Biosurfactant Production by Bacillus strains isolated from sugar cane mill wastewaters

Abstract

Biosurfactants possess diverse chemical properties and provide important characteristics to the producing microorganisms, which can act as surface-actives and emulsifiers of hydrocarbon and others water insoluble substances. Most of them are lipopeptides synthetized by Bacillus. This study evaluated the biosurfactant production by strains of Bacillus previously obtained from liquid residues of sugar-alcohol industry. The bacterial isolates LBPMA: BSC, BSD, J1, J2 and L1 were cultivated in medium that induces production of biosurfactants (Landy medium). During 48 h of incubation, at intervals of 12 h, the total contents of proteins, reducing carbohydrates and surfactant activity of the filtrated growth media free of cells were evaluated. The results showed that these strains use glucose as a source of carbon, energy and for synthesis of surfactant. In this medium (24 h), the best producer of biosurfactant was the strain LBPMA-J2, molecularly identified as Bacillus thuringiensis. Once the supernatant free of cells of this microorganism disperses the oil phase in the water, this strain has potential for being utilized on bioremediation processes.