Biogas as a source of renewable energy can be produced from variety of organic materials such as agricultural residue, animal manure, municipal wastewater, etc. Anaerobic digestion of organic material is decomposing of organic content in the absence of oxygen. In this procedure organic material is decomposed by bacteria to variety of end product in which the main gasses are Methane and Carbon dioxide.
Enteric fermentation is a digestive process by which carbohydrates are broken down by microorganisms into simple molecules for absorption into the bloodstream of an animal.