畜禽粪便中雌激素降解菌的筛选及抗生素对其降解性能的影响

The contamination with estrogenic hormone (EH) is a worldwide environmental problem, posing great threats to human health and ecology risk. EH has generally been detected with high concentrations in livestock manure, which is recognized as a most important source of EH in the environment. The EH in livestock manure may enter into soil, surface water, and groundwater along different ways. Clearly, understanding the chemical and biological processes of EH in livestock manure is essential to assess their exposure in humans and ecological species and evaluate the potential risks of EH contamination..In the last decades, researchers try to propose effective techniques to eliminate the EH contaminants in livestock manure, among which microbial biodegradation draws much attention. Several functional bacteria with EH-metabolism properties have been screened from the environment. However, most of them are derived from the soil and sediment. While there is still few literatures documented the EH-functional bacteria obtained from livestock manure, which would more readily present and function in the livestock manure. In addition, antibiotics commonly accompanied with EH in livestock manure. But the impacts of antibiotics on the EH biodegradation havenot yet been elucidated heretofore. .To this end, this project seeks to (1) screen the functional bacteria from the fresh livestock manure, and elucidate the biodegradation process and mechanism of EH by them. (2) investigate the impacts of antibiotics on the EH biodegradation by the screened functional bacteria. Basing on the activities and drug tolerance of EH-functional bacteria and enzyme responses to antibiotics, the involved mechanisms of the antibiotics-influenced biodegradation of EH by functional bacteria will be clarified. This work may be fundamental for the development of effective techniques to eliminate the EH in livestock manure, and results would benefit the agricultural solid waste management, elimination of EH environemntal risk, and human and ecological health.

作为环境中雌激素的一个重要来源，养殖业畜禽粪便中雌激素污染问题很受关注。分离筛选具有雌激素降解性能的功能降解菌、并施用于畜禽粪便，有望实现其雌激素的高效降解。然而，抗生素在畜禽粪便中与雌激素共存，其对功能菌降解雌激素的性能有何影响？国内外至今尚难检索到相关报道。本项目尝试直接从畜禽粪便中分离、筛选具有高效降解雌激素性能的功能菌，所获取的菌株可望能更佳地适应畜禽粪便的生存环境，阐明其对雌激素的降解规律及机理；探索抗生素对功能菌降解雌激素性能的影响及关键因子，评价功能菌对抗生素的耐药性，分析抗生素作用下功能菌活性、主要酶系活性的动态响应，系统地揭示抗生素影响功能菌降解雌激素的作用规律及内在机制。通过开展本研究，综合地评价利用功能菌去除畜禽粪便中雌激素的可行性，试图为有效地治理畜禽粪便中雌激素污染、规避雌激素环境污染风险、实现畜禽粪便无害化和资源化等提供基础依据。

养殖业畜禽粪便中含有大量雌激素，如何有效地将其去除是实现畜禽粪便无害化处理和资源化利用的前提和关键之一，然而国际上仍缺乏有效、可行的技术。本项目从环境介质中分离获得了具有雌激素降解特性的功能细菌，研究了其对雌激素的降解作用；探讨了畜禽粪便中普遍大量存在的抗生素对功能细菌降解雌激素的影响。取得主要结果如下：（1）建立了超声提取（UE）-固相萃取净化（SPE）-高效液相色谱法同时测定畜禽粪便中雌激素（雌三醇、17β-雌二醇、炔雌醇和双酚A）的分析方法。利用本方法得到的雌激素检测结果平行性好、检出限低，适用于畜禽粪便中多种雌激素的检测分析。（2）分离获得了6株具有雌激素降解性能的功能细菌。分别为Rhodococcus sp. JX-2、Serratia sp. S、Sphingomonas sp. E2S、Novosphingobium sp. CS-3、Novosphingobium tardaugens sp.nov. ARI-1、Pseudomonas aeruginosa EE2-J，明确了其生物学特性；系统地阐明了功能菌对雌激素的降解性能，优化了降解条件，解析功能菌降解雌激素的途径。（3）研制了功能菌的固定化菌剂。采用海藻酸钠包埋法，将具有雌激素降解功能的单一菌株或混合菌株制备成固定化菌剂，优化了菌剂制备条件，系统地阐明了固定化菌剂对畜禽粪便（牛粪）中雌激素的去除效能和优化条件，为后续将雌激素降解功能菌株实际应用于畜禽粪便中雌激素的处理奠定了良好基础。（4）揭示了常见兽用抗生素对功能菌降解雌激素性能的影响及机制。以菌株JX-2、E2S、ARI-1为例，试验得出了功能菌对常见兽用抗生素最小抑菌浓度（MIC），系统地探明了抗生素对功能菌降解溶液和畜禽粪便（牛粪）中雌激素性能的影响及关键因子，初步揭示相关作用机制。依托本项目，发表论文17篇，其中SCI论文12篇。研究成果为利用功能菌株来有效地去除畜禽粪便中雌激素、实现畜禽粪便中雌激素的无害化处理、规避雌激素环境污染风险等提供基础依据和潜在途径。依托本项目，授权国家发明专利1项、申请国家发明专利2项；开展国际合作与交流2人次，培养博士/硕士研究生6名。