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.

Ethanol production from renewable sources, such as lignocellulosic materials, is already underway in several countries. The interest in the technology stems from concerns about global warming and the environmental impacts of solid waste disposal. Moreover, the conversion of agro-industrial wastes into ethanol is a value-adding strategy. This study aimed to evaluate the physicochemical characteristics of three lignocellulosic materials— rice straw bran, sugarcane bagasse, and corn peel bran—and determine, on the basis of these analyses, their suitability as feedstocks for second-generation ethanol production. Physicochemical characterization included the determination of particle size, moisture, ash, total solids, water activity, crude fat, protein, total extractives, soluble and insoluble lignin, holocellulose, cellulose, hemicellulose, and total carbohydrates. Rice straw bran is composed of 38.33% cellulose and 19.73% hemicellulose, sugarcane bagasse is composed of 27.09% cellulose and 5.61% hemicellulose, and corn peel bran is composed of 55.75% cellulose and 12.93% hemicellulose. The characterization showed the high concentration of cellulose in the residue of the corn peel bran. The results indicate that the three biomasses are suitable raw materials for biofuel production.