Take a few seconds and head over to the BBC World Challenge site to vote for finalists BTTR Ventures — the only US-based finalist!

Did you know that less than 1% of all the coffee harvested each year ends up in your cup? Most of the coffee grounds finish as landfill. Two business school graduates in California, Nikhil Arora and Alejandro Velez, have spotted a money-making opportunity: instead of the grounds going direct to the tip, they collect the ‘waste’ and grow gourmet oyster mushrooms on pods in a humid warehouse. As Nikhil notes, “America is addicted to coffee” and around the world over seven million tonnes are produced every year – that’s a lot of waste. After the grounds are used up, they become compost for organic urban farms in the San Francisco area. Now the business looks set to expand as the health food superstore, ‘Whole Foods’ has begun to sell the gourmet mushrooms.