Isolation and purification of a new enamide biosurfactant from Fusarium proliferatum using rice-bran

Abstract

A new fungus Fusarium proliferatum was isolated from the oil contaminated sludge of the rice-bran oil industry, which was capable of producing biosurfactants when grown on rice-bran. The dark brown honey colored biosurfactant was recovered using ultrasonication as one of the steps in the extraction process. The biosurfactant was purified by column chromatography and structure elucidation of the purified biosurfactant was done with the aid of various spectroscopic techniques viz. FTIR, 2D-NMR, and Mass Spectrometry. The purified biosurfactant reduced the surface tension of the distilled water from 71.2 to 36.6 mN m⁻¹ and the critical micelle concentration was calculated to be 0.33 mg mL⁻¹. The biosurfactant was also capable of emulsifying various hydrocarbons viz. coconut oil, refined oil, kerosene, and n-dodecane. The crude biosurfactant was checked for its anti-oxidant activity using ascorbic acid as a standard and determining the 1,1-diphenyl-2-picryl hydrazyl (DPPH) scavenging activity. The IC₅₀ was calculated and for ascorbic acid it comes out to be 0.056 mg mL⁻¹ and for biosurfactant it was 18.81 mg mL⁻¹.