CHARACTERIZATION OF BIOSURFACTANT BY LUNATA CURVULARY - UFPEDA885 FOR SOIL DECONTAMINATION BY AUTOMOTIVE OIL

Abstract

The aim of this work was to characterize the production of biosurfactant by Curvularia lunata-UFPEDA885 for soil decontamination by automotive oil. A Central Rotational Composite Design was performed with the variables: inoculum size, concentration of NH4NO3, MnSO4H2O and CuSO4H2O. The fungus was inoculated in mineral medium with 2% diesel oil, with cultivation for 72 hours at 40oC. The following were evaluated: surface tension and emulsifying activity, toxicity of the biosurfactant against Cucumis sativus seeds, the microcrustacean Artemia salina and bioremoval of automotive oil in soil by the biosurfactant. Finally, the stability of the emulsion and the effects of pH, temperature and NaCl on the emulsifying activity were evaluated. C. lunata is a biosurfactant producer, reducing surface tension up to 32.9 mN/m. The surface tension reduction was optimized with inoculum, nitrogen and manganese at concentrations of 30 disks, 2g/L and 0.1g/L, respectively, and for copper 0.1g/L. Furthermore, this fungus produces a bioemulsifier capable of promoting the emulsification of up to 98% of automotive oil, with high stability at different pH, temperature and salinity values. The biosurfactant produced by C. lunata UFPEDA885 has 0.02% of proteins, 6.5% of sugars and 87% of total lipids. There was removal of 93.5% of automotive oil contaminating sandy soil and low phytotoxicity against C. sativus seeds, whereas for A. salina toxicity occurred at extract concentrations from 25%. C.lunata is considered promising in the production of biosurfactant with application in bioremediation.