Baker's yeast can be made to produce morphine, codeine and other pain medicines at high levels.

Opioid production is subject to the vagaries of the opium poppy supply chain, so Christina Smolke and her colleagues at Stanford University in California wanted to find alternative ways of making the drugs. They engineered the yeast (Saccharomyces cerevisiae) to express genes from the poppy (Papaver somniferum) and the bacterium Pseudomonas putida M10, then cultured it with thebaine, an opioid intermediary molecule extracted from the poppy. The yeast synthesized high enough levels of several natural and semisynthetic opioids to make the method potentially useful to the pharmaceutical industry, the authors say.

The next step, they add, is to engineer yeast to make these painkillers from simple sugars, eliminating the need for poppies altogether.

Nature Chem. Biol. http://dx.doi.org/10.1038/nchembio.1613 (2014)