Dilute-acid pretreatment and enzymatic hydrolysis of corn stover, switchgrass, Miscanthus, and paper blends

A blended feedstock strategy has been proposed to address the high cost of feedstock access and enable biomass supply systems for biofuel production. Blending takes advantage of the lower end of multiple feedstock supply curves in order to avoid prohibitive costs incurred through reliance on a single resource. Here, measured composition and conversion performance for blends were compared to performance predicted from the weighted average of constituent feedstocks. Corn stover (CS), switchgrass (SWG), paper (MSW), and Miscanthus (MIS) were selected for blending. Compositional analysis, dilute-acid pretreatment, and enzymatic hydrolysis were performed on feedstocks and blends; sugar yields and feedstock reactivity were measured to assess conversion performance. Predicted glucose yields from combined pretreatment and enzymatic hydrolysis corresponded to measured yields for blends of CS/SWG/MSW and CS/SWG/MIS. There were no significant differences in glucose yield for blends of CS/SWG 80/20 and CS/SWG 50/50 relative to corn stover (p > 0.05). Reactivity results suggest that blending CS and SWG at ratios of 50/50 and 80/20 did not lead to an increase in recalcitrance relative to corn stover. Ternary blends of 65/25/10 and 75/15/10 CS/SWG/MSW had glucose yields from combined pretreatment and enzymatic hydrolysis (0.68 ± 0.03 and 0.72 ± 0.02 g/g, respectively) that were equivalent to corn stover (0.72 g/g ± 0.02).  Results suggest that it is possible to formulate blends capable of meeting quality targets and conversion metrics and perform similarly to corn stover in laboratory-scale studies.