Production of Δ9-tetrahydrocannabinolic acid from cannabigerolic acid by whole cells of Pichia (Komagataella) pastoris expressing Δ9-tetrahydrocannabinolic acid synthase from Cannabis satival

Objective The Δ9-tetrahydrocannabinolic acid synthase (THCAS) from Cannabis sativa was expressed intracellularly in different organisms to investigate the potential of a biotechnological production of Δ9-tetrahydrocannabinolic acid (THCA) using whole cells. Results Functional expression of THCAS was obtained in Saccharomyces cerevisiae and Pichia ( Komagataella ) pastoris using a signal peptide from the vacuolar protease, proteinase A. No functional expression was achieved in Escherichia coli . The highest volumetric activities obtained were 98 pkat ml −1 (intracellular) and 44 pkat ml −1 (extracellular) after 192 h of cultivation at 15 °C using P. pastoris cells. Low solubility of CBGA prevents the THCAS application in aqueous cell-free systems, thus whole cells were used for a bioconversion of cannabigerolic acid (CBGA) to THCA. Finally, 1 mM (0.36 g THCA l −1 ) THCA could be produced by 10.5 g CDW l −1 before enzyme activity was lost. Conclusion Whole cells of P. pastoris offer the capability of synthesizing pharmaceutical THCA production