Abstract—

Nitrates do not occur in the formation water of oil reservoirs. A number of oil companies use nitrate injection technology to suppress corrosion of steel equipment and to decrease the concentration of hydrogen sulfide in the oil reservoir. The efficiency of this technology depends on the presence in the oil reservoir of bacteria capable of reducing nitrate to nitrite, the ion inhibiting growth of sulfate-reducing bacteria (SRB); otherwise, nitrate-reducing bacteria adapted to reservoir conditions must be introduced into the reservoir. In this work, we determined the phylogenetic diversity and potential functional activity of bacterial enrichment cultures reducing nitrate in a medium with oil, which were obtained from Tatarstan oil reservoirs. The bacteria accumulating nitrite in the medium were isolated. Growth of enrichment cultures in the medium with oil was accompanied by formation of nitrite and a decrease in the surface and interfacial tension of the medium. High-throughput sequencing of the V3–V4 region of the 16S rRNA gene of nitrate-reducing cultures revealed that Gammaproteobacteria, represented by bacteria of the genus Halomonas in the 5452-NR culture, and Pseudomonas, Stenotrophomonas, and Escherichia–Shigella in the 245D-NR culture, were predominant. Analysis of the obtained 16S rRNA gene libraries using the iVikodak program made it possible to predict the high potential functional diversity of bacteria in the enrichments capable of denitrification with production of nitrite and gaseous nitrogen compounds, and nitrate reduction with formation of nitrite and ammonium, as well as of catabolizing benzoate and other aromatic compounds. Eight strains of nitrate-reducing bacteria of the genera Chromohalobacter, Halomonas, Bacillus, Nocardia, Gordonia, Ensifer, and Pseudomonas, which grew aerobically on oil n-alkanes, were isolated from the enrichments. Enrichment cultures in media with nitrate and oil probably use the aromatic components of oil. Bacteria of the genera Chromohalobacter and Halomonas may be used for introduction into the oil reservoirs with low abundance of nitrate-reducing bacteria to reduce nitrate to nitrite, decrease the concentration of sulfide, and suppress the formation of hydrogen sulfide by sulfate-reducing bacteria in the reservoir.

中文翻译：

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重油储层中硝酸盐还原菌的多样性和生物技术潜力（俄罗斯）

摘要—

硝酸盐不会出现在储油层的地层水中。许多石油公司使用硝酸盐注入技术来抑制钢设备的腐蚀并降低储油罐中硫化氢的浓度。该技术的效率取决于油藏中是否存在能够将硝酸盐还原为亚硝酸盐的细菌，该离子可抑制硫酸盐还原细菌（SRB）的生长。否则，必须将适应水库条件的减少硝酸盐的细菌引入水库。在这项工作中，我们确定了从Ta斯坦油藏获得的含油培养基中减少硝酸盐的细菌富集培养物的系统发育多样性和潜在的功能活性。分离出在培养基中积累亚硝酸盐的细菌。含油培养基中富集培养物的生长伴随着亚硝酸盐的形成以及培养基表面和界面张力的降低。对硝酸盐还原培养物的16S rRNA基因的V3-V4区进行高通量测序，发现以545D -NR培养中的Halomonas属细菌为代表的细菌是丙型杆菌，而以245D-NR培养的假单胞菌，嗜单胞菌和大肠杆菌-志贺氏菌为代表。使用iVikodak程序对获得的16S rRNA基因文库进行分析，可以预测细菌中亚硝酸盐和气态氮化合物产生反硝化作用以及亚硝酸盐和铵态氮形成时硝酸盐还原的富集潜力。以及分解苯甲酸酯和其他芳香族化合物。8株属的硝酸盐还原菌的Chromohalobacter，盐单胞菌，芽孢杆菌属，诺卡氏菌属，大头，Ensifer，和假单胞菌属，其需氧生长在油Ñ烷烃，从该富集分离。硝酸盐和石油在培养基中的富集培养可能使用了石油的芳香成分。下列属的细菌Chromohalobacter和盐单胞菌可用于引入到油藏具有低丰度硝酸盐还原菌的减少硝酸盐为亚硝酸盐，降低硫化物的浓度，并通过在硫酸盐还原细菌抑制硫化氢的形成水库。