Selection of effective biosurfactant producers among Bacillus strains isolated from soils of Georgia

Application of biosurfactants of microbial origin and biosurfactant producing microorganisms in remediation technologies for cleaning sites polluted with organic and metal contaminants is environmentally friendly. Revealing the potential of microorganisms to synthesize surfactants and development of cost-effective bioprocesses for the biosurfactant production is an important direction of industrial biotechnology. Bacillus sp. BK34(7) and Bacillus sp. BK10(4) decreasing the indices of surface tension up to 29–30 mN/m were chosen as a result of multistep screening among 234 isolates from soils collected in Kakheti region of Georgia. The best result of biosurfactant synthesis was obtained on the 2nd day of cultivation. None of tested additional carbon sources (hexadecane, heptadecane, tetradecane, glycerol, molasses, sunflower, corn and olive oils) significantly enhances the ability of strains to reduce surface tension. Ability of these strains to decrease surface tension and emulsion capacity makes them as potential candidates for biosurfactant production.