Genetically engineered yeast brews up heady mix of natural and unnatural cannabinoids

A strain of brewer’s yeast that feeds on sugar and produces cannabis-derived medicinal compounds has been engineered by researchers in the US, who used genes from the cannabis plant to alter the microbe’s metabolism. The yeast converts galactose into compounds such as cannabidiol (CBD) – which is used to treat some forms of epilepsy – and the psychoactive chemical tetrahydrocannabinol (THC), as well as less well-known derivatives that may have interesting medicinal properties.