SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, School of Environment, South China Normal University, Guangzhou, 510006, PR China.
Environmental Molecular Microbiology Research Laboratory, Department of Biotechnology, Thiruvalluvar University, Serkkadu, Vellore, Tamil Nadu, 632 115, India.
Environ Pollut. 2021 Oct 1;286:117556. doi: 10.1016/j.envpol.2021.117556. Epub 2021 Jun 9.
In the present study, produced water sample collected from the Indian crude oil reservoir is used to enrich the bacterial communities. The impact of these enriched bacterial communities on the biodegradation of crude oil, biofilm formation, and biocorrosion process are elucidated. A crude oil degradation study is carried out with the minimal salt medium and 94% of crude oil was utilized by enriched bacterial communities. During the crude oil degradation many enzymes including alkane hydroxylase, alcohol dehydrogenase, and lipase are playing a key role in the biodegradation processes. The role of enriched bacterial biofilm on biocorrosion reactions are monitored by weight loss studies and electrochemical analysis. Weight loss study revealed that the biotic system has vigorous corrosion attacks compared to the abiotic system. Both AC-Impedance and Tafel analysis confirmed that the nature of the corrosion reaction take place in the biotic system. Very less charge transfer resistance and higher corrosion current are observed in the biotic system than in the abiotic system. Scanning electron microscope confirms that the dense biofilm formation favoured the pitting type of corrosion. X-ray diffraction analysis confirms that the metal oxides formed in the corrosion systems (biotic). From the metagenomic analysis of the V3-V4 region revealed that presence of diverse bacterial communities in the biofilm, and most of them are uncultured/unknown. Among the known genus, Bacillus, Halomonas, etc are dominant in the enriched bacterial biofilm sample. From this study, we conclude that the uncultured bacterial strains are found to be playing a key role in the pitting type of corrosion and they can utilize crude oil hydrocarbons, which make them succeeded in extreme oil reservoir environments.
在本研究中，使用来自印度原油储层的采出水样来富集细菌群落。阐明了这些富集的细菌群落对原油生物降解、生物膜形成和生物腐蚀过程的影响。在最小盐培养基中进行了原油降解研究，其中 94%的原油被富集的细菌群落利用。在原油降解过程中，许多酶，包括烷烃羟化酶、醇脱氢酶和脂肪酶，在生物降解过程中发挥着关键作用。通过失重研究和电化学分析来监测富集细菌生物膜对生物腐蚀反应的作用。失重研究表明，与非生物系统相比，生物系统具有强烈的腐蚀攻击。交流阻抗和 Tafel 分析都证实了腐蚀反应发生在生物系统中。在生物系统中观察到的电荷转移电阻非常小，而腐蚀电流较高。扫描电子显微镜证实了致密生物膜的形成有利于点蚀类型的腐蚀。X 射线衍射分析证实了在腐蚀系统（生物）中形成的金属氧化物。从 V3-V4 区域的宏基因组分析中发现，生物膜中存在多种细菌群落，其中大多数是未培养的/未知的。在已知属中，芽孢杆菌、盐单胞菌等在富集细菌生物膜样本中占优势。从这项研究中，我们得出结论，未培养的细菌菌株被发现对点蚀类型的腐蚀起着关键作用，它们可以利用原油碳氢化合物，这使它们能够在极端的油藏环境中生存。
