Effect of surface-active biomolecules on the dissolution and degradation of crude oil hydrocarbons

BACKGROUND AND OBJECTIVESBiosurfactants with bipolar nature and having two hydrophilic and lipophilic heads increase the microbial degradation of oil hydrocarbons by improving the dissolution and emulsion of these compounds in the aqueous phase (Fenibo et al., ۲۰۱۹). The aim of this study was to investigate the effect of biosurfactant production on the rate of crude oil biodegradation.MATERIALS AND METHODSTo achieve this, two isolated oil-degrading bacteria from oil-contaminated soil included Pseudomonas aeruginosa and Ochrobactrum sp. were selected and the biosurfactant production of isolates were evaluated by oil-spreading and phenol-sulfuric acid methods. Also, the thin layer chromatography (TLC) method was performed to determine the type of the produced biosurfactants. The isolates degrading ability was evaluated in a crude oil-enriched mineral salt medium in triplicate (Zhang et al., ۲۰۱۲).RESULTS AND DISCUSSIONThe results showed that the oil spreading and biosurfactant production values of P. aeruginosa and Ochrobactrum sp. were ۳۰ and ۱ mm, ۲.۰۸ and ۰.۰۲ g/l, respectively. The oil degradatin values of P. aeruginosa and Ochrobactrum sp. were obtained ۳۹.۹ and ۲۲%, respectively. Also, the produced surface-active moleculs was characterized as a glycolipid biosurfactant (rhamnolipid) based on the TLC test. The results showed that the production of biosurfactant by P. aeruginosa isolate led to the improvement of microbial degradation of petroleum hydrocarbons in liquid environment, which is likely due to the increase in the dissolution of hydrophobic compounds in the aqueous phase and the better accessibility of microbes for internalization and use as a source of carbon and energy (Rehman et al., ۲۰۲۱; Das et al., ۲۰۲۰).CONCLUSIONProduction of biosurfactant by oil-degrading bacteria is an effective feature for improving the biodegradation of hydrocarbon compounds, which should be considered in the development of microbial products to remediate oil-contaminated resources