Bioprospecção de biossurfactantes produzidos por fungos filamentosos da caatinga.

Abstract

The Caatinga biome may be a source for obtaining metabolites with unique features, such as biosurfactants of microbial origin, amphipathic molecules capable of reducing the surface tension and emulsify hydrocarbons. This study aimed to bioprospecting biosurfactants produced by Caatinga´s filamentous fungi, collected in Sumé – PB city, stored in a collection at CDSA/UFCG, search for a new source for biosurfactant’s obtaining. In this research, 11 filamentous fungi were evaluated in relation to emulsifier capacity, totaling seven specimens (63.63%) presented results for Emulsification Index (EI), stability after 24 hours and Emulsification Activity (EA), with emphasis for metabolic liquids produced by fungi CDSA17, CDSA54, CDSA71 and CDSA109 that were also evaluated under extreme conditions of temperature, pH and NaCl, with higher EI at temperature of 60°C, pH 5.0 and 7.0, and salt concentration 10%. The kinetic study was carried out with the fungus CDSA109, demonstrating a correlation of 0.731 between cell concentration and EI with higher activity at 72 hours, possibly in the stationary growth phase. In factorial design 2², in duplicate, analyzing variable of shaking (100 and 200 rpm) and glucose concentration (15 g/L and 25 g/L), tested filamentous fungi showed different behaviors and higher IE were obtained under conditions of 100 rpm and glucose concentration of 15 g/L. Using the microculture technique was possible to identify CDSA17, CDSA71 and CDSA109 as belong to Aspergillus genus. Agreed of overhead, it is clear that Caatinga´s filamentous fungi have potential to produce biosurfactants.