It would be interesting if there were Carbon-based recipes for say, Inserters, Belts, and Carbon-based recipes for all of the machines the mod adds as well as T2 and T3 Assemblers and other vanilla machines. Or perhaps some kind of new renewable resource for some of these. I mean, you could even explain becoming independent of copper via Neural Gel Packs and Capacitance Gel. They could act as a bio-based electricity and information conductor (Like in Star Trek). Maybe Sand Miners could also be used to mine stone, allowing Stone to be usable as a renewable resource for building walls and gates and perhaps being used in some recipes as well.

This could be further extended upon by having some mod compatibility, for instance with Bob's Mods, Angel's Mods, or AAI. Some options to make integration with say AAI a bit easier as well as further add complexity to the mod could be:

1. Add a recipe to turn wood planks into wood logs, allowing BioTech to support AAI vehicles by providing a renewable Vehicle Fuel source (As you can make them out of Wood Logs. This isn't super important though because with Recursive Blueprints you can make automatic tree farms)
2. Make use of AAI's motors and engines, and also provide renewable recipes for said motors via carbon, stone, glass, neural gel packs, or some other new renewable resource.
3. Introduction of Rubber that can be used for various purposes to support AAI vehicles, and it being a renewable resource could make it useful for various recipes.
4. As sulfur is considered an organic element and there are natural ways to produce renewable sulfur which could add some extra complexity to the mod as well as being used to make stronger rubbers and as a fertilizer, perhaps in the creation of a BioTech-only efficiency module (Only usable in BioTech machines) or as some other efficiency/productivity booster as well as more tiers of rubber for recipe use.
5. Production of renewable but significantly less efficient Hydrogen-based fuel cells for Nuclear Reactors.
6. Carbon-based recipes for Modular/Power Armor and modules.
7. Neural Gel Packs usable in a "Neural Pathway" recipe to carry electricity with a renewable resource to machines and other buildings.
8. Fiber Optic cables usable for Logistics/Circuit Networks.
9. Carbon-based Logistics and Construction Robots.

Most of these should be relatively simple to code as they are just adding new recipes and expanding upon what you've already done, but already provide a lot of potential for cross-mod compatibility and further expanding upon the idea of the mod.