Avaliação do potencial de bactérias para degradar derivados do petróleo e produzir biossurfactantes

Abstract

The present research work describes the evaluation of the potential by two bacteria strains isolated from the oil polluted ef uent, for degrading petroleum derivatives and producing biosurfactants, preliminarily identi ed as Acinetobacter spp. and Bacillus spp. Their biodegradation potential was assessed by their being cultivated in mineral broth containing glycerol, gasoline, kerosene or diesel as the only source of carbon and energy. Both bacteria degraded glycerol, gasoline, kerosene and diesel and produced biosurfactants. In general, the bacteria showed better and worse performances under the presence of glycerol and diesel, respectively. Bacillus spp., as a rule, did not grow and did not produce biosurfactant when cultivated in medium with diesel, surviving, however, under the spore form. The supplementation of that culture with 0.04 % of yeast extract, however, stimulated growth and production of biosurfactants production, reaching 95% of emulsi cation. Those bacteria were shown to be susceptible to heat, being destroyed at a 46ºC temperature, at 1 mg/L of sodium hypochloride and pH below 5.0. On the other hand, they resisted to 5% NaCl, a desirable characteristic for use in marine bioremediation programs.