| 摘要 |
PURPOSE:To produce L-threonine by a fermentation method by culturing a variant strain, belonging to the genus Providencia and having requirement for histidine and collecting the L-threonine from the resultant culture. CONSTITUTION:L-Threonine which is one of essential amino acids is produced by a fermentation method. In the process, a microorganism, belonging to the genus Providencia and having requirement for histidine and the ability to produce the L-threonine is cultured. The microorganism is a variant strain obtained by subjecting a microorganism belonging to the genus Providencia to treatment, such as irradiation with ultraviolet rays or using N-methyl-N'-nitro-N- nitrosoguanidine. The L-threonine is produced and accumulated in the culture medium. After completing the culture, the L-threonine is collected by a method using an ion exchange resin, concentration, etc. Thereby, the L-threonine is produced with high productivity. |
