Glutamate Fermentation-2: Mechanism of l-Glutamate Overproduction in Corynebacterium glutamicum

The nonpathogenic coryneform bacterium, Corynebacterium glutamicum, was isolated as an l-glutamate-overproducing microorganism by Japanese researchers and is currently utilized in various amino acid fermentation processes. l-Glutamate production by C. glutamicum is induced by limitation of biotin and addition of fatty acid ester surfactants and β-lactam antibiotics. These treatments affect the cell surface structures of C. glutamicum. After the discovery of C. glutamicum, many researchers have investigated the underlying mechanism of l-glutamate overproduction with respect to the cell surface structures of this organism. Furthermore, metabolic regulation during l-glutamate overproduction by C. glutamicum, particularly, the relationship between central carbon metabolism and l-glutamate biosynthesis, has been investigated. Recently, the role of a mechanosensitive channel protein in l-glutamate overproduction has been reported. In this chapter, mechanisms of l-glutamate overproduction by C. glutamicum have been reviewed.