O. Georgieva*, N. Karadzhova

Maritsa Vegetable Crops Research Institute (MVCRI), 32 Brezovsko shosse, 4003 Plovdiv, Bulgaria

(Manuscript received 19 July 2021; accepted for publication 14 April 2022)

Abstract. The influence of the nutrient medium, the amount of inoculate and the initial acidity on the accumulation of the biomass of the antagonistic fungus Trihoderma viride during submerged cultivation was studied. As a result of the conducted research, biotechnological parameters were optimized for the production of a biological product by the method of submerged cultivation. A balanced semi-synthetic nutrient medium has been developed in which the fungus performs a full cycle of ontogenesis, forming chlamydospores and phialoconidia. The produced biomass with a titer of more than 1.106 chlamydospores in 1 ml can be used both for the production of liquid form of the preparation and for the production of preparations on solid substrates.