Improving Sugar Yields and Reducing Enzyme Loadings in the Deacetylation and Mechanical Refining (DMR) Process through Multistage Disk and Szego Refining and Corresponding Techno-Economic Analysis

Deacetylation and mechanical refining (DMR) has the potential to be a highly efficient biochemical conversion process for converting biomass to low toxicity, high concentration sugar streams. To increase the cost-effectiveness of the DMR process, improvements in enzymatic sugar yields are needed, in addition to reducing the refining energy consumed, and decreasing the enzyme usage. In this study, a second refining step utilizing a Szego mill was introduced, resulting in significant improvements in sugar yields in enzymatic hydrolysis at equivalent or lower refining energy inputs. The multistage DMR process increased the monomeric glucose and xylose yields to approximately 90% and 84%, respectively, with an energy consumption of 200 kWh/ODMT. SEM imaging revealed that Szego milling caused significant surface disruption and severe maceration and delamination of the biomass structure. Our results show that the DMR process is a very promising process for the biorefinery industry in terms of economic feasibility.