Screening of sustainable biosurfactant produced by indigenous bacteria isolated from Egyptian oil fields for microbial enhanced oil recovery

Abstract

Microbial enhanced oil recovery (MEOR) stands out as an environmentally and economically significant approach utilizing microorganisms and their bio-products to reduce residual oil, and hence improve oil recovery. Due to the pollution that synthetic surfactants entail and their very expensive costs, there is a growing necessity for clean, eco-friendly alternatives. This research focuses on exploring the potential of producing biosurfactants by indigenous bacteria isolated from Egyptian Oil Fields. Five crude oil and formation water samples were collected from four Egyptian Oil Fields located in the Western Desert (WD). Nine bacterial strains were isolated and screened for biosurfactant production using different assays, followed by the extraction and purification of crude biosurfactants. The most promising biosurfactant-producing strains that showed their ability to produce effective biosurfactant according to biosurfactant screening assays were selected for further studies and identified through 16S rRNA gene sequencing. Furthermore, core-flooding micromodel experiments were conducted to evaluate the effectiveness of these extracted biosurfactants compared to a synthetic surfactant, Sodium Dodecyl Sulfate (SDS), in improving oil recovery. Results showed that the most promising biosurfactant-producing strains that exhibited notable performance and ability to produce effective biosurfactants were namely A-LB, C-LB2, and B-YM2. Therefore, they were selected for further studies and identified through 16S rRNA gene sequencing. 16S rRNA gene sequencing results showed that namely A-LB, C-LB2, and B-YM2 were identified as Bacillus massiliigabonensis, Pseudomonas nitritolerans, and Aninetobacter seohaensis, respectively. Finally, core flooding results showed that the biosurfactant produced by Bacillus massiliigabonensis demonstrated significant performance by recovering 69.96% of additional oil, whereas 68.11% and 63.34% of additional oil were recovered using biosurfactants produced by Pseudomonas nitritolerans, and Aninetobacter seohaensis, respectively. It was also noticed that the biosurfactant produced by Bacillus massiliigabonensis demonstrated significant potential in improving oil recovery compared to the synthetic surfactant (61.78%), it outperformed 8.18% more additional oil. These findings validate the effectiveness of the produced biosurfactants over synthetic surfactants emphasizing their potential as sustainable and cost-effective alternatives for enhanced oil recovery in Egyptian oil fields.