磷霉素降解菌株的筛选及其降解性能研究

Screening and degradation characterization of fosfomycin-degrading bacterial strains

以磷霉素为唯一碳源,从驯化污泥中纯化筛选出3株降解磷霉素的菌株(F1、F2、F3),对其进行形态学、生理生化特征以及16S r DNA序列分析,鉴定其菌属,分析其生长特征;选用生长适应期较短的菌株F3开展不同p H和温度条件下菌株对磷霉素降解性能的研究,并用一级动力学方程对其降解过程进行拟合。结果表明:菌株F1鉴定为微杆菌属(Microbacterium sp.),菌株F2和F3均鉴定为贪铜菌属(Cupriavidus sp.)。菌株F3对磷霉素的降解性能受温度和p H的影响,在种液接种量为20%、转速为150 r/min、磷霉素浓度为20 mg/L时,菌株F3对磷霉素的最适降解条件:p H为5. 0,温度为20℃。菌株F3对磷霉素的降解符合一级动力学特征,拟合方程相关系数(R^2)> 0. 88; p H为5. 0、温度为20℃时,半衰期(t1/2)为31. 36 d。

Fosfomycin-degradation strains were isolated from acclimated activated sludge feeding fosfomycin as the sole carbon source.Three fosfomycin-degradation strains,named F1,F2 and F3,were screened out and their morphological observation,physiological and biochemical characteristics,as well as 16S rDNA sequence were analysed to identify the genus and the growth characteristics.Strain F3 had a faster growth adaptation period,and was selected to study the degradation of fosfomycin.The effects of operation parameters such as temperature and pH on fosfomycin degradation were explored,and the degradation process was fitted by the first-order kinetic equation.The results showed that strain F1 belonged to Microbacterium sp.and strain F2 and F3 both belonged to Cupriavidus sp.The degradation process of fosfomycin of strain F3 was affected by temperature and pH.The optimal conditions were pH 5.0 and temperature 20℃when the inoculum was 20%,the rotation speed was 150 r min,and the fosfomycin concentration was 20 mg L.The degradation process fitted well with pseudo-first-order kinetic model,and the correlation coefficient R 2 exceeded 0.88.When pH was 5.0 and temperature was 20℃,the half-life period was 31.36 d.