Ajinomoto Co., Ltd.

Wataru Hibino

Masakazu Sugimoto

Tsuyoshi Nakamatsu

Mikiko Suga

Tsuyoshi Osumi

Mika Ito

Yusuke Takahashi

Takahiro Asano

Akihiro Watanabe

Yasuhiko Yoshihara

Harufumi Miwa

Shintaro Iwatani

Satoshi Okutani

Kazuya Kondo

Masayuki Araki

Fumito Ohnishi

A method is described for producing an L-amino acid or a nucleic acid by culturing a microorganism having an ability to produce the L-amino acid or nucleic acid in a liquid medium in a fermentation tank containing a stirring impeller, and optionally adding seed crystals to the medium as required to produce and accumulate crystals of the L-amino acid or nucleic acid in the medium, and collecting crystals of the L-amino acid or nucleic acid from the culture. The power density of the stirring impeller is controlled to be 2.4 kW/mor lower after either precipitation of the crystals or addition of the seed crystals.

Method for producing an L-amino acid or a nucleic acid

A coryneform bacterium which has enhanced intracellular pyruvate carboxylase activity obtained by increasing copy number of a gene encoding the intracellular pyruvate carboxylase, or by enhancing function of a expression regulatory sequence for the gene, and has L-glutamic acid-producing ability is cultured in a medium so that L-glutamic acid should be produced and accumulated in the culture, and L-glutamic acid is collected from the culture.

Method for producing L-glutamic acid by fermentation

Disclosed is a coryneform bacterium having resistance to azaserine or &bgr;-(2-thienyl)-DL-alanine and having L-serine productivity. Also, disclosed are D-3-phosphoglycerate dehydrogenase derived from a coryneform bacterium, in which feedback inhibition by L-serine is desensitized; the D-3-phosphoglycerate dehydrogenase, which is obtainable from a coryneform bacterium having resistance to azaserine or &bgr;-(2-thienyl)-DL-alanine and having L-serine productivity; the D-3-phosphoglycerate dehydrogenase having an amino acid sequence depicted in SEQ ID NO: 12 in Sequence Listing or the sequence including substitution, addition or deletion of one or more amino acids, wherein an amino acid residue corresponding to the 325th glutamic acid residue of the amino acid sequence in the SEQ ID NO: 12 is replaced with an amino acid other than glutamic acid; the D-3-phosphoglycerate dehydrogenase that has an amino acid sequence depicted in SEQ ID NO: 11 in Sequence Listing; a DNA coding for the D-3-phosphoglycerate dehydrogenase described above; the DNA that has a base sequence depicted in SEQ ID NO: 13 in Sequence Listing; a coryneform bacterium which harbors a recombinant DNA containing the DNA; and a method of producing L-serine, comprising the steps of cultivating the bacterium described above in a medium to allow accumulation of L-serine in the medium, and collecting the L-serine from the medium.

Method of producing L-serine by fermentation

L-serine is produced by cultivating in a medium a coryneform bacterium having L-serine productivity in which an activity of at least one of phosphoserine phosphatase and phosphoserine transaminase is enhanced, preferably, further having introduced therein a gene coding for D-3-phosophoglycerate dehydrogenase in which feedback inhibition by L-serine is desensitized, allowing L-serine to accumulate in the medium, and collecting the L-serine from the medium.

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Kawasaki, Japan

Wataru Hibino