Nearly 20 amino acids can be produced by microbial fermentation technology. However, microbial cells have an automatic metabolic regulation system that prevents excessive accumulation of amino acids. If a large number of amino acids are accumulated in the culture medium, it is necessary to remove or break through the metabolic regulation mechanism of microorganisms. Amino acid fermentation is an important achievement in controlling this mechanism. The isolation and screening of wild strains from nature and the control of their cell membrane permeability are conducive to the secretion of large amounts of L-glutamic acid, which is also an important way to obtain excellent strains of L-glutamic acid fermentation microorganisms. Secondly, through artificial mutation of L-glutamic acid producing strains, various amino acid-producing mutant strains are bred, which is an effective method to obtain excellent strains of other amino acid-producing microorganisms.