Objective  In this paper, the characteristics of spore production and enzyme production of Aspergillus oryzae 3.042 from solid-state koji-making Hongqu rice wine grains were studied in order to provide theoretical support for the preparation of seasoning liquid from Aspergillus oryzae solid-state fermentation of Hongqu rice wine grains.

  Method  Hongqu rice wine grains was used as the main raw material. Aspergillus oryzae strain 3.042 was used as the starter. The enzyme activities of acidic, neutral and alkaline proteases, protein enzymatic hydrolysis rate, and ammonia nitrogen conversion rate were used as indicators. The researches on Hongqu rice wine grains and bran were studied to make the effects of culture material ratio, fermentation time and other factors on the growth and enzyme production of Aspergillus oryzae clear.

  Results  The suitable ratio of koji culture material is Hongqu rice wine grains∶bran∶water = 1∶0.8∶1.4. Cultured under this condition for 72 h, the amount of spores, acid protease, alkaline protease, neutral protease of koji , glutaminase were up to 9.93, 1160.94 U·g⁻¹, 1157.47 U·g⁻¹, 1788.40 U·g⁻¹, 10.49 U·g⁻¹. The amino acid nitrogen, enzymatic hydrolysis rate and ammonia nitrogen conversion rate in the crude oil obtained by the koji fermentation were 8.2 g·L⁻¹, 63.40% and 37.08% respectively.Used Hongqu rice wine grains as culture material ratio. The crude sauce has a high flavor, red brown color and luster. The sauce is rich in flavor and has a typical soy sauce style.

  Conclusion  Hongqu rice wine grains are suitable for solid-state koji-making by Aspergillus oryzae, and the suitable ratio is bran:Hongqu rice wine grains:water =1:0.8:1.4.