Abstract
Herein, corn stover (CS) was pretreated by less corrosive lewis acid FeCl3 acidified solutions of neat and aqueous deep eutectic solvent (DES), aqueous ChCl and glycerol at 120 °C for 4 h with single FeCl3 pretreatment as control. It was unexpected that acidified solutions of both ChCl and glycerol were found to be more efficient at removing lignin and xylan, leading to higher enzymatic digestibility of pretreated CS than acidified DES. Comparatively, acidified ChCl solution exhibited better pretreatment performance than acidified glycerol solution. In addition, 20 wt% water in DES dramatically reduced the capability of DES for delignification and xylan removal and subsequent enzymatic cellulose saccharification of pretreated CS. Correlation analysis showed that enzymatic saccharification of pretreated CS was highly correlated to delignification and cellulose crystallinity, but lowly correlated to xylan removal. Recyclability experiments of different acidified pretreatment solutions showed progressive decrease in the pretreatment performance with increasing recycling runs. After four cycles, the smallest decrease in enzymatic cellulose conversion (22.07%) was observed from acidified neat DES pretreatment, while the largest decrease (43.80%) was from acidified ChCl pretreatment. Those findings would provide useful information for biomass processing with ChCl, glycerol and ChCl-glycerol DES.
Highlights
Lignocellulosic biomass, endowed with characteristics like wide availability, renewability and cheap cost, has been considered as an eco-friendly alternative to petrochemical sources
Whether without or with addition of water, pretreatment with FeCl3 acidified choline chloride (ChCl)-glycerol deep eutectic solvent (DES) preserved the same amount of glucan in the pretreated solids, while acidified aqueous DES resulted in increased solid recovery yield, due to the reduced removal of xylan and lignin compared to acidified neat DES
Chen, et al [20] observed that aqueous ChCl-glycerol DES containing 20% water led to almost unchanged glucan recovery and decreased removal of xylan and lignin during switchgrass pretreatment compared to neat DES, which was in well agreement with our results
Summary
Lignocellulosic biomass, endowed with characteristics like wide availability, renewability and cheap cost, has been considered as an eco-friendly alternative to petrochemical sources. Research efforts have been devoting to conversion of these lignocelluloses to value-added products including fine chemicals, functional materials and biofuels, with the aim to compete with petroleum-derived equivalents in a sustainable and eco-efficient production process [1]. High-efficient extraction and utilization of carbohydrate plays decisive roles in lignocellulosic bioconversion, which consists of three independent steps, i.e., pretreatment, enzymatic hydrolysis and microbial fermentation [3,4]. Pretreatment to deconstruct the recalcitrant structure of cellulosic feedstock is believed to be a prerequisite step for enzymatic depolymerization of polysaccharides in lignocellulose with commercially available (hemi)cellulolytic enzymes. There are still some tough challenges remain to be addressed for some of aforementioned conventional pretreatments, such as long processing time (up to days), high-energy consumption, poor pretreatment performance, corrosion to the equipment, high cost of waste pretreatment or chemical recovery, etc. [7]
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call