高锰酸钾灭活铜绿微囊藻及胞内毒素释放机制

Inactivation of Microcystis aeruginosa by Permanganate and Release Kinetics of Intracellular Microcystin

摘要:

采用高锰酸钾对微囊藻毒素MC LR进行氧化试验，结果表明MC LR氧化降解符合二级动力学模型，铜绿微囊藻细胞外代谢有机物（EOM）和细胞内代谢有机物（IOM）背景下，MC LR降解速率常数分别为368.3 (mol·L-1)-1·s-1和400.2 (mol·L-1)-1·s-1.同时，采用高锰酸钾对铜绿微囊藻进行预氧化试验，研究不同氧化剂投加量、氧化时间对铜绿微囊藻活性、藻毒素MC LR的释放的影响.结果表明，高锰酸钾对藻活性、细胞内MC LR的释放均符合二级动力学模型.氧化过程中存在两个氧化剂暴露剂量临界点，细胞灭活临界点及毒素释放临界点.细胞灭活临界点之前氧化剂主要与EOM和藻细胞细胞壁上的分泌物反应，藻活性缓慢降低，细胞灭活临界点之后，氧化剂直接与细胞壁反应，导致藻细胞迅速丧失活性，同时藻活性下降速率常数由0.49~2.35 (mol·L-1)-1·s-1突变至5.00~19.38 (mol·L-1)-1·s-1.毒素释放临界点之前藻细胞基本保持完整，MC LR释放不明显，毒素释放临界点处藻细胞发生明显破裂和溶解，细胞内MC LR大量释放，同时，MC LR释放速率常数在临界点前后由0.55~1.45 (mol·L-1)-1·s-1突变至0.96~14.45 (mol·L-1)-1·s-1.3维荧光光谱（EEM）分析发现，当高锰酸钾暴露剂量达到细胞灭活临界点时，EOM中类腐殖质峰开始出现，暴露剂量达到毒素释放临界点时，类腐殖质峰显著增加，与藻细胞活性及胞内MC LR释放规律类似.

Abstract:

Oxidation of Microcystin LR (MC LR) in background of Microcystis aeruginosa intracellular organic matter (IOM) and extracellular organic matter (EOM) by potassium permanganate was studied. MC LR degradation followed second order kinetic with the rate constants of 368.3 and 400.2 (mol·L-1)-1·s-1 in EOM and IOM background respectively. Meanwhile, pre oxidation of Microcystis aeruginosa by potassium permanganate was studied. The impacts of permanganate dosage and reaction time on quantum yield, release of intracellular MC LR and other featured organic matter were investigated. The release of intracellular MC LR and decrease of quantum yield both followed second order kinetic with turning point at permanganate exposure respectively. Permanganate mainly reacted with EOM and the cell bounded organic matter before exposure value arriving quantum yield turning point. Thereafter, permanganate directly reacted with cell wall of algae causing the rapid reduce of quantum yield with the rate constant greatly increased from 0.49~2.35 (mol·L-1)-1·s-1 to 5.00 ~19.38 (mol·L-1)-1·s-1. Similarly, MC LR was slightly released while permanganate exposure value below release turning point, where algae cells kept relatively integrated. Subsequently, algae damage occurred after the release turning point, inducing mass of intracellular MC LR release with the rate constant greatly increased from 0.55~1.45 (mol·L-1)-1·s-1 to 0.96~14.45 (mol·L-1)-1·s-1. Humus like peak was observed emerging at quantum yield turning point and becoming evident at release turning point, which is very similar to the pattern of quantum yield dropping and intracellular MC LR releasing.