Key Laboratory of Agri-food Safety of Anhui Province, School of Resources and Environment, Anhui Agricultural University, Hefei 230036, PR China.
School of Environmental Science and Engineering, Yangzhou University, Yangzhou 225127, Jiangsu, PR China.
Ecotoxicol Environ Saf. 2022 Oct 1;244:114045. doi: 10.1016/j.ecoenv.2022.114045. Epub 2022 Aug 30.
The antidepressant fluoxetine (FLX) has gained increasing attention due to its frequent detection in aquatic environments and negative effects on non-target organisms. However, knowledge on the ecotoxicological effects of FLX and its removal by microalgae is still limited. In this study, the ecotoxicological effects of FLX (10 -1000 μg/L) were assessed using batch cultures of the freshwater microalgae Chlorella pyrenoidosa for 10 days based on changes in growth, antioxidant response, and photosynthetic process. The removal efficiency, removal mechanism, and degradation pathway of FLX by C. pyrenoidosa were also investigated. The results showed that the growth of C. pyrenoidosa was inhibited by FLX with a 4 d EC of 0.464 mg/L. Additionally, FLX significantly inhibited photosynthesis and caused oxidative stress on day 4. However, C. pyrenoidosa can produce resistance and acclimatize to FLX, as reflected by the declining growth inhibition rate, recovered photosynthetic efficiency, and disappearance of oxidative stress on day 10. Despite the toxicity of FLX, C. pyrenoidosa showed 41.2%- 100% removal of FLX after 10 days of exposure. Biodegradation was the primary removal mechanism, accounting for 88.2%- 92.8% of the total removal of FLX. A total of five metabolites were found in the degradation processes of FLX, which showed less toxicity than FLX. The main degradation pathways were proposed as demethylation, O-dealkylation, hydroxylation, and N-acylation. Our results not only highlight the potential application of microalgae in FLX purification, but also provide insight into the fate and ecological risk of FLX in aquatic environments.
氟西汀（FLX）作为一种抗抑郁药，由于其在水生环境中的频繁检出以及对非靶标生物的负面影响而受到越来越多的关注。然而，FLX 的生态毒理学效应及其被微藻去除的知识仍然有限。在这项研究中，采用淡水微藻蛋白核小球藻（Chlorella pyrenoidosa）的批式培养，基于生长、抗氧化响应和光合作用的变化，评估了 FLX（10-1000μg/L）的生态毒理学效应。还研究了 C. pyrenoidosa 对 FLX 的去除效率、去除机制和降解途径。结果表明，FLX 抑制 C. pyrenoidosa 的生长，其 4d 的半数效应浓度（EC）为 0.464mg/L。此外，FLX 在第 4 天显著抑制光合作用并引起氧化应激。然而，C. pyrenoidosa 可以产生抗性并适应 FLX，表现为生长抑制率下降、光合作用恢复效率提高，以及第 10 天氧化应激消失。尽管 FLX 具有毒性，但 C. pyrenoidosa 在暴露 10 天后对 FLX 的去除率达到 41.2%-100%。生物降解是主要的去除机制，占 FLX 总去除率的 88.2%-92.8%。在 FLX 的降解过程中发现了总共 5 种代谢物，其毒性均小于 FLX。提出了 FLX 的主要降解途径为去甲基化、O-脱烷基化、羟化和 N-酰化。我们的研究结果不仅突出了微藻在 FLX 净化中的潜在应用，还深入了解了 FLX 在水生环境中的归趋和生态风险。
