一株氯氰菊酯降解真菌的筛选鉴定及其降解特性研究

从雅安市售砖茶中分离筛选出一株对氯氰菊酯具有较高降解能力的真菌菌株YAT,根据其形态学及ITS序列分析,将该菌鉴定为黑曲霉(Aspergillus niger).菌株YAT在PD培养基中168 h内对50 mg·L-1氯氰菊酯的降解率为54.83％,对氯氰菊酯的降解率与菌体生物量呈正相关.动力学研究表明,菌株YAT降解氯氰菊酯的过程符合一级动力学方程,在测试的底物(氯氰菊酯)浓度、温度、pH范围内,氯氰菊酯半衰期为85.750～281.958 h,较高温度及偏碱性条件有利于氯氰菊酯的降解,底物浓度越高,其半衰期越长.此外,菌株YAT对50 mg·L-1溴氰菊酯、氰戊菊酯、氟氯氰菊酯和氯菊酯的120 h降解率分别为27.53％、58.00％、53.23％和25.34％.

Isolation and identification of a cypermethrin degrading fungus and its degradation characteristics

A fungal strain named YAT with high cypermethrin degrading capability was isolated from brick tea in Ya'an. According to its morphological characteristics and the results of ITS sequences analysis, strain YAT was identified as Aspergillus niger. The cypermethrin degradation rate and biomass of YAT yield had a positive correlation, and it's cypermethrin degradation rate could reach 54.83% in PD medium with 50 mg·L^-1 substrate in 168 h. Dynamics study indicated that the process of degradation fitted well with a first-order kinetics model. The degradation half-life of cypermthrin was 85.750~281.958 h over a certain range of cypermethrin concentration, temperature and pH. High temperature and alkaline conditions favored the degradation of cypermethrin, while high cypermethrin extended the half-life of cypermthrin-degrading. In addition, the strain YAT was also able to degrade other pyrethroids such as deltamethrin, fenvalerate, cyfluthrin and permethrin (50 mg·L^-1), with the degradation ratesof 27.53%, 58.00%, 53.23% and 25.34% in 120 h, respectively.