Cooking with sawdust In a book about post-war Japan (Embracing Defeat, Dower) the author mentions a process for making sawdust at least partially edible, so it could be used in recipes in a 1:4 ratio with flour for cooking. The author says the sawdust was "fermented," as I recall. My question is whether this is anything more than marginally possible. After all, kimchee, yogurt, beer, and other fermented foods aren't necessarily easier to digest. Is there a fermentation process involving bacteria that break down cellulose that might make wood even slightly nutritious? My impression is that in forests the process of breaking down wood does not initially involve bacteria but other microorganisms; on the other hand, ruminants such as cows use bacteria to help them metabolize. Thanks for any insight.

Yes. I think it would certainly be possible for raw sawdust to be made digestible by humans through some sort of fermentation process with some kind of microbe or another.

Pickling (as is done with kimchee and cucumbers and lots of other fruits) uses naturally occurring bacteria that are artificially selected for by using a strong brine solution so that most microbes die but the ones that naturally survive in strong brine also convert the organic materials they find (raw cucumber or cabbage) into different organic materials (pickled cucumber or pickled cabbage in the case of kimchee).

If you could find a microbe that could digest wood (there are many I'm sure; the gut bacteria in termites provide evidence of at least one or some), and if you could find a way to select for that particular microbe, then fermenting sawdust for nutritious human consumption becomes feasible. The only remaining problem is finding that particular microbe whose excretions were digestible to humans.