scholarly journals Anaerobic biosynthesis of rhamnolipids by Pseudomonas aeruginosa: performance, mechanism and its application potential for enhanced oil recovery

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Feng Zhao ◽  
Qingzhi Wang ◽  
Ying Zhang ◽  
Liying Lei

Abstract Background Pseudomonas 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. Results Pseudomonasaeruginosa 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. Conclusion The 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.

2018 ◽  
Vol 40 (1) ◽  
pp. 33-40
Author(s):  
Nafian Awaludin ◽  
Cut Nanda Sari

The decrease in oil production is caused by the ageing of oil production wells. The enhanced oil recovery (EOR) technology is proven to increase oil reserves and production in mature oil fields. One EOR technology that has proven to be efficient in increasing oil production is microbial EOR by using biosurfactant. The most effective biosurfactant is rhamnolipid produced by Pseudomonas aeruginosa, the bacteria of which can lower the interfacial tension between the petroleum and water. In biosurfactants production thanks to these bacteria, the substrate as the source of carbon in the fermentation process is needed. The sources of carbon used in this study are glucose, glycerol, molasses, banana peels, and waste from Pseudomonas aeruginosa by using Busnell Hass medium as a liquid medium of bacterial growth. Biosurfactants production results are; 74mg/L from glucose; 63mg/L from banana peels; 66mg / L from glycerol; 85mg/L from waste cooking oil; and 64mg/L of molasses with the following decreasing surface tension: 33.55 mN/m from glucose; 32.51 mN/m from banana peels; 27.55 mN/m from glycerol; 22.46 mN/m from waste cooking oil; and 31.49 mN/m from molasses. In addition, the decrease of interface tension of glucose; banana peels; glycerol; waste cooking oil; and molasses are as follows : 15.2 mN/m; 13.78 mN/m; 8:15 mN/m; 0.14 mN/m; and 11.2 mN/m respectively.Menurunnya produksi minyak bumi disebabkan karena sumur produksi yang sudah tua. Teknologi enhanced oil recovery (EOR) terbukti mampu meningkatkan cadangan dan produksi lapangan minyak mature. Salah satu teknologi EOR yang dikenal efi sien dalam meningkatkan perolehan minyak adalah microbial enhanced oil recovery menggunakan biosurfaktan. Biosurfaktan yang paling efektif adalah rhamnolipid yang dihasilkan oleh bakteri Pseudomonas aeruginosa yang dapat menurunkan tegangan antarmuka antara minyak bumi dengan air. Dalam produksi biosurfaktan oleh bakteri ini, diperlukan substrat sebagai sumber karbon dalam proses fermentasi. Sumber karbon yang digunakan pada penelitian ini adalah glukosa, gliserol, molase, kulit pisang, dan minyak jelantah. Penelitian ini bertujuan untuk mengetahui sumber karbon yang paling optimum dalam menghasilkan biosurfaktan dari Pseudomonas aeruginosa dengan menggunakan busnell hass medium sebagai media cair pertumbuhan bakteri. Produksi biosurfaktan yang dihasilkan adalah 74mg/L dari glukosa; 63mg/L dari kulit pisang; 66mg/L dari gliserol; 85mg/L dari minyak jelantah; dan 64mg/L dari molase dengan penurunan tegangan permukaan berturutturut: 33,55 mN/m dari glukosa; 32,51 mN/m dari kulit pisang; 27,55 mN/m dari gliserol; 22,46 mN/m dari minyak jelantah; dan 31,49 mN/m serta memiliki penurunan tegangan antarmuka dari glukosa; kulit pisang; glisero; minyak jelantah; dan molase berturut-turut adalah 15,2 mN/m; 13,78 mN/m; 8,15 mN/m; 0,14 mN/m; dan 11,2 mN/m.


Soft Matter ◽  
2021 ◽  
Author(s):  
Massinissa Hamouna ◽  
Aline Delbos ◽  
Christine Dalmazonne ◽  
Annie Colin

In the context of enhanced oil recovery or soil remediation, we study the role of interactions between polymers and surfactants on the injectivity of formulations containing mixtures of polymers and...


2021 ◽  
Author(s):  
Yongsheng Tan ◽  
Qi Li ◽  
Liang Xu ◽  
Xiaoyan Zhang ◽  
Tao Yu

<p>The wettability, fingering effect and strong heterogeneity of carbonate reservoirs lead to low oil recovery. However, carbon dioxide (CO<sub>2</sub>) displacement is an effective method to improve oil recovery for carbonate reservoirs. Saturated CO<sub>2</sub> nanofluids combines the advantages of CO<sub>2</sub> and nanofluids, which can change the reservoir wettability and improve the sweep area to achieve the purpose of enhanced oil recovery (EOR), so it is a promising technique in petroleum industry. In this study, comparative experiments of CO<sub>2</sub> flooding and saturated CO<sub>2</sub> nanofluids flooding were carried out in carbonate reservoir cores. The nuclear magnetic resonance (NMR) instrument was used to clarify oil distribution during core flooding processes. For the CO<sub>2</sub> displacement experiment, the results show that viscous fingering and channeling are obvious during CO<sub>2</sub> flooding, the oil is mainly produced from the big pores, and the residual oil is trapped in the small pores. For the saturated CO<sub>2</sub> nanofluids displacement experiment, the results show that saturated CO<sub>2</sub> nanofluids inhibit CO<sub>2</sub> channeling and fingering, the oil is produced from the big pores and small pores, the residual oil is still trapped in the small pores, but the NMR signal intensity of the residual oil is significantly reduced. The final oil recovery of saturated CO<sub>2</sub> nanofluids displacement is higher than that of CO<sub>2</sub> displacement. This study provides a significant reference for EOR in carbonate reservoirs. Meanwhile, it promotes the application of nanofluids in energy exploitation and CO<sub>2</sub> utilization.</p>


2021 ◽  
Author(s):  
Tinuola Udoh

Abstract In this paper, the enhanced oil recovery potential of the application of nanoparticles in Niger Delta water-wet reservoir rock was investigated. Core flooding experiments were conducted on the sandstone core samples at 25 °C with the applications of nanoparticles in secondary and tertiary injection modes. The oil production during flooding was used to evaluate the enhanced oil recovery potential of the nanoparticles in the reservoir rock. The results of the study showed that the application of nanoparticles in tertiary mode after the secondary formation brine flooding increased oil production by 16.19% OIIP. Also, a comparison between the oil recoveries from secondary formation brine and nanoparticles flooding showed that higher oil recovery of 81% OIIP was made with secondary nanoparticles flooding against 57% OIIP made with formation brine flooding. Finally, better oil recovery of 7.67% OIIP was achieved with secondary application of nanoparticles relative to the tertiary application of formation brine and nanoparticles flooding. The results of this study are significant for the design of the application of nanoparticles in Niger Delta reservoirs.


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