Methanogens , growing anaerobically on cellulosic material , produce
Methane
Methane and CO2
Methane and H2
Methane , CO2 and H2
Certain bacteria grow anaerobically on cellulosic material and produce large amounts of methane along with carbon dioxide and hydrogen. These bacteria are collectively called methanogens. Examples of methanogens are Methanococcus Methanobacterium
They play a very important role in nutrition of cattle by digesting the cellulosic material.