Produção de biossurfactante por Streptomyces sp. isolado de liquens da região amazônica para aplicação como agente antifúngico

Abstract

Biosurfactants are amphiphilic molecules produced by micro-organisms that consist of a hydrophilic portion and a hydrophobic portion. The hydrophilic portion consists of mono-oligo-or polysaccharides, proteins or peptides and the hydrophobic portion contains saturated, unsaturated and hydroxy fatty acids or alcohols. Many micro-organisms produce surfactants with antibacterial, antifungal, antitumor, antiparasitic and herbicide use in medicine and agriculture. In this sense, producing a biosurfactant by Streptomyces sp. DPUA1559 isolated Amazon region, grown in medium containing soybean oil and waste frying peptone was performed using a 22 factorial design to investigate the effects and interactions on the response variables surface tension, emulsification index and production yield. The production of the biosurfactant was confirmed by reduction of surface tension. The critical micelle concentration (CMC) was 10 mg/ml and the average surface tension at the focal point was about 25,34 mN/m in a yield of 1,17 g/l. The isolated biosurfactant showed emulsification index 89% to 95% engine oil and engine oil residual. The kerosene emulsification showed a 40%, while the diesel oil was not emulsified effectively. For vegetable oils (corn, canola, soybean, and sunflower) emulsion was formed around 47%. The isolated biosurfactant was stable when subjected to extreme environmental conditions of pH, temperature and NaCl concentration and showed no toxicity when tested against the micro-crustacean Artemia salina and seeds of vegetables lettuce (Lactuca sativa L.) and cabbage (Brassica oleracea L.). The characterization of biomolecule analysis demonstrated the chemical composition of 20% protein and 38% carbohydrate. Molecular characterization on polyacrylamide gel electrophoresis SDS-PAGE showed the biosurfactant a single protein band and 14.3kDa character acid. The spectral analysis method by FT-IR-Atr revealed a chemical structure composed mainly of peptides with different polarities. The strains of Microsporum canis isolates from dogs superficial mycoses were susceptible in the presence of biosurfactant isolated presenting a growth inhibition at concentrations of 1.9 to 1000 μg/ml.