Major improvement in the rate and yield of enzymatic saccharification of sugarcane bagasse via pretreatment with the ionic liquid 1-ethyl-3-methylimidazolium acetate ([Emim] [Ac])

• Published in: Bioresource technology 2011-11, Vol.102 (22), p.10505-10509
• Main Authors: Sant’Ana da Silva, Ayla, Lee, Seung-Hwan, Endo, Takashi, P.S. Bon, Elba
• Format: Article
• Language: English
• Subjects: 1-Ethyl-3-methylimidazolium acetate; Acetates; Bagasse; Biological and medical sciences; Biomass; Biotechnology - methods; Carbohydrate Metabolism - drug effects; Cellulase - metabolism; cellulose; Cellulose - metabolism; Dissolution; Enzymatic saccharification; Food industries; Fundamental and applied biological sciences. Psychology; glucose; Glucose - analysis; Hydrolysis - drug effects; Imidazoles - pharmacology; Ionic liquid pretreatment; Ionic liquids; Ionic Liquids - pharmacology; Kinetics; lignin; Nanostructure; Saccharification; Saccharum - chemistry; Solubility - drug effects; solubilization; Specific surface; Sugarcane bagasse; surface area; Temperature; Use and upgrading of agricultural and food by-products. Biotechnology; Water - chemistry; Xylose - analysis
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2011.08.085

► [Emim] [Ac] was selected as a powerful ionic liquid for the pretreatment of bagasse. ► Almost 100% of cellulose-to-glucose conversion was obtained. ► It was possible to obtain fibrillated materials as small as 100nm. ► Specific surface area (SSA) was increased 100-fold in comparison to untreated bagasse. ► The SSA increase and crystallinity decrease are the main effects of [Emim] [Ac]. In this study, sugarcane bagasse was pretreated by six ionic liquids (ILs) using a bagasse/IL ratio of 1:20 (wt%). The solubilization of bagasse in the ILs was followed by water precipitation. On using 1-ethyl-3-methylimidazolium acetate [Emim] [Ac] at 120°C for 120min, 20.7% of the bagasse components remained dissolved and enzymatic saccharification experiments resulted on 80% glucose yield within 6h, which evolved to over 90% within 24h. Moreover, FE-SEM analysis of the precipitated material indicated a drastic lignin extraction and the exposure of nanoscopic cellulose microfibrils with widths of less than 100nm. The specific surface area (SSA) of the pretreated bagasse (131.84m2/g) was found to be 100 times that of untreated bagasse. The ability of [Emim] [Ac] to simultaneously increase the SSA and to decrease the biomass crystallinity is responsible for the improved bagasse enzymatic saccharification rates and yields obtained in this work.