低温下好氧颗粒污泥对四环素类抗生素的生物强化降解模式及作用机制研究

The aerobic sludge granulation technology has obvious advantages in many aspects such as high efficiently degradation on conventional organic matter and enhanced removal of nitrogen and phosphorus, but it is not easy to remove the undegradation organics and cultivate the granular sludge at low temperatures. It should be of great importance to research on the biodegradation of pharmaceutical and personal care products (PPCPs) at low temperature as soon as possible in the northern in view of the current prevalence of PPCPs in China. In this project, typical antibiotic -- tetracycline compounds treated as the target pollutants will obtain the functional bacterial strain with selective breeding at low temperature by postgenomics and selective pressure separation technology, and establish kinetics model of matrix degradation, and then the biological transformation and pathway of biodegradation of pollutants are investigated. Furthermore, a mixed bacterial strain system which owns ecological synergy effect is designed, then the biofortification model of granular sludge system on degradation for tetracycline compounds will be set up, as well as the analysis methods of this kind of functional strain such as High-throughput sequencing technologies will also be established. Thus, it is convenient to investigate the microbial community structure and function succession in the construction and operation process of this strengthened system, and by functional annotation analysis to study the dynamic process in the formation and migration between these functional strains and aerobic granules at low temperature in order to reveal the mechanism of biological enhancement and explain the relationship between the biofortification effect and the property of degradation. The implementation of the proposed project will not only possibly provide a favorable chance to develop a kind of microorganism bacterium agent which could high efficiently remove tetracycline organics, but also provide a thinking solution to treat antibiotic-wastewater in the northern cold regions.

好氧颗粒污泥在高效降解一般有机物、强化脱氮除磷等方面具有明显技术优势，但不易去除难降解有机物且颗粒污泥低温下较难培养，针对我国目前PPCPs普遍存在的情况，在北方低温环境下启动这方面的研究具有重要意义。本项目拟以典型四环素类抗生素为目标污染物，应用后基因组学和选择性压力分离技术等，在低温条件下选育得到功能菌株，建立基质降解动力学模型，考察污染物的生物转化及代谢途径。围绕具有生态效应的菌株体系，构建降解四环素类抗生素颗粒化体系的生物强化模式；利用高通量测序技术等分析微生物群落特征，考察强化体系微生物群落的结构动态和功能演替，并通过功能注释分析等探究关键菌株与好氧颗粒污泥在低温下形成和迁移的变化过程，揭示生物强化的作用机制，阐明好氧颗粒化体系生物强化与降解性能之间的功效关系。项目的实施不但可能为开发具有高效降解四环素类污染物能力的微生物菌剂提供有利条件，而且为含抗生素污染的水处理提供解决思路。

抗生素废水具有COD、氨氮、总磷浓度高且存在抗生素类污染物，排入受纳水体将对生态环境和人类健康带来潜在危害。现有处理工艺对常规有机物有较好去除效果，而氨氮、磷和抗生素的去除尚存在较大难度。针对该类废水中抗生素类有机物去除难等问题，开发高效、经济的水处理技术势在必行。本研究提出好氧颗粒污泥（AGS）生物处理技术，利用培育的功能菌株实现特征污染物的降解。主要研究内容包括低温好氧颗粒污泥体系的快速启动；建立降解四环素类抗生素颗粒化体系的生物强化模式；污染物的生物转化及代谢途径；强化体系微生物群落的结构动态和功能演替；关键菌株与好氧颗粒污泥在低温下形成和迁移的变化规律。.研究结果表明：以贮存颗粒污泥为接种污泥启动反应器，能有效缩短颗粒的培养时间，其污泥性能和除污效能表征良好。反应器中存在小颗粒、成熟颗粒和空腔颗粒三种形态的污泥的动态平衡。好氧颗粒污泥去除四环素（TC）和土霉素（OTC）的过程，前期以吸附为主，后期以降解为主。筛选获得两株TC的高效降解菌Achromobateraegrifaciens和Achromobatermarplatennsis。在中性条件下，两株菌的生长及对四环素的降解最佳。以此功能菌为生物强化剂，进而确定不同周期对四环素类抗生素和常规污染物去除效果的影响。同时，筛选两株具有OTC 降解能力的功能菌株，对GSBR工艺进行强化。基于高通量测序技术，得到Zoogloea(动胶菌属)、Tolumonas (甲苯单胞菌属)、Enterobacter(肠杆菌属)和Flavobacterium(黄杆菌属)为4组共有优势菌种。通过Alpha、Beta多样性分析表明，较短的运行时间有助于提高微生物的多样性。通过检测发现有 22 种 TC 和13 种 OTC 中间产物，以此推测分析二者的降解途径。通过宏基因组检测技术分析表明，AGS 降 解 TC 过程存在显著差异的微生物（P<0.5）包括 Sphingopyxis、Ruminococcus、 Fluviicola 等，而降解 OTC 过程存在显著差异微生物包括 Leclercia、Haloferula、Sphingopyxis 等。本项目研究结果利用含四环素类的畜禽废水进行了验证，确定功能菌株具有高效降解四环素类污染物的能力，其降解率在69.6%-87.8%之间。同时为含抗生素污染物的实际废水处理工程提供了解决思路。