Isolation method for lysine-excreting mutants of Arthrobacter globiformis

To improve the yield of lysine by the isolate, auxotrophic mutants were isolated. Among the mutants, only one auxotrophic mutant required vitamin B12. This mutant produced alpha-alanine. About 200 mutants resistant to the lysine analog S-(2-aminoethyl)-L-cysteine were isolated and some of them produced well above the wild type.