Scientists Hacked Yeast to Make THC. Now Comes the Hard Part

German scientists have successfully reengineered yeast to produce THC. Now comes the hard part.

Earlier this month, researchers at the Technical University of Dortmund published a paper detailing their successes in genetically engineering the fungus to produce the main active compound in weed, which has been a dream of stoners for more than a decade. The question is now whether anyone will be capable of scaling this research up to the point where yeast-produced THC is worth the effort.

As is the case with many nascent synthetic biology projects, the researchers were able to make just a tiny quantity of THC. This has generally remained a problem when it comes to making biofuels, and it remains a problem with making THC, morphine, or most any other compounds we want bacteria or fungus to make for us.

It's generally a question of scale, at this point. Much of the work is being done in universities or at small startups. There is one California-based company called Amyris, however, which has set up major synthetic biology factories in Brazil. The company has had success synthetically and sustainably producing squalane, a petroleum often used in cosmetics that is traditionally sourced from the liver of sharks.

"We've actually started to make enough of it at a kiloton scale to change how we source materials," Jack Newman, coufounder of Amyris, said at a recent DARPA conference in New York City. "We're able to make better materials using synthetic biology now that we've gained control of the programming of cells."

That's the ultimate goal when it comes to THC, and scaling these bioengineered processes up is the main objective of Hyasynth Bio, a Montreal-based startup that hopes to eventually sell THC and other cannabinoids created in yeast.

"Making a lot of it is the bigger challenge, and that's what we're specializing in," Kevin Chen, CEO of Hyasynth, told me. "News about morphine made in yeast has been popular lately, but they would need to produce 400,000 times more before it's able to be used industrially—large scale stuff is really at the bleeding edge of science with this field."

Chen said that his company hopes to begin synthesizing THC and other cannabinoids toward the end of next year as an "approximate timeline," but, as with many of these projects, it's tough to say when or if this work will ever become commercially viable. He said the German team's work "gives us some new clues about the pathways involved in making THC."

"We're still doing a lot of basic research and experiments, and the goal is still the same—to produce cannabinoids in yeast," he said.

Although marijuana plants themselves are quite good at making THC and other cannabinoids, Chen says that there's certainly room for a synthetically produced competitor.

Once his team or someone else cracks the code of mass production, they will theoretically be able to tinker with concentrations of the chemicals they want, such as cannabidiol. This could lead to more targeted therapies and different highs (or no high at all, even).

"People tend to think about the nature of the plant more than the chemistry of it," he said. "If you're just using the plant, you're kind of limiting yourself in a sense, because there's a lot of research that remains to be done about how the different cannabinoids react with the body."

It all sounds very promising, but it's still not time to replace all your weed memorabilia with artistic renderings of yeast cells.