Study of Crude Oil Degradation by Gas Chromatography-Mass Spectrometry and Methanoic Acid and Biosurfactant Production by Pseudomonas sp.

Due to the advantages of biosurfactants such as low environmental toxicity, biological degradation, and effectiveness in wide ranges of pH and temperature, the industrial production of them has been significantly increased. Bioremediation is the strategy of reducing or eliminating petroleum compounds using microorganisms that are capable of decomposing petroleum hydrocarbons by producing biosurfactants. The purpose of this study was to investigate the biosurfactant production and bioremediation of crude oil by the isolated bacterium from Isfahan Oil Recovery plant activated sludge.

Quantitative and qualitative methods of screening such as hemolysis in blood agar medium, oil distribution, oil degradation, oil emulsification and surface tension reduction measurements were used for detection of biosurfactant production. Residual petroleum hydrocarbons were analyzed using gas chromatography (GC-MS) analysis. The bacterium was identified by biochemical tests and 16S rRNA sequencing.

The results from analysis of the composition by thin layer chromatography and Fiore infrared analysis showed that the produced biosurfactant had rhamnolipid content. The isolated bacterium was identified Pseudomonas Sp. The Pseudomonas sp. that was isolated from activated sludge of the oil refinery plant in Isfahan was able to produce rhamnolipid biosurfactant and decreased the surface tension of crude oil down to 27 mN/m. Gas chromatography analysis showed the removal of 80.45% of petroleum hydrocarbons within 20 days by the isolate. Methanoic acid accounts for 23% of the remarkable produced compounds.

The results of this study showed that the BA3 isolate was capable of producing the most biosurfactant and also the decomposition of crude oil hydrocarbons. Therefore it has the ability to be used in bioremediation, crude oil decomposition and elimination of the environmental pollutions from oil industries. Also the produced methanoic acid can be used as an antibacterial substance in animal feed.