废水生物处理胞外多糖特性及其对生物聚集体性能的影响机制研究

Microorganisms participate in biological wastewater treatment in the form of aggregates, and extracellular polysaccharides play an important role in the structure and function of the microbial aggregates. Are there any significant differences in the extracellular polysaccharides characteristics among the sludge flocs, biofilms and granular sludge? What is the role of extracellular polysaccharides in the bioaggregation process? How do reactor operating parameters affect the characteristics of extracellular polysaccharide? Current knowledge on these aspects is quite limited. In this study, high resolution chromatogram, spectrum, mass spectrum will be employed to characterize properties of extracellular polysaccharides collected from the three typical microbial aggregates to get multi-dimensional properties including molecular weights, residues, characteristic chemical bond et al. The "structure-activity" relationship between the aggregates, obtained from a start-up phase and different working conditions, and extracellular polysaccharides properties will be established. The key polysaccharide substances and special unit structures will be identified, using chemical directional interference such as enzymolysis and methylation, to reveal the effects of extracellular polysaccharides on bioaggregation and aggregate's properties. This study will clarify the intrinsic links among extracellular polysaccharides, microbial aggregates and the reactor operation parameters, and result in a practical reactor control strategy that can regulate the characteristics of extracellular polysaccharide. This reserach is expected to provide a theoretical support for biological wastewater treatment.

废水生物处理过程中微生物通过形成聚集体参与反应，而胞外多糖对微生物聚集体的结构和功能有重要作用。那么活性污泥、生物膜、颗粒污泥等结构和功能特征差异十分显著的聚集体胞外多糖特征是否有显著差异？扮演着怎样的角色？反应器的运行参数又是怎样影响胞外多糖特性的？相关研究还十分欠缺。本申请拟组合使用高分辨率色谱、光谱、质谱等技术对三种典型聚集体胞外多糖样品进行多维度表征，获得分子量、残基、特征化学键等信息，考察其与形成过程和运行条件改变时聚集体性能的相关性，建立胞外多糖和微生物聚集体性能的“构效关系”；采用酶解等定向干扰和甲基化等化学修饰手段，识别关键多糖物质和特殊单元结构，以初步揭示胞外多糖对微生物聚集行为和聚集体性能的影响机制。本项目将厘清胞外多糖与生物聚集体、反应器宏观运行参数等内在联系，提出基于生物聚集体胞外多糖特性调控的可实际操作的反应器宏观控制策略，为废水生物处理工程实践提供理论支持。

废水生物处理过程中微生物通过形成聚集体参与反应，而胞外多糖是胞外聚合物的主要组分，种类繁多、结构复杂，对微生物聚集体的结构和功能具有重要作用。但已有研究多关注胞外蛋白，鲜有聚焦于胞外多糖的研究。本项目采用并组合多种分析技术和手段，解析了活性污泥、生物膜和颗粒污泥等典型生物聚集体胞外多糖的含量、官能团、分子量等多维度理化信息，明确典型微生物聚集体胞外多糖的特征和差异。考察了氮磷营养物缺乏下活性污泥絮体和不同进水模式下颗粒污泥聚集体性能，阐明了胞外多糖特性的变化机制及其对微生物聚集体的影响及“构效关系”。指出胞外多糖支链和支化度是维持颗粒污泥聚集性能和稳定性的重要因素，从胞外多糖的角度揭示了影响微生物聚集行为和聚集体性能的机制。针对好氧颗粒污泥在启动和运行过程中易于发生污泥膨胀的问题，提出基于胞外多糖特性调控的反应器宏观控制策略。本项目结合典型微生物聚集体性能和反应器运行参数，从宏观到微观，多层次、多角度对胞外多糖性质进行了剖析。研究成果拓展和丰富了有关微生物聚集体胞外多糖的认识，深化了对胞外多糖结构和功能的理解，可为废水生物处理工程实践提供理论支持。