Comparison of acid and alkali catalyzed ethylene glycol organosolv pretreatment for sugar production from bagasse.

In this study, five acid or alkali catalyzed ethylene glycol (EG) organosolv pretreatments were proposed and compared for sugar production from bagasse. The results showed that compared with single EG/H ₂ O pretreatment, the EG/H ₂ O-HCl pretreatment was more efficient for both hemicellulose (~99.3%) and lignin (~67.1%) remove due to the synergistic effect of HCl and EG. The EG/H ₂ O-NaOH pretreatment was also beneficial for lignin remove (~90.9%), but it was weak for hemicellulose degradation (~28.8%). Both EG/H ₂ O-HCl and EG/H ₂ O-NaOH pretreatments have good capacity to reserve the cellulose in pretreated solids. Following enzymatic saccharification, the largest glucose recovery yield from EG/H ₂ O-HCl pretreatment was 94.3%, a slightly higher than this from EG/H ₂ O-NaOH pretreatment (92.5%). However, its xylose recovery yield was only 77.3%, significantly lower than that of EG/H ₂ O-NaOH pretreatment (93.5%). Besides, a certain amount of lignin also can be recovered from above acid or alkali catalyzed organosolv pretreatments through diluting or acidizing the pretreated liquids.
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