Liu Yafeng, Ren Jing, Wang Xiangrong, Fan Zhengqiu
Department of environmental science & engineering, Fudan University, Shanghai, 200433, China.
PLoS One. 2016 Jun 9;11(6):e0156236. doi: 10.1371/journal.pone.0156236. eCollection 2016.
Microcystin-LR (MCLR) is the most common cyanotoxin in contaminated aquatic systems. MCLR inhibits protein phosphatases 1 and 2A, leading to liver damage and tumor formation. MCLR is relatively stable owing to its cyclic structures. The combined UV/H2O2 technology can degrade MCLR efficiently. The second-order rate constant of the reaction between MCLR and hydroxyl radical (·OH) is 2.79(±0.23)×1010 M-1 s-1 based on the competition kinetics model using nitrobenzene as reference compound. The probable degradation pathway was analyzed through liquid chromatography mass spectrometry. Results suggested that the major destruction pathways of MCLR were initiated by ·OH attack on the benzene ring and diene of the Adda side chain. The corresponding aldehyde or ketone peptide residues were formed through further oxidation. Another minor destruction pathway involved ·OH attack on the methoxy group of the Adda side chain, followed by complete removal of the methoxy group. The combined UV/H2O2 system is a promising technology for MCLR removal in contaminated aquatic systems.
微囊藻毒素-LR（MCLR）是受污染水体系统中最常见的蓝藻毒素。MCLR可抑制蛋白磷酸酶1和2A，导致肝损伤和肿瘤形成。由于其环状结构，MCLR相对稳定。紫外/过氧化氢联合技术可有效降解MCLR。以硝基苯为参比化合物，基于竞争动力学模型，MCLR与羟基自由基（·OH）反应的二级反应速率常数为2.79(±0.23)×1010 M-1 s-1。通过液相色谱-质谱联用分析了可能的降解途径。结果表明，MCLR的主要破坏途径是由·OH攻击苯环和Adda侧链的二烯引发的。通过进一步氧化形成相应的醛或酮肽残基。另一条次要的破坏途径是·OH攻击Adda侧链的甲氧基，随后甲氧基被完全去除。紫外/过氧化氢联合系统是去除受污染水体系统中MCLR的一种很有前景的技术。
