啶氧菌酯降解菌的分离鉴定及其降解特性研究

Isolation,identification and degrading characterization of a picoxystrobin degrading strain

【目的】筛选可高效降解啶氧菌酯的微生物资源,并研究其降解特性,为啶氧菌酯等甲氧基丙烯酸酯类农药残留的微生物修复提供新资源。【方法】采用富集培养法分离啶氧菌酯降解菌,以生理生化特征结合16S rRNA序列系统发育分析鉴定降解菌;利用气相色谱仪(HPLC)测定啶氧菌酯残留量,分析其降解特性;采用气相色谱质谱联用仪(GCMS)测定降解菌降解啶氧菌酯的中间代谢产物,分析降解菌降解啶氧菌酯的代谢途径。【结果】分离获得一株能以啶氧菌酯为唯一碳源的降解菌株(PY3),其生理生化特征结合16S rRNA序列系统发育分析结果表明,PY3菌株属沼泽红假单胞菌(Rhodopseudomonas palustris)。PY3菌株最佳生长条件测定和降解特性分析结果表明,PY3菌株生长和降解啶氧菌酯的最佳条件为pH6.0、35℃,在最佳降解条件下培养11d,对50mg/L啶氧菌酯的降解率可达72.0%。PY3菌株降解啶氧菌酯的途径包括苯环和N杂环间氧桥键断裂后酯化,以及苯环和N杂环开环反应。【结论】沼泽红假单胞菌PY3菌株具有高效降解啶氧菌酯的活性和较广的pH和温度耐受性,且具有应用于农田生态环境中啶氧菌酯等甲氧基丙烯酸酯类农药残留物微生物修复的潜力。

【Objective】The microorganisms which could effectively degrade picoxystrobin were selected and their degrading characteristics were analyzed. It would provide new resources for microbial remediation of methoxy acrylates pesticide residue such as picoxystrobin.【Method】Picoxystrobin degrading strains were isolated by enrichment culture,and the degrading strains were analyzed and identified through physiological,biochemical characteristics and phylogenetic analysis of 16S rRNA gene sequences. Residue of picoxystrobin was quantified by gas chromatograph(HPLC),and the degrading characteristics were also studied. Metabolics of picoxystrobin in degrading process were identified by gas chromatograph- mass spectrometer(GCMS),and metabolic pathways of degrading process of the strain on picoxystrobin were analyzed.【Result】A degrading strain PY3 which took picoxystrobin as the only carbon source was isolated. Physiological, biochemical characteristics and phylogenetic analysis of 16S rRNA sequences indicated that strain PY3 was Rhodopseudomonas palustris. The optical growth and degrading picoxystrobin conditions of strain PY3 were pH 6.0 and 35 ℃. Under the optimal degradation conditions,up to 72.0% of 50 mg/L picoxystrobin could be degraded by strain PY3 in 11 d. Metabolic pathways of picoxystrobin degraded by strain PY3 included oxygen bridge bond between benzene ring and N-containing heterocyclic ring braking and ring-opening reaction of benzene ring and N-containing heterocyclic ring.【Conclusion】R. palustris PY3 has excellent picoxystrobin degradation capacity and broad pH and temperature tolerance. It can be applied to repair of methoxy acrylates pesticide residues such as picoxystrobin in field eco-environment.