The present invention relates to a method for the production of biosurfactant by Bacillus thuringiensis serovar thuringiensis SMT2 (GenBank Accession number JX559762) utilizing media supplemented with mustard seed meal and whey. The biosurfactant produced at 5X concentration has an efficiency, in terms of EI of 90% which is twice as that of commercial surfactant Tween 20.