Produção de xilanases por fermentação em estado sólido, de farelo de trigo utilizando consórcios fúngicos

Abstract

This study aimed to find alternatives for wheat bran disposal destination generated in food industry sector, thus contributing to the reduction of the resultant impact of residue deposition in the environment. The poten- tial of the wheat bran as a substrate for xylanase production by solidstate fermentation using fungal con- sortiums as well as Aspergillus oryzae (ATCC9362) and Trichoderma reesei (2768) was valued . The use of non-washed and non-autoclaved wheat bran as carbon and energy source in solid-state fermentation by A. oryzae fungus showed greater percentage of produced protein after 72h of cultivation. The use of a central composite rotatable design (CCRD), 23 factorial planning with three repetitions at the central point as well as six axial points, coupled with Surface Response Methodology (SRM) allowed to assay the influence of hu- midity, pH, and grain size (independent variables or factors) on the xylanase activity (dependent variable or response) as well as to optimize the best conditions for the enzyme production. The results showed that all factors and their combinations were significant at 95% confidence level. The optimized xylanase activi- ty was (1.84 ± 0.01) UI/mL, obtained at 40% humidity and pH 3.3 with a grain size of 900.0 μm. The produced broth was stable for 3 months and approximately had 50% of the initial xylanase activity at 4°C. SDS-PAGE assay showed that xylanase has 30kDa molar mass. The obtained enzymatic broth was efficient to modify wheat flours as shown by the falling number rheologic parameters and alveography assay