A filamentous fungus best known for producing industrial enzymes may soon find a role in pharmaceutical manufacturing. Researchers at the VTT Technical Research Centre of Finland are investigating Trichoderma reesei as an alternative protein expression system for biologics.
The fungus has been long used in the food and textile industries to produce cellulases. It can secrete more than 100 grams of protein per liter—an output that could translate into significantly lower production costs for therapeutic proteins.
“The productivity is very high, and the process is already well established,” said Antti Aalto, Ph.D., research team leader at VTT, speaking at the CHI PepTalk conference in San Diego (January 19-22, 2026). Unlike mammalian systems such as CHO cells, T. reesei secretes proteins directly into the culture broth, simplifying downstream purification and reducing infrastructure costs.
Preliminary economic analyses at VTT suggest production costs could fall below $20 per gram at commercial scale—potentially undercutting conventional mammalian platforms. Decades of industrial fermentation experience with the fungus may also ease scale-up challenges. Sometimes strain lose their expression in large-scale production. “But we think that, by selecting expression strains carefully and monitoring the bioprocess constantly, we should be able to avoid it,” says Aalto.
Regulatory hurdles remain. Moving from industrial grade to pharma grade demands a rigorous look at genetic stability, downstream purification, and regulatory perception.
T. reesei is naturally adapted to grow on lignocellulosic biomass—plant-based materials rich in cellulose and hemicellulose. Transitioning an industrial microbe into pharmaceutical manufacturing requires rigorous quality controls. Alternative feedstocks such as agricultural waste—viable in food applications—are unlikely to meet current pharmaceutical standards.
Still, as biopharma companies seek to lower carbon footprints and cost of goods, T. reesei could offer a high-yield, lower-cost platform for producing monoclonal antibodies and other biologics—bringing an industrial workhorse into the drugmaking spotlight.