Produção, caracterização e aplicação biológica do biossurfactante por Streptomyces spp. isolados da Região Amazônia

Abstract

The biosurfactants are amphiphilic biomolecules produced by micro-organisms and are capable of reducing the surface tension between liquids, less toxic, biodegradable, exhibit antimicrobial activity and are used in pharmaceutical and cosmetic products. This study evaluated the ability to produce biosurfactant using low-cost organic substrate by Streptomyces spp. isolated from lichens in the Amazon region. The used mediums for selection were: peptone and glycerol (medium A) and peptone /yeast extract and Caryocar brasiliense oil (medium B). Four other medium were used to select the best agro-industrial residues: cornsteep liquor and soybean oil (medium I), cornsteep liquor, soybean waste frying oil (medium II), peptone and the waste oil motor (medium III), peptone and soybean frying waste oil (medium IV) were evaluated for the production of biosurfactant by microrganisms tests. The biosurfactant production was followed by measuring the surface tension and emulsification index. Two 24 full factorial design were carried out to verify the effects and interations of pH, temperature, relationship between medium volume and Erlenmeyer volume (RVME) and agitation, cornsteep liquor, waste frying soybean oil and inoculum concentration on maximum variation of ST, EI and yield. The biosurfactant was concentrated, isolated and characterized by Infrared Spectroscopy Fourier Transform (FT-IR) and gas chromatography (GC). Ten strains of Streptomyces spp. were selected and among the best biosurfactant producer was the Streptomyces sp. DPUA1566. The medium II, at 28 ° C, pH 7.0, 150 rpm, 4% inoculum concentration and RVME of 90% were designated as optimal conditions for the biosurfactant production. The biosurfactant showed stability when submitted at 90°C and thermal (4–120°C), pH (6–12) and tolerance under high salt concentrations (2–12%). The biosurfactant showed a yield of 3.11 g/L, critical micelar concentration (CMC) of 0.08%, and reducing the superficial tension of the water from 72 to 28.77 mN/m. Biosurfactant showed 85% protein and15% lipids. The fatty acid composition revealed the presence of C16:0 - 4.9% (palmitic), C16:1 - 1.1% (palmitoleic), C18:0 - 4.0% (estearic), C18:1 - 80.0% (oleic) and C18:2 - 10.0% (linoleic acid). The biosurfactant was characterized as a lipoprotein called Bioelan. The biosurfactant did not show toxicity against Artemia salina, Lactuca sativa L. and Brassica oleracea L.. The evaluation of the antimicrobial activity of these compounds showed MIC ranging from 15 mg/mL to 60 mg/mL and CBM of 30 mg/mL against multiresistant strains Staphylocossus aureus isolates of buffalo mastitis from Alagoas state. The biosurfactant produced by Streptomyces sp. DPUA1566 grown in culture medium of cost low represents a new stable surfactant, belonging to the lipoproteins group, with potential properties for use by pharmaceutical, cosmetic, food and veterinary productions.