Analysis of the effect of cellulose particle size on the rate of microbial hydrolysis for bioethanol production

This study develops a new approach to analyze the effect of particle size on the rate of the microbial hydrolysis of cellulose under anaerobic conditions. The new approach is based on the quantitative analysis of the ratios of the cellulose-particle surface areas and those of the microorganisms. It is shown that the effectiveness of the microbial-hydrolysis process is expected to depend both on the particle size and on the cellulose/biomass ratio. At low cellulose/biomass ratios, a decrease in particle size is expected to bring an increase in the rate of microbial hydrolysis, because the rate is limited by the cellulose availability. At high cellulose/biomass ratios, the cellulose particle size is expected to have no or limited effect on the hydrolysis rate, because the rate is limited by the biomass concentration. The available literature data on the rate of microbial cellulose hydrolysis are critically analyzed and a new kinetic model for the microbial hydrolysis of particulate substances is developed.