Induced Mutation, Development of Multiple Analogue Resistant Strain and Protoplast Fusion for L-Methionine Fermentation by Corynebacterium glutamicum

Corynebacterium glutamicum X1 , a L-glutamic acid producing wild strain which accumulated mild amount of Lmethionine (only 0.6 mg/ml) in the broth ,was subjected to mutational treatments using EMS and UV irradiations to develop a high L-methionine producing mutant. High L-methionine yielding strain Corynebacterium glutamicum X168 was selected in this study which was then subjected to protoplast fusion with a multiple L-methionine analogueresistant strain Corynebacterium glutamicum X124. A high L-methionine yielding, multiple L-methionine analogue resistant mutant Corynebacterium glutamicum X300 was derived in this study which accumulated 9.6 mg /ml Lmethionine in the fermentation broth.