Methanogens are present in

Methanogenic bacteria are commonly found in anaerobic sludge during sewage treatment, and they also inhabit the rumen (a part of the stomach) of cattle. In the rumen, these bacteria play a crucial role in breaking down cellulose. They grow on cellulose and produce methane along with CO₂ and H₂.  Cellulose is a complex carbohydrate found in plant materials, as well as in the nutrition of cattle. Cellulose is difficult for animals to digest on their own, but with the help of methanogenic bacteria in their rumen, cattle can effectively break down cellulose into simpler substances that they can absorb and utilise for energy.