Recycled ionic liquid 1-ethyl-3-methylimidazolium acetate pretreatment for enhancing enzymatic saccharification of softwood without cellulose regeneration

Abstract

In this work, pretreatment of wood meals using a recycled ionic liquid (IL), 1-ethyl-3-methylimidazolium acetate ([Emim] Ac), enhanced glucose liberation by enzymatic saccharification, without dissolution of cellulose and lignin. In contrast, previous studies on IL pretreatment have mostly focused on lignocellulosic dissolution to regenerate cellulose and removing lignin. Softwood (Cryptomeria japonica) was pretreated with [Emim]Ac at 60-100 °C for 2-8 h without collecting regenerated cellulose. The pretreatment did not have a strong effect on wood component dissolution (weight of residues: 91.7-98.8%). The residues contained relatively high amounts of lignin (26.6-32.6%) with low adsorption of [Emim]Ac (0.9-2.7%). Meanwhile, the crystallinity index (C r I) of cellulose in the wood was significantly reduced by pretreatment, from 50.9% to 28.4-37.1%. In spite of the high lignin contents in the residues, their glucose liberation values by enzymatic saccharification using a cellulase mixture were 3-16 times greater than that of untreated wood. A good correlation was found between the saccharification effectiveness of pretreated samples and the C r I. Although lignin dissolved in [Emim]Ac continued to accumulate after repeated use of [Emim]Ac, the pretreatment was found to be effective for three consecutive cycles without the need to remove the dissolved materials.

Cellulose solvent-based pretreatment for enhanced second-generation biofuel production: a review

“…Due to the current high price of ILs for an economically viable pretreatment process, efficient recovery and recycling of ILs is vital. [589][590][591][592] Besides, the wastage of ILs can cause environmental issues associated with slow degradation and toxicity to downstream processes 589,590 Mai et al 593 reviewed different methods for the recovery of ILs in detail. Here, we discuss briey the methods of IL recovery with application in the IL pretreatment of lignocelluloses.…”

Silk-Cellulose Acetate Biocomposite Materials Regenerated from Ionic Liquid

“…The Ge crystal was cleaned with ethanol and dried between samples. To process the results, spectra from each sample were analyzed using the OPUS software [ 16 , 39 ].…”

“…The Ge crystal was cleaned with ethanol and dried between samples. To process the results, spectra from each sample were analyzed using the OPUS software [16,39]. The solids were added in the order of proteins first, followed by carbohydrates.…”

“…Studies have shown that ionic liquids (ILs) are adequate compounds that could successfully carry out this task [12,13,15]. Ionic liquids are charged molecules that exist as liquids at room temperatures [16]. ILs are often defined as molten salts or even liquid electrolytes with melting points below 100 • C. ILs consist of cations and anions, which differ in size and possess conformational flexibility.…”

Preparation of Dissolving Pulp by Totally Chlorine-free Bleaching：Roles of Hardwood Syringyl and Guaiacyl Lignins

“…Scans were of the θ-2θ type, with sample angles in the 10-30°(2θ) range over scan times of 348 s (6,000 steps at 0.05 s/ step) . According to a previous paper by Hamida and others 20) , crystallinity indices (CrI) were calculated using following equation: Crl＝ ［ (I max -I min ) /I max ］ ×100. Fig.…”