Endoglucanase production by Cellulomonas sp

Currently, ethanol is produced commercially from conventional feedstocks such as sugarcane and cornstarch, but in the medium to long term it will be strategic for countries like Brazil, Argentina and the US to produce ethanol from lignocellulosic biomass. The use of lignocellulosic biomass would reduce considerably the competition for use of land for food production. Moreover, agro-industrial waste such as sugarcane bagasse and wood industry residues can be used. To convert cellulose to fermented sugars, cellulases have fundamental importance. From a screen of bacterial strains isolated from different biomes with the aim of identifying high cellulase producers, a strain of Cellulomonas sp. from Missiones, Argentina, was selected. In this work, the effects of process variables on cellulase production by Cellulomonas sp. were studied using sugarcane bagasse, elephant grass and carboxymethylcellulose. The fractional factorial design was carried out testing the effect of six variables on enzyme production: temperature, pH and substrate, yeast extract, NaNO₃ and inoculum concentration. After 72 and 96 h of fermentation, each sample was taken for enzyme activity measurement (FPase, b-glucosidase and endoglucanase). FPase and b-glucosidase activities were not detected in any of the conditions tested. The best endoglucanase activity was obtained using sugarcane bagasse after 96 h of cultivation (235 mU/mL). The best endoglucanase activities obtained using carboxymethylcellulose and elephant grass were 121 and 197 mU/mL, respectively, after 96 h of fermentation.