Rheology evolution of high solids content and highly viscous lignocellulose system in biorefinery fermentations for production of biofuels and biochemicals

Rheological property of high solids content and highly viscous slurries of lignocellulose biomass in biorefinery fermentations is crucially important for designing large scale reactors. Rheology studies on pre-processing, pretreatment and enzymatic hydrolysis of high solids content lignocellulose biomass have been experimentally investigated and applied to reactor designs of the corresponding steps. Fermentation is the final step to complete the gap of the overall chart of rheology models of lignocellulose biorefinery process. This study experimentally measured rheology behaviors of biorefinery fermentations in three typical forms for biofuel and biochemical production under high solids content and highly viscous slurries. The advanced dry biorefining technology was adopted and excellent fermentation behaviors were achieved using corn stover as material, in which the yield of cellulosic ethanol, L-lactic acid, gluconic and xylonic acids reached up to 81.6, 96.0, 101.5 g/L and 34.4 g/L, respectively. Rheology results found that product generation and simultaneous hydrolysis conversion both played a key role in rheology evolution of fermentation processes. This rheology study provided a crucial basis for large scale bioreactor design in industrial lignocellulose biorefinery operations under high solids loading.