微生物菌群JSM004对微囊藻毒素的生物降解

Biodegradation of Microcystins by Indigenous Mixed Bacterial Population JSM004

以太湖水华蓝藻中提取纯化的微囊藻毒素(microcystins,MCs)作为微生物生长的碳源和氮源,从富营养化的太湖水体中分离筛选到MCs高效降解菌群JSM004,24h内可以将初始浓度分别为3.64和2.62mg·L-1的MC-RR和MC-LR完全降解。在研究关于环境因子对JSM004降解效率的影响中,发现菌群JSM004的生长受温度和pH值影响较大,而且其对MCs的降解效率也随之变化。结果表明,在接近实际水体的中性和弱碱性环境中,JSM004对MCs的降解活性最强,加入不同含碳和含氮化合物能够促进混合微生物菌群的生长,但是对MCs的降解却有明显的延滞作用。与对照组相比,MCs被完全降解的时间至少推迟24h。在实验室条件下,JSM004可在72h内完全降解太湖水中高浓度的MCs。研究结果表明微囊藻毒素降解菌群JSM004具有良好的MCs降解效果,有实际应用前景。

The indigenous mixed bacterial populations JSM004 were isolated from eutrophic waters of Taihu by using the MCs extract from cyanobacteria of blooms as the sole carbon and nitrogen source. This isolate showed high MCs-degrading activity, which could completely degrade 3.64 mg.L^-1 of MC-RR and 2.62 mg.L^-1 of MC-LR within 24 h. Subsequently, the effects of environmental factors on the MCs- degradation by JSM004 were investigated, and the results showed that both temperature and pH value could affect the growth of JSM004 as well as its MCs-degrading rate. It was demonstrated that JSM004 showed highest MCs-degrading activity in natural or slight alkali culture fluids. The addition of other carbon or nitrogen compounds could promote the growth of JSM004, but cause a prolonged lag phase more than 24 h to completely degrade MCs as compared to the control group. Under the laboratory conditions, JSM004 could completely degrade high levels of MCs of lake water in 72 h. In conclusion, JSM004 could be considered as one of the prospective candidates in the application of MCs removal because of its high efficiency of MCs-degradation.