A Novel Approach for Assessing the Proteolytic Potential of Filamentous Fungi on the Example of Aspergillus spp.

Abstract

Proteolytic enzymes produced by filamentous fungi can degrade various fibrous and globular proteins along with other metabolites that may also find application in biotechnology. In this study, the effect of proteolytic enzymes of 22 Aspergillus strains on various proteins was investigated using protein-containing diagnostic media. Subsequently, a new parameter estimating secreted proteinases specificity towards fibrous or globular proteins without its advanced biochemical research -index of severity of proteolytic action (ISPA) -was suggested. This index determines mycozymes specificity in following manner: its value increases with greater affinity to fibrous proteins, decreases if there is higher affinity to globular proteins. ISPA value was the lowest (0.52) for Aspergillus domesticus, indicating the highest specificity to globular proteins, the highest one (1.26) for A. glaucus, whose proteinases best hydrolyzed fibrous proteins. However, the highest overall proteolytic potential was observed for Aspergillus melleus. The ability to produce acid, alkali and extracellular pigments was evaluated for all isolated strains as well.