It’s methane fermentation, so methane is the only carbon/energy source. Depending on processing, you end up with something similar to brewers yeast you find at some grocery stores or a more purified protein powder. For animal feed it would likely be the former. Inputs are methane, salts, water and electricity to the run the bioreactors. I assume there’s some amount of pure oxygen or nitrogen supplementation to reach the most efficient ratios.

It uses only methane as the carbon source, not food or agricultural byproducts. This process has a lot of potential if the efficiency is high enough and they could potentially expand production to other valuable organic compounds.