Enzymatic hydrolysis of cellulose recovered from ionic liquid-salt aqueous two-phase system

Abstract

Regenerated cellulose can be prepared by treatment with an ionic liquid (IL) and an anti-solvent such as water, which significantly enhances the enzymatic hydrolysis in comparison to crystalline cellulose. The IL-aqueous two-phase system (IL-ATPS) is consisted of IL-condensed top phase and salt-condensed bottom phase, which could be suitable to produce regenerated cellulose with smaller amount of IL. Using IL-ATPS with different pH, the enzymatic saccharification efficiency of crystalline cellulose was determined. The use of 1-allyl-3-methylimidazolium chloride resulted in relatively higher yield of glucose production as compared to 1-butyl-3-methylimidazolium chloride. The IL-ATPS showing optimal pH for cellulase was prepared with mixed salt (NaH₂PO₄/Na₂HPO₄ = 5/1 (wt/wt)), which provide a regenerated cellulose with the pH range of 4.8-4.9 in enzymatic reaction mixture. Using such regenerated cellulose as feed of saccharification, the final yield of glucose was about 70%.

Keywords: Cellulase; Cellulose; Ionic liquid: aqueous two-phase system.