After 56 genetic operations, yeast cells can produce the cancer drug vinblastine. This way you can prevent shortages of this natural alkaloid, write Jay Keasling (UC Berkeley) and a group of Danish colleagues in Nature.

As far as they can tell, this is the most complex biosynthesis pathway ever transferred to a micro-organism. In total, it comprises 31 steps. According to Keasling, it proves that you can have just about any natural substance made by yeast cells, which have the great advantage of being able to work effortlessly on an industrial scale.

Pink periwinkle

Vinblastine inhibits cell division. The substance has been used for half a century against various cancers, including Hodgkin’s disease. It is unpleasant stuff, but there is still nothing better. It is extracted from leaves of the pink periwinkle, Catharanthus roseus, (see large photo) an ornamental plant native to Madagascar. But for one gram of chemotherapy you need at least 500 kilograms of leaves, and recently there has already been a prolonged shortage. In the lab, you can now chemically synthesise vinblastine, but the many stereocentres make synthesis a laborious procedure that is difficult to scale up.