基于胞内储存物质及相关功能酶的强化生物除磷过程重金属胁迫响应机制与优化调控研究

The microorganisms in enhanced biological phosphorus removal (EBPR) have to face the dual responsibilities-heavy metal stress and water purification (phosphorus removal) due to the increasing heavy metal pollution in municipal wastewater. So the response of EBPR process to heavy metal stress is a comprehensive and complicated process. Therefore, we will investigate the response mechanism and optimal regulation of EBPR process to heavy metal stress based on intracellular storage compounds and related functional enzymes. Main research contents include: Based on the observation of the dynamic changes of intracellular storage compounds (PHA、polyP and glycogen) and the identification of microbial populations by molecular biology technology,the relationship between the intra- cellular storage compounds, microbial populations and phosphorus removal efficiency of EBPR process under heavy metal stress will be established and the response mechanism of EBPR process to heavy metal stress will be revealed. The tracking study will be performed to understand the translocation and accumulation of heavy metal in polyphosphate accumulating organisms (PAOs). The enzyme production, enzyme kinetics, and metabolic products will also be studied in the presence of heavy metal. The response mechanisms of PAOs to heavy metal stress will be understood scientifically in terms of enzyme kinetics and metabolism pathway of phosphorus. An optimal regulation technology of EBPR process under heavy metal stress will be developed according to the combination of response mechanisms and dynamic changes of response index under enhanced regulation measures. The study will deepen theoretically the understanding of Influence mechanism of heavy metal to EBPR process and provide a theoretical basis to practical engineering application.

城市污水中重金属污染日益严重，使强化生物除磷（EBPR）中微生物承担着重金属胁迫与净化水质（除磷）双重职责，因此EBPR过程对重金属胁迫的响应是一个综合复杂的过程。为此，本项目拟开展基于胞内储存物质及相关功能酶的EBPR过程对重金属胁迫响应机制与优化调控研究，包括：考察重金属胁迫下EBPR中微生物胞内储存物质（PHA、polyP、糖原）动态变化规律，结合系统微生物种群分子生物学检测，建立胞内储存物质及微生物种群与EBPR除磷效率的关联，剖析重金属胁迫响应机制；追踪重金属在PAOs体内动态输送与积累过程，研究重金属胁迫下PAOs除磷功能酶、酶促反应动力学及代谢产物，从酶动力学及磷生物代谢过程阐明PAOs对重金属胁迫响应机制；将重金属响应机制与强化调控措施下响应指标相结合，研发重金属胁迫下EBPR过程优化调控技术。本研究有望从理论上深化重金属对EBPR过程影响机理的认识，为实际程应用提供指导。

城市污水中重金属污染日益严重，使强化生物除磷（EBPR）中微生物承担着重金属胁迫与净化水质（除磷）双重职责，因此EBPR过程对重金属胁迫的响应是一个综合复杂的过程。为此，本项目以城市污水中常见的Zn，Cd和Ni为研究对象，开展基于胞内储存物质及相关功能酶的EBPR过程对重金属胁迫响应机制与优化调控研究。研究表明较高浓度（大于1mg/L）的重金属即使是短期的暴露也会导致系统除磷性能的显著下降，而低浓度（小于0.1mg/L）的重金属短期暴露造成的影响不太显著，但是暴露时间超过30天也会使得生物强化除磷性能完全崩塌。关键酶活性研究结果表明重金属的存在显著抑制了关键酶PPX的活性，导致活性污泥在厌氧阶段的释磷性能受阻，并且污泥胞内重金属的存在还会导致胞内活性氧物质（Reactive Oxygen Species，ROS）产量显著升高，这也可能是重金属抑制PPX活性的原因。此外随着重金属生物毒性的增强，EBPR对其的最高耐受浓度也逐渐下降。本研究有望从理论上深化重金属对EBPR过程影响机理的认识，为实际程应用提供指导。