Yes, certain types of microbes can be used as a source of energy through a process called microbial fuel cell (MFC) technology.
In an MFC, microbes such as bacteria or archaea are used to catalyze the oxidation of organic matter (such as wastewater or biomass) in the anode compartment of a specially designed electrochemical cell. As the microbes oxidize the organic matter, they transfer electrons to the anode, creating a flow of electrical current. This current can then be harnessed as a source of electricity.
MFC technology is still in its early stages of development and has not yet been widely adopted as a source of energy. However, it has the potential to be a sustainable and renewable energy source, as it can use a wide range of organic materials as fuel, and the microbes used in the process are naturally occurring and can be replenished relatively easily. Additionally, MFCs have been explored as a way to treat wastewater and generate electricity simultaneously, providing a dual benefit.