(1) Utilization of light energy, such as cyanobacteria.

(2) According to the energy released in the oxidation process of nitrifying bacteria and other substances, the chemical energy released in the oxidation process of NH3 can be utilized,

NH3 is both a nitrogen source and an energy source.

Autotrophic microorganisms are organisms that can produce themselves. Generally, chemical energy is used, such as sulfur bacteria, iron bacteria and nitrifying bacteria. Many microorganisms are heterotrophic, including saprophytic and parasitic. Most fungi are saprophytic, such as mushrooms, fungus, tremella, yeast and so on. , and a few are parasitic on living animals and plants, such as pneumococcus. All viruses are parasitic.

According to the different carbon and energy sources required by microorganisms, the nutritional types of microorganisms are summarized as follows.