烟嘧磺隆降解菌Chryseobacterium sp.LAM-M5的分离、鉴定及其降解机理研究

为获得更丰富的烟嘧磺隆降解菌资源,以合肥某烟嘧磺隆生产厂活性污泥为研究对象,从中分离并筛选得到一株能以葡萄糖为唯一碳源、烟嘧磺隆为唯一氮源生长的菌株,根据其表型特征、16S rRNA序列相似性、DNA-DNA杂交值(DDH)和平均核苷酸一致性(ANI)的分析结果,将其鉴定为Chryseobacterium lacus ...

Isolation and Identification of Nicosulfuron Degrading Strain Chryseobacterium sp.LAM-M5 and Study on Its Degradation Pathway

In order to obtain more nicosulfuron-degrading bacterial resources,the activated sludge samples from a nicosulfuron manufacturer in Hefei city were used for study object,from which an isolated and screened strain grew well with glucose as sole carbon source and nicosulfuron as sole nitrogen source.Based on its phenotypic characteristics,the 16S rRNA gene sequence similarity,the values of DNA-DNA hybridization and average nucleotide identity,it was identified as Chryseobacterium lacus LAM-M5.This strain degraded 92.39% of 50 mg/L nicosulfuron within 7 d.Liquid chromatography mass spectrometry was used to detect and identify the metabolites after mixing culture of LAM-M5 and nicosulfuron,and 5 major substances were detected.The metabolic pathway of LAM-M5 degrading nicosulfuron was primarily speculated based on the chemical structure and characteristics of intermediates.High performance liquid chromatography was employed to isolate and identify the acids generated during the degradation of nicosulfuron by strain LAM-M5,and the results showed that L-malic acid was predominant.It was deduced that strain LAM-M5 metabolized the glucose into L-malic acid when its growth was stressed by the nicosulfuron,from which the environmental pH decreased and the nicosulfuron hydrolyzed,thus the stress was released.Through the analysis of the whole genome sequence of strain LAM-M5,7 annotated genes that may contribute to the degradation of nicosulfuron were predicted.The results reveal that strain LAM-M5 has excellent ability of degrading nicosulfuron and may have promising application potential in the microbial remediation of nicosulfuron-polluted environment.