Biosurfactant quality generated from fungi using agro-wastes (maize husk, rice husk, and augarcane bagasse)

Abstract

Biosurfactants are amphiphilic compound that contain hydrophilic and hydrophobic moieties produced extracellularly by microorganism on cell surface or excreted extracellularly thereby reducing surface and interfacial tension between molecules at the surface and interface, respectively. This study was aimed on the isolation and identification of biosurfactant producing fungi; the production of biosurfactants from the identified fungi in a submerged fermentation using sugarcane bagasse, rice husk and maize husk as carbon sources and the evaluation of quality of biosurfactants generated. The biosurfactant production was assayed for 21 days with constant agitation for at most four times daily in an incubator (300C). The emulsification ability of the biosurfactant produced was analyzed on two hydrocarbons: diesel and kerosene. In diesel, the emulsification index (EI) showed highest in biosurfactant produced by Aspergillus niger in Rice Husk (BAR) after 72 hours (E72) (80.30±0.30%) and lowest in biosurfactant produced by Fusarum oxysporum in sugarcane bagasse after 24 hours (E24) (BFS) (33.43±0.10%). In kerosene, the highest emulsification index was observed in biosurfactant produced by Fusarum oxysporum in Maize Husk (BFM) E72 (94.25±0.25%) and lowest in biosurfactant produced by Fusarum oxysporum in sugarcane bagasse (BFS) E48 (52.53±0.10%). Therefore, comparing the biosurfactants produced by Fusarum oxysporum and Aspergillus niger, Fusarum oxysporum exhibited more emulsification ability than Aspergillus niger. The result of EI showed that Maize Husk and Rice Husk are good substrates for biosurfactant production while Fusarum oxysporum is the better biosurfactant producing fungi. In comparing the hydrocarbons, more emulsion was noticed in diesel than kerosene. The result of oil spreading assay with spent engine oil showed that biosurfactants produced by Fusarum oxysporum grown on Rice Husk had the highest area of displacement (13.88±0.01cm2) while biosurfactant produced by Aspergillus niger grown on Sugarcane Bagasse showed the least area of displacement (4.91±0.00cm2). The carbon sources used in this work are good for the production of biosurfactant. Upscaling of the process will yield biosurfactants applicable in industries.