Production of Δ9-tetrahydrocannabinolic acid from cannabigerolic acid by whole cells of Pichia (Komagataella) pastoris expressing Δ9-tetrahydrocannabinolic acid synthase from Cannabis sativa l.
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- Zirpel, B., Stehle, F. & Kayser, O. Biotechnol Lett (2015) 37: 1869. doi:10.1007/s10529-015-1853-x
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.
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 gCDW l−1 before enzyme activity was lost.
Whole cells of P. pastoris offer the capability of synthesizing pharmaceutical THCA production