[Biosynthesis of the antibiotic, grizin, by prototrophic revertants of Streptomyces griseus biochemical mutants].

Spontaneous and nitrosomethylbiuret-induced prototrophic revertants of various biochemical mutants of Str. griseus producing grisin, a streptothricin antibiotic, were isolated. The antibiotic production level of the revertants was studied. It was found that most of the prototrophic revertants synthesized much higher amounts of grisin than the initial biochemical mutants. It was also shown that a number of the prototrophic revertants of the methionine- and arginine-dependent mutants synthesized 20-23% higher amounts of grisin as compared to the control.