河口底泥来源真菌Trichoderma asperellum对壬基酚的降解路径

从壬基酚(Nonylphenol,NP)污染严重的李村河口底泥中分离纯化出可实验室培养的真菌,以高浓度NP为环境选择压力筛选出了一株目标菌株,18S rDNA确定其归属为棘孢木霉(Trichoderma asperellum)。实验室内研究了该菌株对NP的生物降解过程,LC/MS分析其代谢产物,据此提出了NP可能的生物降解路径。菌株的生长曲线表明NP能促进其生长,该菌株3 d对5 mg/L NP的降解率为71.4%,7 d的降解率达到87.2%,14 d则达到了92.2%。LC/MS分析确定了NP四种代谢产物,分别是2-甲基-1-苯基丁醇、3,5-二羟基苯甲酸、苯二酚和苯甲醚(或苄醇)。提出了两种NP可能的生物降解路径,Ⅰ是最终转化成苯二酚,Ⅱ是最终转化成苯甲醚或苄醇。

Nonylphenol biodegradation pathway by Trichoderma asperellum from the estuary sediment

Several fungi were isolated from the LICUN river estuary sediment,where was contaminated seriously by nonylphenols (NPs).One target strain that can degrade NP was purified and selected by environmental selection pressure in high NP concentration media.It was identified as Trichoderma asperellum according to its sequence analysis of 18S rDNA.The NP biodegradation was studied in laboratory.The biodegradation metabolites were determined by LC/MS and used for establishing probable NP degradation pathway.The growth curve of the strain indicated that NP can promote its growth.It showed that NP at the concentration of 5 mg/L was eliminated from the culture medium by 71.4% during 3 d of incubation,whereas during 7 d of incubation by 87.2% and 14 d of incubation by 92.2%.Four compounds (2-methyl-1-phenyl butanol,3,5-dihydroxy benzoic acid,hydroquinone and anisole (or benzyl alcohol)) were identified as degradation metabolites by LC/MS.Two probable NP biodegradation pathways were proposed.NP was eventually converted to hydroquinone in PathⅠ,and to anisole (or benzyl alcohol) in path Ⅱ.