Partial purification and some technological properties of Rhizomucor miehei protease

Abstract

The research aimed to study the feasibility of using the protease from a local isolate of Rhizomucor miehei in cheese-making as a substitute to calf rennet, that is expensive to produce. The partial purification for the crude enzyme was conducted by using gel filtration column (Sephadex G-100). The enzymatic indices of the partially purified fungal protease were compared with those of the commercial rennet. The results showed an increase in the specific activity of the purified enzyme, as it reached 3756.18 Soxhlet unit (SU)/mg, with a recovery of 4.9%. The protease from Rhizomucor miehei exhibited superior specific milk-clotting activity and milk-clotting activity/ proteolytic activity ratio, where they reached 3756.18 SU/mg, and 362.50, respectively compared to 1576.01 SU/mg and 58.64, respectively, in the commercial rennet. The fungal protease was used in the production of white cheese according to the traditional method, where the optimal enzyme-to-milk ratio was determined for the yield and sensory properties of the resulted cheese, which was estimated at 6000 SU/L. Cheese made by using the partially purified fungal protease was quite similar to cheese made by using commercial rennet, in terms of yield and sensory properties.