Dataset Information

Rhamnolipids Produced by Indigenous Acinetobacter junii from Petroleum Reservoir and its Potential in Enhanced Oil Recovery.

ABSTRACT: Biosurfactant producers are crucial for incremental oil production in microbial enhanced oil recovery (MEOR) processes. The isolation of biosurfactant-producing bacteria from oil reservoirs is important because they are considered suitable for the extreme conditions of the reservoir. In this work, a novel biosurfactant-producing strain Acinetobacter junii BD was isolated from a reservoir to reduce surface tension and emulsify crude oil. The biosurfactants produced by the strain were purified and then identified via electrospray ionization-Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR-MS). The biosurfactants generated by the strain were concluded to be rhamnolipids, the dominant rhamnolipids were C26H48O9, C28H52O9, and C32H58O13. The optimal carbon source and nitrogen source for biomass and biosurfactant production were NaNO3 and soybean oil. The results showed that the content of acid components increased with the progress of crude oil biodegradation. A glass micromodel test demonstrated that the strain significantly increased oil recovery through interfacial tension reduction, wettability alteration and the mobility of microorganisms. In summary, the findings of this study indicate that the newly developed BD strain and its metabolites have great potential in MEOR.

SUBMITTER: Dong H

PROVIDER: S-EPMC5097926 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

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Rhamnolipids Produced by Indigenous <i>Acinetobacter junii</i> from Petroleum Reservoir and its Potential in Enhanced Oil Recovery.

Dong Hao H Xia Wenjie W Dong Honghong H She Yuehui Y Zhu Panfeng P Liang Kang K Zhang Zhongzhi Z Liang Chuanfu C Song Zhaozheng Z Sun Shanshan S Zhang Guangqing G

Frontiers in microbiology 20161107

Biosurfactant producers are crucial for incremental oil production in microbial enhanced oil recovery (MEOR) processes. The isolation of biosurfactant-producing bacteria from oil reservoirs is important because they are considered suitable for the extreme conditions of the reservoir. In this work, a novel biosurfactant-producing strain <i>Acinetobacter junii</i> BD was isolated from a reservoir to reduce surface tension and emulsify crude oil. The biosurfactants produced by the strain were purif ...[more]

PMID: 27872613

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Project description:BackgroundPseudomonas aeruginosa, the rhamnolipids-producer, is one of dominant bacteria in oil reservoirs. Although P. aeruginosa strains are facultative bacteria, the anaerobic biosynthesis mechanism of rhamnolipids is unclear. Considering the oxygen scarcity within oil reservoirs, revealing the anaerobic biosynthesis mechanism of rhamnolipids are significant for improving the in-situ production of rhamnolipids in oil reservoirs to enhance oil recovery.ResultsPseudomonas aeruginosa SG anaerobically produced rhamnolipids using glycerol rather than glucose as carbon sources. Two possible hypotheses on anaerobic biosynthesis of rhamnolipids were proposed, the new anaerobic biosynthetic pathway (hypothesis 1) and the highly anaerobic expression of key genes (hypothesis 2). Knockout strain SGΔrmlB failed to anaerobically produce rhamnolipids using glycerol. Comparative transcriptomics analysis results revealed that glucose inhibited the anaerobic expression of genes rmlBDAC, fabABG, rhlABRI, rhlC and lasI. Using glycerol as carbon source, the anaerobic expression of key genes in P. aeruginosa SG was significantly up-regulated. The anaerobic biosynthetic pathway of rhamnolipids in P. aeruginosa SG were confirmed, involving the gluconeogenesis from glycerol, the biosynthesis of dTDP-L-rhamnose and β-hydroxy fatty acids, and the rhamnosyl transfer process. The engineered strain P. aeruginosa PrhlAB constructed in previous work enhanced 9.67% of oil recovery higher than the wild-type strain P. aeruginosa SG enhancing 8.33% of oil recovery.ConclusionThe highly anaerobic expression of key genes enables P. aeruginosa SG to anaerobically biosynthesize rhamnolipids. The genes, rmlBDAC, fabABG, rhlABRI, rhlC and lasI, are key genes for anaerobic biosynthesis of rhamnolipid by P. aeruginosa. Improving the anaerobic production of rhamnolipids better enhanced oil recovery in core flooding test. This study fills the gaps in the anaerobic biosynthesis mechanism of rhamnolipids. Results are significant for the metabolic engineering of P. aeruginosa to enhance anaerobic production of rhamnolipids.

