Biosurfactant role in microbial enhanced oil recovery

Biosurfactants or biological surfactants are chemical compounds with a wide structural variety produced by microorganisms such as bacteria, yeast, and fungi. They are amphiphilic compounds with a hydrophilic (amino acids or peptides, disaccharides or polysaccharides, anions or cations) and a hydrophobic (saturated or unsaturated fatty acids) moiety. In recent years, nontoxic and biodegradable biosurfactants have received great attention from many industries, including enhanced oil recovery and the upstream sector of the oil industry. Oil as the main source of energy cannot be fully extracted from the subsurface reservoirs naturally. As such, EOR technology has assisted engineers to extract the unrecovered oil but is still limited, especially in the case of bitumen. Applications of biosurfactants and other bioproducts of bacteria have attracted great attention in enhanced oil recovery along with bitumen extraction due to their extensive surface properties and environmentally friendly natures. Biosurfactants with other bioproducts are produced during microbial injection in oil reservoirs known as a microbial enhanced oil recovery technique. This chapter starts with a brief introduction of oil production stages during the life of an oil reservoir followed by enhanced oil recovery. An overview of biosurfactants is discussed along with their classifications. The influencing factors in biosurfactant production are also described precisely. An illustration of the effectiveness of biosurfactants in microbial enhanced oil recovery methods and bitumen extraction is furnished. Different promising mechanisms in crude oil recovery and bitumen extraction by biosurfactants are deliberated briefly. Screening criteria and worldwide field implementation are documented to provide an idea about the applications and effectiveness of biosurfactants in oil recovery. Finally, challenges and the needed future research in the context of biosurfactants assisted oil recovery are highlighted. © 2021 Elsevier Inc. All rights reserved.