A lignin-first strategy to recover hydroxycinnamic acids and improve cellulosic ethanol production from corn stover

Abstract

The goal of this research is to develop a partial delignification process for corn stover that simultaneously improves accessibility of enzymes to cellulose and recovers hydroxycinnamic acids (HCA) as a value-added product from the lignin. We recover HCAs from corn stover with a mild base extraction employing sodium hydroxide, ethanol, and water. The total HCA yield was 33.5 wt% on a lignin basis and approximately 6 wt% on a corn stover basis. This partial delignification pretreatment allowed 85 wt% of total available glucose to be recovered by enzymatic hydrolysis using an enzyme loading that is only 10% of the level recommended for recovering sugars from lignocellulosic biomass. Technoeconomic analysis indicates that recovery of HCAs could reduce the selling price of ethanol by $0.26 L-1. That part of the lignin not removed as HCA becomes a co-product of enzymatic hydrolysis suitable for thermochemical processing into additional biofuels and/or chemicals.