Caracterização de um novo exopolissacarídeo produzido por fungo filamentoso isolado de casca de palmeira

Abstract

Exopolysaccharide (EPS) are biomacromolecules produced by some micro-organisms and excreted to culture medium. EPS production has aroused researchers interest due to their technological and bioactive activity, antitumor, antioxidant, antiviral and immunoestimulatory properties. Considering technological relevance in the new biopolymers identification, the present study aimed to evaluate the new EPS production, as well as their initial characterization. Factorial planning methodology, by delineation composite central rotational (23) was employed to assess the influence of agitation, concentration of sucrose and concentration of peptone variables on the EPS production and biomass mycelial. The exopolyssacharide produced was subjected to analysis of water solubility, infrared spectroscopy, nuclear magnetic resonance carbon-13, scanning electron microscope and diffractometry X-ray. EPS antioxidant potential was studied through the evaluation of kidnapping hydroxyl radical, removal of hydrogen peroxide and potential reducer. It was also evaluated the potential antimicrobial by disk diffusion method. The variables studied did not influence significantly (p0.05) in the production of the EPS at the levels evaluated. The maximum production of EPS obtained was 1.9 g/L when employed in sucrose (27.5 g/L) and peptone (1.5 g/L) concentraiton and agitation of 25 rpm. The EPS presented 68,55% (m/v) of water solubility. The spectra of FT-IR and NMR 13C showed polysaccharides typical regions with the presence of glucose ring with configuration β and molecules of up to 6 carbons with the presence of succinate and acetate. Micrographs obtained by electron microscopy indicated that the EPS produced presented aspect heterogeneous with smooth regions and spirals containing granules with a diameter of 90 to 990 nm. Diffraction analysis x-ray diffraction showed that the EPS presented amorphous regions and semicrystalline structure. The EPS presented a power reducer 0,126, removal ability of hydroxyl radical (74,5%) and 14,28% of the removal of hydrogen peroxide capacity. It has not been verified antimicrobial activity against E. coli, S. typhimurium, L. plantarum, S. aureus, C. tropicalis and C. albicans at concentrations up to 1.1 g/L. The results suggest that the EPS produced has been shown to have potential for applications in biological due to the high water solubility and antioxidant ability.