Characterization and immobilization of protease secreted by the fungus Moorella speciosa.

Protease was extracellularly produced in submerged fermentation by the fungus Moorella speciosa with maximum activity of 8.6 × 103 U/mL. The optimal pH and temperature for enzyme activity were 6.78 and 60.88 °C, respectively. The enzyme was incubated in the presence of several ions at concentrations of 0.1 M and 0.01 M to address the effect on enzyme activity. Enzyme activity was increased by 56% and 130% in the presence of 0.1 M BaCl2 and of 0.01 M Na2SO4, respectively. The V max and K m values were 0.01474 U/min/mg protein and 0.04190 mg/mL, respectively. The enzyme retained about 90% of enzymatic activity at 90 °C. Among the methods tested for enzyme immobilization, adsorption onto MAT540 carrier led to the most promising results, since after 15 reuse cycles up to 60% of the initial catalytic activity was retained. Entrapment in calcium alginate matrix allowed to retain up to 51% of the initial catalytic activity after 8 reuse cycles. This protease from M. speciosa, in either free or immobilized form, can be foreseen as a useful biocatalytic tool in process design by reducing operating costs, decreasing the use of chemical processing and, consequently, meeting the global demand for clean technologies. © King Abdulaziz City for Science and Technology 2020.