A strain of Mucor named M2, which could produce protease, was isolated from a traditional fermented soybean product. Culture conditions of proteases produced by M2 were studied therefore. The results showed that nitrogen source and carbon source preferred for protease production were soybean protein isolate and glucose, while inorganic salts preferred were KH2PO4, CaCl2 and MgCl2. The suitable culture conditions for protease production were as follows: culture temperature was 28°C, inoculation volume was 2%, liquid level was 100 mL in 300 mL triangle bottle at pH 5, rotating speed was 150 r/min and culture time was 48 h. The obtained protease activity in culture was about 4.35 U/mL. The protease produced by Mucor was analyzed with SDS-PAGE. The protease had a molecular weight of 36.4 kD.
