[set fair (OP)]

A friend was asking me about aphids and ants a couple of weeks ago, then I was watching Putin's weatherman describing a nuclear winter.

So the aphids feed on sap. In order to get enough protein they drink excess amounts of sugary water. This is secreted and ants lap up the calories and guard the aphids. It follows that ants have another source of protein. Maybe some ants and termites get their protein from wood. It may not contain much protein but the insects eat a specific fungus which they cultivate by providing it with wood. It would make sense if they use a  fungus which fixed nitrogen and produced protein. They've had millennia to coevolve with the fungus. So could we use the same fungus to feed ourselves on wood during a nuclear winter?

[alancalverd]

Yes. Try "Quorn" mycoprotein (other brands are available). It's a very adequate substitute for beef. Not sure what substrate they use, possibly sterilised horseshit (the real stuff, not what comes out of politicians' mouths) as preferred by mushroom growers, but maybe other organic fibers.

[paul cotter]

Referring to the original question "could we eat wood?", of course we can. I recommend oak for starters, mahogany for the main course and teak for desert. It will not deliver any nutrition unfortunately and one's dentist bill could be problematic. Bottom line: not recommended. Fungi cannot produce a high nitrogen content substance such as protein is without a feedstock with high nitrogen content- wood on it's own would not be sufficient. I know about those fungus cultivating ants but I don't know the details of what they use.

[Bored chemist]

Wood has a nitrogen content of about 0.1% or less.
Proteins are about 14% nitrogen.
So wood is about 1% protein.
But, if the fungus "eats" the wood, oxidises the cellulose and lignin for energy and keeps hold of the nitrogen then it can accumulate enough nitrogen to make its proteins from.
And, in principle, we can eat that protein.
Mushrooms are about 3% protein.
That's not bad.
But by the simple expedient of feeding the mushrooms to pigs, we can get bacon (36% protein)
The question is how much effort is that compared to growing beans?
OK, in a nuclear winter, that's not easy.
But, if we still have a society, we can still burn oil, run the generators and run the grow lights.

We know how to do that so it might be the easy option.

How about taking teh wood, treating it with dilute acid, neutralising it with chalk and then fermenting it to alcohol and distilling that off.
The nitrogen is left behind.
Add slaked lime  and redistill it and you will get ammonia.
You can react that with acid and feed that "fixed nitrogen" to ruminants like cattle and sheep (which can probably digest sawdust- though I doubt they would be happy or healthy).
The best thing to do is not vote for people like Putin, or those who praise/ admire him.

It's all fun and games until the energy runs out. Everything else can be recycled.

[alancalverd]

On my planet, there is plenty of nitrogen in the atmosphere. Following a nuclear war, quite a lot of it will be available as chemically reactive oxides. But there will be a shortage of edible sheep.

[Bored chemist]

On my planet the reactive oxides of nitrogen in a nuclear winter will be short-lived because they will be reduced by organic stuff in smoke.
The N2O might survive for a while, but I don't think it will achieve a lot.