Application of molecular biology methods in identifying biosurfactant producers from oil contaminated sites

Crude oil is a major source of energy around the world. Recently the petroleum industry is facing many problems in extracting oil from mature wells. Many enhanced oil recovery (EOR) techniques are used, including microbial enhanced oil recovery (MEOR). Microbes produce different metabolites: biosurfactant, biopolymer, acids, solvents, and gases which can be used to increase oil recovery from reservoirs. Biosurfactants are amphiphilic molecules which can be used in MEOR; it reduces surface tension (ST) and interfacial tension (IFT) between oil and water, consequently, releasing oil trapped by capillary forces in rock pores. There are various microorganisms producing different types of biosurfactants (low or high molecular mass). As reported previously, surfactin and lichenysin are the best lipopeptidal-biosurfactants produced by Bacillus species which reduces the surface tension of water from 72-27 mN/m. Molecular biology methods are well adapted for identification and conservation of such novel microorganisms. Recent progress in molecular biology tools has played an important role in petroleum biotechnology. In this present review, genetic regulation of surfactin and lichenysin, factors affecting biosurfactant production and different techniques used to screen biosurfactant producers, are discussed briefly.