| 摘要 |
PURPOSE:To produce L-threonine at a low cost, by culturing a microbial strain belonging to Proteus genus, resistant to the methionine metabolism antagonistic substance, and capable of producing L-threonine, thereby producing and accumulating L-threonine. CONSTITUTION:A microbial strain belonging to Proteus genus, resistant to the methionine metabolism antagonistic substance, and capable of producing L- threonine (e.g. Proteus rettgeri ETR10-43, FERM-P No.7395) is inoculated in a nutrient medium, and cultured under shaking or aeration at about 5-9pH and about 24-37 deg.C, to produce and accumulate L-threonine in the culture liquid. The microbial cells are removed by filtration, and the filtrate is acidified with hydrochloric acid, and passed through a strongly cationic ion exchange resin. The objective L-threonine can be separated by eluting the adsorbed component with dilute ammonia water, removing ammonia, and concentrating the eluate.
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