DEGRADATION OF CHLORINATED PHENOLS BY A TOLUENE ENRICHED MICROBIAL CULTURE

Biotransformations of several chlorinated phenols were studied in aero bic cultures enriched on glucose, methane, phenol and toluene and accl imated to 16 chlorinated compounds. The toluene enrichment culture deg raded pentachlorophenol (PCP) and 2,4,6-trichlorophenol (2,4,6-TCP), w hile the cultures enriched on glucose, methane or phenol showed little or no activity. The phenol and toluene enriched cultures rapidly degr aded 2,4-dichlorophenol (2,4-DCP) but not 2,6-DCP or 2,4,5-TCP. Degrad ation of chlorophenols by the toluene enriched culture did not occur e ndogenously but continued when another carbon source, acetate, was int roduced. Degradation of chlorophenols proceeded after starvation and i n the presence of chloramphenicol, suggesting constitutive enzymatic a ctivity. The initial steps of PCP degradation by the toluene enriched culture involved dechlorination and hydroxylation of an ortho carbon t o form tetrachlorocatechol. Tetrachloroguaiacol was identified as a mi nor, dead-end metabolite of PCP degradation by the toluene enriched cu lture.