炔草酯降解菌Sphingopyxis sp.WP68的分离鉴定与降解特性

Isolation, identification and characterization of clodinafop-propargyl degrading Sphingopyxis sp. WP68

【背景】炔草酯可以高效防除麦田恶性杂草,但炔草酯的生产和使用也对环境造成了破坏,对动物和人类健康造成了威胁。【目的】分离筛选炔草酯高效降解菌株,研究其降解特性,为炔草酯污染生物修复提供优良菌种资源。【方法】采集农药厂活性污泥样品,通过富集培养和含有炔草酯的LB培养基进行炔草酯降解菌株的分离,通过形态和生理生化特性以及16S rRNA基因序列分析确定其分类学地位,通过单因素试验从温度、pH、接种量和底物浓度等方面考察菌株对炔草酯的降解特性,并利用UPLC-MS分析降解产物。【结果】筛选出一株炔草酯高效降解菌株WP68,经鉴定为鞘氨醇盒菌(Sphingopyxis sp.),该菌株在37°C和pH值为8.0时,10 h内可将200 mg/L的炔草酯降解98.26%。利用UPLC-MS鉴定菌株WP68降解炔草酯的产物为炔草酸。确定了该菌株降解炔草酯的最适温度、pH值、接种量、底物浓度分别是37°C、8.0、5%、200mg/L。菌株WP68还能降解氰氟草酯和精喹禾灵。【结论】Sphingopyxis sp. WP68对炔草酯有较强的降解能力和较高耐受性,在炔草酯污染土壤修复中具有潜在的应用前景。

[Background]Although clodinafop-propargyl(CP)can efficiently control malignant weeds in wheat field,the producing and using of CP cause damage to the environment,and pose a threat to the health of animal and human.[Objective]We isolated an efficient CP-degrading bacterium and studied its degradation characteristics to provide microbial resource for bioremediation of CP pollution.[Methods]The active sludge sample was collected from a pesticide factory.The CP-degrading bacterium was isolated by enrichment cultivation and Luria-Bertani(LB)medium containing CP,and identified by morphological,physiological characteristics and analysis of 16 S rRNA gene sequence.Single factor experiments were used to evaluate the degradation characteristics including temperature,pH,inoculum,substrate concentration.The degradation product of CP was identified by UPLC-MS.[Results]An efficient CP-degrading strain WP68 was isolated and identified as Sphingopyxis sp..Strain WP68 was able to degrade 98.26%of 200 mg/L of CP within 10 h under the condition of 37°C and pH value of 8.0.The optimal culture conditions for strain WP68 degrading CP were temperature 37°C,pH 8.0,inoculum 5%,and substrate concentration 200 mg/L.The degradation product of CP was identified as clodinafop acid(CA)by UPLC-MS.Strain WP68 was also capable of degrading cyhalofop-butyl and quizalofop-p-ethyl.[Conclusion]Based on the high efficient degradation ability and high CP-tolerance,Sphingopyxis sp.WP68 has the potential prospect in bioremediation of CP-contaminated soil.