In order to produce amino acids using microorganisms, it is important to find a microorganism with a high potential for producing amino acids. One gram of natural soil contains about 100 million microorganisms. From these a useful one can be picked out.
Once a microorganism suitable for the fermentation method has been selected, it is necessary to enhance its potential, that is, to make improvements to take full advantage of the potential of the organism.
Generally, microorganisms produce the 20 kinds of amino acids only in the amounts necessary to themselves. They have a mechanism for regulating the quantities and qualities of enzymes to yield amino acids only in the needed amounts. Therefore, it is necessary to release this regulatory mechanism in order to manufacture the target amino acid in large amounts.
The yield of an amino acid depends on the quantities and qualities of the enzymes. The yield increases if the enzymes involved in the production of the target amino acid are present in large quantities under workable conditions, while it decreases if the enzymes are present in small quantities. Suppose that a microorganism has a metabolic pathway A (a) B (b) C (c) D (a, b, and c are enzymes). In order to produce only amino acid C in large amounts, you have to enhance the actions only of enzymes a and b and to get rid of the action of enzyme c. Strains are improved using various techniques to make this process possible.
A fermentation tank is filled with syrups/sugars derived from sugar cane, corn, and cassava, and then fermentation conditions are set so that the stirring conditions, air supply, temperature, and pH are optimum. Finally, only the target amino acid is obtained from this fermented broth in high purity.