College of Architecture and Environment, Sichuan University, Chengdu 610065, PR China.
College of Architecture and Environment, Sichuan University, Chengdu 610065, PR China.
J Hazard Mater. 2022 Jun 5;431:128540. doi: 10.1016/j.jhazmat.2022.128540. Epub 2022 Feb 22.
Sulfamethoxazole (SMX), one of the most widely used sulfonamides antibiotics, is frequently detected in the livestock wastewater. Currently, the focus needs to shift from performance effects to understanding of mechanisms and intermediate toxicity analysis. Our study found that SMX (0.5, 1, and 2 mg/L) stimulated methane production by promoting the process of acetogenesis and homo-acetogenesis. Since 1 mg/L SMX could inhibit the transformation of butyric acid, thus, the stimulation of methane was weak under this condition. Under anaerobic conditions, acetate kinase (AK) and cytochrome P450 enzymes (CYP450) continued to participate in SMX degradation. The increase in SMX concentration affected the release of metabolic enzymes, causing changes in SMX degradation pathways. Based on the main biotransformation products, five biotransformation pathways were proposed, the major transformation reactions including hydroxylation, hydrogenation, acetylation, deamination, oxidation, the elimination of oxygen atoms on sulfonyl, isoxazole ring and NS bond cleavage. Toxicity prediction analysis showed that the toxicities of most SMX transformation products were lower than that of SMX.
磺胺甲恶唑（SMX）是最广泛使用的磺胺类抗生素之一，经常在牲畜废水中被检测到。目前，研究重点需要从性能影响转移到对机制的理解和中间毒性分析上。我们的研究发现，SMX（0.5、1 和 2mg/L）通过促进产乙酸作用和同型产乙酸作用来刺激甲烷生成。由于 1mg/L SMX 可以抑制丁酸的转化，因此在此条件下，甲烷的刺激作用较弱。在厌氧条件下，乙酰激酶（AK）和细胞色素 P450 酶（CYP450）继续参与 SMX 的降解。SMX 浓度的增加会影响代谢酶的释放，从而改变 SMX 的降解途径。基于主要的生物转化产物，提出了五条生物转化途径，主要的转化反应包括羟化、氢化、乙酰化、脱氨、氧化、磺酰基、异恶唑环和 NS 键断裂上的氧原子消除。毒性预测分析表明，大多数 SMX 转化产物的毒性低于 SMX。
