The authors described an improved method for the determination of the slime substance produced in the culture fluids of natto bacteria and other strains of Bacillus group as well as some investigations on the conditions for the production and various factors affecting the yield of the slime substance.
Only three N-sources, glutamic acid, aspartic acid or asparagine were essential for the production of the slime subsance.
The yield of the slime substance was proportional to the concentration of glutamic acid in the culture inedia.
The slime productions by other strains of Bacillus group were inferior to those of natto bacteria.
The quality of natto was improved by the addition of glutamic acid to the material (coocked soybeans).