Optogenetic control puts biosynthesis into – and out of – the spotlight

Scientists have come up with a bright idea for simply engineering microbes to overcome the difficulties of balancing enzyme pathways used to make useful chemicals. Introducing an ‘optogenetic circuit’ means that brewer’s yeast switches from a fermentation that makes ethanol as normal in light to one that gives the biofuel candidate isobutanol in darkness. And by doing so, the scientists produce isobutanol concentrations five times greater than previously achieved by yeast strains.