Biosynthesis of Tetrahydrocannabinolic Acid - from Biotransformation Studies to Biotechnological Production

Tetrahydrocannabinolic acid (THCA) is a phenolic compound from the spectrum of cannabinoids in Cannabis sativa. THCA or its decarboxylated form THC are used for recreational Cannabis consumption, but both compounds are also of high interest in rational medicine. Due to legalization and acceptance of Cannabis sativa and the pure compound THC, there is a high demand by patients and a strong wish for stricter regulation and standardization of clinically used drugs. 

To meet this demand a biotechnological and recombinant THC is of interest by physicians and regulation authorities world wide. In this work all relevant biosynthetic enzymes (CBGAS, THCAS) starting from olivetolic acid as feeding substance were cloned, functionally expressed and assembled in S. cerevisieae or P. pastoris. Biosynthetic primary pathways were in silico analyzed for the identification of metabolic bottle necks and metabolic engineering. Both enzymes were structurally mutated and engineered for improved efficacy and again assembled in metabolic altered production organisms. A full bioreactor design was worked out and implemented in a batch wise mode. By analysis of feeding conditions, temperature, pH, oxygen saturation an upstream process was developed to allow higher yield production by engineered microorganisms. In this talk concepts and strategies of a comprehensive bioprocess approach from biology to engineering is described in details. 

References: 

1. Zirpel, B., Stehle, F., Kayser, O. (2015) Production of Δ9-tetrahydrocannabinolic acid from cannabigerolic acid by whole cells of Pichia (Komagataella) pastoris expressing Δ9-tetrahydrocannabinolic acid synthase from Cannabis sativa L. Biotechnol. Lett., 37:1869-1875 

2. Gruchattka, E., Hädicke, O., Klamt, S., Schütz, V., Kayser, O. (2013) In silico profiling of Escherichia coli and Saccharomyces cerevisiae as terpenoid factories. Microbial Cell Factories, 12: 84 

3. Degenhardt, F., Stehle, F., Kayser, O. (2015) The biosynthesis of cannabinoids (Preedy, R. Editor) in The Handbook of Cannabis and Related Pathologies: Biology, Diagnosis, Treatment, and Pharmacology. Academic Press (Elsevier) in press