Do you think microbes can also be used as a source of energy? If yes,how?

(N/A) Yes,microbes can be used as a source of energy. Bacteria such as $Methanobacterium$ are used for the generation of $gobar$ gas or biogas.
The generation of biogas is an anaerobic process in a biogas plant,which consists of a concrete tank ($10-15$ feet deep) with sufficient outlets and inlets.
The dung is mixed with water to form a slurry and fed into the tank.
The digester of the tank is filled with numerous anaerobic methane-producing bacteria,which produce biogas from the slurry.
Biogas can be removed through a pipe and used as a source of energy,while the spent slurry is removed from the outlet and used as a fertilizer.