According to the GST-fusion proteins, cell-free extracts of the recombinant H. jecorina strain PEC/PSC1 were applied in the enzymatic assay. The formation of ManNAc ( Figure 3a2 ) and NeuNAc could be detected (Figure 3b2 ). This demonstrates that both enzymes are also fully functionally expressed in the recombinant H. jecorina strain PEC/PSC1. Neither ManNAc nor NeuNAc was detected using cell-free extracts from the parental strain in the assay (Figure 3a3 and 3b3) , indicating that these pathways are normally not active in Hypocrea.