Activation of CO2-reducing methanogens in oil reservoir after addition of nutrient

Nutrient addition as part of microbial enhanced oil recovery (MEOR) operations have important implications for more energy recovery from oil reservoirs, but very little is known about the in situ response of microorganisms after intervention. An analysis of two genes as biomarkers, mcrA encoding the...

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Bibliographic Details
Published in:Journal of bioscience and bioengineering 2016-12, Vol.122 (6), p.740-747
Main Authors: Yang, Guang-Chao, Zhou, Lei, Mbadinga, Serge Maurice, You, Jing, Yang, Hua-Zhen, Liu, Jin-Feng, Yang, Shi-Zhong, Gu, Ji-Dong, Mu, Bo-Zhong
Format: Article
Language:English
Subjects:
fthfs
mcrA
Microbial enhanced energy recovery
Oil reservoir
Quantitative real-time PCR
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Summary:Nutrient addition as part of microbial enhanced oil recovery (MEOR) operations have important implications for more energy recovery from oil reservoirs, but very little is known about the in situ response of microorganisms after intervention. An analysis of two genes as biomarkers, mcrA encoding the key enzyme in methanogenesis and fthfs encoding the key enzyme in acetogenesis, was conducted during nutrient addition in oil reservoir. Clone library data showed that dominant mcrA sequences changed from acetoclastic (Methanosaetaceae) to CO2-reducing methanogens (Methanomicrobiales and Methanobacteriales), and the authentic acetogens affiliated to Firmicutes decreased after the intervention. Principal coordinates analysis (PCoA) and Jackknife environment clusters revealed evidence on the shift of the microbial community structure among the samples. Quantitative analysis of methanogens via qPCR showed that Methanobacteriales and Methanomicrobiales increased after nutrient addition, while acetoclastic methanogens (Methanosaetaceae) changed slightly. Nutrient treatment activated native CO2-reducing methanogens in oil reservoir. The high frequency of Methanobacteriales and Methanomicrobiales (CO2-reducers) after nutrient addition in this petroleum system suggested that CO2-reducing methanogenesis was involved in methane production. The nutrient addition could promote the methane production. The results will likely improve strategies of utilizing microorganisms in subsurface environments. •Nutrient addition activated CO2-reducing methanogens in the oil reservoir.•Nutrient addition decreased Firmicutes as acetogens in the oil reservoir.•The functional community in oil reservoir could be switched by the intervention.
ISSN:1389-1723
1347-4421
DOI:10.1016/j.jbiosc.2016.06.011