PUBLICATION VI Process technological effects of deletion and amplification of hydrophobins I and II in transformants of Trichoderma reesei

Transformants of the Trichoderma reesei strains QM9414 and Rut-C30 were constructed in which the genes for the two major hydrophobin proteins, hydrophobins I (HFBI) and II (HFBII), were deleted or amplified by molecular biological techniques. Growth parameters and foam production of the transformant strains were compared with the corresponding properties of the parent strains by cultivation in laboratory bioreactors under conditions of catabolite repression (glucose medium) or induction of cellulolytic enzymes and other secondary metabolites (cellulose and lactose media). All the transformed strains exhibited vegetative growth properties similar to those of their parent. The ∆hfb2 (but not the ∆hfb1) transformant showed reduced tendency to foam, whereas both strains overproducing hydrophobins foamed extensively, particularly in the case of HFBII. Enzyme production on cellulose medium was unaltered in the ∆hfb2 transformant VTT D-99676, but both the ∆hfb2 and HFBII-overproducing transformants exhibited somewhat decreased enzyme