All of these antibiotics are typical secondary metabolites, and their industrial production is well worked out despite the fact that the biochemistry and genetics of their biosynthesis are only partially understood. Section 11.7 Vitamins produced microbially include vitamin B 12 and riboflavin, whereas the most important amino acids produced commercially are glutamic acid, aspartic acid, phenylalanine, and lysine. High yields of amino acids are obtained by modifying regulatory signals that control synthesis of the particular amino acid such that overproduction occurs. Section 11.8 Microbial bioconversion employs microorganisms to biocatalyze a specific step or steps in an otherwise strictly chemical synthesis. Give an example of a microbial bioconversion.
Microorganisms are ideal for the large-scale production of enzymes.
Many enzymes are used in the laundry industry to remove stains from clothing, and thermostable and alkali-stable enzymes have many advantages in these markets. When an enzyme is used in a large-scale process, it may be desirable to immobilize it by bonding it to an inert substrate. The active ingredient in vinegar is acetic acid, which is produced by an acetic acid bacterium oxidizing an alcohol-containing fruit juice. Adequate aeration is the most important consideration in ensuring a successful vinegar process. A number of organic chemicals are produced commercially by use of microorganisms, of which, the most important economically is citric acid, produced by certain fungi.