Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources of the Ministry of Education, Engineering Research Center of Environmental DNA and Ecological Water Health Assessment, Shanghai Ocean University, Shanghai, 201306, China.
Environ Sci Pollut Res Int. 2024 Jul;31(35):48062-48072. doi: 10.1007/s11356-024-34238-1. Epub 2024 Jul 17.
Microalgae can promote antibiotic removal, which has attracted growing attention. However, its synergistic removal performance with bacteria in antibiotic pollutants is still poorly understood. In this study, firstly, we selected two green algae (Dictyosphaerium sp. and Chlorella sp.) and exposed them to Enrofloxacin (ENR) to observe their extracellular polysaccharides (EPS) concentration dynamic and the removal of antibiotics. Secondly, EPS was extracted and added to in situ lake water (no algae) to investigate its combined effect with bacteria. The results indicate that both Dictyosphaerium sp. and Chlorella sp. exhibited high tolerance to ENR stress. When the biomass of microalgae was low, ENR could significantly stimulate algae to produce EPS. The removal rates of Dictyosphaerium sp. and Chlorella sp. were 15.8% and 10.5%, respectively. The addition of EPS can both alter the microbial community structure in the lake water and promote the removal of ENR. The LEfSe analysis showed that there were significant differences in the microbial marker taxa, which promoted the increase of special functional bacteria for decomposing ENR, between the EPS-added group and the control group. The EPS of Dictyosphaerium sp. increased the abundance of Moraxellaceae and Spirosomaceae, while the EPS of Chlorella sp. increased the abundance of Sphingomonadaceae and Microbacteriaceae. Under the synergistic effect, Chlorella sp. achieved a maximum removal rate of 24.2%, while Dictyosphaerium sp. achieved a maximum removal rate of 28.9%. Our study provides new insights into the removal performance and mechanism of antibiotics by freshwater microalgae in water bodies and contribute to the development of more effective water treatment strategies.
微藻可以促进抗生素的去除，这一点引起了越来越多的关注。然而，其与抗生素污染物中的细菌协同去除性能仍知之甚少。在本研究中，首先，我们选择了两种绿藻（Dictyosphaerium sp. 和 Chlorella sp.）并将其暴露于恩诺沙星（ENR）中，以观察其胞外多糖（EPS）浓度的动态变化和抗生素的去除情况。其次，提取 EPS 并添加到原位湖水中（无藻类），以研究其与细菌的联合作用。结果表明，Dictyosphaerium sp. 和 Chlorella sp. 对 ENR 胁迫均表现出较高的耐受性。当微藻生物量较低时，ENR 可显著刺激藻类产生 EPS。Dictyosphaerium sp. 和 Chlorella sp. 的去除率分别为 15.8%和 10.5%。EPS 的添加既可以改变湖水中的微生物群落结构，又可以促进 ENR 的去除。LEfSe 分析显示，添加 EPS 组与对照组之间在微生物标记分类群方面存在显著差异，这促进了专门用于分解 ENR 的功能细菌的增加。Dictyosphaerium sp. 的 EPS 增加了 Moraxellaceae 和 Spirosomaceae 的丰度，而 Chlorella sp. 的 EPS 增加了 Sphingomonadaceae 和 Microbacteriaceae 的丰度。在协同作用下，Chlorella sp. 的最大去除率达到 24.2%，而 Dictyosphaerium sp. 的最大去除率达到 28.9%。本研究为淡水微藻在水体中去除抗生素的性能和机制提供了新的见解，并为开发更有效的水处理策略做出了贡献。
