Breeding By Induced Mutation Of High Citric Acid Producing Strains By The Radial Of ～(60)Co-γ

A.Niger Co827 is a high citric acid – producing strain, which has stablecitric acid production,transformation ratio,fermention. It can ferment ,butnot .In this paper, the effects of thee different mutagens (the ultravioletra, the radial of Co⁶⁰ -γ, particle α)on the citric acid producing strainA.niger were studied. It was demonstrated that the effect of the radial ofCo⁶⁰ -γ was more efficient. A high citric acid producing strain was obtainedby a series of screenings. After having optimized the culture media(carbonsource, nitrogen source, mineral salts, etc.), The optical medium was obtained.By comparing the specialities of the original strain and the high citric acidproducing strain in the genetic stability, in the different original densitiesof sugar in 50 m³ fermentation tank , it was concluded that the strain RD-2081was more suitable to the original density of sugar 17 % than the original strain.And the morpHologies of the two strains were compared.