Abstract: The present invention relates to a novel process for liquefaction of solid organic matter by biological method. By this process the solid organic matter can be hydrolyzed using anaerobically treated water containing a consortium of fermentative micro-organisms thus resulting in an organic liquid which can be digested easily when applied to an anaerobic reactor for the recovery of valuable product namely biogas. The consortium comprises of the fermentative microorganism selected from the bacteria of the genera Bacteroides, Clostridium, Lactobacillus, Streptococcus, Peptococcus, Selenomonas in any combination. This process has potential application in all the industries wherever the solid organic matters are generated as a waste posing a major problem for their disposal, adding thereby to environmental pollution.