微生物协同利用石油烃作用的机理研究

Petroleum hydrocarbon contamination in the environment and the shortage of light oil in oilfields have become big issues all over the world. It has been known that certain microorganisms are able to utilize petroleum hydrocarbons as carbon and energy sources for growth and biosurfactant biosynthesis, and thus, microbial degradation of petroleum hydrocarbons is considered to be an environmental prospective. Microbial consortia are commonly reported to be more effective on petroleum hydrocarbon utilization than the pure cultures of bacteria, and are suggested to be more applicable in bioremediation strategies and oil recovery. However, the mechanisms in which hydrocarbon users in the microbial community benefit from synergistic interactions are still unknown, which will limit the development of related bioremediation technology and microbial enhanced oil recovery (MEOR) techniques. In this study, we will understand the mechanism by investigating the roles of each species in a defined microbial community for the degradation of petroleum hydrocarbons. The research will be composed of two parts: in silico modeling of a synergistic petroleum hydrocarbon-degrading consortium comprised of three hydrocarbon-degrading bacterial strains with known genomic information to analyze the mutualistic cell-to-cell communication through metabolic exchanges among the species; in vitro validating experiments in responding to each potential mechanism. It is prospected that our study will not only fill the gap between knowledge on microbial relationship and petroleum hydrocarbon metabolism, but will also provide theoretical basis and methods for the development of efficient bioaugmentation and MEOR technology to treat petroleum hydrocarbons in the environment and to explore heavy oil from the oilfields, respectively.

在治理石油污染和开采重油资源的各种技术中，通过微生物进行石油污染物降解和原油乳化的生物技术被认为具有广阔的前景和优势。由于自然界中微生物总存在于群落中，其中微生物之间的相互作用及其对群落结构与功能的影响，决定着利用微生物群落进行石油污染治理和原油开采的可行性。然而，人们对群落中微生物作用途径与协同作用机制尚缺乏系统深入的了解。为此，本项目拟在实验室前期工作基础上，以三株石油烃代谢细菌为研究对象，构建群落代谢网络模型，利用多种生物信息学手段与代谢组研究方法，分析群落中各微生物的石油组分代谢途径及引起各菌互利共生的种间代谢物，然后利用基因敲除和透析培养等研究手段，结合群落代谢网络模型，深入研究石油烃中间代谢物或细胞生长因子的种间交换在石油组分协同利用中的贡献，力图为促进高效稳定的石油污染治理修复技术和重油开采技术的开发，并为微生物生态学和环境生物技术的发展提供相关实验数据与实践尝试。

通过微生物进行石油污染物降解和重油乳化的生物技术被认为具有广阔的前景和优势。由于自然界中微生物总存在于群落中，微生物之间的相互作用决定着微生物采油和环境治理的可行性。目前，由于缺乏对群落中微生物代谢途径与协同作用机制的深入了解，人们尚无法有针对性地提高微生物技术在原油开采工业中的应用效率。本项目以中国油田中分离出的两株石油烃降解细菌Dietzia sp. DQ12-45-1b和Pseudomonas stutzeri SLG510A3-8为研究对象。实验表明，在以人工原油为唯一碳源对上述两株菌进行混合培养时，烷烃的降解率均高于两菌纯培养的结果。为探明两菌协同降解烷烃的机制，我们构建了群落代谢网络模型iBH1918，该模型包含935个Dietzia基因和983个Pseudomonas基因、2669个化学反应、1273种代谢物。我们利用流量平衡分析方法（Flux balance analysis），分析了在以十六烷为唯一碳源环境中引起两菌互利共生的种间代谢物，包括两种氨基酸、十一种小分子酸、葡萄糖及尿嘧啶，并通过两菌混合培养的湿实验中胞内蛋白组与胞外代谢组数据验证了模型预测的准确性。该研究成果与研究思路为下一步深入研究石油烃中间代谢物的种间交换在石油组分协同利用中的贡献打下了基础，将促进利用模型优化两菌协作的能力，力图为促进高效稳定的石油污染治理修复技术和重油开采技术的开发，并为微生物生态学和环境生物技术的发展提供相关实验数据与实践尝试。