Transformation of Trichoderma reesei with a constitutively expressed heterologous fungal chitinase gene

A uridine auxotrophic mutant (pyrG) of Trichoderma reesei was successfully transformed to constitutively produce chitinase using a construct containin g an Aphanocladium album cDNA chitinase gene fused in frame to the glyceral dehyde-3-phosphate dehydrogenase promoter of Aspergillus nidulans. The tran sformation frequency was high (897-1,421 transformants mu g(-1) DNA) and up to 70% of the stable transformants exhibited extracellular chitinase activ ity Molecular characterization of the transformed strains demonstrated that the chitinase gene had integrated into the T. reesei genome. The transform ed T. reesei expressed an extracellular enzyme at a specific activity 6.5-f old higher than the intracellular level at peak production, and the enzyme had a calculated molecular mass of 52 kDa. (C) 1999 Elsevier Science Inc. A ll lights reserved.