Jay Keasling, a professor in the departments of bioengineering and of chemical and biomolecular engineering at UC Berkeley who also holds a senior faculty scientist position at Berkeley Lab, led a team that genetically modified brewer’s yeast (Saccharomyces cerevisiae) to produce cannabinoids via biosynthesis. The authors introduced cannabis genes into the yeast’s metabolic pathways to produce cannabinoid precursor molecules, such as olivetolic acid, from the simple sugar galactose. From olivetolic acid, the yeast was able to produce the key cannabinoid cannabigerolic acid (CBGA), which could in turn be used to produce Δ9-tetrahydrocannabinolic acid (THCA) and cannabidiolic acid (CBDA).