Project description:In this work, a newly engineered alumina quantum dot-based nanofluid (α-AQDs; D ~ 4 nm; amorphous solid) and one commercial alumina nanoparticle-based nanofluid (γ-ANPs; D ~ 20 nm; crystalline type) with the capability of strong colloidal dispersion at reservoir conditions, such as, high salinity, divalent ions (Ca2+) and high temperature was compared. The main goal of this research was to study the crude oil displacement mechanisms of alumina suspensions as a function of variety in size and particle morphology in aged carbonate rocks. The strong interaction potential between the particles was achieved by the citric acid and a special composition of a carboxylate-sulfonate-based polyelectrolyte polymer as an effective dispersant compound on the surface, leading to a negative particle charges and an additional steric and electrostatic repulsion. Wettability alteration upon exposure to fluids using the contact angle and the Amott cell were performed on saturated carbonate plug samples and rock slices. While, dynamic core displacements were conducted to test the water/nanofluid/oil flow and nanoparticle retention behavior thorough typical pore throats underground the reservoir conditions. The stability results revealed that PE-polymer was able to create a long-term colloidal fluid during 30 days. It was found that mass concentration of nanofluid increased with decreasing in particle size. The optimal amount of particles in aqueous solution was obtained 0.05 wt% for ANPs, increased up to 0.1 wt% for AQDs. Analysis of experiments showed that wettability alteration was the main mechanism during nanofluid injection. Laboratory core-flooding data proved that the enhanced oil recovery due to a less concentration state by ANPs was consistent with AQDs at higher concentrations. In addition, permeability-impairment-behavior study was discussed in terms of possible mineral scale deposition and alumina release on the rock surface. Results showed that a large extent of permeability damage caused by mineral scale (55-59%). Alumina quantum dot-based nanofluids were found a minimum impairment (2-4%) and a significant reduction of ~ 10% in permeability was observed for ANPs-based nanofluid.

Project description:Subsurface petroleum reservoirs are an important component of the deep biosphere where indigenous microorganisms live under extreme conditions and in isolation from the Earth's surface for millions of years. However, unlike the bulk of the deep biosphere, the petroleum reservoir deep biosphere is subject to extreme anthropogenic perturbation, with the introduction of new electron acceptors, donors and exogenous microbes during oil exploration and production. Despite the fundamental and practical significance of this perturbation, there has never been a systematic evaluation of the ecological changes that occur over the production lifetime of an active offshore petroleum production system. Analysis of the entire Halfdan oil field in the North Sea (32 producing wells in production for 1-15 years) using quantitative PCR, multigenic sequencing, comparative metagenomic and genomic bins reconstruction revealed systematic shifts in microbial community composition and metabolic potential, as well as changing ecological strategies in response to anthropogenic perturbation of the oil field ecosystem, related to length of time in production. The microbial communities were initially dominated by slow growing anaerobes such as members of the Thermotogales and Clostridiales adapted to living on hydrocarbons and complex refractory organic matter. However, as seawater and nitrate injection (used for secondary oil production) delivered oxidants, the microbial community composition progressively changed to fast growing opportunists such as members of the Deferribacteres, Delta-, Epsilon- and Gammaproteobacteria, with energetically more favorable metabolism (for example, nitrate reduction, H2S, sulfide and sulfur oxidation). This perturbation has profound consequences for understanding the microbial ecology of the system and is of considerable practical importance as it promotes detrimental processes such as reservoir souring and metal corrosion. These findings provide a new conceptual framework for understanding the petroleum reservoir biosphere and have consequences for developing strategies to manage microbiological problems in the oil industry.

Dataset Information

Rhamnolipids Produced by Indigenous Acinetobacter junii from Petroleum Reservoir and its Potential in Enhanced Oil Recovery.

Publications

Rhamnolipids Produced by Indigenous <i>Acinetobacter junii</i> from Petroleum Reservoir and its Potential in Enhanced Oil Recovery.

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