Histidine Production by Auxotrophic Histidine Analog-resistant Mutants of Corynebacterium glutamicum

Corynebacterium glutamicum mutants carrying both auxotrophy and histidine analogresistance were derived by a mutagenic treatment, and their histidine productivity was com pared with that of a triazolealanine (TRA)-resistant histidine producer, C. glutarnicurn KY-10260.As a result, a leucine auxotrophic TRA-resistant mutant, RU-88 was selected out of 164 auxotrophic derivatives of KY-10260.It produced histidine at a distinctly higher concentration than the parent strain under every condition tested.The concentration reached 11mg/ml or 5.8% (w/w) of the initial sugar.Addition of an excessive amount of leucine to the medium inhibited the histidine production together with the by-production of valine by this mutant.Thiazolealanine-resistant mutants derived from a tyrosine auxotroph, a phenylalanine auxotroph and a tryptophan auxotroph gave the same or lower production in com parison with KY-10260.