Detoxification strategy of Microcystis aeruginosa to the toxicity of Cd(Ⅱ):role of EPS in alleviating toxicity  

作　　者：Xingye HAN Fangyuan LIU Yibo ZHANG Kai CHENG Heyun WANG Hongmei GE 

机构地区：[1]Innovation Demonstration Base of Ecological Environment Geotechnical and Ecological Restoration of Rivers and Lakes,School of Civil Engineering,Architecture and Environment,Hubei University of Technology,Wuhan 430068,China [2]School of Environmental Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074,China [3]National Engineering Research Center of Advanced Technology and Equipment for Water Environment Pollution Monitoring,Wuhan 430068,China

出　　处：《Journal of Oceanology and Limnology》2024年第3期802-815,共14页海洋湖沼学报（英文）

基　　金：Supported by the National Natural Science Foundation of China(Nos.31800457,32170383)。

摘　　要：Although many studies have found that cadmium(Cd)can be toxic to microalgae,only a few reports focused on the role of extracellular polymeric substances(EPS)in Cd(Ⅱ)detoxification.The biochemical and physiological endpoints of Microcystis aeruginosa,including the composition and functional groups of soluble EPS(SL-EPS),loosely bound EPS(LB-EPS),and tightly bound EPS(TB-EPS),were detected to elucidate the toxicity and detoxification mechanisms of Cd(Ⅱ)for cyanobacteria.Toxicological and physiological assays on M.aeruginosa showed that the 0.25-mg/L Cd(Ⅱ)resulted in a larger inhibition on growth and F_(v)/F_(m).Nevertheless,Cd(Ⅱ)significantly induced much higher contents of superoxide dismutase(SOD),intracellular microcystin LR(MC-LR),extracellular MC-LR,and EPS.Scanning electron microscopy with energy dispersive X-ray spectroscopy confirmed that Cd(Ⅱ)was absorbed into the EPS layer.Fourier transform infrared spectrum analysis revealed that the functional groups bound with Cd(Ⅱ)of algae biomass,SL-EPS,LB-EPS,and TB-EPS were somewhat different.The C=O/C=N groups ofδ-lactam or protein were their prominent functional groups,suggesting that amide or proteins in the EPS played a key role in the adsorption in Cd(Ⅱ).The concentration of 0.25 mg/L of Cd(Ⅱ)may change the chemical structure of EPS by altering the production of protein-like substances containing tryptophan.This study indicated that M.aeruginosa could detoxify Cd(Ⅱ)stress via induction of antioxidant capacity(higher SOD activity and MC synthesis),EPS production,and modification in chemical structure of EPS.

关 键 词：Microcystis aeruginosa CADMIUM extracellular polymeric substances(EPS) MICROCYSTIN DETOXIFICATION 

分 类 号：X173[环境科学与工程—环境科学]