A biotechnology company called Calysta, based in Menlo Park, California, is set to announce the first ever large-scale factory that uses microbes to turn natural gas – methane – into a high-protein food for the animals we eat. The factory, which will be built in the US in collaboration with food-giant Cargill, will produce 200,000 tonnes of feed a year. The methane-made food has already been approved in the European Union for feeding to farmed fish and livestock such as pigs. Calysta is seeking approval in the US, too – and not just for farm animals. “We want to take it all the way to cats and dogs, and potentially even humans,” says the head of Calysta, Alan Shaw.