Glycine: Facilitating Delignification while Suppressing Cellulose Degradation During Corn Straw Pretreatment

This study reported that glycine promoted S-type lignin removal via strong hydrogen bonding interactions (confirmed by the ¹³C NMR upfield shift) while suppressing cellulose degradation by competing for cellulose hydroxyl sites. Efficient pretreatment of corn straw was achieved at 25 wt % solids loading using [Bmim][DCA]-Gly system, attaining 78.11% delignification. Pretreatment converted the straw surface from dense to loose and porous, with β-O-4 cleavage inducing lignin depolymerization. The regenerated lignin had an elevated S/G ratio and contained PhGlc linkages. The cellulose recovery rate was 95.45%. With 5 FPU/g enzyme loading, the saccharification yield reached 95.69%, 2.75 times that of untreated material. The [Bmim][DCA]-Gly system was successfully recycled four times while maintaining high cellulose recovery and saccharification efficiency, providing a green strategy for biomass pretreatment.