Recombinant process for producing steryl esterase

Researchers at the Technical Research Center (VTT) of Finland have isolated the ste1 gene encoding a steryl esterase from Melanocarpus albomyces fungus and used it to transform other organisms to produce the enzyme. First, the group used the gene, minus an intron that the wild type gene contains, to transform Pichia pastoris yeast under an inducible aldehyde oxidase (AOX1) promoter. Because production level was low, the group then expressed the gene in the wood rot fungus (Trichoderma reesei) under the inducible cellobiohydrolase (cbh1) promoter. Although production was satisfactory, about 60% of the enzyme was bound to the mycelium of the fungus or to solid particles in the medium or was in the form of aggregates. However, treatment with Trion X-100 recovered active enzyme.