Dehalococcoides mccartyi Strain JNA Dechlorinates Multiple Chlorinated Phenols Including Pentachlorophenol and Harbors at Least 19 Reductive Dehalogenase Homologous Genes

Abstract

Pentachlorophenol and other chlorinated phenols are highly toxic ubiquitous environmental pollutants. Using gas chromatographic analysis we determined that Dehalococcoides mccartyi strain JNA in pure culture dechlorinated pentachlorophenol to 3,5-dichlorophenol (DCP) via removal of the ortho and para chlorines in all of the three possible pathways. In addition, JNA dechlorinated 2,3,4,6-tetrachlorophenol via 2,4,6-trichlorophenol (TCP) and 2,4,5-TCP to 2,4-DCP and 3,4-DCP, respectively, and dechlorinated 2,3,6-TCP to 3-chlorophenol (CP) via 2,5-DCP. JNA converted 2,3,4-TCP to 3,4-DCP and 2,4-DCP by ortho and meta dechlorination, respectively. 2,3-DCP was dechlorinated to 3-CP, and, because cultures using it could be transferred with a low inoculum (0.5 to 1.5% vol/vol), it may act as an electron acceptor to support growth. Using PCR amplification with targeted and degenerate primers followed by cloning and sequencing, we determined that JNA harbors at least 19 reductive dehalogenase homologous (rdh) genes including orthologs of pcbA4 and pcbA5, pceA, and mbrA, but not tceA or vcrA. Many of these genes are shared with D. mccartyi strains CBDB1, DCMB5, GT, and CG5. Strain JNA has previously been shown to extensively dechlorinate the commercial polychlorinated biphenyl (PCB) mixture Aroclor 1260. Collectively the data suggest that strain JNA may be well adapted to survive in sites contaminated with chlorinated aromatics and may be useful for in situ bioremediation.

PCB dechlorination hotspots and reductive dehalogenase genes in sediments from a contaminated wastewater lagoon

“…The structural similarity between chlorobenzenes and PCBs could account for this overlap in substrate specificity. D. mccartyi strain JNA is a pure culture that not only was most recently shown to reduce chlorophenols (Fricker et al 2014) but has also been shown to respire by dechlorinating Aroclor 1260 congeners, primarily by flanked meta dechlorination (Process N) (LaRoe et al 2014). Unlike strains CG1, CG4, and CG5, specific RDases in strain CBDB1 have not been implicated in dechlorination of PCB congeners.…”

Retracted: Acclimation of 2‐chlorophenol‐biodegrading activated sludge and microbial community analysis

“…Chlorophenols are widely used in industry (Peng et al., ). The chlorinated compounds are released into the environment in a variety of ways, such as by discharge of phenolic wastewater, the use of pesticides, and manufacture of pharmaceuticals (Fricker, LaRoe, Shea, & Bedard, ; Marković et al., ). Many chlorophenols have “carcinogenic, teratogenic, and mutagenic” effects, and they are recognized as hazardous environmental pollutants (Khan, Mondal, & Sabir, ; Li et al., ).…”

Acclimation of 2‐Chlorophenol‐Biodegrading Activated Sludge and Microbial Community Analysis

“…Chlorophenols are widely used in industry . The chlorinated compounds are released into the environment in a variety of ways, such as by discharge of phenolic wastewater, the use of pesticides, and manufacture of pharmaceuticals (Fricker, LaRoe, Shea, & Bedard, 2014;Marković et al, 2015). Many chlorophenols have "carcinogenic, teratogenic, and mutagenic" effects, and they are recognized as hazardous environmental pollutants (Khan, Mondal, & Sabir, 2011;Li et al, 2015).…”