油藏样本潜在核心功能微生物群的宏基因组挖掘

Screening potential core functional microbiota of a crude oil sample through metagenomic analysis

【背景】识别出具有驱油功能的内源性微生物群是当前设计高效微生物采油技术的迫切需求。【目的】通过宏基因组分析找出原位油藏微生物中具有产酸/产气功能的潜在核心微生物群。【方法】利用室内模拟体系,对原位油藏微生物进行有机营养(从有氧到无氧)的激活,运用生物信息、多元统计分析以及网络分析等方法,寻找潜在内源性核心功能微生物群。【结果】有机营养激活了原位油藏样本中以Bacillus licheniformis为核心的产酸菌群(包括Coprothermobacter proteolyticus、Marinobacterspp.、Anaerobaculumhydrogeniformans和Petrotogamobilis),该菌群具有以丙酮酸/乙酰辅酶A为原料发酵乳酸、乙酸以及甲酸的功能;激活了以Enterococcus faecium为核心的产气菌群(包括Shinella zoogloeoides、Paracoccus denitrificans、Paracoccus spp.和Enterobacter cloacae),该菌群具备以(亚)硝酸盐、(亚)硫酸盐、石油烃为原料生产含氮/硫/碳等气体的能力。2个核心菌群内部分菌同时具有产酸和产气通路基因,激活过程中2个菌群的丰度变化呈负相关关系。【结论】利用有机营养激活体系及宏基因组测序分析技术,筛选出了油藏样本中具备产酸、产气能力的核心功能菌群,为后续进一步的功能菌株研究提供了潜在靶标及功能指向。

[Background]Understanding functional microbiota inside crude oil samples is crucial in microbiota design for enhancing oil recovery.[Objective]Identifying potential core functional microbiota from a crude oil sample that have ability to produce acid/gas through metagenomic analysis.[Methods]The compositional and functional changes of the indoor activated crude oil samples were obtained with the metagenomic data.The potential endogenous core functional microbiota related to the production of gas and acid were obtained through bioinformatics,multivariate statistics and network analysis.[Results]The co-abundance analysis deduced that Bacillus licheniformis,along with Coprothermobacter proteolyticus,Marinobacter spp.,Anaerbaculum hydrogeniforms and Petrotoga mobilis that clustered as a group,were the core functional bacteria relevant to the change of the pH value.Functional analysis of strains in this group through draft genome assembly indicated that the pathways for acid production,including for lactic acid,acetic acid and formic acid fermentation using pyruvate/acetyl coenzyme A,were enriched.Enterococcus faecium was considered as the core microbe in another group,which had Shinella zoogloeoides,Paracoccus deniticans,Paracoccus spp.and Enterobacter cloacae.Among these,Enterobacter cloacae was positively correlated with total gas production.The assembled bins in this group had the ability to produce nitrogen/sulfur/carbon using nitrate(nitrite)/sulfate(sulfite)/petroleum hydrocarbon.These two groups both had a small number of microbes that have dual ability for gas and acid production and the two groups were negatively correlated.[Conclusion]We had screened out core acid/gas producing microbiota in a crude oil sample through organic activation and metagenomic sequencing technology.These findings provided potential strain targets for further research.