92. QUORN

This is a radical development which could greatly increase carrying capacity (i.e. the ability of the earth to feed large numbers of people using fewer resources). Quorn is mycoprotein -- a meat-like food produced by fungi from corn syrup, ammonia and air. In short, it is protein grown in vats. It is vastly more efficient as a protein source than the chicken or cow. Its production requires far less water and land than conventional protein, and it produces less waste. Furthermore, it is a viable commercial product, right now.
QUORN
I've tried this stuff, and it was quite good. The response was also positive at a taste test at Wired Magazine:

For about an hour on Thursday, the office went a bit Quorn crazy, with 10 or so people popping into the coffee bar to taste this advanced food. The feedback was mostly positive. Everyone liked it, and some people said they loved it. Several said that the nuggets were indistinguishable from chicken, and others said that while they could taste a difference, they thought Quorn was very similar to meat.Source

More mycoprotein facts:

Many attempts have been made to manufacture foods that are rich in protein as cheaper alternatives to meat. Microorganisms can be made to grow on some industrial or agricultural waste materials (e.g. paper, wood sugar-refining waste) that contain the right balance of nutrients. They can produce protein rapidly and efficiently. In addition, protein products from microorganisms, such as the commercially available mycoprotein Quorn, are suitable for vegetarians.Source

One calculation suggests that the protein requirements of 1 billion people could be satisfied by a vat protein facility covering only 4 square kilometers of land. (Source: How Many People Can the Earth Support?, Joel E. Cohen, P. 327).