Why scientists use yeast to make marijuana compounds

The marijuana market may be exploding, but there is very little land available for cannabis cultivation. In search of a more efficient and greener way to meet the demand, researchers have figured out how to turn yeast, an essential organism for bread and beer manufacturing, into factories producing cannabinoids.

This week, the newspaper Nature published the first publicly available study to fully demonstrate how this can work. "The simplest way to explain it is that we removed cannabis from the genes responsible for making cannabinoids [the active compounds in cannabis]and then we put them in yeast, "says Jay Keasling, a chemist at the University of California at Berkeley and co-author of the study.

Generally, giving yeast sugar allows it to produce ethanol, which is why it is an essential ingredient in the production of beer and wine. But because we know a lot about yeast and it's easy to grow on a large scale, scientists are increasingly "pirating" yeast to produce various medications. In this case, the yeast absorbed sugar and produced a variety of important cannabis compounds. "It took a lot of engineering to get there," adds Keasling. "In a sense, we created a Korean by bringing together genes from many different organisms that would work together to create these cannabinoids."

This yield of cannabinoids included the psychoactive ingredient tetrahydrocannabinol (THC), as well as cannabidiol (CBD), a non-psychoactive cannabinoid all over the place. (The Keasling team was able to produce about 8 milligrams of THC per liter of yeast solution and a little less for CBD.) But while these two compounds are getting all the attention, cannabis actually contains over 100 cannabinoids and the Keasling team has also able to produce some of the rarest, and even some that do not occur naturally, opening the possibility of new drugs.

Scientifically speaking, these innovative methods of creating cannabinoids are important if we want to conduct a comprehensive research on their effects, says Samuel Banister, a chemist at the University of Sydney, who has not participated in the study. study. "There is a lot of cannabinoids in cannabis, but most of them are produced in tiny amounts," he says. Extracting these chemicals from plants requires intensive work and a lot of money. Even extracting THC and CBD, which plants produce in relatively large quantities, can be difficult, and marijuana farms are frequently linked to negative environmental effects. It's slow too. As Kevin Chen, CEO of Montreal-based Hyasynth Bio, another company trying to grow cannabinoids from yeast, points out, a cannabis plant takes three months to grow and about a week to mature.

It is therefore not surprising that there is a lot of interest in this area. Keasling founded his own company, Demetrix, a few years ago, while Hyasynth has been around since 2014. There is Librede and Amyris in California, and last fall the Boston-based synthetic biology company Ginkgo Bioworks, announced its intention to join the race produce cannabinoids in cultivation.

All are trying to do the same thing, but there are many different ways to make yeast to produce cannabinoids. The big challenge for every business is efficiency. "The quantities produced are not enough for commercial purposes," adds the Banister of the Keasling paper. "It proves the principle." We now know that it can be done – but how much and at what cost?

Jason Poulos, CEO of Librede, said Nature Keasling yields should be multiplied by 100 to be economically competitive compared to conventional extraction methods. And Jen Wipf, who helps run the cannabinoids project for Ginkgo, agrees that the main hurdle is to prove that the system will remove a significant portion of the "cost and changes" of farming methods.

For his part, Chen de Hyasynth said his goal was to make the CBD ten times cheaper than what is currently available on the market and that he hopes to "build hundreds of kilograms in a giant facility somewhere" from here two to three years. . Keasling gives a similar delay to Demetrix, which is in line with analysts' forecasts that it will take another 18 months before these cannabinoids are profitable enough to be sold to drug companies or other interested buyers. Thus, giant cannabinoid breweries will not replace marijuana farms anytime soon, but tiny microbes may well let them get into the ring.