Properties of Revertants Appearing in l-Leucine Fermentation Culture Broth |
| |
Authors: | Tomoki Azuma Toshihide Nakanishi Hiroshi Hagino |
| |
Institution: | Technical Research Laboratories, Hofu Plant, Kyowa Hakko Kogyo Co., Ltd., Kyowa-machi, Hofu, Yamaguchi 747, Japan |
| |
Abstract: | The l-leucine productivity of an l-leucine producing strain, H-1204, of Corynebacterium glutamicum substantially decreased during a large-scale culture or repetitive subculturing. This instability was found to be due to the appearance of revertants with lower or no l-leucine productivity. Strains in the culture broth could be roughly classified into three types on the basis of their phenotypes: l-type, original l-leucine producing strain, ValL Leu+ (valine leaky); M-type, Val+ Leu+ (prototroph); V-type, Val+ Leu- (leucine auxotroph). The appearance of these revertants was determined to be caused by the distribution imbalance of α-ketoisovaleric acid, the common precursor for l-leucine and l-valine biosynthesis. |
| |
Keywords: | |
|
|