L-Glutamic acid, L-proline or L-arginine is produced by culturing a bacterium
belonging to the genus Escherichia, which is L-isoleucine auxotrophic and has ability
to produce L-glutamic acid, L-proline or L-arginine, in a medium containing L-isoleucine,
to produce and accumulate L-glutamic acid, L-proline or L-arginine in a culture,
and collecting L-glutamic acid, L-proline or L-arginine from the culture.