Study On Mutation And Breeding Of Soy Brewing Aspergillus Oryzae By Ion Implantation

In order to improve the material utilization and the quality of soy sauce, a new method of mutagenesis was used to Aspergillus oryzae 3042.Aspergillus oryzae 3042 was mutagenized and breeded by N⁺ implantation. Implanting ion energy was 20 kev and implanting dose ranged from 5×10¹⁴ to 5×10¹⁵ ions/cm² Through calculating the survival curve, it was found that the survival curve accorded with the "saddle" curve. At the same time, the mutation curve of Aspergillus oryzae accorded with the "saddle" curve too, and they had good correlation. It meant that the survival curve and the mutation curve got their peak at the same implanting dose. Therefore, the best N⁺ implanting dose was found.By determining the protease and cellulase that produced by Aspergillus oryzae, a enzyme-productive mutants A100-4 was attained. Its protease activity was 30% more than Aspergillus oryzae 3042 and its cellulase activity was 40% more than Aspergillus oryzae 3042. In the production trial, its total nitrogen and amino acid nitrogen were all higher than those of Aspergillus oryzae 3042. It had got the goal that was preconcerted.