二氯喹啉酸降解菌HN36的分离、鉴定及降解特性研究

从生产二氯喹啉酸农药厂的污水处理池污泥中分离到1株二氯喹啉酸降解菌,命名为HN36。根据表型特征、生理生化特性和16SrDNA序列系统发育分析,鉴定为博德特氏菌属(Bordetellasp.)。该菌可以利用二氯喹啉酸作为唯一碳源和能源进行生长,二氯喹啉酸质量浓度为400mg/L时,48 h降解率为96.2%。降解二氯喹啉酸的最适pH值为7,最适温度为30℃,初始接种量在一定范围内(1.5%~5%)与降解率呈正相关。二氯喹啉酸初始质量浓度在100~400 mg/L时,降解效果较好。菌株HN36还能利用喹啉、苯酚、邻苯二酚和邻苯二甲酸进行生长,但不能利用萘和1,2-二氯苯。

On the way of isolating, identifying and characterization of quinclorac-degrading bacterium HN36

The paper is to present our research results on the way of isolating,identifying and characterization of quinclorac-degrading bacterium HN36.The paper also involves the way on how to isolate the bacterium from the activated sludge collected from the sewage-treating system of a pesticide manufacturer.The strain of the bacterium we have identified as Bordetella sp. in accordance with its physiological and biochemical characters and a similarity analysis of its 16S rDNA sequence.As we know,the strain HN36 can grow well even with the quinclorac herbicide being the only carbon source.The bacterium proves to be able to decompose 96.9% of quinclorac at its original concentration of 400 mg/L within 48 h.And the main influential factors affecting its degradation rate are the temperature,pH value,inoculum size and initial substrate concentration.To be exact,the optimal pH and temperature for the degradation proves to be 7 and 30 ℃,respectively.The degradation rate tends to increase from 20 ℃ to 30 ℃ whereas the degradation rate tends to decrease when the temperature exceeds 30 ℃.Similarly,when pH rises from 4 to 7,the degradation rate would increase,however,the degradation rate tends to decrease when the pH rises further.Therefore,the degradation efficiency proves to be related positively to the initial inoculum size(1.5%-5%).When the initial inoculum size was beyond 7%,the degradation efficiency would not be effected.On the other hand,when the initial concentration remains from 100-400 mg/L,the stain will be likely to degrade the quinclorac quickly.On the contrary,the degradation rate tends to drop significantly when the initial concentration is over 500 mg/L.In addition,the strain HN36 would be able to degrade some other aromatic compounds,including quinoline,phenol,catechol and phthalic acid,whereas naphthalene and 1,2-dichlorobenzene could not.Thus,the results of degradation characteristics to quinclorac herbicide indicate that strain HN36 has a great potential in its use as a bioremedy of quinclorac-contaminated soil and water.