Abstract: Rice dregs and wheat bran were used as raw materials. Monascus rubber, Aspergillus oryzae and Aspergillus niger were adopted as culture strains. The optimal strains match, inoculum size and culture time were confirmed by analyzing the changes of diastatic enzyme activity, neutral protease activity and acid protease activity. 5% Aspergillus oryzae and 5% Aspergillus niger were both inoculated for two days after inoculated by Monascus rubber for four days. Then, the optimum culture pH, culture temperature, original moisture content and raw material match were obtained by orthorgonal experiment. The optinal results were: culture temperature 31℃, ratio of rice dregs to wheat bran 6 to 4, original moisture content 35% and pH 5. On these optimum conditions, the diastatic enzyme activity arrives at 4212 U/g dry encymic dregs, the acid protease activity is 2130 U/g. dry encymic dregs and the neutral protease activity is 2521U/g dry encymic dregs.

Key words: rice dregs, mixed culture, Monascus rubber, enzyme activity analysis