Partial acid hydrolysis of cellulosic materials as a pretreatment for enzymatic hydrolysis

TLDR

Partial acid hydrolysis was performed in a continuous‑flow reactor on oak, corn stover, newsprint, and Solka Floc at 160–220 °C, 0–1.2 % acid for 0.22 min, followed by 48 h enzymatic hydrolysis with Trichoderma reesei cellulase at 50 °C. The pretreatment increased glucose yields for all substrates except Solka Floc, with some cases achieving up to 100 % of the theoretical glucose after 24 h, attributed to hemicellulose removal, reduced polymerization, and possible cellulose crystallinity changes.

Abstract

Abstract Partial acid hydrolysis was studied as a per treatment to enhance enzymatic hydrolysis, such a pretreatment was carried out in a continuous flow reactor on oak corn Stover, newsprint, and Solka Floc at temperatures ranging from 160 to 220°C, acid concentration ranging from 0 to 1.2%, and a fixed treatment time of 0.22 min. The resulting slurries and solids were than hydrolyzed with Trichoderma ressei QM 9414 cellulase at 50°C for 48 hr. For all substrates except Solka Floc, increased glucose yields were achieved during enzymatic hydrolysis of the pretreated materials as compared to hydrolysis of the original substrate. In several cases, after pretreatment, 100° of the potential glucose content of the substrate was converted to glucose after 24hr of enzymatic hydrolysis. It is felt that the increased glucose yields achieved after this pretreatment are due to acid's removal of hemicellulose, reduced degree of polymerization, and possibly due to a change in the crystal structure of the cellulose.