中文摘要：

从蓝藻爆发期的上海市淀山湖表层水体中筛选分离降解微囊藻毒素-RR（MC-RR）的细菌，研究其降解特性。根据分离菌株的细胞形态结构、生理生化特征及其16SrDNA序列分析鉴定降解菌，高效液相色谱法测定该菌株降解MC-RR的能力。分离菌株DHU-38（GenBank序列登录号为HM047515）属荧光假单胞菌（Pseudomonas fluorescens）。微囊藻毒素降解实验结果表明，该菌株能在以MC-RR为唯一碳源、氮源的无机盐培养基中生长，6d内可将初始质量浓度为20mg／L的MC-RR降解为6．23mg／L，降解效率达到69％。菌株DHU-38的最适生长温度是30℃，最适生长pH值为7．0。酵母粉、蛋白胨、葡萄糖等营养物质可以明显促进菌株对MC-RR的降解效率，尤其是加入100mg／L酵母粉后，6d降解率达到89．6％。

英文摘要：

A strain of Microcystin-RR （MC-RR）degrading bacterium was isolated from the surface waters in Dianshanhu, Shanghai and identified based on its morphology, physiology and phylogenetic analysis of 16S rDNA sequence. The degradation ability of this strain was evaluated with high performance liquid chromatography. Strain DHU-38 was identified to be closely related to Pseudomonas fluorescens（GenBank accession number is HM047515）. DHU-38 could grow on mineral salt medium supplied with MC-RR as sole carbon and nitrogen source. Initial MC-RR of 20 mg/L was degraded to 6.23 mg/L in 6 days and the average biodegradation rate is 69%. The optimum condition of degrading bacterium DHU-38 was at 30℃, pH 7.0. Yeast extract, peptone and glucose could significantly enhance the degradation rate of MC-RR. Especially, strain DHU-38 could degrade MC-RR by 89.6% in liquid mineral salt medium with 100 mg/L yeast extract.