Produção de biossurfactantes por fungos isolados do solo amazônico

Abstract

Surfactants play an important hole in pharmaceutical, food and oil industries. Synthetic surfactants have been presenting problems related to their toxicity and recalcitrance. This situation increases the interest on natural surfactants produced by microorganisms (biosurfactants). Just a few studies were conducted investigating the production of these substances by fungi isolated from the Amazon region. The aim of this study was investigate the production of biosurfactants by fungi isolated from soil in the Amazon forest. The isolation of micro-organisms of the soil samples was performed by the method of successive dilutions. The identification of the isolates was performed by investigating the micromorphological characteristics (microculture technique). For selection of biosurfactants producers, the strains were submitted submerged bioprocess and the filtrated from the cultures were subjected to investigation by techniques “collapse of the drop” and “emulsification index”. The selected isolate was subjected to optimize the production of the biosurfactant by a factorial design 24 evaluating the influence of the concentration of carbon and nitrogen sources, pH and bioprocess time. Finally, the biosurfactant produced by the selected strain was semi-purified and tested for stability (thermal and ionic). It was isolated 100 fungal strains, 9 of them showed good emulsification index (E24> 40) and Penicillium 8CC2 was screened as the best biosurfactant producer. The investigation of the influence of the bioprocess factors showed that the best condition for obtaining the biosurfactant was by using soybean oil (20 g/L), yeast extract (30 g/L) pH 6.0 and 9 days. The evaluation of thermal (100 ° C for 60 min) and ionic (30% NaCl) stability showed that none of the two factors destabilized emulsified produced. The main contributions that were achieved in the present work was the isolation of biosurfactant producer Penicillium 8CC2 and a preliminary definition of bioprocess parameters.