微囊藻毒素降解菌的筛选、鉴定及其降解活性研究

采用从巢湖水华蓝藻细胞中提取、提纯的藻毒素（Microcystins,MCs）为微生物生长的唯一碳源和氮源,通过平板分离纯化,从巢湖底泥中分离出5株能够降解藻毒素的菌株,并对其中降解活性较高的一株进行分子鉴定。应用PCR技术克隆到16S rDNA片段,核苷酸序列分析结果表明,该菌的16S rDNA的全序列与吉氏库特菌kurthia gib-soniistrain HC050630C-1的相似性达99%。微囊藻毒素降解实验结果表明,用15mg/L乙醇作为外加碳源时可显著提高菌株M9降解MCs的能力,在48h内对初始浓度分别为17.1mg/L的MC-RR和11.3mg/L的MC-LR的降解率分别达到70.0%和81.6%。而葡萄糖对菌株M9的生长有明显抑制作用。

Screening, identification of a microcystins degrading bacteria strain and its activity for the biodegradation of microcystins

Five strains of bacteria which could biodegrade microcystins were screened from the sediment of Chaohu lake using extracted and purified MCs as the carbon and nitrogen sources.Experimental results showed that the strain M9 had the highest degrading capacity,and the molecular identification of strain M9 was conducted according to the result of the phylogenetical analyses of 16S rDNA sequence.BLAST sequence analysis showed that it had a 99% similarity to that of Kurthia gibsonii strain HC050630C-1.Strain M9 could degrade 70.0% of 17.1mg/L MC-RR and 81.6% of 11.3mg/L MC-LR with 15mg/L of ethanol as an external carbon source in 48h.However,the obvious inhibition could be observed when glucose was used as external carbon source.