Combining glycerol pretreatment with persulfate oxidation to obtain cellulosic ethanol and dye adsorbent from maize cob

Pretreatment is a major step in bioethanol production as it breaks the structure of lignocellulosic biomasses, improving the enzymatic digestibility and ethanol yield during fermentation. The present study proposes pretreatments of maize cob based on glycerol and persulfate, as well as their combinations. The greatest delignification, hemicellulose removal, and cellulose enrichment were obtained in combined pretreatments. The addition of persulfate in acidified glycerol solution matches the performance of the separate strategies, presenting similar chemical composition and sugar release in enzymatic hydrolysis. Enzymatic hydrolysis lignins (EHL) were easily obtained by simple filtration after saccharification, and they provided high adsorption capacity of methylene blue dye. The persulfate in the pretreatments affects the EHL increasing adsorption capacity. The unusual methodology described in this study provided a successful combination in enzymatic digestibility, and as a trigger of chemical modifications of EHL, due to the synergistic action of glycerol, water, sulfuric acid, and persulfate. Graphical abstract