基于生态因子调控废水处理中光合细菌能量与聚-β-羟丁酸（PHB）合成途径促进胞内PHB累积的研究

The unique advantage of photosynthetic bacteria wastewater (PSB) treatment technology is that it can remove pollutants and poly-β-hydroxybutyrate resource utilization simultaneously. The core of resource recovery in PSB wastewater treatment system is the poly-β-hydroxybutyrate increase, and the biochemical engineering method is an effective approach for the poly-β-hydroxybutyrate increase. However, PSB own unique energy metabolisms, which makes the theory and technology of traditional biochemical engineering cannot be directly used in PSB wastewater treatment system. In this work, the molecular regulation mechanisms o f PSB energy metabolism in the wastewater treatment system will be investigated thoroughly. The main environmental and cultural factors which influence the poly-β-hydroxybutyrate accumulation in PSB wastewater treatment system will be determined and optimized. The main pathways and the regulation mechanisms of those factors on the key enzymes activity, proteins and genes in the poly-β-hydroxybutyrate synthesis will be analyzed. The pathways and regulation mechanisms of those factors on key enzymes activity, protein s and genes in the energy production process of aspiration and photosynthesis will be analyzed. Besides, the key enzymes activity, three-dimensional conformation, and proteins and genes expression under different regulation environments will be studied. All these studies will determine the main factors which regulate the poly-β-hydroxybutyrate accumulation, reveal the special molecular mechanisms of consummate the PSB poly-β-hydroxybutyrate synthesis and energy metabolism pathways, implement and consummate the theory and method of biological engineering on PSB metabolisms, and finally and lay a foundation for the industrial application of PSB wastewater treatment and poly-β-hydroxybutyrate resource recovery.

光合细菌废水处理技术能够同时实现有机物去除及胞内聚-β-羟丁酸累积资源化。资源化的核心是提高聚-β-羟丁酸产量，生化工程方法是提高聚-β-羟丁酸产量的有效途径，而光合细菌具有独特的能量代谢途径，且聚-β-羟丁酸合成与能量代谢密切相关，因此生化工程理论与技术不能直接应用。本项目提出深入系统地探讨生化工程调控废水处理中光合细菌能量与聚-β-羟丁酸合成途径促进其累积的分子生物学机制，明确并优化光合细菌废水处理中影响聚-β-羟丁酸产量的主要影响因素；研究主要影响因素调控聚-β-羟丁酸合成途径中关键酶及其调控基因表达的分子生物学机制；解析主要因素影响调控呼吸产能代谢与光合产能代谢途径中关键酶及其调控基因表达的分子生物学机制。以上研究将明确光合细菌废水处理中调控聚-β-羟丁酸累积的主要因素，揭示其调控光合细菌能量与聚-β-羟丁酸合成途径的分子生物学机制，为实现光合细菌废水处理资源化的工业应用奠定基础。

光合细菌污水处理技术具有废水处理的同时累积聚-β-羟丁酸（PHB）资源再利用的优势。但是，在污水处理过程光合细菌PHB产量不高，限制了光合细菌污水处理过程中菌体资源化再利用的发展。因此，本研究利用生态因子调控方法提高光合细菌废水处理过程中PHB产量。研究内容和结果如下：1. 筛选出六个生态因子同时优化，最佳条件为光照强度 6000 lux、氧气条件微氧 0.3-0.9 mg/L、铁离子浓度 20 mg/L、镁离子浓度 10 mg/L、苹果酸浓度 600 mg/L 、三十烷醇浓度 1 mg/L。在六个生态因素最佳条件下，PHB高达 2756 mg/L，是空白对照组的3倍，COD去除率也达到91%；2. 解析了除苹果酸外其他主要生态影响因子能够通过上调产能代谢途径中关键酶基因表达和酶活性（柠檬酸合成酶 cs、α-酮戊二酸脱氢酶 sucA、琥珀酸脱氢酶 sdhB、hscA、rus、crtA）提高了ATP产量以提高聚-β-羟丁酸累积的分子生物学机制；3. 明晰了除微量元素外的主要生态影响因子能够通过上调聚-β-羟丁酸合成途径中关键酶基因表达和酶活性（β-酮硫解酶 phbA、乙酰乙酰辅酶A还原酶 phbB、PHB合成酶 phbC）以提高聚-β-羟丁酸产量的分子生物学机制。本研究补充和完善了废水处理过程中光合细菌生态学理论；运用生态因子调控技术促进了废水处理中光合细菌胞内聚-β-羟丁酸产量的累积，实现光合细菌废水处理中的资源化。