PRODUCTION AND CHARACTERIZATION OF BIOSURFACTANT FROM BACILLUS SUBTILIS USING WASTE BREADS

Abstract

Biosurfactants are amphiphilic biological compounds which are produced by various fungi and bacteria that reduce surface and interfacial tensions. In this study, a biosurfactant-producing microorganism was isolated from a soil sample which was collected from Cukurova University campus. The microorganism was identified as Bacillus subtilis by 16 S rRNA gene sequencing method and by investigating its biochemical properties obtained from VITEK-II Compact Identification System. Production of the biosurfactant was carried out by Bacillus subtilis using waste bread as substrate in culture medium. The biosurfactant production process was followed by surface tension measurement, emulsification index assay, determination of carbohydrate groups, foam stability and antimicrobial and antifungal activity observation of biosurfactant. Bacilllus subtilis showed very good hemolytic activity and diameter of the hemolytic zone was observed to be larger than 3 cm i.e. complete hemolysis (++++). Xylen was the best substrates for emulsification index (39%) of biosurfactant produced from Bacillus subtilis. Surface tension of biosurfactant was determined as 48.64 mN/m by using pendant drop method. The rhamnose test was positive which indicates that biosurfactant could be of rhamnolipid type. Biosurfactant had a good foaming stability and the purified biosurfactant exhibited antimicrobial and antifungal activities. Consequently, biosurfactant produced by Bacillus subtilis will provide improved wash efficiency as a detergent additive due to its characteristic features.