By Okuda, Frank
Biosurfactants are amphipathic compounds produced extracellularly by microorganisms on cell surfaces, or excreted extracellularly. They contain hydrophilic and hydrophobic moieties that reduce surface and interfacial tension between molecules at the surface and interface respectively. The present study was focused on development of economical methods for biosurfactant production by the use of unconventional substrates. The research investigated the potential of utilizing agroindustrial (red cashew pomace) wastes to replace synthetic media for cultivation of Pseudomonas aeruginosa and biosurfactant production. The organism was able to grow and produce surfactant. The pseudomonas strains were screened for biosurfactant activity using haemolysis and oil spreading test. The surfactant was able to form emulsions with various vegetable oils and hydrocarbons being more effective against palm oil (70.3 ±0.57), olive oil (65.3 ±0.57) and kerosene (60.0 ±0.57). The surface-active compound retained its properties during exposure to elevated temperatures (up to 100°C), relatively high salinity (8% NaCl) and a wide range of pH values (2-12). The biosurfactant was extracted after 10 days using chlorofoam: methanol and the dry weight was calculated as 1.0g/L. Preliminary characterization by the use of basic biochemical tests revealed that the compound is a glycolipid. The biosurfactant produced was used in this study to explore the possible potential for cleaning up pesticides (chlorpyrifos) residue in tomatoes. Different concentration of biosurfactant solution (5ppm, 10ppm, 20ppm and 40ppm) were able to reduce 100ppm pesticide (chlorpyrifos) contaminated tomatoes to below maximum residue limit of 0.5ppm. The results of this study suggest the possible use of red cashew pomace in biosurfactant production and its useful properties in environmental and industrial application.