c-di-GMP在低温好氧颗粒污泥形成过程中的作用

在低温条件下运行好氧颗粒污泥反应器，絮状污泥颗粒化过程中信号分子可通过传导作用引起各层物质之间的组分变化，通过研究胞外聚合物及污泥相关疏水性的变化规律，并观察此过程中微生物菌群的群落演替特点，揭示环二鸟苷酸（c-di-GMP）在低温好氧颗粒污泥形成过程中的变化规律与影响作用.结果表明：接种污泥在颗粒化过程中，胞外聚合物含量从48mg/gMLVSS增长至139mg/gMLVSS，其中以TB层蛋白质增长为主，在颗粒化过程中，c-di-GMP含量由62μg/gMLVSS增至600μg/gMLVSS，始终影响微生物运动及生物膜形成，促使具备胞外聚合物分泌功能的菌群加快分泌胞外聚合物，促进好氧颗粒污泥的形成.各个阶段污泥中微生物种群存在较大差异，在反应器运行初始阶段与c-di-GMP合成相关的菌群占据优势，同时在后期表现出较好的脱氮除磷能力，在低温条件下好氧颗粒污泥微生物菌群发生演替并最终形成稳定的菌群结构.

Effect of c-di-GMP in the formation of aerobic granular sludge at low temperature

Along with the granulation process of floc sludge, signal molecules can lead to the variations of extracellular polymeric substances (EPS). In order to investigate the variations and effects of cyclic diguanylate (c-di-GMP) in the formation of aerobic granular sludge at low temperatures, the correlation analysis was carried out based on EPS, relative hydrophobicity (RH), zeta potential and community succession. The experimental results showed that EPS content increased from 48 to 139mg/g MLVSS during granulation, among which the significant increase was attributed to tightly bound-EPS (TB-EPS). The c-di-GMP content increased from 62 to 600μg/g MLVSS, which resulted in microbial succession and biofilm formation, and further improved the secretion of EPS and the formation of aerobic granular sludge. In addition, notable discrepancies were discovered in the microbial population, and the communities associated with the biosynthesis of c-di-GMP prevailed during the formation of aerobic granular sludge. The community succession was obvious and stable microbial community was eventually formed at low temperature, which was conducive to good performance of nitrogen and phosphorus removal.