Microcystin-LR biodegradation by Sphingopyxis sp USTB-05
Microcystin-LR biodegradation by Sphingopyxis sp USTB-05
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DOI：
10.1007/s11783-010-0261-7
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发表时间：
2011-12-01
影响因子：
--
通讯作者：
Pan, Gang
中科院分区：
文献类型：
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作者：
Xiao, Chengbin;Yan, Hai;Pan, Gang
从滇池成功分离到一株具有生物降解微囊藻毒素- lr （MC-LR）唯一碳氮源的菌株。该菌株鉴定为Sphingopyxis sp. USTB-05，为国内首次分离到的mcs生物降解Sphingopyxis sp.。Sphingopyxis sp. USTB-05对MC-LR的平均生物降解率为28.8 mg中心点L-1 / d，明显高于目前报道的其他细菌。菌株USTB-05生长和降解MC-LR的最适温度和pH分别为30℃和7.0℃。研究了从桂水湖采集的蓝藻细胞对MC-LR的释放以及菌株和无细胞提取物（CE）对MC-LR的生物降解作用。结果表明，初始浓度为4.0 mg中心点L-1的MC-LR可在4 d内被Sphingopyxis sp. USTB-05降解，初始浓度为28.8 mg中心点L-1的MC-LR可在3 h内被含有350 mg中心点L-1蛋白的Sphingopyxis sp. USTB-05降解。在MC-LR酶解过程中，高效液相色谱上观察到两种中间代谢物和一种终端产物。此外，MC-LR及其代谢产物的相似扫描图谱表明，MC-LR的Adda侧链在所有产物中都保持完整。
A promising bacterial strain for biodegrading microcystin-LR (MC-LR) as the sole carbon and nitrogen source was successfully isolated from Lake Dianchi, China. The strain was identified as Sphingopyxis sp. USTB-05, which was the first isolated MCs-biodegrading Sphingopyxis sp. in China. The average biodegradation rate of MC-LR by Sphingopyxis sp. USTB-05 was 28.8 mg center dot L-1 per day, which was apparently higher than those of other bacteria reported so far. The optimal temperature and pH for both strain USTB-05 growth and MC-LR biodegradation were 30A degrees C and 7.0, respectively. The release of MC-LR from the cyanobacterial cells collected from Lake Guishui and the biodegradation of MC-LR by both strain and cell-free extract (CE) were investigated. The results indicated that MC-LR with the initial concentration of 4.0 mg center dot L-1 in water was biodegraded by Sphingopyxis sp. USTB-05 within 4 d, while MC-LR with the initial concentration of 28.8 mg center dot L-1 could be completely removed in 3 h by CE of Sphingopyxis sp. USTB-05 containing 350 mg center dot L-1 protein. During enzymatic biodegradation of MC-LR, two intermediate metabolites and a dead-end product were observed on an HPLC chromatogram. Moreover, the similar scanning profiles of MC-LR and its metabolic products indicate that the Adda side-chain of MC-LR was kept intact in all products.