Biosurfactant production by Bacillus subtilis SL and its potential for enhanced oil recovery in low permeability reservoirs

Abstract

Microbial enhanced oil recovery (MEOR) technology is an environmental-friendly EOR method that utilizes the microorganisms and their metabolites to recover the crude oil from reservoirs. This study aims to research the potential application of strain SL in low permeability reservoirs. Strain SL is identified as Bacillus subtilis by molecular methods. Based on the mass spectrometry, the biosurfactant produced by strain SL is characterized as lipopeptide, and the molecular weight of surfactin is 1044, 1058, 1072, 1084 Da. Strain SL produces 1320 mg/L of biosurfactant with sucrose as the sole carbon source after 72 h. With the production of biosurfactant, the surface tension of cell-free broth considerably decreases to 25.65 ± 0.64 mN/m and the interfacial tension against crude oil reaches 0.95 ± 0.22 mN/m. The biosurfactant exhibits excellent emulsification with crude oil, kerosene, octane and hexadecane. In addition, the biosurfactant possesses splendid surface activity at pH 5.0–12.0 and NaCl concentration of 10.0% (w/v), even at high temperature of 120 °C. The fermentation solution of strain SL is applied in core flooding experiments under reservoir conditions and obtains additional 5.66% of crude oil. Hence, the presented strain has tremendous potential for enhancing the oil recovery from low-permeability reservoirs.

A new bacterial-derived biosurfactant for biotechnological applications in the oil industry: production, optimization, biosurfactant functional and physicochemical characterization

“…These results are of growing interest as the prospective application of BioS in numerous industrial processes necessitates thermal stabilities. Previous research works exhibited similar findings(Chen et al 2017;Ghazala et al 2017;Kiran et al 2017;Martins et al 2018;Feng et al 2019;Purwasena et al 2019;Zouari et al 2019;Jimenez et al 2021;Mnif et al 2021aMnif et al , 2021bUmar et al 2021;Wu et al 2022).…”

“…As shown in Figure 3(c), the BioS of MI27 shows a maximum emulsification of around 45%, which is obtained at concentrations greater than or equal to 1,000 mg/L. In this aim, numerous bacterial-derived surfactin, exhibited emulsification activities of around 67.6% for those derived from B. subtilis isolate LSFM-05 (de Faria et al 2011), around 98% as reported by Long et al (2017), around 55% for surfactin-like BioS produced by novel strain B. nealsonii S2MT (Phulpoto et al 2020), between 58 and 64% for B. subtilis #309 derived surfactin (Janek et al 2021) and between 56, 67, 54 and 60% for B. subtilis LS-derived surfactin isoforms (Wu et al 2022). This emulsification property makes BioS excellent candidates for the bioremediation of water and soil contaminated with oils and hydrocarbons (Maier & Soberon 2000).…”

“…We denote an improvement in the surfactant's effectiveness as the values of ST and CMC decrease. By way of comparison, we note, for example, that the MI27-derived BioS is more effective than surfactin isoforms produced by Bacillus subtilis isolate LSFM-05 (de Faria et al 2011), those produced by B. subtilis SL having a CMC value of 154 mg/L and a ST of 28.68 mN/m (Wu et al 2022) and surfactin isoforms produced by Bacillus nealsonii S2MT (Phulpoto et al 2020). In means of the ST reduction power, it is more efficient than surfactin isoforms produced by B. subtilis BS-37 displaying a CMC value of mg/L (Liu et al 2014), Bacillus amyloliquefaciens MO13-derived surfactin isoforms displaying a CMC value of 36 mg/L and an ST of 27 mN/m (Moro et al 2022), engineered surfactin isoforms produced by B. subtilis 168 having a CMC value of 38-36 mg/L with potential ST of 28 mN/m (Hu et al 2021) and surfactin isoforms derived from B. subtilis #309 having a CMC value of 15 mg/L with potential ST of 28 mN/m (Janek et al 2021).…”

“…Similar results are observed for emulsifying activity with higher attenuation than foaming power. These results go in favor of broadening its purview of use in different areas, especially for the enhanced oil recovery and biological remediation of sea water contamination (Chen et al 2017;Ghazala et al 2017;Kiran et al 2017;Martins et al 2018;Feng et al 2019;Purwasena et al 2019;Zouari et al 2019;Jimenez et al 2021;Mnif et al 2021aMnif et al , 2021bUmar et al 2021;Wu et al 2022).…”

Research advances of microbial enhanced oil recovery

“…Microbial enhanced oil recovery (MEOR) attracts broad attention with the advantages of environment-friendliness and low-cost ( Wu et al., 2022 ). Microbial enhanced oil recovery (MEOR) is one of the tertiary oil recovery approaches which uses ex-situ/in-situ microorganisms and their metabolites like biopolymers, biosurfactants, bio-enzymes, biogases, solvents, and biogenic acids to modify the flow characteristics of residual oil in the reservoirs to enhance oil recovery ( Niu et al., 2020 ; Patel et al., 2015 ).…”