1. energy: microorganisms can use a variety of energy sources for metabolic activities, such as light energy in photosynthesis, inorganic compounds in chemical synthesis, and degraded organic substances. Carbon metabolism pathway: microorganisms can use different carbon sources for metabolism, including organic carbon and inorganic carbon. Organic carbon metabolism can produce energy through respiration or fermentation. Inorganic carbon metabolism mainly includes carbon fixation and reduction processes, such as carbon fixation in photosynthesis and carbon reduction in nitrification.
2. Nitrogen metabolic pathway: Microorganisms can use different forms of nitrogen sources for metabolic activities, including inorganic nitrogen and organic nitrogen. Inorganic nitrogen metabolism mainly includes ammoniation, nitrification, denitrification and nitrogen fixation, while organic nitrogen metabolism mainly involves protein degradation and amino acid metabolism.