Ajinomoto Co., Ltd.

Hiroko Kishino

Hisao Ito

Hiroshi Matsui

Osamu Kurahashi

Nobuharu Tsujimoto

Masako Izui

Yukiko Ono

Ken-ichi Hashiguchi

A microorganism, which has an ability to produce L-amino acid, especially L-phenylalanine, L-tryptophane, L-tyrosine, L-threonine, or L-isoleucine, in which a phosphoenolpyruvate-producing ability is enhanced, is cultivated in a medium so that the L-amino acid is produced and accumulated in the medium to collect the L-amino acid.

Process for producing L-amino acids

An L-isoleucine-producing bacterium belonging to the genus Escherichia which carries a thrABC operon which comprises a thrA gene coding for aspartokinase I-homoserine dehydrogenase I substantially released from the inhibition by L-threonine and an ilvGMEDA operon which comprises an ilvA gene coding for threonine deaminase substantially released from the inhibition by L-isoleucine and whose region required for attenuation is removed; and an L-isoleucine-producing bacterium belonging to the genus Escherichia carrying the thrABC operon, an lysC gene coding for aspartokinase III substantially released from the inhibition by L-lysine, and the ilvGMEDA operon. The bacteria permit biosynthesis of a sufficient amount of L-isoleucine.

L-isoleucine-producing bacterium and method for preparing L-isoleucine

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Kawasaki, Japan

Hiroko Kishino