UC Berkeley synthetic biologists have engineered brewer’s yeast to produce marijuana’s main ingredients—mind-altering THC and non-psychoactive CBD—as well as novel cannabinoids not found in the plant itself.
Feeding only on sugar, the yeast are an easy and cheap way to produce pure cannabinoids that today are costly to extract from the buds of the marijuana plant, Cannabis sativa.
“For the consumer, the benefits are high-quality, low-cost CBD and THC: you get exactly what you want from yeast,” said Jay Keasling, a UC Berkeley professor of chemical and biomolecular engineering and of bioengineering and a faculty scientist at Lawrence Berkeley National Laboratory. “It is a safer, more environmentally friendly way to produce cannabinoids.”
Cannabis and its extracts, including the high-inducing THC, or tetrahydrocannabinol, are now legal in 10 states and the District of Columbia, and recreational marijuana—smoked, vaped or consumed as edibles—is a multibillion-dollar business nationwide. Medications containing THC have been approved by the Food and Drug Administration to reduce nausea after chemotherapy and to improve appetite in AIDS patients.
CBD, or cannabidiol, is used increasingly in cosmetics—so-called cosmeceuticals—and has been approved as a treatment for childhood epileptic seizures. It is being investigated as a therapy for numerous conditions, including anxiety, Parkinson’s disease and chronic pain.
But medical research on the more than 100 other chemicals in marijuana has been difficult, because the chemicals occur in tiny quantities, making them hard to extract from the plant. Inexpensive, purer sources—like yeast—could make such studies easier.
Plus, he added, there is “the possibility of new therapies based on novel cannabinoids: the rare ones that are nearly impossible to get from the plant, or the unnatural ones, which are impossible to get from the plant.”
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