[Research advances in biodegradation of chlorophenols in environment]

This paper examines the biodegradation of chlorophenols by microbes and deals with the chlorophenols-degrading microbes and the usage of biotechnology with special emphasis on degradation mechanisms. Dechlorination is the first critical step in the bacterial degradation of many chloroniated pollutans. Under aerobic condition, the degradation of mono- and dichlorophenols is shown to be initiated by oxygenation into chlorocatechols, and dechlorination occurs only after ring cleavage of the chlorocatechols. The degradation of polychlorinated phenols starts by hydrolytic para-hydroxylation, yielding chlorinated para-hydroquinone. The anaerobic biodegradation of chlorophenols occurs by reductive dechlorination, a process by which chlorines are replaced with hydrogen.