Application of the Biosurfactant Produced by Candida Sphaerica as a Bioremediation Agent

Environmental pollution caused by petroleum and its derivatives, such as diesel fuel, heavy oil, fuel residues, mineral oil and engine oil, is an issue of importance regarding both economic development and ecological restoration. Considerable amounts of petroleum products contaminate groundwater and soil as a consequence of leaks and spills from petroleum refinery processes, oil transportation and storage tanks. While contamination is caused by accidents in some cases, it is often the result of negligent disposal. Biosurfactants have received considerable attention in the field of environmental remediation processes. These substances influence such processes due to their efficacy as dispersion and remediation agents as well as their environmentally friendly characteristics, such as low toxicity and high biodegradability. Thus, this study investigated the potential application of a biosurfactant for enhanced removal capability of motor oil from contaminated sand and water, under laboratory conditions. The biosurfactant was produced by the yeast Candida sphaerica grown in distilled water supplemented with 9% ground nut oil refinery residue and 9% of corn steep liquor were used with their producer microorganism in the remediation of motor oil contained in sand and sea water. Sand oil bioremediation experiments were carried out for 90 days, while in sea water the period was 30 days. The results showed that the addition of the biosurfactant increased the degradation of the oil in the sand to 90%. With regard to the removal of oil on seawater, it was observed that removal percentages were around 85%. In this way, the biosurfactants produced, besides being obtained from low cost substrates, demonstrated efficiency in the removal of oils in sand and water, allowing the substitution of chemical treatment agents by environmental friendly agents.