Screening of producers of proteolytic enzymes effective against fibrillar and globular proteins, among the microfungi associated with insects

Thirty cultures of microfungi associated with insects were isolated and identified. These cultures were used to study the formation of proteolytic enzymes by the injection seeding method on agarized nutrient media containing sources of specific fibrillar and globular protein substrates. Data was collected on the presence of caseinolytic (EI from 1.00 to 2.75), collagenolytic (EI from 1.00 to 3.25), gelatinolytic (EI from 1.00 to 1.84), elastolytic (EI from 1.00 to 1.50), keratinolytic (EI from 1.00 to 2.00), and hemoglobin hydrolysis abilities (EI from 1.00 to 1.67) for promising strains. Promising strains were identified that showed high activity against tested substrates – nos 12 (Penicillium hirsutum 1), 19 (Cladosporium sphaerospermum 1), 21 (Aspergillus unguis 1), and 25 (Cladosporium herbarum 1). Submerged cultivation of these promising strains was carried out, and the proteolytic activity of extracellular proteases in the culture liquid was determined in relation to various protein substrates. The highest level of total proteolytic activity was determined in the culture liquid of Aspergillus ochraceus 1 (E_azocasein = 1.686 con.units/ml), collagenolytic activity during cultivation of the strain Cladosporium herbarum 1 (E_azocoll = 0.110 con. units/ml), as well as elastolytic activity using the chromogenic peptide substrate S‑4760 in the culture fluid of the micromycete Aspergillus unguis 2 (E_S‑4760 = 7.366 mmol pNA × 10^–3/ml/min) under conditions of deep cultivation of insect-­associated microfungi strains.