Cyanobacterial blooms releasing harmful cyanotoxins, such as microcystin (MC) and cylindrospermopsin (CYN), are prominent threats to human and animal health. Constructed wetlands (CW) may be a nature-based solution for bioremediation of lake surface water containing cyanotoxins, due to its low-cost requirement of infrastructure and environmentally friendly operation. There is recent evidence that microcystin-LR (MC-LR) can efficiently be removed in CW microcosms where CYN degradation in CW is unknown. Likewise, the mechanistic background regarding cyanotoxins transformation in CW is not yet elucidated. In the present study, the objective was to compare MC-LR and CYN degradation efficiencies by two similar microbial communities obtained from CW mesocosms, by two different experiments setup: 1) in vitro batch experiment in serum bottles with an introduced CW community, and 2) degradation in CW mesocosms. In experiment 1) MC-LR and CYN were spiked at 100 µg L⁻¹ and in experiment 2) 200 µg L⁻¹ were spiked. Results showed that MC-LR was degraded to ≤1 µg L⁻¹ within seven days in both experiments. However, with a markedly higher degradation rate constant in the CW mesocosms (0.18 day⁻¹ and 0.75 day⁻¹, respectively). No CYN removal was detected in the in vitro incubations, whereas around 50 % of the spiked CYN was removed in the CW mesocosms. The microbial community responded markedly to the cyanotoxin treatment, with the most prominent increase of bacteria affiliated with Methylophilaceae (order: Methylophilales, phylum: Proteobacteria). The results strongly indicate that CWs can develop an active microbial community capable of efficient removal of MC-LR and CYN. However, the CW operational conditions need to be optimized to achieve a full CYN degradation. To the best of our knowledge, this study is the first to report the ability of CW mesocosms to degrade CYN.

蓝藻水华释放有害的蓝藻毒素，例如微囊藻毒素（MC）和圆柱藻毒素（CYN），对人类和动物健康构成重大威胁。人工湿地（CW）可能是一种基于自然的解决方案，用于含有蓝藻毒素的湖面水的生物修复，因为它对基础设施的低成本要求和环境友好的操作。最近有证据表明，微囊藻毒素-LR (MC-LR) 可以在 CW 微观世界中有效去除，而 CW 中 CYN 的降解情况未知。同样，关于 CW 中蓝藻毒素转化的机制背景尚未阐明。在本研究中，目的是通过两种不同的实验设置，比较从 CW 中生态系统获得的两个相似微生物群落的 MC-LR 和 CYN 降解效率：1）在引入 CW 群落的血清瓶中进行体外批量实验，以及 2 ）在 CW 介观环境中的退化。在实验1)中，MC-LR和CYN以100μg L ^{-1 的}浓度加标，而在实验2)中，MC-LR和CYN以200μg L ^{-1 的}浓度加标。结果表明，两个实验中 MC-LR 在 7 天内均被降解至≤1 µg L ^{-1 。}然而，CW 中生态系统的降解速率常数明显较高（分别为 0.18 天^-1和 0.75 天^-1）。在体外培养中没有检测到 CYN 去除，而大约 50% 的加标 CYN 在 CW 中观系统中被去除。微生物群落对蓝藻毒素处理反应显着，其中嗜甲基科（目：嗜甲基目，门：变形菌门）相关细菌的增加最为显着。结果强烈表明，CW 可以形成活跃的微生物群落，能够有效去除 MC-LR 和 CYN。然而，需要优化 CW 操作条件以实现 CYN 的完全降解。据我们所知，这项研究是第一个报告 CW 中宇宙降解 CYN 的能力的研究。