海洋环境中环烷烃的降解潜力与微生物新功能类群研究

环烷烃在海底油藏和凝析油中的丰度均较高，其环境效应不容忽视。然而，有关环烷烃的生物降解却鲜有报道。本项目拟通过现场富集实验获得对环烷烃特异响应/降解的培养物，通过扩增子高通量测序研究海洋环境中环烷烃的降解潜力与微生物功能类群的多样性。在实验室内模拟低温、贫营养环境条件，分别以环烷烃、正构烷烃、多环芳烃为唯一碳源和能源从环境样品中富集烃类降解菌群，并通过高灵敏度光氧计监测烃代谢进程。然后，通过比较宏基因组学和宏转录组学分析环烷烃降解菌与其它烃类降解菌在系统发育学、催化关键基因上的差异。最后，通过分离难培养关键微生物的纯培养或单细胞，研究其生理生化特征，获得其基因组图谱。通过该研究，期望从海洋环境中获得对环烷烃特异响应/降解的新功能微生物，揭示它们与贫营养的海洋γ变形菌纲（Oligotrophic Marine Gammaproteobacteria）在系统发育上的关系，发现新的功能基因资源。

The abundance of cyclic alkanes (c-alkanes) is relatively high both in subsurface hydrocarbon reservoirs and condensates. They pose significant risk to the marine ecosystems for their obvious toxicity. However, little is known about the biodegradation of c-alkanes. In this study, we plan to enrich the c-alkanes-degrading consortia from various marine samples on board, and determine the degradation potential of c-alkanes and biodiversity of functional microbes through the construction of amplicon library and high throughput sequencing. Moreover, another experiment is designed to grow different hydrocarbon-degrading consortia under the environment relevant conditions (low temperature and oligotrophic) in the lab. The respiration of hydrocarbons is monitored through a high-sensitive fiber-optic oxygen meter. Then, the difference of key players and functional genes is analyzed between c-alkanes-degrading consortia and n-alkanes/aromatics-degrading consortia through comparative metagenomics and metatranscriptomics. Finally, we plan to isolate several pure cultures/single cells of uncultured key microbe, study their physiological features, and obtain the complete genomes of the isolates. In this study, we expect to reveal the degradation potential of c-alkanes in the marine environment, discover new functional microbes responding specifically to c-alkanes, determine the phylogenetic relationship between the emerging functional microbes and Oligotrophic Marine Gammaproteobacteria, and explore new genetic resources which is promising in the clean-up of c-alkanes.