First, light energy inorganic nutrition type: light energy autotrophic type can grow in a completely inorganic environment. Microorganisms with CO2 as carbon source and light as energy source, and inorganic substances (such as hydrogen sulfide, etc. ) to reduce CO2 and synthesize cellular organic matter are called photoautotrophic microorganisms. Photoautotrophic microorganisms include cyanobacteria (including chlorophyll), purple sulfur bacteria and green sulfur bacteria. Because of photosynthetic pigments, they can convert light energy into chemical energy (ATP) which can be directly used by the body. Two. Photoautotrophic microorganism: This kind of microorganism can not use carbon dioxide as the main carbon source or the only carbon source, but can use light as energy source and organic compounds as donors to reduce CO2 and synthesize cell matter, which is called photoheterotrophic microorganism. For example, Rhodotorula bacteria can use isopropanol as a hydrogen donor to reduce carbon dioxide. Three. Chemotactic inorganic trophic type: Chemotactic autotrophic type takes CO2 or carbonate as the sole or main carbon source, and takes the energy released when inorganic compounds are oxidized as energy source, and the microorganisms that synthesize cell substances are called chemoautotrophic microorganisms. Such bacteria include sulfide bacteria, nitrifying bacteria, hydrogen bacteria, iron bacteria and so on. Sulfur bacteria and nitrifying bacteria are closely related to production, and they play an important role in the transformation of natural substances. Four. Chemo-organic trophic type: Chemo-heterotrophic type These microorganisms use organic compounds as carbon sources and the energy generated in the oxidation process of organic compounds as energy sources to synthesize cell materials. This kind of microorganism is called chemotactic heterotrophic microorganism. Most bacteria, fungi and protozoa belong to this type.