is it possible to carbonate ethanol for use as a solvent?
the closest i could find was carbonating vodka, but im not sure if it would translate well to relatively pure ethanol seeing as how it is diluted (40-50% ABV as opposed to 99%)

I don't see how dissolving CO2 in ethanol could make a difference. What are you trying to do?

well i noticed that when i replaced lemon from lemon tek with soda, the ground mushrooms would float and get caught in the foam caused by carbonation, which would help the floating material soak faster and sink. also the bubbles forming and rising from the bottom would move the material around (which you could amplify by shaking). it just seemed to work really efficiently for me, and i thought it would help with an ethanol extraction....

I'm struggling to find data on CO2's solubility in pure ethanol at standard temperature and pressure. If you have the means though this should be something rather easy to test.

Generate CO2 gas from acid base interaction on bicarbonate or carbonate salt, or a CO2 tank/cartridge(if you can control it or have a regulator). Pass the probably 'wet' gas over a suitable drying agent, I'd imagine CaCl2(drive-way de-icer would do but double check with the literature). Bubble this into preferably a de-gassed(via vacuum) solution of 'dry' Ice cold ethanol. Purge with a vaccuum and replenish with CO2 3 times or so. I don't think the solubility of CO2 in ethanol would be very high unless the water content was larger than neglige-able but I've been wrong many times before. Similar to beer.

If you're simply looking for a way to put a stream of bubbles of atmospheric air into a solution you could use maybe an air-stone and an aqaurium pump or similar.

As far as CO2 aiding a crude mushroom extraction goes I don't think it would do too much for the cause. I find tea to be very simple and effective. Tinctures store for longer periods of time.

I don't know how significantly the carbonated ethanol would work? If it's purely ethanol with dissolved CO2, I think that would have very little effect on your extraction since soda is acidic because of the carbonic acid formed when the CO2 dissolves in water (aside from other additives such as phosphoric acid and such), but since you're talking about anhydrous ethanol, the carbonated ethanol would simply do what normal ethanol does in the tek you are using with some bubbling if carbon dioxide is in fact somewhat soluble in ethanol. If that's what you're looking for then success for you.