Coal, oil and natural gas are the main energy sources in human life. With the development of human society and the improvement of living standards, the energy that needs to be consumed is increasing day by day. However, these energy materials gifted by nature are gradually accumulated through thousands of years of crustal changes. Although the quantity is large, it is limited after all. Therefore, people will eventually face an energy crisis one day. Of course, energy can be obtained in many ways. For example, solar energy is a huge energy source. In addition, such as geothermal, hydraulic, nuclear fission can release a lot of thermal energy. Experimental studies have shown that the use of microorganisms to generate electricity has shown a bright future to people.

       There are many types of batteries, and fuel cells are a rising star in this family. A general battery is composed of three parts: a positive electrode, a negative electrode, and an electrolyte. The same is true for a fuel cell: let the fuel react chemically at one end of the negative electrode and lose electrons; let the oxidant react at one end of the positive electrode, and get electrons that run from the negative electrode through the wire. Bacterial incubators are the same as ordinary batteries, and there is current flowing through the wires at this time. Fuel cells can use hydrogen, hydrazine, methanol, formaldehyde, methane, ethane, etc. as fuel, and use oxygen, air, hydrogen peroxide, etc. as oxidants. Now we can use the so-called "electrode active substances" produced by the life activities of microorganisms as battery fuel, and then convert chemical energy into electrical energy through a method similar to a fuel cell to become a microbial battery.

      As electrode active materials of microbial batteries, mainly hydrogen, formic acid, ammonia, etc. For example, many bacteria that can produce hydrogen have been found, among which there are more than 30 kinds of chemoheterotrophic bacteria, which can ferment organic substances such as sugars, alcohols, and organic acids. Absorb the chemical energy in it to meet the needs of its own life activities, and at the same time release another part of the energy in the form of hydrogen. With this hydrogen as fuel, a hydrogen-oxygen microbial battery can be produced.

      What to do with the urine of astronauts in a closed spaceship? NASA has designed an ingenious scheme: use Bacillus in microorganisms to process urine, produce ammonia gas, and use ammonia as a The electrode active material is used to obtain a microbial battery, which not only processes urine, but also obtains electrical energy. Generally, under the conditions of spaceflight, each person discharges 22 grams of urea per day and can get 47 watts of electricity. In the same way, microorganisms (bacterial incubators) can also obtain nutrients and energy from the organic matter of wastewater to produce the fuel required by the battery. Although the microbial battery is still in the stage of experimental research, it indicates that in the near future, more energy will be provided to human beings.