Identification and characterization of milk-clotting proteases produced by two species of mold

Abstract

Two strains of fungi were isolated and identified as Aspergillus tamarii and Penicillium pinophilum which showed good enzymatic activity on casein, 1933.33U and 1822, 21U, respectively. The search for milk clotting enzymes by fermentation at acid pH on culture medium containing whey and, after purification by molecular exclusion chromatography, affinity chromatography and SDS-PAGE helped to find two enzymes having a coagulant activity and approximately molecular weight of 35 and 30 KDa for Aspergillus tamarii and Penicillium pinophilum, respectively. The optimum pH of activity was 5.5 for both strains and the optimum temperature was 50 and 35°C for A. tamarii and P. pinophilum, respectively.

Keywords: Aspergillus, Penicillium, milk-clotting enzyme, extraction and purification

African Journal of Biotechnology, Vol 13(11), 1275-1280