Figure 4
From: Comparative study of sulfite pretreatments for robust enzymatic saccharification of corn cob residue
Variation of sulfonic group and weak acid groups after sulfite pretreatments. RM represents the raw material of corn cob residue, while Neutral, Acidic, Alkaline and Ethanol represent corn cob residue treated with sulfite in neutral, acidic, alkaline and ethanol environment, respectively.