Pretreatment of Pussy Willow and Korean Pine Using Various Ionic Liquids and their Mixtures with Organic Solvents for Enzymatic Saccharification

초록

Different ionic liquids (ILs) and their mixtures with organic solvents (OSs) were investigated to determine their effects on pretreatment for enzymatic saccharification of pussy willow and Korean pine. Combinations of three ILs, namely (1-ethyl-3-methylimidazolium acetate ([EMIM]Ac), 1-butyl-3-methylimidazolium bromide ([BMIM]Br), and 1,3-dimethylimidazolium methyl sulfate ([MMIM]MeSO4)) and three OSs (N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), and dimethyl sulfoxide (DMSO)) were used. Acremonium cellulase and Optimash BG were used for enzymatic saccharification. The viscosity of ILs and their mixtures with OSs was reduced by adding and increasing the OS amount in mixtures. The viscosity of [BMIM]Br was considerably decreased by the addition of OSs. For both species, the water-soluble fractions (WSFs) obtained using pure ILs decreased with increasing OS content in mixtures. For all co-solvent systems, the WSFs for pussy willow were twice as large as those for Korean pine. For both species, the yields of glucose and xylose were higher for [EMIM]Ac and its mixtures with OSs than for [BMIM]Br, [MMIM]MeSO4, and their mixtures. However, only small differences between glycan and xylose yields among the products pretreated by [BMIM]Br, [MMIM]MeSO4, and their mixtures were observed. The overall xylose yields for pussy willow were higher than those for Korean pine for all pretreatments because xylan is the main hemicellulose component of hardwood.

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