A modular biosynthetic production platform for psilocybin was developed in the model microbe Escherichia coli. Multiple genetic optimization techniques improved psilocybin titer by 32-fold. Further fermentation optimization in a fed-batch study achieved a production titer of 1.16 g/L of psilocybin, the highest titer reported from a recombinant organism to date. This work demonstrates progress toward the industrial bioproduction of psilocybin for clinical use.
Psilocybin, the prodrug to the psychoactive compound in 'magic' mushrooms, is being studied as a treatment for depression and anxiety. Previous biosynthesis in E. coli using genes from Psilocybe cubensis achieved maximum titers of 1.16 g/L. This work tested genes from four psilocybin-producing mushroom species and found that psiD and psiK from P. cubensis performed best, while psiM from Psilocybe cyanescens increased selectivity for the intermediate baeocystin. The strain Gymdi30, with psiM from Gymnopilus dilepis, produced 1.46 ± 0.13 g/L psilocybin, the highest reported titer to date. Comparative proteomic analysis during high and low productivity identified metabolic bottlenecks. This represents a significant improvement toward a biosynthetic manufacturing route for psilocybin.