Casca de café como recurso renovável para a produção de celulases via fermentação em estado sólido com Aspergillus fumigatus

Abstract

Coffee is one of the main commodities produced by Brazil, and during the processing of the fruits, approximately 50% of the It are discarded in the form of waste. An alternative for reusing this residue is its application as a substrate in solid state fermentation (SSF) to obtain products with high added value, such as cellulases. In this context, the present work aimed to evaluate the potential of fresh coffee husk and pre-treated by alkaline solution in microwave, as an inducer in the production of cellulases by SSF using the fungus Aspergillus fumigatus. Cultivation conditions related to moisture content (50 – 70 %) and substrate content (60 – 80 %) were evaluated using a DCCR experimental design. Tests with in natura and pre-treated CC obtained FPase activities of 1,046 U/gms and 2,315 U/gms, respectively, after 120 hours of FES under conditions of 70 % CC and 70% humidity. Statistical analyzes demonstrated that moisture content is the parameter with the greatest influence on cellulase production by A. fumigatus, and conditions of 68 to 70% provide greater FPase activities. Enzymatic partial characterization showed that the crude enzyme extract has stability under conditions of pH 5 – 6 and 40 – 60 °C. In addition, Cu2+ , Co2+ , and Mn2+ ions can be used as cofactors. The enzymatic hydrolysis test of CC with the crude enzyme extract provided 1,5 g/L reducing sugars after 48 hours. These results highlight the potential of cellulases produced by A. fumigatus for industrial applications