Characterization of partially purified and immobilized partially purified protease extracted from silver catfish (Pangasius sutchi) viscera / Siti Noorsyarafana Sahim and Normah Ismail

Viscera is known as one of the richest sources of proteolytic enzymes. However, the biggest problem regarding enzyme is the rapid deterioration and lose in functional properties due to inefficient treatment and improper storage condition. Therefore, in this study, protease from silver catfish viscera have been extracted, partially purified by acetone precipitation method and immobilized in the calcium alginate beads. Concentrations of 2.99 % (w/v) sodium alginate and 0.30 M calcium chloride were used to produce the immobilized partially purified protease. Then, the partially purified and immobilized partially purified protease were characterized in different range of pH, temperature and storage period in order to establish a greater protease stability during storage and increase in its efficiency. Proteolytic activity of the partially purified and immobilized partially purified protease in the alginate beads were measured by using casein as a substrate. The highest proteolytic activity for partially purified protease was recorded at pH 4 (5709.76 CDU/mg) and 40 °C (6061.14 CDU/mg) and for immobilized partially purified protease at pH 5 (3987.85 CDU/mg) and 50 °C (4956.54 CDU/mg). For storage stability, the partially purified protease has optimum storage temperature at – 40 °C while the immobilized partially purified protease at 4 °C. of 17.44 and 24.50 %, respectively for 6th days of storage. At optimum storage condition, the partially purified protease and immobilized partially purified protease have storage efficiency of 17.44 and 24.50 %, respectively for 6th days of storage.