School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0512, USA; School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China; College of Environmental Science and Engineering, Hunan University, Changsha 410082, China.
School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0512, USA.
Sci Total Environ. 2022 Sep 1;837:155756. doi: 10.1016/j.scitotenv.2022.155756. Epub 2022 May 6.
Bio-electrochemically assisted anaerobic methanogenic systems (An-BES) are highly effective in wastewater treatment for methane production and degradation of toxic compounds. However, information on the treatment of antibiotic-bearing wastewater in An-BES is still very limited. This study therefore investigated the effect of tetracycline (TC) on the performance, microbial community, as well as functional and antibiotic resistance genes of An-BES. TC at 1 and 5 mg/L inhibited methane production by less than 4.8% compared to the TC-free control. At 10 mg/L TC, application of 0.5 and 1.0 V decreased methane production by 14 and 9.6%, respectively. Under the effect of 1-10 mg/L TC, application of 1.0 V resulted in a decrease of current from 42.3 to 2.8 mA. TC was mainly removed by adsorption; its removal extent increased by 19.5 and 32.9% with application of 0.5 and 1.0 V, respectively. At 1.0 V, current output was not recovered with the addition of granular activated carbon, which completely removed TC by adsorption. Metagenomic analysis showed that propionate oxidizing bacteria and methanogens were more abundant in electrode biofilms than in suspended culture. Antibiotic resistance genes (ARGs) were less abundant in biofilms than in suspended culture, regardless of whether voltage was applied or not. Application of 1.0 V resulted in the enrichment of Geobacter in the anode and Methanobacterium in the cathode. TC inhibited exoelectrogens, propionate oxidizing bacteria, and the methylmalonyl CoA pathway, leading to a decrease of current output, COD consumption, and methane production. These findings deepen our understanding of the inhibitory effect of TC in An-BES towards efficient bioenergy recovery from antibiotic-bearing wastewater, as well as the response of functional microorganisms to TC in such systems.
生物电化学辅助厌氧甲烷系统（An-BES）在废水处理中用于甲烷生产和有毒化合物降解非常有效。然而，关于 An-BES 中处理含抗生素废水的信息仍然非常有限。因此，本研究考察了四环素（TC）对 An-BES 性能、微生物群落以及功能和抗生素抗性基因的影响。与无 TC 对照组相比，1 和 5mg/L 的 TC 对甲烷生产的抑制作用小于 4.8%。在 10mg/L TC 下，施加 0.5 和 1.0V 分别使甲烷产量降低了 14%和 9.6%。在 1-10mg/L TC 的作用下，施加 1.0V 导致电流从 42.3mA 降低至 2.8mA。TC 主要通过吸附去除；施加 0.5 和 1.0V 时，其去除程度分别增加了 19.5%和 32.9%。在 1.0V 下，添加颗粒活性炭未能恢复电流输出，因为活性炭完全通过吸附去除了 TC。宏基因组分析表明，在电极生物膜中，丙酸氧化菌和产甲烷菌比在悬浮培养中更为丰富。无论是否施加电压，抗生素抗性基因（ARGs）在生物膜中的丰度都低于悬浮培养中的丰度。施加 1.0V 导致阳极中的 Geobacter 和阴极中的 Methanobacterium 富集。TC 抑制了外电子体、丙酸氧化菌和甲基丙二酰辅酶 A 途径，导致电流输出、COD 消耗和甲烷生产减少。这些发现加深了我们对 TC 在 An-BES 中对从含抗生素废水中高效生物能源回收的抑制作用的理解，以及功能微生物对系统中 TC 的反应。
