Optimized psilocybin production in tryptophan catabolism‐repressed fungi

By deleting genes involved in L-tryptophan catabolism, psilocybin production was increased fivefold in baker's yeast and tenfold in the filamentous fungus Aspergillus nidulans. Process optimization in A. nidulans batch cultures yielded a final psilocybin titre of 267 mg/L with a space-time-yield of 3.7 mg/L/h. The engineered strain demonstrates suitability as a production chassis for psilocybin and other tryptamine-derived pharmaceuticals.

Study at a glance

Abstract

Abstract The high therapeutic potential of psilocybin, a prodrug of the psychotropic psilocin, holds great promise for the treatment of mental disorders such as therapy‐refractory depression, alcohol use disorder and anorexia nervosa. Psilocybin has been designated a ‘Breakthrough Therapy’ by the US Food and Drug Administration, and therefore a sustainable production process must be established to meet future market demands. Here, we present the development of an in vivo psilocybin production chassis based on repression of l ‐tryptophan catabolism. We demonstrate the proof of principle in Saccharomyces cerevisiae expressing the psilocybin biosynthetic genes. Deletion of the two aminotransferase genes ARO8 / 9 and the indoleamine 2,3‐dioxygenase gene BNA2 yielded a fivefold increase of psilocybin titre. We transferred this knowledge to the filamentous fungus Aspergillus nidulans and identified functional ARO8 / 9 orthologs involved in fungal l ‐tryptophan catabolism by genome mining and cross‐complementation. The double deletion mutant of A. nidulans resulted in a 10‐fold increased psilocybin production. Process optimization based on respiratory activity measurements led to a final psilocybin titre of 267 mg/L in batch cultures with a space–time‐yield of 3.7 mg/L/h. These results demonstrate the suitability of our engineered A. nidulans to serve as a production strain for psilocybin and other tryptamine‐derived pharmaceuticals.