Yeast has been engineered to produce the main psychoactive compound in marijuana - tetrahydrocannabinol (THC). Responsible for the majority of marijuana's psychological effects - including the high - THC can also be use to treat symptoms of HIV infection and chemotherapy and researchers are hoping their yeast will be able to pump it out more efficiently than producing synthetic versions.

"This is something that could literally change the lives of millions of people," Kevin Chen from Hyasynth Bio, a US-based company that's been engineering yeasts to produce both THC and cannabidiol - another active compound that has shown promise as a medical treatment - told The New York Times.

Back in August, researchers from the University of California, Berkeley in the US announced that they'd figured out how to make 'home-made' heroin using a modified form of sugar-fed yeast and an enzyme extracted from poppies. They discovered that a certain type of enzyme can turn glucose sugars into morphine, and were able to successfully express it in a simple form of genetically engineered yeast. ...[Continue reading on ScienceAlert]