The method that has been developed transforms a sugar found in common brewer’s yeast (the fungus Saccharomyces cerevisiae), which is called galactose, into tetrahydrocannabinol (THC) THC is the main psychoactive compound in cannabis (Cannabis sativa).
Tests at University of California Berkeley have shown that the altered yeast can additionally produce cannabidiol, which is different major cannabinoid which medical consensus suggests has therapeutic benefits, such as for anti-anxiety or pain-reducing effects. CBD also shows promise for treating problems such as epilepsy, post-traumatic stress disorder (PTSD) and some forms of addiction.
Based on the trials, it is hoped that the technique can be used to manufacture THC, CBD and rare cannabinoids at a low-cost and in a way that does not have a significant environmental impact. This is in contrast to the traditional means, where cannabis cultivation is a prime example of an energy-intensive and environmentally-destructive industry.
Speaking with The Verge, lead researcher Jay Keasling, discusses the process: “The simplest way to explain it is that we took the genes out of cannabis that are responsible for making cannabinoids [the active compounds in cannabis], and then we put them into yeast.”
In other words, the researchers have turned the yeast into chemical factories, using a genetic engineering process that involved co-opting their metabolism so that, instead of turning sugar into alcohol, they convert sugar into other chemicals that are then modified by added enzymes to produce a new product, such as THC. The require product is secreted by the yeast into the general environment.
The research is described in the journal Nature. The research paper is titled “Complete biosynthesis of cannabinoids and their unnatural analogues in yeast.”
