Biosurfactants are amphiphilic compounds produced by bacteria and fungi to reduce surface and interfacial tension. This work was designed to produce biosurfactants from the fermentation of submerge cashew bagasse (Anacardium occidentale) using a microorganism Pseudomonas aeruginosa. The proximate components of the biosurfactant was determined. Results show that yellow cashew fruit bagasse contains lipid (11.34 ± 0.16%), protein (26.67 ± 0.66%), carbohydrate (49.37 ± 0.60%), moisture (5.78 ± 0.17%), ash (2.70 ± 0.04%) and fibre (2.86 ± 0.09%). Biosurfactants activity was characterized based on emulsification index and oil displacement capacity. The yield of biosurfactants was, 0.71 g; when only cashew was used; 0.93 g for cashew and glucose and nutrient broth 0.12 g respectively. The preliminary biochemical characterization revealed that the biosurfactants contained carbohydrates and lipids designated as glycolipids. The biosurfactants showed antimicrobial activity against a range of Gram positive and Gram negative bacteria strains with diameters of zone and growth inhibition: Escherichia coli, 38.70 ± 1.30 mm; Staphylococcus aureus, 38.00 ± 2.94 mm; Klebsiella, 31.00 ± 2.20 mm and Bacillus cereus, 28.70 ± 1.70 mm. These results suggest that cashew fruits bagasse serve as cheap carbon source for the production of glycolipid biosurfactants with useful industrial applications.
Key words: Biosurfactants, fruit bagasse, yellow cashew, characterization and Pseudomonas aeruginosa.