SYNTHESIS AND CHARACTERIZATION OF BIOSURFACTANT USING WASTE FROM OIL PROCESSING INDUSTRY AS SUBSTRATE BY Pseudomonas aeruginosa (MTCC 424)

The purpose of this study was to produce biosurfactant by the waste of vegetable oil (soya bean and rice bran) processing industries like spent bleaching earth which contains approximately 14 to 25% residual oil respectively. More oil % was found in the spent on rice bran so here the same was used. The spent bleaching earth is a type of waste solid substance which is generated as an ingredient of the cleansing and decolorization process in the edible oil industry. It is usually deposited in the landfills or waste dumps. Pseudomonas was selected for its nutritional and biochemical versatility as well as for the simplicity of the culture conditions. The process opted for the growth of bacteria was steam sterilization and dry heat sterilization followed by microbial culture in basal salt medium with residual oil. Further biosurfactant was screened by various examination methods such as surface tension measurement, emulsification assay E24, CTAB methylene blue assay, oil dislocation (displacement), drop collapse and effect of environmental factors on biosurfactant activity was studied. Rhamnolipid biosurfactant produced by Pseudomonasaeruginosa is determined by the formation of insoluble ion pairs with various cationic substances. Emulsification index (%) shows the positive result for drop collapse, oil displacement, and CTAB methylene blue assay. The NMR and FTIR analysis show that the concentration and purely screened Rhamnolipid product contained L-rhamnosyl-b-hydroxydecanoyl-b-hydroxydecanoate (RL1) and L-rhamnosyl L-rhamnosyl-bhydroxydecanoyl-bhydroxydecanoate (RL2). Effect of environmental factors like salt, temperature and pH on surface tension was studied to analyze the solubility of biosurfactant. The optimum pH was found 6.8 and the optimum concentration of rhamnolipids produced was 8.5 g/l.