Development of a cannabinoid yeast factory: improving geranyl pyrophosphate production through metabolic engineering - Abstract
As the population ages there is a growing concern about the impact of neurological diseases on the
healthcare system. Neurological diseases (e.g. Alzheimer’s Disease) are the fastest growing cause of death in
the United States and the development of new drugs has been very slow. Natural products are powerful
sources for the discovery of new medications—recently, cannabinoids have been identified as a general class
of natural compounds with a wide range of proven therapeutic effects, including treatment of
neurodegenerative diseases. In fact, studies of cannabinoids led to the discovery of the endocannabinoid
system (ECS), regarded as one of the most important modulators of nervous system processes and a
targetable system for neurological diseases. Since then, cannabinoids have been found to have efficacy in
treating pain, neuroinflammation, and bone loss, among many other conditions. Cannabinoids can be found in
many plants; the most well-known is Cannabis sativa, from which a variety of cannabinoids have been isolated
and shown to be medically relevant. However, it is difficult to source cannabinoids in high purity, inhibiting
research and making large scale commercial production problematic. A biosynthetic approach to producing
these natural products not only addresses these problems but allows a detailed understanding of the natural
product chemistry, furthering medical research and pharmaceutical development into the ECS.
To enable the development of natural cannabinoids as therapeutic agents, Librede has developed a
biosynthetic cannabinoid production/drug discovery platform by genetically engineering yeast with selected
portions of the Cannabis sativa metabolic pathways. The production of cannabinoids in yeast is an ideal
platform because fermentation and genetic engineering are well-established, low cost, and scalable. Librede’s
biosynthetic cannabinoid production platform is modular; by adding or removing expression of different
enzymes, different cannabinoids can be produced as desired, even cannabinoids produced in low abundance
naturally. Using this approach, in preliminary work we have produced Cannabidiolic acid (CBDA) in yeast, the
world’s first biosynthetically-produced cannabinoids outside of plants. Although this proof-of-concept work
showed that cannabinoids can be produced by yeast, the yield of CBDA production was limited by the
availability of a specific chemical intermediate, geranyl pyrophosphate (GPP). In order to make our platform
feasible for research and cannabinoid production, we will improve GPP levels by reducing its diversion to
alternative products by knocking out or down-regulate diverting metabolic pathways, as well as increasing GPP
production.
