The optimal technology conditions of making high-quality bran-koji were obtained based on the productivity of the acid-tolerant α-amylase and the glucoamylase produced by the strain TR12, which were affected by the factors includeding nitrogen source, carbon source, minerals, moisture, culture time, and culture temperature.
After 96 hours of fermentation, the activity of acid-resistant a-amylase and saccharifying enzyme reached a high level of 86.37u/mL and 25229.7 u/mL respectively.