微生物—Fe3O4相互作用介导的环丙沙星厌氧生物降解机理研究

Extensive use of ciprofloxacin for animal husbandry have led to the frequent detection of ciprofloxacin residues in the manure. The residual ciprofloxacin in the manure not only have an inhibitory effect on methane production, but also is resistant to digestion. Although an interaction between Fe3O4 and microbes can facilitate biodegradation of CIP during anaerobic digestion, it still is unclear about the role of Fe3O4, biodegradation pathways of ciprofloxacin and relevant microbial processes, due to complex anaerobic digestion process. In addressing these questions, here, using the enrichments obtained in the presence of magnetite nanoparticles, ciprofloxacin (CIP) and manure, we will investigate the role of Fe3O4 in ciprofloxacin degradation by combined use of electrochemistry, analytical chemistry and spectroscopic approaches. The metabolomics technology will be used to investigate the effect of interaction between Fe3O4 and microbes on anaerobic degradation pathway of ciprofloxacin. The molecular biological techniques will be used to explore the relationship of functional players with ciprofloxacin degradation. This proposal will provide an in-depth understanding on the relationship among Fe3O4, ciprofloxacin, intermediate products, and functional players. The proposal will be beneficial for development of innovative process to improve the ciprofloxacin degradation and bioremediation of antibiotics-contaminated soil.

由于氟喹诺酮类抗生素环丙沙星广泛用于畜禽养殖中，致使粪便中经常检测到环丙沙星的残留。在处理畜禽粪便的厌氧消化反应器中，残留的环丙沙星不但影响甲烷生产，还难以降解。虽然微生物—Fe3O4相互作用可促进环丙沙星快速厌氧降解，但是由于厌氧消化过程的复杂性，在Fe3O4的作用机制、环丙沙星厌氧降解途径、和关键微生物种类与功能特征等方面尚不清楚。本项目以自主富集的环丙沙星降解复合菌系为研究对象，基于电化学、分析化学等技术手段，探索环丙沙星降解过程中Fe3O4作用机制；基于代谢组学技术，探索微生物—Fe3O4互作对环丙沙星的降解途径的影响；利用分子生物学手段，解析环丙沙星降解过程中功能微生物与环丙沙星降解之间的联系；揭示Fe3O4、环丙沙星、中间代谢产物、功能微生物之间的相互关系。这些研究对开发新型的环丙沙星等抗生素生物降解技术与工艺和修复抗生素污染的土壤皆具有一定的理论意义和实际价值。

微生物-Fe3O4相互作用可显著促进环丙沙星降解。本项目共富集和选育出3种高效降解环丙沙星的复合菌剂。并对其环丙沙星降解动力学、菌群结构与功能等方面详细研究了复合菌剂的降解特征，揭示了菌群结构与环丙沙星降解之间的关系。首次确定通过Clostridium或Brevundimonas与Desulfovibrio 之间的种间电子传递完成环丙沙星降解过程，而Fe3O4作为快速的电子传递通道则加速种间电子传递过程，导致环丙沙星降解率>94%, 降解半衰期<15d。代谢产物分析表明：环丙沙星主要是通过脱羧、羟化和哌嗪基团降解等路径完成降解。以复合菌剂为研究对象，进一步研究了各种工艺参数（例如：产氢发酵液组成，停留时间等）对环丙沙星降解的影响，建立了生物刺激和生物强化二者联合应用降解环丙沙星的技术方案，为我国粪水处理和控制抗生素污染提供一条可选的路径。在Chemical Engineering Journal, Chemosphere等期刊发表SCI论文6篇。