介体催化强化Cr(VI)生物还原机理及其调控策略研究

Since chemical detoxification of metal-contaminated water is generally very expensive and often results in secondary effects on the environment, the cost-effective and eco-friendly biological treatment has attracted more interests. However, the biological treatment generally takes a long time to complete the reduction process. Based on above questions and the previous research results of the accelerating effect of redox mediators on the transformation of pollutions, the project is to explore the mechanism and regulatory strategies of hexavalent chromium bioreduction enhanced by redox mediators. The main contents of this project include the following: 1)The efficient Cr(VI) reduction microorganisms are isolated, screened and identified, and the influencing factors of the reduction process by these microorganisms are optimized; 2)redox mediators with different/similarity structure are screened and optimized, and the characterization systems of redox mediators are established; 3)the mechanism of Cr(VI) bioreduction enhanced by redox mediators is elucidated from electrochemistry, enzymology and metabolization; 4)the relationship between the structure of the redox mediators and their accelerating effects is explored, and the model of electron transfer with redox mediators is established and verified;5)the main control factors of the bioreactor are optimized, and the regulatory strategies of Cr(VI) bioreduction are founded by discussing the relationship between control factors and bioreactor efficiency. This study is valuable to explore the feasibility of utilization of anarobic biological techniques and provide the theoretical and technical support for the real wastewater treatment engineering.

项目针对重金属生物处理技术转化速率低、耗时长的问题，基于氧化还原介体催化强化污染物厌氧生物转化的研究热点和前期研究的基础，以典型重金属Cr(VI)为模型化合物，以介体调控电子传递为核心，构建氧化还原介体催化强化Cr(VI)生物还原的实验体系，开展如下研究：1）分离、筛选高效的Cr(VI)降解菌株，考察和优化菌株对Cr(VI)生物还原过程的影响因素；2）优化、筛选不同结构/类似结构的高效介体，建立相应的特性表征体系；3）从电化学、酶学和生物代谢等多角度展开研究，阐明介体催化强化Cr(VI)生物还原的作用机理；4）解读介体结构和催化效果之间的关系，构建和验证介体调控电子传递的构-效模型；5）优化反应器关键调控因素，探究各调控因素对反应器效能影响的规律，建立Cr(VI)生物转化技术调控策略。本项目的研究将拓展重金属污染生物转化研究的内涵，具有重要的理论意义、较强的学术前沿性和广阔的应用前景。

本研究针对重金属生物处理技术转化速率低、耗时长的问题，基于氧化还原介体催化强化污染物厌氧生物转化的研究热点，以典型重金属Cr(VI)为模型污染物，以介体调控电子传递为核心，构建氧化还原介体催化强化Cr(VI)生物还原的实验体系，开展了如下的实验研究：分离、筛选高效的Cr(VI)降解菌株，考察和优化菌株对Cr(VI)生物还原过程的影响因素；优化、筛选不同结构/类似结构的高效介体，建立相应的特性表征体系；从电化学、酶学和生物代谢等多角度展开研究，阐明介体催化强化Cr(VI)生物还原的作用机理；解读介体结构和催化效果之间的关系，构建和验证介体调控电子传递的构-效模型；开发了新型醌基功能材料。本项目的研究将拓展重金属污染生物转化研究的内涵，具有重要的理论意义、较强的学术前沿性和广阔的应用前景。研究结论如下：.1)分离、筛选得到高效Cr(VI)降解菌株CR1，经鉴定该菌株为Mangrovibacter plantisponsor菌属，考察和优化了菌株对Cr(VI)的生物还原的调控影响因素。2)考察了水溶性氧化还原介体对Cr(VI)生物还原过程的影响。选用五种结构相似的水溶性蒽醌作为氧化还原介体，考察了取代基数量和位置对其调控效果的影响，并筛选出最优介体，对其加速Cr(VI)生物还原过程的影响因素和参数变化进行了系统研究，并对其加速机理进行了初步探讨。3)考察了通过乙酸纤维素包埋法负载的非水溶性氧化还原介体对Cr(VI)生物还原过程的影响。选用六种结构相似的非水溶性蒽醌作为氧化还原介体，构建了非水溶性氧化还原介体加速微生物还原Cr(VI)体系，筛选出最优介体，对其加速Cr(VI)生物还原过程的影响因素和参数变化进行了系统研究，并对其加速机理进行了初步探讨。4)考察了八种特异性电子传递抑制剂对AQS调控菌株CR1还原Cr(VI)的影响，推测得到AQS调控菌株CR1还原Cr(VI)的电子传递机制模型。5)开展氧化还原介体催化强化Cr(VI)生物还原的酶学研究，并对介体催化强化Cr(VI)生物转化过程ATP的变化进行了监测，从酶学机理和生物能量代谢方面对介体调控Cr(VI)生物还原的作用机理进行了初步探讨。6)分别采用磺酸型和氯取代蒽醌作为醌基模型，用化学方法固定在聚对苯二甲酸乙二醇酯表面成功合成两种新型功能生物材料，两种材料均具有良好的生物催化性能和稳定的生物相容性。