1. Introduction
The biogas is produced through anaerobic digestion using corn stover, which is an important way to utilize agricultural waste and reduce environmental pollution. However, there are still several problems in this process including lower production and utilization. The main reason is that the lignin, cellulose and hemicellulose of corn stover are difficult to degrade [1], and the contents of them are all high. The pretreatment is to make the lignin, cellulose and hemicellulose of corn stover degrade into small molecule organisms [2], [3] and [4].