Using Amazon forest fungi and agricultural residues as a strategy to produce cellulolytic enzymes

The successful strategy to produce cellulolytic enzymes includes both microorganism selection and improved fermentation process conditions. This work describes the isolation, screening and selection of biomass-degrading fungi species from the Amazon forest and analyzes the enzymatic complex produced by a selected strain of Aspergillus fumigatus cultivated using different agro-industrial residues (wheat bran, sugarcane bagasse, soybean bran, and orange peel) as substrate in solid state fermentation (SSF). The profile of endoglucanase (CMCase), FPase, β-glucosidase and xylanase enzymatic activities obtained during 120 h of cultivation is presented. Enzyme activities up 160.1 IU g−1 for CMCase, 5.0 FPU g−1 for FPAse, 105.82 IU g−1 for β-glucosidase and 1055.62 IU g−1 for xylanase were achieved. The enzymatic extract with higher CMCase activity was used to run a zymogram analysis that showed 3 bands of endoglucanase activity. Characterization studies of this extract showed that the CMCase was most active at either 65 °C or pH 3–3.5, indicating that this microorganism produces a thermophilic and acid endoglucanase. These data demonstrate that the fungal isolates from the Amazon forest are a potential source of cellulases and xylanases, providing support to further studies related to the use of these microorganisms to obtain the enzymes needed for biomass conversion.

► Cellulase production is a critical step in the economics of second generation ethanol. ► Screening of microorganism can contribute to finding new cellulolytic enzymes. ► Amazon forest fungi were able to efficiently produce cellulases and xylanases.