Synthetic Biology Approaches for the Production of Cannabinoid Precursors in E. coli

  • Nicole Prandi

Student thesis: Phd

Abstract

During the last decade, cannabinoid-based pharmaceuticals have become increasingly available, mainly as a result of changes in legislation in many countries. For example, tetrahydrocannabinol (THC) and cannabidiol (CBD) are currently used to treat a number of chronic pathologies due to their analgesic, antiemetic and antispasmodic properties. These compounds are mainly extracted from the Cannabis sativa plant, which poses challenges in terms of providing a stable supply of pure high-quality compounds. Fermentative production in E. coli could represent a more sustainable and reliable alternative but comes with its own set of challenges. In particular, obtaining plant secondary metabolites in commercially viable yields in bacteria represents a major obstacle. Obtaining a platform strain for the production of the main cannabinoids will not only allow producing THC and CBD, but also facilitates expanding the synthetic pathway with tailoring enzymes to produce new pharmaceuticals. This thesis describes the creation of a synthetic pathway for the production of cannabinoid precursors in E. coli. The production of the first intermediate, olivetolic acid, was achieved by expressing the first two enzymes of the cannabinoid biosynthetic pathway, a tetraketide synthase (TKS) and olivetolic acid cyclase (OAC) from Cannabis sativa in E. coli. A prenyltransferase (Ater APT) to catalyse the following step of the pathway, the prenylation of olivetolic acid in CBGA, was identified. Enzymatic activity could be observed in cell extracts but no CBGA was produced when TKS, OAC and Ater APT were expressed in living E. coli cultures. Further experiments identified the availability of the precursors as a bottleneck for this CBGA synthesis. Olivetolic acid production was then increased 35-fold compared to the starting conditions by optimising the production protocol.
Date of Award31 Dec 2021
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorNigel Scrutton (Supervisor), Rainer Breitling (Supervisor) & Eriko Takano (Supervisor)

Keywords

  • escherichia coli
  • natural products
  • biotechnology
  • cannabinoids
  • synthetic biology
  • MIB

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