Production of biosurfactants through biodesulfurization of spent engine oil - an experimental study

Spent engine oil, a mixture of aliphatic and aromatic compounds, is one of the frequent environmental pollutants. In this paper, biodesulfurization of spent oil using Rhodococcus sp. was studied. Batch studies were conducted varying the oil to aqueous medium ratio of 10:90 to 90:10. The results demonstrated that maximum desulfurization of 80% was obtained at the oil to aqueous phase ratio of 70:30. Kinetic parameters of Monod type growth model, namely, mu(max), maximum specific growth rate and K-s, the half saturation constant were determined by varying the initial sulfur content of spent oil in the range of 0.16-1.05% (w/v). Gas chromatography-mass spectrometry was done to identify the compounds present in treated and untreated spent engine oil. The surface tension and emulsification indices of both oil and aqueous phases were also determined at different reaction times.