Abstract:

Two 3-deoxy- α -arobino-heptulosonate-7-phosphate synthase (DS) genes from Corynebacterium glutamicum AS10111, and its alanine and tyrosine auxotrophic and anti-trimethyl-tryptophane mutant C. glutamicum JLC1 were cloned and sequenced. The recombinant plasmid pZ8-1-DSM was constructed by using the DS gene from C. glutamicum JLC1 and expressed in transformed C. glutamicum JLC1. The results showed that the DS activity of recombinant C. glutamicum JLC1  (pZ8-1-DSM)is 5.9 and 7.3 times of that of the host and C. glutamicum wild-type strains, respectively, and its L-tryptophan yield reaches 14.9 g/L, highter 65% than that of the host strain. In conclusion, the DS activity and L-tryptophan yield can be effectively improved by over-expression of DS gene in Corynebacterium glutamicum.

Key words: Corynebacterium glutamicum, L-tryptophan, 3-deoxy-α-arobino-heptulosonate-7-phosphate synthase (DS), over-expression