Stack-pretreatment is introduced to gain higher biogas production from corn stover through solid state
anaerobic digestion. The purpose of this study is to find the effects of naturally microbial pretreatment on
stalk lignin, cellulose and hemicellulose degradation, and biogas production. The result indicates that the
corn straws which had been stack-pretreated for 20 days decreases of the content of the middle corn
straws cellulose, hemi-cellulose and lignin by 5.8%, 16.8% and 5.7% respectively lower than that of the
untreated samples.