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

Definitely, microbes can be used in production of energy. Methanogens are bactarium that are involved in production of biogas which is commonly known as gobar gas.

A typical biogas plant is made up of a concrete tank which is 10-15 feet deep in which

bio-wastes are collected and a slurry of dung is fed. A floating cover is placed over the slurry, which keeps on rising as the gas is produced in the tank due to the microbial activity. The biogas plant has an outlet that is connected through a pipe to supply biogas to nearby houses.

• Also certain microbes such as Saccharomyces cerevisiae are involved in prodution of bioethanol that helps in reduction of CO2 emission.