Extracellular protease from Mucor pusillus was purified 18-fold with 7.56% recovery by ion-exchange chromatography and gel filtration. The enzyme was found to be monomeric in nature, having a molecular mass of 49 kDa. The enzyme acted optimally at 50°C and was stable in the temperature range 30-50°C. It was completely inactivated by heating for 30 min at 65°C. The optimum of activity for the purified extract was observed at milk CaCl 2 concentration of 0.02 M and at milk pH of 5. These properties, except for temperature, were similar to those of rennet.

Streptomyces sp. B-PNG23 was selected as a promising cellulolytic strain and tested for its ability to produce cellulases from agroindustrial residues. A pH value of 7 and temperature of 28°C were found to be optimal for maximum enzyme production. The highest endoglucanase activity was obtained in a medium comprised of wheat bran (2 g/l), yeast extract (2 g/l), NaCl (2 g/l), NH4Cl (2.5 g/l), and (0.4 g/l) of MgSO4. The enzyme was active at a broad range of pH (5-8) and temperatures (40-70°C). The optimum pH and temperature were 6 and 50°C, respectively. In the presence of metal ions Mn2+, Cu2+ and NH4 + the activity of the enzyme increased significantly. The enzyme retained 50% of its activity after heating at 50°C for 6 h. This enzyme could be considered as a thermotolerant biocatalyst that could be utilized in biotechnological applications

Mucor pepsin, a protease used in milk coagulation, is purified by ion-exchange and by molecular exclusion on Sephadex G100. The molecular weight (MW) is determined by polyacrylamide gel electrophoresis under denaturing conditions in presence of sodium dodecyl sulfate (SDS) and by molecular exclusion chromatography. Approximate evaluation of molecular mass was conducted by elution of known MW proteins (BSA: 67 kDa, pepsin: 35 kDa and trypsin: 23.8 kDa) on Sephadex G-100 under the same conditions as the experimental sample. The electrophoretic profile shows that the active fraction studied appears as a single homogeneous band (monomeric form). According to the curve calibration, the molecular mass of the coagulant fraction is about 48 kDa. For Mucor, the observed MW value seems to be enigmatic. However, this result is confirmed by a proteomic analysis with close MW values obtained using conventional techniques. The protease studied by the Scafold ver. Software 2.0 and the analysis of the protein similarities indicate a MW of 46 kDa and the protease sequence of 427 amino acids.