Abstract
Extracellular proteinase activities produced by 36 strains in the genus Monascus were determined at various pHs using casein and Azocoll as substrates. These strains were grouped into three types (A, B, and C) according to the pH-activity profiles of their proteinases.
Type A was characterized by only acid proteinases with an optimal pH around 3 and was found in eight strains of six species of Monascus (i.e., M. araneosus, M. fuliginosus, M. kaoliang, M. pilosus, M. pubigerus, and M. vitreus). Type B was characterized by only alkaline proteinases with an optimal pH about 8-9 and was found in 24 strains of nine species and two varieties of Monascus (i.e., M. albidus, M. albidus var. glaber, M. anka, M. anka var. rubellus, M. araneosus, M. kaoliang, M. major, M. purpureus, M. ruber, M. rubiginosus, and M. serorubescens). Type C was characterized by the two kinds of proteinases observed in types A and B and was found in three strains of one species of Monascus (i.e., M. kaoliang).
It was revealed in this study that Monascus spp. secreted extracellular alkaline proteinases. However, there was not any considerable correlation between the classification system of the genus Monascus and the type of proteinase produced.
