Combined effect of hot water and deep eutectic solvent (DES) pretreatment on a lignocellulosic biomass mixture for improved saccharification efficiency
Individual and combined effect of HW and DES on mix solids was studied.
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Maximum delignification of 76.3% for HW-ChCl/LA was achieved.
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Increase in delignification and results in higher glucose yield during saccharification.
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Glucose yield for HW-ChCl/LA treated mix solids during saccharification was 94.5 wt%.
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Combining pretreatment methods of different nature can benefit the biorefineries.
Abstract
The combined effect of hot water (HW) and deep eutectic solvent (DES) on the solubilization of hemicellulose and lignin present in a lignocellulose mixture (rice straw, napier grass, and sugarcane bagasse in a 1:1:1 ratio) was investigated. The selected DES for present study included choline chloride (ChCl) with urea (U), glycerol (G), and lactic acid (LA) at a molar ratio of 1:2 w/w. The selection of different lignocellulosic biomass was made taking into account the similar percentage of hemicellulose and lignin. The hot water and DES pretreatment was performed with biomass loading of 1:10 w/v, 121 °C, 40 min. and 130 °C, 95 min, and 150 rpm, respectively. The HW-ChCl-LA resulted in 4.51-fold increase in cellulose digestibility at 72 h (20.63 ± 0.68% to 93 ± 3.62%). The FTIR spectrum for pretreated solids showed significant changes in the wavelength related to hemicellulose and lignin.
