Genetic and Biochemical Studies on the Formation of Protease in Aspergillus sojae

The mutant strain X816 synthesizing protease and amylase at high rates was crossed with original strain K.S. which is characteristic of abundant sporulation and stable growth, for the purpose of breeding a new koji mold endowed with both parental merits. Diploid strains obtained from these crosses show the intermeadiate character in general both in the formation of these enzymes and in sporulation.

In this paper, the genetic characters of these diploid strains as well as the mode of changes of these enzyme activities during hybrid formation are described.