Tetracycline (TC) is a widely used pharmaceutical and personal care product (PPCP), and considering its biotoxicity in aquatic systems, the metabolism and stimulation of TC in wastewater purification processes are still deserving of concern. This study reveals the stimulation of TC biodegradation by acetate in bioelectrochemical systems (BESs). Attributed to the abundance of exoelectrogens Geobacter (mainly G. sulfurreducens) and putative TC-degraded bacteria (PTDB) in the electroactive biofilm samples, 94% of 100 mg/L TC decomposed within 48 h. Limited acetate (0.1 g/L, AC-0.1) as a cosubstrate enhanced the removal efficiency of TC by 44% when compared to abundant acetate (1 g/L, AC-1) and controls. This resulted from the enhancement of PTDB and the stability of the Geobacter population under limited acetate stimulation. With the differentiation of the microbial community, ubiquinone and other terpenoid-quinone biosynthesis and histidine metabolism were significantly upregulated in AC-0.1 but downregulated in AC-1, another factor that enhanced the removal efficiency of TCs. Here, we concluded that limited acetate could partially relieve the selective pressure of TC and improve the biodegradation of TC, and the catabolism pathways, as well as the main metabolites, were stimulated by acetate and its concentration.

四环素（TC）是一种广泛使用的药物和个人护理产品（PPCP），考虑到其在水生系统中的生物毒性，TC在废水净化过程中的代谢和刺激仍然值得关注。本研究揭示了生物电化学系统 (BES) 中乙酸盐对 TC 生物降解的刺激作用。归因于电活性生物膜样品中大量的产电菌Geobacter（主要是G.sulfurreducens）和推定的 TC 降解细菌（PTDB），100 mg/L TC 的 94% 在 48 小时内分解。与丰富的醋酸盐（1 g/L，AC-1）和对照相比，作为共底物的有限醋酸盐（0.1 g/L，AC-0.1）将 TC 的去除效率提高了 44%。这是由于 PTDB 的增强和有限醋酸盐刺激下的地杆菌种群。随着微生物群落的分化，泛醌和其他萜类醌的生物合成和组氨酸代谢在 AC-0.1 中显着上调，但在 AC-1 中下调，这是提高 TCs 去除效率的另一个因素。在这里，我们得出结论，有限的醋酸盐可以部分缓解 TC 的选择压力并改善 TC 的生物降解，并且分解代谢途径以及主要代谢物受到醋酸盐及其浓度的刺激。