基于EBPR菌群模式体系的微生物聚集体生长动力学及相关代谢网络研究

Growth of diverse species in complex microbial aggregates is a fundamental issue for microbial ecology and physiology, but has been rarely studied so far. Understanding of the microbial growth dynamics and growth-related intracellular or intercellular metabolic networks could provide key information to further comprehend in situ or natural microbial ecology and the isolation of those uncultured microbes in these cell aggregates. In this project, the enhanced biological phosphorus removal (EBPR) system will be studied to explore the typical polyphosphate accumulating organisms (PAOs) and the other bacterial growth dynamics in the microbial aggregates. The determination of the growth rates are based on the high-throughput sequencing metagenomics and the genome binning algorithm. Growth curves for different bacteria will be tackled by counting the coverages of their genomes in the metagenomic datasets collected in different time points. Meanwhile, PAO growth-rate-related metatranscriptomics will be analyzed to uncover the growth-related intracellular or intercellular metabolic networks. The effects of the key metabolites and microbes on PAOs will be further tested by adding them into the system and examining the growth rate change in PAOs. As the first time, the growth rate was treated as phenotype and correlated with the gene expression pattern in the complex microbial aggregates. The results will provide new insight into the metabolisms in EBPR system and key information in the PAO growth or even isolation. Moreover, this project could be a paradigm to study the microbial growth dynamics and growth-related metabolic networks in complex natural or artificial systems.

以微生物聚集体为代表的复杂体系中各微生物种类的生长是一个基础但尚未引起重视的课题。研究聚集体内各种细菌的生长、与生长相关的代谢以及细菌种间的代谢网络，可为理解原位和自然条件下的微生物生态学和那些迄今未可培养的细菌种类的培养提供重要科学依据。本课题拟针对污水强化生物除磷体系这一典型的包括聚磷菌在内的多菌聚集体进行生长动力学研究。研究将应用添加内标的宏基因组学和单菌基因组拼装方法，基于基因组的测序覆盖度获得主要细菌种类的生长曲线。同时，采用宏转录组方法，考察各菌种与聚磷菌生长速度相关的基因表达以及菌内和菌间代谢网络。最后，验证生长动力学和代谢网络指示的关键代谢物和细菌对聚磷细菌的促生长效果。研究首次将聚集体中的各菌株生长速率这一表型与基因表达相结合，将进一步加深对强化生物除磷体系代谢过程的理解并为分离典型聚磷细菌提供关键信息，同时可作为复杂体系中不同微生物物种的生长动力学和代谢网络研究的范例。