Microbial biodegradation of microcystin-RR by bacterium Sphingopyxis sp. USTB-05  

作　　者：Mulan Zhang Gang Pan Hai Yan 

机构地区：[1]State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China [2]Department of Biological Science and Technology, School of Applied Science, University of Science and Technology Beijing, Bering 100083, China

出　　处：《Journal of Environmental Sciences》2010年第2期168-175,共8页环境科学学报（英文版）

基　　金：supported by the Chinese National Key Project for Basic Research (No.2008CB418105);the National Natural Science Foundation of China(No.20621703,20477050);the Important-Direction-Project funded by the Chinese Academy of Sciences

摘　　要：A strain, USTB-05, isolated from Lake Dianchi, China, degraded the cyanobacterial toxin microcystin-RR （MC-RR） at the rate of 16.7 mg/L per day. Analysis of 16S rDNA sequence showed that the strain was Sphingopyxis sp. Enzymatic degradation pathways for MC-RR by Sphingopyxis sp. USTB-05 were identified. Adda-Arg peptide bond of MC-RR was cleaved and then a hydrogen and a hydroxyl were combined onto the NH2 group of Adda and the carboxyl group of arginine to form a linear molecule as intermediate product within the first few hours. Then, through dehydration reaction, two hydrogen of amino group on arginine reacted with adjacent hydroxyl on carbon to form a linear MC-RR with two small peptide rings as the final product after 24 hr. These biodegradation pathways were different from those reported for other strains, implying that MC-RR may undergo different transformations and different products were formed due to various bacteria in natural lakes and reservoirs.A strain, USTB-05, isolated from Lake Dianchi, China, degraded the cyanobacterial toxin microcystin-RR （MC-RR） at the rate of 16.7 mg/L per day. Analysis of 16S rDNA sequence showed that the strain was Sphingopyxis sp. Enzymatic degradation pathways for MC-RR by Sphingopyxis sp. USTB-05 were identified. Adda-Arg peptide bond of MC-RR was cleaved and then a hydrogen and a hydroxyl were combined onto the NH2 group of Adda and the carboxyl group of arginine to form a linear molecule as intermediate product within the first few hours. Then, through dehydration reaction, two hydrogen of amino group on arginine reacted with adjacent hydroxyl on carbon to form a linear MC-RR with two small peptide rings as the final product after 24 hr. These biodegradation pathways were different from those reported for other strains, implying that MC-RR may undergo different transformations and different products were formed due to various bacteria in natural lakes and reservoirs.

关 键 词：MICROCYSTIN-RR BIODEGRADATION Sphingopyxis sp. USTB-05 enzymatic pathways Lake Dianchi 

分 类 号：Q939.1[生物学—微生物学] G644[文化科学—高等教育学]