Plant waste residues as inducers of extracellular proteases for a deuteromycete fungus Trichoderma atroviride

The ability of Trichoderma atroviride F-534 to utilize plant waste byproducts derived from processing of vegetables and fruits, as the major source of organic carbon and nitrogen for growth and protease production, was tested. The submerged cultivation of T. atroviride F-534 in the mineral base of the Czapek–Dox medium supplemented with plant waste byproducts resulted into copious biomass formation and was accompanied by secretion of several proteolytic enzymes. Zymography analysis of fungal culture filtrates showed that the high-molecular weight (HMW) protease(s) (from 100 kDa to 230 kDa) represent the major portion of secreted enzymes. Serine-type proteases and metalloproteases were predominant, although all known types of proteolytic enzymes were detected dependent on the type of inducer (substrate). The most conspicuous feature of secreted proteases was that the zymography patterns were unique for each plant material tested. These results confirm our previous finding obtained with purified proteins. Results also suggest that HMW protease(s) may participate in the heterotrophic/saprophytic/mode of life of this fungus. Their identity remains, however, obscure.