title: Analysis of microbial communities in the oil reservoir subjected to CO2-flooding by using functional genes as molecular biomarkers for microbial CO2 sequestration.
abstract: Sequestration of CO2 in oil reservoirs is considered to be one of the feasible options for mitigating atmospheric CO2 building up and also for the in situ potential bioconversion of stored CO2 to methane. However, the information on these functional microbial communities and the impact of CO2 storage on them is hardly available. In this paper a comprehensive molecular survey was performed on microbial communities in production water samples from oil reservoirs experienced CO2-flooding by analysis of functional genes involved in the process, including cbbM, cbbL, fthfs, [FeFe]-hydrogenase, and mcrA. As a comparison, these functional genes in the production water samples from oil reservoir only experienced water-flooding in areas of the same oil bearing bed were also analyzed. It showed that these functional genes were all of rich diversity in these samples, and the functional microbial communities and their diversity were strongly affected by a long-term exposure to injected CO2. More interestingly, microorganisms affiliated with members of the genera Methanothemobacter, Acetobacterium, and Halothiobacillus as well as hydrogen producers in CO2 injected area either increased or remained unchanged in relative abundance compared to that in water-flooded area, which implied that these microorganisms could adapt to CO2 injection and, if so, demonstrated the potential for microbial fixation and conversion of CO2 into methane in subsurface oil reservoirs.
authors: State Key Laboratory of Bioreactor Engineering and Institute of Applied Chemistry, East China University of Science and Technology Shanghai, China.
authors: Jin-Feng
authors: JF
authors: Liu
authors: State Key Laboratory of Bioreactor Engineering and Institute of Applied Chemistry, East China University of Science and Technology Shanghai, China.
authors: Xiao-Bo
authors: XB
authors: Sun
authors: State Key Laboratory of Bioreactor Engineering and Institute of Applied Chemistry, East China University of Science and Technology Shanghai, China.
authors: Guang-Chao
authors: GC
authors: Yang
authors: State Key Laboratory of Bioreactor Engineering and Institute of Applied Chemistry, East China University of Science and Technology Shanghai, China.
authors: Serge M
authors: SM
authors: Mbadinga
authors: School of Biological Sciences, University of Hong Kong Hong Kong, China.
authors: Ji-Dong
authors: JD
authors: Gu
authors: State Key Laboratory of Bioreactor Engineering and Institute of Applied Chemistry, East China University of Science and Technology Shanghai, China.
authors: Bo-Zhong
authors: BZ
authors: Mu
keywords: CO2 fixation; bioconversion; functional genes; methane; microbial communities; oil reservoir