Key Laboratory of Environmental Medicine Engineering, Ministry of Education of China, School of Public Health, Southeast University, Nanjing 210009, China.
Department of Civil and Environmental Engineering, University of California, Irvine, CA 92697, USA.
Toxins (Basel). 2020 Mar 15;12(3):183. doi: 10.3390/toxins12030183.
Microcystins (MCs), which are produced by harmful cyanobacteria blooms, pose a serious threat to environmental health. However, the effect of MCs on the bacterial community under anaerobic conditions is still unclear. This study examined the dynamic changes of MC-degrading capacity, metabolic activity, and structure of the bacterial community in lake sediment repeatedly treated with 1 mg/L microcystin-LR (MC-LR) under anaerobic conditions. The results showed that the MC-degrading capacity of the bacterial community was increased nearly three-fold with increased treatment frequency. However, the metabolic profile behaved in exactly opposite trend, in which the overall carbon metabolic activity was inhibited by repeated toxin addition. Microbial diversity was suppressed by the first addition of MC-LR and then gradually recovered. The 16S amplicon sequencing showed that the dominant genera were changed from and to , , and . Furthermore, the increase in the relative abundance of , , , and was positively correlated with the MC-LR treatment times. This indicates that they might be responsible for MC degradation under anaerobic conditions. Our findings reveal the relationship between MC-LR and the sediment bacterial community under anaerobic conditions and indicate that anaerobic biodegradation is an effective and promising method to remediate MCs pollution.
微囊藻毒素（MCs）是由有害蓝藻水华产生的，对环境健康构成严重威胁。然而，MCs 对厌氧条件下细菌群落的影响尚不清楚。本研究考察了在厌氧条件下，反复用 1mg/L 微囊藻毒素-LR（MC-LR）处理后，湖底沉积物中 MC 降解能力、代谢活性和细菌群落结构的动态变化。结果表明，随着处理频率的增加，细菌群落的 MC 降解能力增加了近三倍。然而，代谢谱却呈现出完全相反的趋势，即随着毒素的反复添加，整体碳代谢活性受到抑制。微生物多样性受到 MC-LR 首次添加的抑制，然后逐渐恢复。16S 扩增子测序表明，优势属从 和 变为 、 、 。此外， 、 、 、 相对丰度的增加与 MC-LR 处理次数呈正相关。这表明它们可能是在厌氧条件下进行 MC 降解的原因。我们的研究结果揭示了 MC-LR 与厌氧条件下底泥细菌群落之间的关系，并表明厌氧生物降解是修复 MCs 污染的一种有效且有前途的方法。
