Abstract
The petroleum industry is one of the most pivotal sectors of the global economy but with it comes the production of atrocious amounts of waste especially during production and refining of the oil. Oil sludge which is an example of such waste has been categorized as hazardous because it is composed of asphaltenes, heavy metals and heavy hydrocarbons such as long-chain paraffins among others. The bioremediation of hydrocarbons in this waste is limited by low availability; biosurfactants were therefore applied to evaluate their efficacy in promoting the bioremediation process. The biosurfactants were produced by a hydrocarbon-degrading bacterium identified by 16S ribosomal RNA as Serrati sp. Biosurfactants were applied to the batch reactors containing oil sludge in different concentrations of 7 g/L, 14 g/L, and 28 g/L. The biosurfactants enhanced oil sludge biodegradation by 23.38%, 70.28%, and 55.6% respectively in 14 days. The increase in biosurfactant concentration showed a subsequent increase in microbial growth after every biosurfactant amendment due to the increase in bioavailability of the pollutants to the microbes which is utilized as the carbon and energy source. The biosurfactants were characterized by Fourier-transform infrared spectroscopy and Thin Layer chromatography showing the presence of amino acids. The biosurfactant produced by the hydrocarbon-degrading bacteria of Serratia sp. SA1 showed great potential in improving the bioremediation of recalcitrant hydrocarbons in the oil sludge and can, therefore, be used as an alternative to chemical surfactants.
