PURPOSE: To remove the soy smell of soy less, and at the same time, to prepare a feed having high nutritive value or a Bacillus natto preparation effective as a remedy for the intestinal disorder of animals, by fermenting bean curd refuse and soy lees both having low commercial values with bacteria belonging to Bacillus subtilis.

CONSTITUTION: For example, 1.5kg of bean curd refuse (80% water content) is mixed with 1.5kg of soy lees (20% water content). Bacillus subtilis is inoculated in the mixture and cultured in a chamber maintained at 40°C for 3 days. The cultured product is dried to obtain the objective product.