Further evidence on differentiation of Aspergillus sojae from Aspergillus oryzae by electrophoretic patterns of cellulase, pectin-lyase, and acid proteinase

Abstract

Cellulase (β-1,4-glucan-4-glucanohydrolase, EC. 3.2.1.4), pectin-lyase (EC. 4.2.2.3), and acid proteinase (aspergillopeptidase A) (EC. 3.4.4.17) extracted from wheat bran solid culture of 23 strains of Aspergillus oryzae and 21 strains of Aspergillus sojae showed species-specific patterns on electrophoresis in polyacrylamide gels. The electrophoretic patterns of the cellulase were independent of age or cultural conditions. The pectin-lyase patterns were also independent of culture age except early phase of growth. The species-specific patterns were clear at the stage of the maximum production of acid proteinase. With the exception of one strain, no variation of the electrophoretic mobilities of these key enzymes were observed between the strains of the same species. The results provide further evidence to support the establishment of A. sojae as a species distinct from A. oryzae and the use of the electrophoretic zymograms as a taxonomic aid.