Imagine a world where gas emitted from landfills can be turned into edible protein that ends up on your plate as a burger or a steak.

That's what some scientists are hoping for. Calysta Inc. in California and String Bio in the Indian city of Bangalore are among biotechnology firms that have separately discovered ways to turn methane into protein.

Bacteria found in soil are fed a liquid containing the emitted gas, sparking a fermentation process similar to making beer. Instead of alcohol, protein is released into the water, which is then dried into a brown powder. The product is already being used in animal feed, the first step toward readying it for human consumption.