The production of selected extracellular enzymes by Trichoderma reesei M-7 on two different media containing either sweet whey in combination with 4% lactose or solely 4% lactose was examined and compared. It was found that the activity of cellulases expressed as FPU (filter paper unit) in both media differed and was unfavourable for whey containing medium. On the contrary, reverse results were observed for other examined enzymes i.e protease, laminarinase and chitinase which had higher activities on whey then on lactose medium. Furthermore, it was observed that the lactic acid concentration in the cultures of whey medium did not inhibit the secretion of cellulolytic enzymes independent of the initial pH values of the media. One of the reasons for low secretion of cellulolytic and xylanolytic enzymes by Trichoderma reesei M-7 on whey media could be explained by the high level of proteolytic activity which probably caused proteolysis of both cellulases and xylanases. Besides, the acidity of undiluted whey was below 5,5 and thus could inhibit the growth of Trichoderma reesei M-7. The application of whey for successful production of cellulases and xylanases by the examined strain needs identification of factors leading to low secretion of these enzymes and modification of the medium composition of whey.

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