一株新型四环素降解菌的分离鉴定及降解条件优化

Isolation,identification and degradation conditions optimization of a novel tetracycline degrading bacterium

以四环素为目标污染物,成功从武汉一污水处理厂的活性污泥中分离出了1株四环素降解菌。该菌株经过形态学鉴定和16S rDNA序列测定,确定为假单胞菌(Pseudomonas sp.)。采用单因素实验方法探究了pH、温度、接种量和外加碳源乙酸钠浓度对菌株降解四环素的影响,并进一步进行响应面优化实验,最后确定菌株降解四环素的最佳条件为:温度32.2℃、pH=8.6、接种量3.7%(体积分数)、乙酸钠质量浓度2.5 g/L。该菌株在最佳条件下对10~80 mg/L的四环素降解率达到90%的降解周期从7 d缩短为4 d,对150 mg/L的四环素降解周期也缩短到5 d。

In this study,tetracycline was used as a target pollutant,and a new strain of tetracycline degrading bacterium was successfully isolated from active sludge of a wastewater treatment plant in Wuhan.The bacterial strain was identified as Pseudomonas sp.by morphology and 16S rDNA sequence determination.The effects of pH,temperature,inoculation amount and the concentration of external carbon source(sodium acetate)on the degradation of tetracycline were investigated by single factor experiment,and then the conditions were optimized by response surface optimization experiment.Finally,the optimal conditions were:temperature 32.2℃,pH 8.6,inoculation amount 3.7%and sodium acetate mass concentration 2.5 g/L.Under the optimal conditions,the degradation cycle(degradation rate reaching 90%)for 10-80 mg/L tetracycline was cut down to 4 days from 7 days,and the degradation cycle for 150 mg/L tetracycline was cut down to 5 days.