Production of enzymatic complex from agro-industrial biomass and its application in combustible ethanol

Abstract

Waste biomass and agro-industrial by-products, for production ethanol, will meet much of the great demand for this product. To reduce costs and optimize production, this study investigated solid-state fermentation (SSF) to obtain crude enzyme complex (CEC) from different agro-industrial biomasses (sugarcane bagasse, corn peel bran, rice straw bran and roasting and ground coffee residue) using cellulolytic fungi. The most promising CEC were evaluated in simultaneous hydrolysis and fermentation (SHF) for ethanol production by Saccharomyces cerevisiae in a culture broth containing sugarcane bagasse treated by steam explosion, and roast and ground coffee residue. In SSF with bioreactor volume of 0.25 L, containing 40 g of the biomass mixture and 40 g of sterile water with resuspended cells (1.0 x108 spores/g of solid medium) and temperature of 30±2 ºC, the strains Trichoderma reesei and Penicilium oxalicum provided the best enzyme activity. The CEC of T. reesei provided a concentration of 7.5 g L-1 of ethanol in a substrate containing treated sugarcane bagasse (60%) and roast and ground coffee residue (40%), under SHF conditions (pH 4.5, 35±2 °C, 48 h). The results obtained in this study show a promising alternative for correct disposal and use of residues and agro-industrial by-products by use in the production of enzymes and lignocellulosic ethanol.