Production of Biosurfactant using a crude oil degrading strain of Pseudomonas aeruginosa RGB-3

Biosurfactants have emerged as promising eco-friendly agents for enhancing crude oil recovery and bioremediation. In this study, Pseudomonas aeruginosa RGB3 was assessed for biosurfactant production using various low-cost carbon sources and for its crude oil degradation capability. The FTIR analysis confirmed the production of rhamnolipid-type biosurfactants, as evidenced by the characteristic hydroxyl, ester, amide, and glycosidic functional groups. These molecules significantly enhanced the solubilization and emulsification of hydrophobic hydrocarbons, thereby increasing their bioavailability for microbial degradation, as supported by GC–MS analysis, which revealed the strain’s ability to degrade 18 different hydrocarbons. Biosurfactant production varies depending on the carbon source supplied. Among all tested media, sunflower oil supported the highest biosurfactant yield (1.99 g/L), followed by edible waste oil (1.64 g/L) and glycerol (1.075 g/L). These substrates also recorded the highest specific yields (0.44–0.47 g/g), indicating their suitability as efficient and low-cost carbon sources. In contrast, glucose and soybean oil produced lower yields, while crude oil and starch supported moderate production levels. Functional assays, including oil spreading, emulsification index, foaming, and drop collapse, confirmed the strong surface-active properties of the produced biosurfactants. Overall, the results demonstrate the high potential of P. aeruginosa RGB3 as an effective biosurfactant producer and crude oil degrader. The use of inexpensive substrates further supports its application in cost-effective microbial enhanced oil recovery (MEOR) and the bioremediation of petroleum-contaminated environments.