寡养单胞菌G1对杀螟硫磷的降解研究

Study on degradation characteristics of fenitrothion by Stenotrophomonas acidaminiphila G1

杀螟硫磷属于有机磷杀虫剂,其对水生生物、哺乳动物和其他非靶标生物的神经毒性和遗传毒性已引起广泛关注,因此研究其在水中的降解非常必要。以实验室前期筛选的一株有机磷农药高效降解菌株G1(鉴定为寡养单胞菌)为材料,探究了菌株G1对杀螟硫磷在水中的降解特性。结果表明:菌株G1在1h内对于20mg·L^(-1)杀螟硫磷的降解率达到90%,降解半衰期仅为17.2min,具有高效降解效能。菌株G1对杀螟硫磷的降解最适温度为37℃,最适pH为7~8;降解效率与初始接菌量呈正相关,与初始底物浓度呈负相关;在5 mmol·L^(-1)不同金属离子作用下,K^(+)、Na^(+)表现促进菌株G1对杀螟硫磷的降解,而Co^(2+)、Mg^(2+)、Ca^(2+)、Cr^(3+)、Fe^(3+)等离子具有抑制降解效应;菌株G1可以将杀螟硫磷分解为3-甲基-4-硝基苯酚和O,O二甲基硫代磷酸酯。研究结果为杀螟硫磷农药的环境微生物降解修复提供技术支撑。

Fenitrothion was a kind of organophosphorus insecticides.Its neurotoxicity and genotoxicity to aquatic organisms,mammals and other non-target organisms have attracted widespread attention,so it is necessary to study its degradation in water.In this paper,an organophosphorus pesticide degradation strain G1(identified as oligotrophomonas)was selected as the material to explore the degradation characteristics of fenitrothion in water.The results show that:the degradation rate of strain G1 for 20 mg·L^(-1) fenitrothion were reached 90%within 1 h The degradation half-life is only 17.2 min The optimum temperature and pH for fenitrothion degradation by strain G1 was 37℃,and 7-8,respectively;the degradation efficiency was positively correlated with the initial inocula-tion amount of strain G1 and negatively correlated with the initial substrate concentrations;Under the condition of 5 mmol·L^(-1) metal ions,K+and Na+could promote the degradation of fenitrothion by strain G1,while Co^(2+),Mg^(2+),Ca^(2+),Cr^(3+),Fe^(3+)could inhibit the degradation.Meanwhile,fenitrothion could be degraded to 3-methyl-4-nitrophenol and O,O dimethyl phosphorothioate by strain G1.The results provide technical support for the environmental microbial degradation and remediation of fenitrothion pesticides.