Abstract: A method for producing L-glutamic acid by fermentation, which comprises culturing a microorganism having L-glutamic acid-producing ability at a first pH that is suitable for growth of the microorganism, and then culturing the microorganism at a second pH that is suitable for L-glutamic acid production by the microorganism and is lower than the first pH.

Abstract: L-Glutamic acid is produced by culturing in a liquid culture medium a microorganism belonging to the genus Enterobacter or Serratia and having an ability to produce L-glutamic acid, which increases in an activity of enzyme catalyzing a reaction for L-glutamic acid biosynthesis, or which decreases in or is deficient in an activity of an enzyme catalyzing a reaction branching from a pathway for L-glutamic acid biosynthesis and producing a compound other than L-glutamic acid, and collecting produced L-glutamic acid from the culture medium.

Abstract: L-Glutamine is produced by culturing a coryneform bacterium which has L-glutamine producing ability and has been modified so that its intracellular glutamine synthetase activity should be enhanced, preferably which has been further modified so that its intracellular glutamate dehydrogenase activity should be enhanced, in a medium to produce and accumulate L-glutamine in the medium and collecting the L-glutamine.

Abstract: A method for producing L-glutamic acid by fermentation, which comprises culturing a microorganism having L-glutamic acid-producing ability at a first pH that is suitable for growth of the microorganism, and then culturing the microorganism at a second pH that is suitable for L-glutamic acid production by the microorganism and is lower than the first pH.

Abstract: L-Glutamic acid is produced by culturing a coryneform bacterium having L-glutamic acid producing ability, in which trehalose synthesis ability is decreased or deleted by, for example, disrupting a gene coding for trehalose-6-phosphate synthase, a gene coding for maltooligosyltrehalose synthase, or both of these genes to produce and accumulate L-glutamic acid in the medium, and collecting the L-glutamic acid from the medium.

Abstract: A method for producing L-glutamic acid which comprises culturing a microorganism belonging to the genus Klebsiella, Erwinia or Pantoea and having an ability to produce L-glutamic acid in a culture medium, and collecting produced L-glutamic acid from the culture medium. The microbial strain used is preferably a strain which decreases in or is deficient in an activity of an enzyme catalyzing a reaction branching from a pathway for L-glutamic acid biosynthesis and producing a compound other than L-glutamic acid, or a strain which increase in an activity of an enzyme catalyzing a reaction for L-glutamic acid biosynthesis.

Abstract: L-Glutamic acid is produced by culturing in a liquid culture medium a microorganism belonging to the genus Enterobacter or Serratia. Further, the microorganism having an ability to produce L-glutamic acid, which increases in an activity of enzyme catalyzing a reaction for L-glutamic acid biosynthesis, or which decreases in or is deficient in an activity of an enzyme catalyzing a reaction branching from a pathway for L-glutamic acid biosynthesis and producing a compound other than L-glutamic acid, and collecting produced L-glutamic acid from the culture medium.

Abstract: L-Glutamic acid is produced by culturing in a liquid culture medium a microorganism belonging to the genus Enterobacter or Serratia and having an ability to produce L-glutamic acid, which increases in an activity of enzyme catalyzing a reaction for L-glutamic acid biosynthesis, or which decreases in or is deficient in an activity of an enzyme catalyzing a reaction branching from a pathway for L-glutamic acid biosynthesis and producing a compound other than L-glutamic acid, and collecting produced L-glutamic acid from the culture medium.

Abstract: A method for producing L-glutamic acid which comprises culturing a microorganism belonging to the genus Klebsiella, Erwinia or Pantoea and having an ability to produce L-glutamic acid in a culture medium, and collecting produced L-glutamic acid from the culture medium. The microbial strain used is preferably a strain which decreases in or is deficient in an activity of an enzyme catalyzing a reaction branching from a pathway for L-glutamic acid biosynthesis and producing a compound other than L-glutamic acid, or a strain which increase in an activity of an enzyme catalyzing a reaction for L-glutamic acid biosynthesis.

Abstract: A fermentative process for producing L-glutamic acid efficiently and at low cost is disclosed. Also disclosed are microorganisms having improved ability to produce L-glutamic acid. These microorganisms belong to the genus Escherichia, have resistance to an aspartic acid antimetabolite, and are deficient in .alpha.-ketoglutaric acid dehydrogenase activity. The process comprises cultivating one of these microorganisms in a liquid medium, accumulating L-glutamic acid in the culture medium, and collecting L-glutamic acid. In particular, E. coli AF13199 (FERM BP-5807).