The research was carried out to study the biological activity of proteases of filamentous fungi, in particular the recombinant protease of Aspergillus ochraceus BMKF41040 micromycete, on a biological model of a unicellular organism - a culture of Paramecium caudatum ciliates. The test object Paramecium caudatum is characterized by a short life cycle, rapid reproduction, it is a convenient model for studying the response of an organism to the effects of preparations. The experiment consisted of 3 stages: rapid assessment of the biological activity of the recombinant protease of Aspergillus ochraceus BMKF41040 micromycete on the culture of infusoria in the stationary growth phase; the assessment of the biological effect of the studied object on the mechanisms of adaptation and cell resistance under the damaging effect of an unfavorable factor; the assessment of the biological activity of the studied objects by the reproduction intensity of ciliates. The results of the studies have shown that the recombinant protease of Aspergillus ochraceus BMKF41040 micromycete does not have a negative and stimulating effect on ciliates and does not affect their reproduction rate. It exhibits moderate biological activity in the test with the action of an unfavorable factor.