Could you develop a rocket fuel by using organics.
Corn can and is used to produce fuel.
You would have to ferment the Organics or the produce off the trees.
I think they are referred to a nuts although some look like apples.
The concept of alternative fuel sources is very interesting, and it will enrich the game. Alternatives to Hydrazine provide more paths for players to advance and explore the game world - introducing a lot of choice I think everyone will enjoy. Ethyl groups in general are common substances in chemistry; coming from organic fermentation, or extraction from natural gas in the form of ethane. It would be weird not to have some given its ubiquity. Natural gas ties into a former suggestion of mine: Gas Hydrate as a mineable resource.
Early sources of Ethanol could be made from fermentation (as @individual-1 suggested; maybe with Carbon Dioxide byproduct); later on in game progression, players reaching outer planets/moons find and refine Gas Hydrate into Petroleum/Ethanol. Perhaps there would be distinction between both, one being Bioethanol, and the later Petroleum; however, serving the same purpose. That way Ethanol fuel sources can be used on both hospitable, and inhospitable planets (biosphere vs. anti-biome planets).
To expand Ethanol uses even more... Ethanol, much like Isopropyl Alcohol, can sanitize. Both are solvents that dissolve lipids; the substance many microorganisms are made from. Suggestions have been made to introduce Space Diseases, or some kind of evasive parasite that preys on Astroneers. Combined with another suggestion, a Terrain Tool Projector Augment, Astroneers will spray down hostile biomass, or parasitic creatures. Think the Facehugger from Aliens, but instead of guns, Astroneers just slash the little beasties with a dose of super space hand sanitizer.