Concomitant production and downstream processing of alkaline protease and biosurfactant from Bacillus licheniformis RG1: Bioformulation as detergent additive

Concomitant production of protease and biosurfactant was optimized using agro-products, namely cornstarch and soy flour as carbon and nitrogen sources, respectively, by response surface methodology. An overall 2.3-fold increase for both protease (2954 U/ml) and biosurfactant (41%) was achieved. Ultrafilteration using a 100 kDa membrane allowed a cost-effective purification of both protease and biosurfactant where the surfactant traps the protease on the membrane thereby detaining both in the retentate. These products were found to have a shelf life of 1 year in the dry form prepared by mixing sodium sulphate in the retentate. Thus, concomitant production of protease and surfactant, their easy formulation makes them attractive detergent additives.