摘要
[ Objective ] This study aimed to clarify the mechanism of enzymatic degradation of organochlorine insecticide chlordane by the white rot fungus Pldebia brevispora. [ Method ] The degradation characteristics of chlordane were determined by the crude enzyme extracted from P. brevispora strain by pure culture, ultrasonic fragmentation and centrifuge separation. [ Result] About 33.2% and 10.4% of chlordane were degraded respectively by intracellular enzyme and extracellular enzyme within 20 min. At pH 5.0 and 3℃, the crude enzyme showed the greatest degradation activity （49.9%）, with its Michaelis-Mentn＇s constant （Km ） and maximum degradation rate （ Vmax ） of 3.49 and 8.38 ttmol/min, respectively. [ Conclusion] Extracellular enzyme can degrade chlordane through dehydrogenation or dehydrochlorination. Intracellular enzyme plays a major role in chlordane degradation. It can transform chlordane to some hydroxylated metabolites through hydroxylation or substitution of chlorine atom by hydroxyl group.
[ Objective ] This study aimed to clarify the mechanism of enzymatic degradation of organochlorine insecticide chlordane by the white rot fungus Pldebia brevispora. [ Method ] The degradation characteristics of chlordane were determined by the crude enzyme extracted from P. brevispora strain by pure culture, ultrasonic fragmentation and centrifuge separation. [ Result] About 33.2% and 10.4% of chlordane were degraded respectively by intracellular enzyme and extracellular enzyme within 20 min. At pH 5.0 and 3℃, the crude enzyme showed the greatest degradation activity （49.9%）, with its Michaelis-Mentn＇s constant （Km ） and maximum degradation rate （ Vmax ） of 3.49 and 8.38 ttmol/min, respectively. [ Conclusion] Extracellular enzyme can degrade chlordane through dehydrogenation or dehydrochlorination. Intracellular enzyme plays a major role in chlordane degradation. It can transform chlordane to some hydroxylated metabolites through hydroxylation or substitution of chlorine atom by hydroxyl group.
基金
Supported by the Scientific Research Fund for the Returned Overseas Chinese Scholars,State Education Ministry
