**Abstract**

Abstract The possibility of using the recipient strain *Penicillium verruculosum* B1-537 (ΔniaD) as a producer of laboratory and industrial enzymes was considered. The advantage of this strain is its ability to secrete a basic cellulase complex consisting of cellobiohydrolases, endoglucanases, and β-glucosidase, which exceeds in its hydrolytic ability the enzyme complex of *Hypocrea* (*Trichoderma*) strains. Using the expression system, the basic complex of cellulases of the recipient strain *Piptochaetium verruculosum* B1-537 (ΔniaD) was supplemented with new (booster) enzymes that are necessary to increase its hydrolytic activity. Enzyme preparations adapted to the processing of various types of renewable plant biomass were obtained.

**Keywords:** *Penicillium verruculosum*, *Trichoderma*, cellulase complex, cellulose bioconversion, renewable plant biomass, industrial enzymes
