In this work, for modelling the anaerobic digestion of microcrystalline cellulose, two surface-related models based on cylindrical and spherical particles were developed and compared with the first-order kinetics model. A unique dataset consisting of particles with different sizes, the same crystallinity and polymerisation degree was used to validate the models. Both newly developed models outperformed the first-order kinetics model. Analysis of the kinetic constant data revealed that particle size is a key factor determining the anaerobic digestion kinetics of crystalline cellulose. Hence, crystalline cellulose particle size should be considered in the development and optimization of lignocellulose pre-treatment methods. Further research is necessary for the assessment of impact of the crystalline cellulose particle size and surface properties on the microbial cellulose hydrolysis rate.
Keywords: anaerobic digestion; microcrystalline cellulose; modelling; surface-related kinetics.