Abstract
The processes of bioremediation appear as an innovative technology in the removal of compounds derivate from oil, among others pollutants. Nowadays, it has been given considerable emphasis to the environmental impacts caused by chemical surfactants due to their high toxicity and non-biodegradable properties. Biosurfactants are natural surfactants produced or bacteria, yeasts or fungi from different substrates. Biosurfactants have some advantages over petroleum based surfactants, such as biodegradability, production from renewable substrates, low toxicity, biocompatibility, diversity for chemical structure, effectiveness even at extreme conditions of temperature, pH and salinity. Due to these advantages, biosurfactants are good candidates to be used in environmental applications and in different industries such as petroleum, food production, cosmetics and pharmaceutics. In this work we used a medium formulated with distilled water supplemented with 5% corn steep liquor, 5% molasses and 5% soybean waste frying oil as substrates to produce a biosurfactant from Candida bombicola, at 28 °C during 144h under 200rpm. The tensoactive properties of the biosurfactant were determined, and its isolation, preliminary chemical characterization and environmental application were described. The isolated biosurfactant showed a yield of 8.4g/L. The biosurfactant reduced the water surface tension to 30mN/m, with a critical micelle concentration of 0.5%. The biosurfactant demonstrated stability with regard to surface tension reduction in a range of temperatures (5 to 120 °C) and pH values (2 to 12) as well as tolerance to high concentrations of NaCl (2 to 10%). The biosurfactant was characterized as glycolipid and demonstrated ability to remove 70% of motor oil adsorbed to porous surface. The results obtained with the biosurfactant produced show the promising properties of this biomolecule for use in bioremediation of hydrophobic compounds.
