INFLUENCE OF CULTIVATION CONDITIONS ON SYNTHESIS AND SECRETION OF PROTEASES BY THE FUNGI ALTERNARIA-ALTERNATA AND FUSARIUM-OXYSPORUM

The influence of cultivation conditions on synthesis and secretion of proteases by the fungi Alternaria: alternata and Fusarium oxysporum wa s studied. The presence of protein in the culture medium was shown to be a necessary prerequisite for the production of extracellular protea ses. The production of these proteases attained their maximums by the 3rd - 6th day of A. alternata cultivation and by the 3rd - 4th day of F. oxysporum cultivation, depending directly on protein concentration in the medium. The secreted proteolytic activity was maximal in the cu lture of A. alternata grown at 20 degrees C and in the culture of F. o xysporum grown at 24 degrees C. The employment of the culture medium f ree of sugar induced a fivefold decrease in the activity of extracellu lar proteases. Addition of cycloheximide to the medium caused a 90% de crease in proteolytic activity, which may point to the synthesis of st udied proteases de novo.