When scaling up the process of deep cultivation of the fungus Irpex lacteus (Fr.) Fr., a producer of exoenzymes of the cellulase complex, on a nutrient medium containing corn processing waste, the reproducibility of the results obtained in small volumes of the nutrient medium was established only at the initial stages of cultivation. The high enzymatic activity of the cellulase producer strain was observed from the 3rd to the 10th day of cultivation. A decrease in the enzymatic activity of the culture fluid was observed on the 15th day of cultivation.