gene, which encodes an extradiol aromatic ring cleavage dioxygenase was successfully amplified and cloned. Phylogeny-based pairwise alignment of nucleotide sequences suggested that the cloned gene belongs to the extradiol dioxygenase family, but it showed high diversity to the traditional bphC gene. Results of the present investigation revealed that the Stenotrophomonas sp. JSG1 is an effective novel bacterium, which can be used in the PCB remediation studies.