Colonies of bacteria could save the Pentagon billions

PLAQUE ON TEETH, slime on stones, gunge around taps and showers. Biofilms—slimy, durable colonies of bacteria—are everywhere. Much of the research into them focuses on the they can cause in people. But they can damage inanimate objects, too.Some biofilms contain sulphate-reducing bacteria, for instance, which respire using sulphate rather than oxygen. The end product is hydrogen sulphide, which can cause pitting in steel. Other sorts can corrode the inside of a fighter jet’s fuel tanks. On a ship’s hull, bacterial colonies can become a base for seaweed and other growth that increases drag. In 2016, America’s armed forces reckoned unwanted biofilms cost “billions” each year.