Improved glucose yield and concentration of sugarcane bagasse by the pretreatment with ternary deep eutectic solvents and recovery of the pretreated liquid

In this study, a novel ternary deep eutectic solvents (DES) consisting of choline chloride/PEG/hydroxyethyl sulfonic acid (HSA) was developed to effectively improve glucose yield and concentration of sugarcane bagasse, and the conditions of the pretreatment were optimized by response surface method (RSM). Under the optimal conditions, the maximum glucose concentration (GC) could reach 12.39 g/L (HSA concentration 1.34 %, PEG400, 2.3 h, 150 °C), and the maximum glucose yield (GY) was 0.2497 g/g (HSA concentration 1.41 %, PEG400, 2.1 h, 150 °C). Hemicellulose was completely removed, and the maximum lignin removal rate was 86.89 %. After pretreatment, 95 % of the pretreated liquid can be recycled. Finally, the structural and morphological changes of bagasse before and after pretreatment were investigated by scanning electron microscopy (SEM), Fourier Transform infrared analyzer (FT-IR) and X-ray diffraction (XRD).

Low-condensed lignin and high-purity cellulose production from poplar by synergistic deep eutectic solvent-hydrogenolysis pretreatment

This paper presented a green and environmentally friendly method to obtain lignin with a structure similar to milled wood lignin (MWL) and high-purity cellulose from biomass in a two-step process. The first step, maleic acid (MA), choline chloride (ChCl), and ethylene glycol (EG) ternary deep eutectic solvent (DES) pretreatment was performed to obtain lignin with less-condensed structure. The results showed that the obtained lignin had similar properties to MWL under the condition (MA/ChCl/EG = 1:5:15, 80°C, 10 h). The DES recovered still had good cycle performance. The second step, the cellulose-rich residue was hydrogenated with isopropanol-water solvent and Raney nickel to obtain high-purity cellulose. The results showed that the purity of cellulose obtained by catalytic hydrogenolysis was > 94%. The glucose yield after enzymatic hydrolysis was 243.72 mg/g, which was 14.7 times higher than the untreated poplar. Overall, this work was of great significance for the effective separation of biomass.