Characteristics of lignin after kraft or soda-AQ pretreatment was compared.
Quantitative information of different substructures in the lignin was obtained.
Lignin was more degraded during kraft pretreatment than soda-AQ pretreatment.
More cellulose was converted to glucose in the wheat straw after kraft pretreatment.
LCC played a role in the enzymatic hydrolysis of lignocellulosic material.