Medium optimization for L-phenylalanine production by a tryptophan auxotroph of Corynebacterium glutamicum

Summary By screening 15,000 mutants, tyrosine auxotrophs T6, T7, and tryptophan auxotrophs P6, P8, were obtained. After primary production test, mutant P6 was chosen for further investigation. Fractional factorial design(FFD) and steepest ascent method(SAM) were used to optimize the medium component Mutant P6 had 17.1 g/l L-phenylalanine production when 0.44 g/l tryptophan was added. When Corynebacterium glutamicum P6 was cultivated in the optimum medium, L-phenylaianine production increased 22% as compared with the parent strain CCRC 18335, and the interference of tryptophan during the purification process was removed.