Identification and characterization of biosurfactants produced by microorganisms previously isolated having the ability to degrade petroleum

Abstract

Petroleum hydrocarbon pollution poses a major environmental and economic challenge, requiring sustainable remediation strategies. A promising approach relies on the use of biosurfactant-producing microorganisms for the bioremediation of contaminated areas. Biosurfactants enhance microbial biodegradation by increasing the bioavailability of hydrocarbons, thereby making the process more efficient. The present study evaluated the biosurfactant production potential of five bacterial strains: Pseudomonas aeruginosa, Acinetobacter baumannii, Enterococcus gallinarum, Aneurinibacillus migulanus, and Lysinibacillus cavernae, previously isolated from petroleum products and oil-contaminated soils. The E24 % test (24-hour emulsification index) was used to assess the ability of the tested bacteria to produce biosurfactants and emulsify hydrocarbons, specifically diesel and gasoline. Subsequently, the produced biosurfactants were extracted using a chloroform–methanol mixture and characterized by Fourier-transform infrared spectroscopy (FTIR). Their antimicrobial activity was assessed using the agar well diffusion method against Staphylococcus aureus, Escherichia coli, Candida albicans, and Aspergillus flavus. Their antioxidant potential was evaluated using the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay.