College of Engineering, China Agricultural University, Beijing, 100083, PR China.
Key Laboratory for Crop and Animal Integrated Farming, Ministry of Agriculture and Rural Affairs, Nanjing, 210014, PR China.
Environ Res. 2024 Sep 1;256:119225. doi: 10.1016/j.envres.2024.119225. Epub 2024 May 24.
Sulfadiazine (SDZ) is a kind of anti-degradable antibiotics that is commonly found in wastewater, but its removal mechanism and transformation pathway remain unclear in microalgal systems. This study investigated the effects of initial algae concentration and SDZ-induced stress on microalgal growth metabolism, SDZ removal efficiency, and transformation pathways during Chlorella sp. cultivation. Results showed that SDZ had an inhibitory effect on the growth of microalgae, and increasing the initial algal biomass could alleviate the inhibitory effect of SDZ. When the initial algal biomass of Chlorella sp. was increased to 0.25 g L, the SDZ removal rate could reach 53.27%-89.07%. The higher the initial algal biomass, the higher the SOD activity of microalgae, and the better the protective effect on microalgae, which was one of the reasons for the increase in SDZ removal efficiency. Meanwhile, SDZ stress causes changes in photosynthetic pigments, lipids, total sugars and protein content of Chlorella sp. in response to environmental changes. The main degradation mechanisms of SDZ by Chlorella sp. were biodegradation (37.82%) and photodegradation (23%). Most of the degradation products of SDZ were less toxic than the parent compound, and the green algae were highly susceptible to SDZ and its degradation products. The findings from this study offered valuable insights into the tradeoffs between accumulating microalgal biomass and antibiotic toxic risks during wastewater treatment, providing essential direction for the advancement in future research and full-scale application.
磺胺嘧啶（SDZ）是一种在废水中普遍存在的难降解抗生素，但它在微藻系统中的去除机制和转化途径仍不清楚。本研究探讨了初始藻浓度和 SDZ 诱导的胁迫对小球藻培养过程中微藻生长代谢、SDZ 去除效率和转化途径的影响。结果表明，SDZ 对微藻的生长有抑制作用，增加初始藻生物量可以减轻 SDZ 的抑制作用。当小球藻的初始藻生物量增加到 0.25 g/L 时，SDZ 的去除率可达 53.27%-89.07%。初始藻生物量越高，微藻的 SOD 活性越高，对微藻的保护作用越好，这也是 SDZ 去除效率提高的原因之一。同时，SDZ 胁迫会导致小球藻的光合色素、脂质、总糖和蛋白质含量发生变化，以应对环境变化。小球藻降解 SDZ 的主要机制是生物降解（37.82%）和光降解（23%）。SDZ 的大部分降解产物的毒性低于母体化合物，绿藻对 SDZ 及其降解产物高度敏感。本研究结果为废水处理过程中积累微藻生物量和抗生素毒性风险之间的权衡提供了有价值的见解，为未来研究和全面应用提供了必要的方向。
