SINCE the dawn of civilisation, people have used yeast to leaven bread, ferment wine and brew beer. In the modern era, such fermentation has extended its range. Carefully selected moulds churn out antibiotics. Specially engineered bacteria, living in high-tech bioreactors, pump out proteinaceous drugs such as insulin. Some brave souls even talk of taking on the petroleum industry by designing yeast or algae that will synthesise alternatives to aviation fuel and the like.
But fermentation remains a messy process, and one prone to spoilage and waste. Whatever the product, the reaction must generally be shut down after a matter of days to clean out the detritus of biological activity—both cells that have died and the surplus of living ones which growth and reproduction inevitably yield. Alshakim Nelson, a chemist at the University of Washington, in Seattle, and his team, propose to change all that. They have developed a bioreactor that not only keeps…Continue reading