부산대학교 도서관

Surfactants are amphipathic molecules capable of forming microemulsions of oil in water. Currently, the major market for surfactants is the petroleum industry. However, the limitations of these molecules to the extreme conditions encountered in the oil processing main stages have opened space for application of so-called biosurfactants, which are molecules more resistant, biodegradable and non-toxic. Biosurfactants are mainly produced by aerobic microorganisms growing in aqueous medium containing carbon and nitrogen source. These compounds act between fluids of different polarities (oil/water and water/oil), allowing access to hydrophobic substrates and causing a surface tension reduction, an increase in the oil contact area and an enhancement of the oil mobility and bioavailability and decreasing the viscosity. In this research, the application of a biosurfactant from Candida tropicalis UCP0996 in the formulation of a biodispersant was investigated. Cell-free broth obtained from C. tropicalis UCP0996 cultivated in industrial waste was mixed with an inexpensive and non-toxic preservative (0.2% potassium sorbate). The mixture was subjected to a long- term stability study to verify expiry date and recommend storage conditions, and an accelerated stability study to assess the impact of short exposure to adverse conditions outside those idealized for activity of the bioproduct. Properties of the formulated biosurfactant such as surface tension and emulsification were checked at 0, 15, 30, 45, 90 and 120 days. Then, formulated biosurfactant was examined about their dispersing efficiency against motor oil in seawater. As a result, formulated biosurfactant remained stable over time and under extreme conditions of pH, temperature and salinity. Moreover, the use of the formulated biosurfactant as biodispersant allowed reach levels of dispersion above 60 %. Therefore, this research allowed the formulation of a low cost biotechnological product with high durability that maintains the initial properties for many days, demonstrating its potential application in the oil industry as biodispersant.