Glutamic Acid Fermentation: Discovery of Glutamic Acid‐Producing Microorganisms, Analysis of the Production Mechanism, Metabolic Engineering, and Industrial Production Process

In 1956, Japanese researchers isolated the glutamic acid-producing bacterium Corynebacterium glutamicum. Following this discovery, glutamic acid fermentation processes were established, and the mechanism of glutamic acid production has been determined. Methods for induction of glutamic acid production such as biotin limitation, Tween 40 addition, and penicillin addition were also developed. Recently, metabolic regulation during glutamic acid production has been investigated at the molecular level, and the contribution of a mechanosensitive channel to the secretion of glutamic acid has been studied. The discovery of C. glutamicum has also contributed to the development of amino acid fermentation technologies. Consequently, amino acid fermentation has been recognized as one of the big successes in the production of industrially important materials by microbial cells. Moreover, novel microorganisms such as Corynebacterium efficiens, which can produce glutamic acid at high temperatures, and Pantoea ananatis, which can produce glutamic acid under the acidic conditions, were isolated. This chapter summarizes the history of glutamic acid fermentation and recent investigations of the molecular mechanism of glutamic acid production by C. glutamicum. Moreover, metabolic engineering of C. glutamicum for improvement of glutamic acid production, glutamic acid production by other microorganisms, and industrial process of glutamic acid production are discussed.