白腐菌对氯丹的降解性能及降解途径研究

 研究了2株多氯代二苯并二噁英高效降解白腐菌Phlebia lindtneri及Phlebia brevispora对氯丹的降解能力.在2个不同的液体培养体系中,2菌株对于高浓度(25μmol/L)的反式氯丹展现了较高的代谢能力,经6周培养后其降解率均达到50%以上.用GC/MS对其降解产物分析表明,氯丹的降解存在脱氢,脱氯化氢,羟基化以及氯原子的羟基置换4条不同的初始降解途径,除七氯,环氧七氯及氧化氯丹等常见初始代谢产物外,还发现3-羟基氯丹,氯代六氯醇,七氯二醇,羟基六氯,二羟基六氯等大量的羟基化代谢产物.尤其是P. lindtneri可以将曾被认为是终端代谢产物的氧化氯丹进行降解,并通过氯原子的羟基置换作用将其转化成羟基化代谢产物.

Bodegradation of chlordane by white-rot fungi and its metabolic pathway

The metabolism of trans-chlordane was performed with the white-rot fungi species Phlebia lindtneri and Phlebia brevispora, which are capable of degrading polychlorinated dibenzo-p-dioxin, heptachlor, DDT and dieldrin. At the end of 42 days of incubation, over 50% of trans-chlordane was degraded by the fungal treatments in pure cultures. Two fungi transformed trans-chlordane to at least eleven metabolites including a large amount of hydroxylated products such as 3-hydroxychlordane, chlordene chlorohydrin, heptachlor diol, dihydroxydihydrochlordene, mono- and dihydroxychlordene. P. lindtneri in particular can transform oxychlordane, a recalcitrant epoxide product of chlordane, into a hydroxylated product through substitution of chlorine atom by hydroxyl group. The present results indicate that trans-chlordane was transformed to several hydrophilic metabolites, and that hydroxylation reactions play an important role in the metabolism of trans-chlordane by selected Phlebia species.