Evaluation of nutritional and environmental factors for biosurfactant production by soil bacteria

Abstract Biosurfactants are amphiphilic molecules produced by microbes as secondary metabolites, reduce the surface tension between two immiscible phases of liquids or gases and could replace chemically synthesized surfactants in food industries, agrochemical industries, cosmetics, pharmaceuticals, oil recovery and petroleum industries. Biosurfactant production could be altered by providing microbes suitable environments. Thus the current research work evaluated the effect of different carbon and nitrogen sources and influence of pH on biosurfactant production of bacteria isolated from soil sludge prepared by seeding the soil with different hydrocarbons (petrol, diesel and mustard oil).Isolates showing maximum emulsification activity in emulsification assay (≥ 40%) were selected for further optimization of process parameters to enhance the production of biosurfactant. Isolates were screened for biosurfactant production with different carbon sources, nitrogen sources and at different pH. At alkaline pH (pH 9) all the isolates shows maximum emulsification activity up to 92% by PS1. Optimized condition for maximum biosurfactant production by PS1 is Glycerol 2% as carbon source and yeast extract as nitrogen sources at pH 9.DS2 shows maximum biosurfactant production with olive oil and peptone as carbon and nitrogen sources respectively at pH 9.The optimized media constituents concluded for MS4 is Glycerol 2% as carbon sources and peptone as nitrogen source at pH 9.Production of biosurfactant could be enhance by optimizing media constituents at industrial scale.Thus, current work contributed important prospects to enhance the production of biosurfactant by Bacillus species.