(709d) Optimization of Ionic Liquid-Salt Aqueous Two-Phase System for Enzymatic Saccharificaation of Cellulose

Tanimura, K. - Presenter, Osaka University
Suga, K., Osaka University
Yoshimoto, M., Yamaguchi University
Okamoto, Y., Osaka University
Umakoshi, H., Osaka University
Cellulose is an abundant woody biomass gaining attention as a renewable energy source. However, decomposition of cellulose involves multiple steps and large quantities of reagents. The process includes solubilization and decrystallization of cellulose using a solvent (e.g. ionic liquid (IL)), separation of cellulose from the solvent, and digestion of cellulose by cellulase to produce glucose. Aqueous two-phase systems (ATPS), though, can reduce the number of steps because the top and bottom phases can each perform different parts of the overall process. For example, [Bmim]Cl is a solvent effective for pretreatment of cellulose. On the other hand, [Bmim]Cl inhibits the activity of cellulase, an enzyme saccharifies cellulose [1]. Therefore, it is necessary to separate cellulase from [Bmim]Cl and to improve efficiency of saccharification. Aqueous two phase systems (ATPS) can be tailored to have very different properties between the top and bottom phases. Creating an IL-based ATPS can be applied to the integration of cellulose pretreatment and saccharification into "all-in-one" pot. This system will enable us to separate cellulase from [Bmim]Cl and then to carry out an enzymatic saccharification. In this study, an IL-based ATPS was prepared by using [Bmim]Cl and inorganic salts. Phase behaviors of [Bmim]Cl/salt/water systems were investigated. By using Na2HPO4 and NaH2PO4 as salt, the pH condition in the bottom phase could be controlled. The enzymatic hydrolysis reaction was also carried out. Although the bottom phase still included ILs, it is suggested that IL-based ATPS could improve the productivity of glucose.


[1] M. Yoshimoto, K. Tanimura et al., Biotechnol. Prog. 29 (2013) 1190–1196.