Nonenzymatic Sugar Production from Biomass Using Biomass-Derived γ-Valerolactone

TLDR

Widespread production of biomass‑derived fuels and chemicals will require cost‑effective processes to break down cellulose and hemicellulose into sugars. GVL drives thermocatalytic saccharification by fully solubilizing biomass, including lignin, and the resulting carbohydrates can be recovered and concentrated by extracting GVL into an aqueous phase with NaCl or liquid CO₂. Laboratory‑scale experiments produced 70–90 % soluble carbohydrates from corn stover, hardwood, and softwood in a GVL‑water‑acid mixture, and the high‑yield sugars can be upgraded to furans or ethanol at near‑theoretical titers, with preliminary techno‑economic analysis indicating the process could be cost‑competitive for ethanol production.

Abstract

Widespread production of biomass-derived fuels and chemicals will require cost-effective processes for breaking down cellulose and hemicellulose into their constituent sugars. Here, we report laboratory-scale production of soluble carbohydrates from corn stover, hardwood, and softwood at high yields (70 to 90%) in a solvent mixture of biomass-derived γ-valerolactone (GVL), water, and dilute acid (0.05 weight percent H2SO4). GVL promotes thermocatalytic saccharification through complete solubilization of the biomass, including the lignin fraction. The carbohydrates can be recovered and concentrated (up to 127 grams per liter) by extraction from GVL into an aqueous phase by addition of NaCl or liquid CO2. This strategy is well suited for catalytic upgrading to furans or fermentative upgrading to ethanol at high titers and near theoretical yield. We estimate through preliminary techno-economic modeling that the overall process could be cost-competitive for ethanol production, with biomass pretreatment followed by enzymatic hydrolysis.