Kapse Neelam G, Paliwal Vasundhara, Dagar Sumit Singh, Rana Dolly Pal, Dhakephalkar Prashant K
Bioenergy Group, MACS-Agharkar Research Institute, G.G. Agarkar Road, Pune, Maharashtra, 411004, India.
Savitribai Phule Pune University, Ganeshkhind Rd, Pune, Maharashtra, 411007, India.
Antonie Van Leeuwenhoek. 2022 Jan;115(1):19-31. doi: 10.1007/s10482-021-01667-8. Epub 2021 Nov 3.
Laboratory evaluation of hyperthermophiles with the potential for Enhanced Oil Recovery (EOR) is often hampered by the difficulties in replicating the in situ growth conditions in the laboratory. In the present investigation, genome analysis was used to gain insights into the metabolic potential of a hyperthermophile to mobilize the residual oil from depleting high-temperature oil reservoirs. Here, we report the 1.9 Mb draft genome sequence of a hyperthermophilic anaerobic archaeon, Thermococcus sp. 101C5, with a GC content of 44%, isolated from a high-temperature oil reservoir of Gujarat, India. 101C5 possessed the genetic arsenal required for adaptation to harsh oil reservoir conditions, such as various heat shock proteins for thermo-adaptation, Trk potassium uptake system proteins for osmo-adaptation, and superoxide reductases against oxidative stress. Microbial Enhanced Oil Recovery (MEOR) potential of the strain was established by ascertaining the presence of genes encoding enzymes involved in the production of the metabolites such as hydrogen, bio-emulsifier, acetate, exopolysaccharide, etc. Production of these metabolites which pressurize the reservoir, emulsify the crude oil, lower the viscosity and reduce the drag, thus facilitating mobilization of the residual oil was experimentally confirmed. Also, the presence of crude oil degradative genes highlighted the ability of the strain to mobilize heavy residual oil, which was confirmed under simulated conditions in sand-pack studies. The obtained results demonstrated additional oil recoveries of 42.1% and 56.5% at 96 °C and 101 °C, respectively, by the strain 101C5, illustrating its potential for application in high-temperature oil reservoirs. To our best knowledge, this is the first report of genome analysis of any microbe assessed for its suitability for MEOR from the high-temperature oil reservoir.
对具有提高采收率（EOR）潜力的嗜热菌进行实验室评估，常常因难以在实验室中复制原位生长条件而受阻。在本研究中，通过基因组分析来深入了解嗜热菌的代谢潜力，以便从枯竭的高温油藏中驱替残余油。在此，我们报告了从印度古吉拉特邦的一个高温油藏中分离出的嗜热厌氧古菌嗜热栖热菌属101C5的1.9 Mb基因组草图序列，其GC含量为44%。101C5拥有适应恶劣油藏条件所需的基因库，例如用于热适应的各种热休克蛋白、用于渗透适应的Trk钾摄取系统蛋白以及抵抗氧化应激的超氧化物还原酶。通过确定编码参与氢气、生物乳化剂、乙酸盐、胞外多糖等代谢产物生成的酶的基因的存在，确定了该菌株的微生物提高采收率（MEOR）潜力。通过实验证实，这些代谢产物的产生对油藏施压、乳化原油、降低粘度并减少阻力，从而促进了残余油的驱替。此外，原油降解基因的存在突出了该菌株驱替重质残余油的能力，这在填砂实验的模拟条件下得到了证实。所得结果表明，菌株101C5在96°C和101°C时分别额外采收了42.1%和56.5%的原油，说明了其在高温油藏中的应用潜力。据我们所知，这是第一份对从高温油藏中评估其MEOR适用性的任何微生物进行基因组分析报告。
