Although various wastewater treatment systems have been reported to be capable of transforming antibiotics, there is limited knowledge regarding the potential degradation of antibiotics through microbiological processes in a membrane aerated biofilm reactor (MABR) system. Therefore, this study aimed to investigate the metabolism of tetracycline (TC) and nitrogen in a MABR system. Results showed that the TC can initially be adsorbed by extracellular polymeric substances (EPS) and subsequently biodegraded into 17 low toxic intermediates by microbes, demonstrating that MABR could complete TC biotransformation with disruption of its chemical structure. The biodegradation pathways of TC were proposed, which mainly contained demethylation, deamination, hydroxylation, dehydration, dihydroxylation, bond cleavage and ring opening. The analysis of high-throughput sequencing (HTS) technology showed the existence of a diverse microbial community with varied metabolic pathways in the counter-diffusion biofilm system. Results demonstrated that nitrogen removal in the MABR system occurred through multiple pathways, including traditional autotrophic nitrification-heterotrophic denitrification, heterotrophic nitrification, aerobic denitrification, and autotrophic denitrification. Additionally, both tetracycline degrading bacteria (TDB) and archaea (TDA) coexisted in the MABR system, among which Methylophilus could contribute to the demethylation, while Rhizobium, Hydrogenophaga and Ramlibacter were crucial in cracking of aromatic ring for TC biodegradation.

尽管据报道各种废水处理系统能够转化抗生素，但关于膜曝气生物膜反应器 (MABR) 系统中微生物过程可能降解抗生素的知识有限。因此，本研究旨在研究MABR系统中四环素（TC）和氮的代谢。结果表明，TC 最初可以被胞外聚合物 (EPS) 吸附，随后被微生物生物降解为 17 种低毒中间体，表明 MABR 可以在破坏其化学结构的情况下完成 TC 的生物转化。提出了TC的生物降解途径，主要包括去甲基化、脱氨基、羟基化、脱水、二羟基化、断键和开环等。高通量测序（HTS）技术分析表明，反扩散生物膜系统中存在具有不同代谢途径的多样化微生物群落。结果表明，MABR系统的脱氮通过多种途径发生，包括传统的自养硝化-异养反硝化、异养硝化、好氧反硝化和自养反硝化。此外，MABR系统中同时存在四环素降解菌（TDB）和古细菌（TDA），其中 包括传统的自养硝化-异养反硝化、异养硝化、好氧反硝化、自养反硝化。此外，MABR系统中同时存在四环素降解菌（TDB）和古细菌（TDA），其中 包括传统的自养硝化-异养反硝化、异养硝化、好氧反硝化、自养反硝化。此外，MABR系统中同时存在四环素降解菌（TDB）和古细菌（TDA），其中嗜甲基菌有助于去甲基化，而根瘤菌、Hydrogenophaga和Ramlibacter在 TC 生物降解的芳香环裂解中起关键作用。