Yeast engineered to cheaply produce marijuana cannabinoids

In an exciting new breakthrough from scientists at UC Berkeley, common brewer's yeast has been engineered to produce several major cannabinoids found in marijuana. This innovation promises faster, cheaper and easier production of these compounds for use in research and medical treatments.

Yeast is a pretty amazing microorganism. One species in particular, Saccharomyces cerevisiae, has played a fundamental role in human life for thousands of years. From leavening bread to producing our alcohol, S. cerevisiae is a pretty helpful little microbe. Over the last few decades, the advent of genetic engineering has allowed scientists to turn yeast into tiny chemical biofactories to help mass produce a variety of compounds humans need, from insulin to growth hormones.

As scientists learn more and more about the medical properties of certain cannabinoid compounds found in marijuana, there is a growing need to find ways to better manufacture those compounds. Marijuana is not necessarily a difficult plant to grow, however it is energy intensive and its valuable cannabinoids naturally occur in such tiny quantities that mass production is a challenge. Purity of extraction is another issue for scientists, especially when trying to develop medical treatments such as CBD for epilepsy.

Yeast traditionally turns sugar into ethanol but the microorganism can be genetically altered to produce different enzymes that result in different chemical byproducts. The new research demonstrated how, through the addition of over a dozen different genes, the yeast could be engineered to a produce variety of cannabinoids including cannabigerolic acid, tetrahydrocannabinolic acid, and cannabidiolic acid. These compounds, with the addition of heat, easily become the more commonly known cannabinoids CBG, THC, and CBD.

"For the consumer, the benefits are high-quality, low-cost CBD and THC: you get exactly what you want from yeast," explains Jay Keasling, one of the scientists working on the project. "It is a safer, more environmentally friendly way to produce cannabinoids."

Alongside the manufacturing benefits, the new method may allow scientists better opportunities to research some of the rarer and more novel cannabinoids that are nearly impossible to extract from the plant. There are over 100 different, novel chemicals in marijuana plants so this new method paves the way for production in large quantities of pure cannabinoids with an ease and volume that scientists have never experienced.

"The economics look really good," says Keasling. "The cost is competitive or better than that for the plant-derived cannabinoids. And manufacturers don't have to worry about contamination – for example, THC in CBD – that would make you high."

The new research was published in the journal Nature.

Source: UC Berkeley