Setiyo Gunawan : Comparative study of the preparation of reducing sugars hydrolyzed from high-lignin lignocellulose pretreated with ionic liquid, alkaline solution and their combination
Setiyo Gunawan S.T., Ph.D
J. Eng. Technol. Sci., Vol. 47, No. 2, 2015, 137-148
Coconut coir dust Enzymatic hydrolysis Ionic liquid 1,3- methylmethylimidazolium dimethyl phosphate NaOH.
The ionic liquid [MMIM][DMP] was synthesized from the reactants
methyl imidazole [MIM] and trimethylphosphate [TMP] and verified using
1HNMR and FTIR. Coconut coir dust was pretreated with a 1 alkaline solution.
Its crystalline structure increased significantly due to the dissolution of lignin
and hemicelluloses under alkaline conditions, exposing the cellulose. After
NaOH and IL were employed, the XRD showed that peak (002) decreased
significantly and peak (101) almost vanished. This significant decrease in
crystallinity was related to the alteration of the substrate from the cellulose I
structure to the cellulose II structure. The pretreated substrates were hydrolyzed
to convert them to reducing sugars by pure cellulase and xylanase, and the
reaction was conducted at 60°C, pH 3, for 12 or 48 hours. The yields of sugar
hydrolyzed from untreated and NaOH-pretreated substrates were 0.07 and 0.12 g
sugar/g lignocellulose, respectively. Pretreatment with IL or the combination of
NaOH+IL resulted in yields of reducing sugars of 0.11 and 0.13 g/g,
respectively. These findings showed that IL pretreatment of the high-lignin
lignocellulose is a new prospect for the economical manufacture of reducing
sugars and bioethanol in the coming years.