基于SIP和宏基因组学技术的养殖废水典型孕激素降解机制研究

Progestogens are widely used in human and animal for the disease treatment and breeding control, there are hundreds of tons of progestogens released into the environment through livestock wastewate every year. The degradation of progestogens in the livestock wastewater is largely based on microbial activity. It is of great significance to explore the potential efficient microbial species of progestogens degradation and to clarify the degradation mechanism in wastewater. Stable isotope probes (SIP) combined with metagenomics, have advantages in connecting unknown microbial species to their functions directly, break through the limitations of traditional isolation and culture. The overall objectives of the proposal are 1) to collect livestock wastewater polluted by progestogens, determine the microorganisms in the degradation process of progestogens, and screen the functional microbes; 2) to reveal the degradation mechanism of progestogens through the analysis of the intermediate products and functional genes; 3) to study the influence of the environmental factors on bacterial community structures, functional microbes and relevant functional genes; and 4) to establish the relationships between microbial community, progestogens degraders and environmental factors to reveal preliminary response mechanisms of microorganisms and provide microbial resources and theoretical guidance for the microbial remediation of progestogens contaminated water.

孕激素广泛用于人畜的疾病治疗与繁殖控制，每年通过养殖废水进入环境的孕激素高达上百吨。微生物降解是环境中孕激素消减的主要途径，发掘高效的孕激素降解微生物物种、明确其降解机制对污染水体的生物修复具有重要意义。稳定同位素探针（SIP）结合宏基因组学技术突破了传统分离培养的限制，将功能微生物物种与其特定的新陈代谢直接联系起来。本研究拟以养殖废水中常见的典型孕激素去氢孕酮和甲炔诺酮为研究对象，采用SIP结合宏基因组学技术，甄别孕激素降解相关的功能微生物和功能基因；采用先进质谱技术，鉴定孕激素降解产物，推断降解途径；利用分子生态学网络模型解析环境因子、功能微生物、功能基因及孕激素降解行为之间的相互关系，揭示孕激素的微生物降解机制。研究成果可为养殖废水中孕激素的生物降解治理提供微生物资源和理论依据。

孕激素等类固醇激素污染问题受到全球科研工作者及环境工作者的高度重视。本课题结合稳定同位素和高通量测序，甄别和筛选出养殖废水中典型孕激素降解功能微生物；初步研究了废水中土著微生物对规模化养殖废水中孕激素的降解转化规律，微生物对孕激素的降解作用主要包括羟基化、氧化、还原及侧键断裂；考察了不同环境因子及微生物群落对孕激素降解的影响，好氧环境有益于孕激素的降解，COD、TN、NH3-N与孕激素含量呈显著正相关，Bacteroidetes和Tenericutes是有益于孕激素降解的重要细菌群落。研究结果表明，微生物降解是自然界中孕激素消解的关键性作用，降解半衰期等研究数据可为废水处理过程中水力停留时间等参数设定提供有效参考，具有重要的应用价值。从废水中筛选出多株降解菌，为孕激素降解提供有效的生物资源。此外，通过典型孕激素的转化产物的确定及转化途径的推断，为有效评价环境中孕激素的生态风险提供了数据支撑。研究成果可为政府部门制订相关类固醇激素使用规范、生态环境安全规范等提供科学依据。