Researchers at the University of California, Berkeley, have successfully modified yeast to produce cannabinoids.
Their genetically-engineered yeast cells converted sugars into THC and CBD, as well as novel cannabinoids never found in cannabis plants themselves, the journal Nature reported last month. These cannabinoids could hold promise for medical research. Today, medical cannabinoid research is often hindered by the relatively low presence of cannabinoids in cannabis plants, the researchers explained. And extracting these cannabinoids from plants can be costly.
By modifying yeast microbes to convert sugar into cannabinoids, scientists may be able to supply cannabinoids more consistently and cost-effectively — without needing any plants. This could reduce the environmental impact of cannabis cultivation. Indoor cannabis facilities often require tremendous amounts of energy, while outdoor grow operations can pollute water runoff with synthetic nutrients.
Additionally, the novel cannabinoids created in the Berkeley lab — molecules not found in cannabis plants themselves — could unlock new potential for medical research. The UC synthetic biology team published their article in the peer-reviewed journal Nature on February 27.
How it Works
In the lab, they modified cells of brewer’s yeast, which has been used for millennia to create alcoholic beverages. By inserting enzymes and genes from the cannabis plant itself, they altered the genome of the yeast cells. These new, genetically-modified yeast cells successfully produced cannabinoids, including THC (the psychoactive compound in cannabis) and CBD, the non-psychoactive cannabinoid renowned for its potential anti-inflammatory effects.
The research team also modified the yeast to produce other cannabinoids, which occur naturally in cannabis plants but are less understood. These include CBDV (cannabidivarin) and THCV (tetrahydrocannabivarin).
Why This is Important
New scientific studies on cannabinoids may become easier, now that cannabinoids can be produced in yeast. This may open the door to new pharmaceutical applications. “It is a safer, more environmentally friendly way to produce cannabinoids,” said Jay Keasling, a UC Berkeley professor and lead author of the study. Keasling subsequently founded a company, Demetrix Inc., which licensed this cannabinoid-producing technology from UC Berkeley.
“The cost is competitive or better than that for the plant-derived cannabinoids,” Keasling told reporters. “And manufacturers don’t have to worry about contamination — for example, THC in CBD — that would make you high.”
This can be important for medical patients, particularly children with seizure disorders or other medical conditions that can be treated with CBD. It could also be helpful for seniors and others who prefer to avoid psychoactive effects, but who want therapeutic effects from CBD.
Downsides to this Development
Some experts predict it could take up to two years for these synthetic cannabinoids to be cost-effective enough for commercial applications, according to Nature. These cannabinoids would not be the first drug chemicals produced from yeast. Today, scientists are using yeast cells to produce other drugs, including human growth hormone, insulin, blood clotting factors, and anti-malarial drugs.
But other scientists disagree that yeast is the best production method for these molecules. Other companies are genetically-modifying cannabis plants themselves, instead of yeast, to produce cannabinoids that are more adaptable to modern drug ingestion methods. “Everything you can do in yeast, you can do in the plant itself,” one of these biotech companies’ spokespeople told Nature.
Other observers may disagree with the new yeast technology for more fundamental reasons. The Berkeley scientists’ discovery could theoretically make cannabis plants obsolete, by producing cannabinoids more cost-effectively in labs. This could make it difficult for traditional growers to compete.
This debate could trace the same fracture lines as most genetic-engineering debates: Should someone really own a patent on this? Who owns a compound that was originally found in a plant?
As cannabis research expands, researchers will need a reliable supply of cannabinoids. Obtaining cannabinoids from cannabis plants themselves can be tricky, especially because cannabis is still federally illegal. (The UC Berkeley study involved oversight by the US Drug Enforcement Agency.)
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