State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, China.
State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, China.
J Hazard Mater. 2022 Feb 5;423(Pt B):127248. doi: 10.1016/j.jhazmat.2021.127248. Epub 2021 Sep 17.
The fate of antibiotics in activated sludge has attracted increasing interests. However, the focus needs to shift from concerning removal efficiencies to understanding mechanisms and sludge responding to antibiotic toxicity. Herein, we operated two anaerobic sequencing batch reactors (ASBRs) for 200 days with sulfadiazine (SDZ) and sulfamethoxazole (SMX) added. The removal efficiency of SMX was higher than that of SDZ. SDZ was removed via adsorption (9.91-21.18%) and biodegradation (10.20-16.00%), while biodegradation (65.44-86.26%) was dominant for SMX removal. The mechanisms involved in adsorption and biodegradation were investigated, including adsorption strength, adsorption sites and the roles of enzymes. Protein-like substance (tryptophan) functioned vitally in adsorption by forming complexes with sulfonamides. P450 enzymes may catalyze sulfonamides degradation via hydroxylation and desulfurization. Activated sludge showed distinct responses to different sulfonamides, reflected in the changes of microbial communities and functions. These responses were related to sulfonamides removal, corresponding to the stronger adsorption capacity of activated sludge in ASBR-SDZ and degradation capacity in ASBR-SMX. Furthermore, the reasons for different removal efficiencies of sulfonamides were analyzed according to steric and electronic effects. These findings propose insights into antibiotic removal and broaden the knowledge for self-protection mechanisms of activated sludge under chronic toxicities of antibiotics.
抗生素在活性污泥中的命运引起了越来越多的关注。然而，研究重点需要从关注去除效率转移到理解机制和污泥对抗生素毒性的响应上来。本研究采用两个厌氧序批式反应器（ASBR），连续运行 200 天，投加磺胺嘧啶（SDZ）和磺胺甲恶唑（SMX）。结果表明，SMX 的去除效率高于 SDZ。SDZ 的去除主要通过吸附（9.91-21.18%）和生物降解（10.20-16.00%），而 SMX 的去除主要通过生物降解（65.44-86.26%）。进一步探讨了吸附和生物降解的机制，包括吸附强度、吸附位点和酶的作用。色氨酸等蛋白质类物质通过与磺胺类物质形成复合物，对磺胺类物质的吸附起到重要作用。P450 酶可能通过羟化和脱硫作用，催化磺胺类物质的降解。活性污泥对不同磺胺类物质表现出明显的响应，反映在微生物群落和功能的变化上。这些响应与磺胺类物质的去除有关，与 ASBR-SDZ 中活性污泥较强的吸附能力和 ASBR-SMX 中的降解能力相对应。此外，还根据空间和电子效应分析了磺胺类物质去除效率不同的原因。这些发现为抗生素去除提供了新的见解，并拓宽了关于活性污泥在抗生素慢性毒性下自我保护机制的知识。
