Synergistic contribution of hydrosulfide and carbonate anions to the β-O-4 bond cleavage of lignin model compounds in a green liquor pretreatment for enzymatic hydrolysis of lignocellulosic materials
Journal of Wood Science
To examine why green liquor (GL) pretreatment of lignocellulosic materials effectively facilitates enzymatic saccharification under conditions milder than those of a common alkaline cooking process, dimeric b-O-4 type lignin model compounds with and without free phenolic hydroxyl group were reacted in several alkaline solutions including a model solution of GL, which mainly contains Na 2 CO 3 and Na 2 S. The b-O-4 bond of the phenolic model compound was cleaved with a sufficient rate in the
... ent rate in the model solution of GL. The b-O-4 bond cleavage of the non-phenolic model compound was more frequent in the model solution of GL than in other alkaline solutions. These results suggest that b-O-4 bonds present in lignocellulosic materials are effectively cleaved in a GL pretreatment. It was also suggested that HSand CO 3 2synergistically contribute to the b-O-4 bond cleavage of the non-phenolic model compound under GL pretreatment conditions.