In vivo levels of chlorinated hydroquinones in a pentachlorophenol-degrading bacterium

The pentachlorophenol (PCP) monooxygenase and tetrachlorohydroquinone (TCHQ) dehydrogenase activities of Sphingomonas chlorophenolica were analyzed to determine the toxic levels of chlorinated hydroquinones in the cytoplasma. The pathway degradation of PCP in Sphingomonas chlorophenolica ATCC 39723 strain involved a monooxygenase and a TCHQ dehydrogenase that catalyzes the conversion of PCP to TCHQ. Furthermore, the toxicity of TCHQ on the cells was concentration-dependent and low levels of the compound did not induces adverse effects in the cells.