Influence of cellulose content on the enzyme activity in the saccharification digests of furfural residues

Abstract

ABSTRACTFurfural residues, lignocellulosic residues from commercial furfural production, generally consist of cellulose, lignin, and a rather low amount of residual hemicellulose. They represent the most promising potential sources of biomass that are cheap and readily available in large quantities. Furfural residues with cellulose contents of 51.92%, 68.49%, 83.88%, and 94.92% were hydrolysed by a mixture of cellulase and β‐glucosidase with an enzyme loading rate of 7.5 filter paper units/g and 15 cellobiase units/g of cellulose, respectively. We evaluated the filter paper activities of the digested furfural residues containing various cellulose concentrations. Both adsorption and desorption of the cellulase mixture to the lignocellulosic substrate were compared according to the filter paper activities of the digests. The higher the cellulose content of the lignocellulosic substrate, the higher was the apparent adsorption and desorption of the cellulase mixture; this indicates considerable adsorption between the enzyme and the lignin in the furfural residues. The glucose yield of furfural residues increased incrementally according to the cellulose content of the substrate. The highest glucose yield was obtained from the enzymatic hydrolysate of the furfural residue with a cellulose content of 94.92% after a 72‐h saccharification. Furfural residues can be easily hydrolysed to fermentable sugars with mixtures of cellulase and β‐glucosidase. Therefore, furfural residues are potential biomass resources for cellulosic ethanol production. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.