Presumably it would be from ammonia, fixed artificially, just as it often is with crops grown the ordinary way. It would probably convert the nitrogen to protein more efficiently.
I meant the proximate energy source. Are the organisms photosynthetic? Or is solar energy converted to something else? For example, is PV used to make electricity that then powers the microorganisms (by providing them with reduced metal ions they can oxidize)? Or is a chemical energy source synthesized, say methanol as was used for ICI's Pruteen (although that process sourced the methanol from natural gas)?
For those interested, check out the work of Doug Tallamy, an entemologist at the University of Maryland. His basic thesis is that insects drive ecological health and that invasive species that don't have thousands of years of coevolution with native insect populations provide ecological dead zones that are equivalant to concrete.
My opinion based on his work and others is that kudzu and others dramatically reduce biodiversity and upsetting ecological balances that took thousands of years to create. It's wonderful that pests show up to consume kudzu (like the bug referenced in the article), but it's not the same as a native species occupying the same niche that provides forage, pollen, seeds, habitat, and other necessities that make native insect populations thrive, which in turn supports larger fauna like birds, mammals, etc.
Traditional agriculture has "solved all of the scale problems" through the use of pesticides, destructive monocultures, and disruption of the natural water cycle. It's also built on the idea that diesel is cheap both for the tractors to farm in the midwest and the trucks to deliver goods to markets around the country. Should any of those fragile pillars collapse due to regulation (not likely), major environmental catastrophe (pretty likely), or disruptions in the global fossil fuel economy (possible), solutions like vertical farming start making a lot more sense.
