We as the species would be miserable without yeast. The baker's yeast has given us leavened bread for thousands of years. And I do not even want to start imagining a world without beer and wine, which depends on yeast to convert sugar into alcohol.
Researchers turned to yeast to do something more improbable: make CBD and THC cannabis compounds. By loading the yeast with genes from the cannabis plant, they transformed the miracle microbes of the cannabinoid plants. It's a clever plan in a larger movement that consists of methodically separating and recreating the many compounds of marijuana, to better understand the true potential of the plant.
The process is like this. Two different yeasts produce THC or CBD, depending on the type of enzyme they carry. Importantly, both carry the cannabis genes that produce CBGA. "CBGA is that kind of central cannabinoid that is the mother of all other cannabinoids," says Jay Keasling, a chemical engineer at the University of Berkeley, co-author of a new paper Nature detailing the technique.
To make THC, this yeast produces CBGA, which then turns into THCA thanks to the particular enzyme of yeast. For the yeast CBD, its own enzyme transforms the cannabinoid mother of CBGA into CBDA. (Alphabet soup, I know, but stay with me.) Now you have THCA and CBDA, which turn into THC and CBD with the application of heat.
The purpose is no different from what happens with the cannabis plant itself. If you ate raw cannabis, it is unlikely that you will get excited because it is mainly THCA. It is only after you apply heat that the THCA turns into THC. (Although small amounts of THCA become THC over time, as the cannabis flower heals.) The edibles work because the manufacturers first turn THCA into THC with a process called decarboxylation.
The reason researchers and cannabis companies are interested in other methods of producing cannabinoids is that working with the original plant is complicated and complicated. First of all, growing these plants takes a lot of time, water and energy (if you grow indoors). Extracting some cannabinoids from the flower is also a problem. If you are only after CBD, for example, it is possible that your extract is contaminated with THC. This is of particular concern if you wish to isolate CBD for use as a drug: it has been shown, for example, that it is remarkably effective in the treatment of epilepsy.
Having a yeast cell producing pure and non-psychoactive CBD promises to massively simplify production. "Being able to produce it in a way that is not contaminated with THC is a very precious thing," says Keasling. Especially as the FDA might want to tell you a word if you accidentally dosed patients to a psychoactive substance.
Yeast producing cannabinoids can also facilitate the study of cannabis in the first place. We are talking here about an extremely complicated plant, with over 100 different cannabinoids known to date. Some of these compounds are more prevalent than others – modern cannabis varieties are filled with THC, as growers have multiplied intoxicating varieties over the years. But a cannabinoid such as tetrahydrocannabivarin, or THCV, appears in much smaller amounts. "We will now be able to produce these things in a pure and relatively simple way. We may be able to start testing their functions, "says Keasling.
Artificial yeast has already been used before to solve the problem of scarcity. In the 1960s, researchers discovered that taxanes of the Pacific yew bark could fight cancer. All is well, with the exception of the Pacific yew, which, according to advocates of environmental protection, would disappear in the hands of an avid medical facility. But as for this yeast producing cannabinoids, researchers have developed microbes to help make the drug free of deforestation.
For cannabinoids, the main advantage is the scale. The idea is that you could create much larger amounts of CBD in tanks than planting greenhouse-grown cannabis plants much more easily. (This does not mean that some people will still not appreciate their old-fashioned cannabis.) But to make it as effective as possible, you need to work with the highest levels of cannabinoids possible. That is, you want to optimize your yeast to produce a lot of product.
"Can you continue to make it highly concentrated, or does it become toxic to the organisms that you actually use to produce it, and so you have a limit?" Asks Jeff Raber, CEO of Werc Shop, a laboratory that stands out the components of cannabis.
Whatever the obstacles to production, this type of bioengineering has the advantage of giving researchers a powerful platform to explore not only the usefulness of each cannabinoid, whether anxiety or inflammation or epilepsy, but also to see how the many cannabinoids present in the plant can be treated. interact with each other. This is what the so-called surround effect: CBD, for example, seems to mitigate the psychoactive effects of THC.
By selectively selecting these cannabinoids in the laboratory, it will be easier for researchers to play with them separately and separately, without having to go through hundreds of other compounds that you will find in pure flowers. "In the end, a molecule is a molecule," says Raber. Indeed, the cannabinoids made from yeast are the same as those made by the plant. "This gives flexibility in the formulation, perhaps a broader utility and may eventually evolve more rapidly than plants. Regulators may feel much better about these types of approaches than those concerning fields and fields and fields of plant material. "
And that does not stop with cannabinoids. What Raber and others are pursuing is essentially reconstructing the chemical profile of cannabis. Terpenes, for example, are what give the weed its characteristic odor, but you'll find it throughout the plant kingdom: Limonene is not very abundant in cannabis, but it's an abundant product of the industry. citrus. The idea is that instead of having the trouble of extracting small amounts of limonene from a cannabis plant, you can get lemons instead.
The ultimate goal is to be able to adapt cannabis products, such as dyes, to consumer preferences. This would allow a personalized report of CBD to THC, and possibly other cannabinoids and terpenes, which could themselves play a role in the effect of the entourage. Terpenic linalool, for example, may have anti-anxiety effects.
In the short term, let's celebrate yeast, this microbe miracle and creator of all that is good: bread, alcoholic beverages and cannabinoids from bio-engineering.
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