College of Architecture and Environment, Sichuan University, Chengdu 610065, China.
State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
J Hazard Mater. 2024 Dec 5;480:135949. doi: 10.1016/j.jhazmat.2024.135949. Epub 2024 Sep 24.
The antibiotic ciprofloxacin (CIP), detected in various aqueous environments, has broad-spectrum antimicrobial properties that can severely affect methanogenic performance in anaerobic systems. In this study, a novel strategy to alleviate the inhibition of AD performance under CIP press with the direct addition of biochar (BC) prepared from corn stover was proposed and the corresponding alleviation mechanism was investigated. When the dosage of BC was 5 and 20 g/L, the cumulative methane production in AD could reach 317.9 and 303.0 mL/g COD, and the CIP degradation efficiencies reached 94.1 % and 96.6 %, significantly higher than those of 123.0 mL/g COD and 81.2 % in the Control system. BC avoided excessive reactive oxygen species in anaerobic systems and induced severe oxidative stress response, while protecting the cell membrane and cell wall of microorganisms. Microorganisms could consume and utilize more organic extracellular polymeric substances for their growth and metabolism. When BC was involved in AD, fewer toxic intermediates were generated during CIP biodegradation, reducing acute and chronic toxicity in anaerobic systems. Microbial diversity suggested that BC could enrich functional microorganisms involved in direct interspecies electron transfer like Methanosaeta, norank_f_Bacteroidetes_vadinHA17, JGI-0000079-D21 and Syntrophomonas, thus facilitating the methanogenic process and CIP degradation. Genetic analyses showed that BC could effectively upregulate functional genes related to the conversion of butyrate-to-acetate and acetyl-to-methane under CIP stress, while functional gene abundance associated with CIP degradation enhanced partially, about encoding translocases, oxidoreductases, lyases, and ligases. Therefore, BC can be added to AD under CIP press to address its inhibited methanogenic performance.
在各种水生态环境中都检测到了抗生素环丙沙星（CIP），它具有广谱抗菌特性，会严重影响厌氧系统中的产甲烷性能。在这项研究中，提出了一种在 CIP 压力下通过直接添加从玉米秸秆制备的生物炭（BC）来缓解 AD 性能抑制的新策略，并研究了相应的缓解机制。当 BC 的剂量为 5 和 20 g/L 时，AD 中的累积甲烷产量分别达到 317.9 和 303.0 mL/g COD，CIP 降解效率分别达到 94.1%和 96.6%，明显高于对照组的 123.0 mL/g COD 和 81.2%。BC 避免了厌氧系统中过多的活性氧，并诱导了严重的氧化应激反应，同时保护了微生物的细胞膜和细胞壁。微生物可以消耗和利用更多的有机细胞外聚合物来生长和代谢。当 BC 参与 AD 时，在 CIP 生物降解过程中会产生较少的有毒中间产物，从而降低了厌氧系统的急性和慢性毒性。微生物多样性表明，BC 可以富集参与直接种间电子转移的功能微生物，如产甲烷菌、未分类的拟杆菌门 vadinHA17、JGI-0000079-D21 和互营单胞菌，从而促进产甲烷过程和 CIP 降解。遗传分析表明，BC 可以在 CIP 胁迫下有效地上调与丁酸到乙酸和乙酰辅酶 A 到甲烷转化相关的功能基因，而与 CIP 降解相关的功能基因丰度部分增强，大约编码转运蛋白、氧化还原酶、裂解酶和连接酶。因此，在 CIP 压力下，可以向 AD 中添加 BC 来解决其抑制产甲烷性能的问题。
