Paddy straw is one of the most abundant lignocellulosic wastes on the earth. The organic matter of paddy straw can be degraded by the sequential action of hydrolytic, acetogenic and methanogenic bacteria to produce biogas. But, lignin and silica are the main deterrents of microbial action on cellulose/hemi-cellulose component of paddy straw. Thus, for efficient utilization of paddy straw, pretreatment is very essential. This study is, therefore, aimed at comparing chemical, biological and combined (chemical+biological) pretreatment of paddy straw to analyze their potential in increasing paddy...