Production of a new lipoprotein biosurfactant by Streptomyces sp. DPUA1566 isolated from lichens collected in the Brazilian Amazon using agroindustry wastes

The present study describes a new biosurfactant produced by Streptomyces spp. isolated from lichens from the Brazilian Amazon region. Forty-one Streptomyces spp. strains were screened for their ability to produce biosurfactants. A full 24-factorial design was used to investigate the effects of pH, percent aeration, agitation and temperature on surface tension and emulsification index after fermentation by Streptomyces sp. DPUA1566 isolate, which ensured the highest biosurfactant concentration (1.9 g/l) in a medium containing 10 g/L soybean waste frying oil and 20 g/L corn steep liquor at pH 8.5, 150 rpm, 28 °C and air saturation of 80%. The biosurfactant reduced the surface tension of water from 72 to 28 mN/m, with a critical micelle concentration of 0.08%, and was effective over wide ranges of temperature, pH and salt concentration. The biomolecule, which was characterized as a lipoprotein and denominated bioelan, did not exhibit toxicity against vegetable seeds or brine shrimp. Streptomyces sp. DPUA1566 proved to be a promising source of biosurfactant from low-cost waste with potential application either in bioremediation processes or in pharmaceutical and cosmetic industries.