I ran a quick experiment, tinkering with a dried SCOBY.
As I saw one 3D-printing paper pulp (plantbased cellulose) recently, I thought this would be cool to try with the bacterial cellulose. Haven’t seen that here in the forum.
So I ground up a small, fully dried SCOBY with a coffee grinder. I stopped when it was not yet a powder but rather small flakes/crumbs smaller or equal to 1mm. It was about 2 tablespoons full.
I then mixed in methylcellulose powder (wallpaper paste) as a binding and gelling agent. After that, water was added drop by drop until a relatively dough-like consistency was achieved. I molded and pressed that one into a little sheet to see how this would behave once dried.
I then further diluted the leftover half part with water and transfered this mixture into a syringe to see if this could be extruded. This went surprisingly well! The gelling agent made it stable enough to create a small heap that did not sag. Details from the messy, uncontrolled syringe extrusion also preserved well during the drying process.
Ugly, uncontrolled objects, but fine for now!
After drying, I found these objects to be a lot harder and less brittle than I expected them to be. The compressed sheet can handle some significant force before cracking and is resistant to carving with a pointed aluminium pin. The other objects were of similar strength, but could flex a few degrees. That is probably due to not being compressed. But this technique could potentially create hard, rigid shapes!
They even displayed some degree of polishing where I decided to cut one of them.
There obviously was some shrinkage, especially on thick pieces where sinkmarks could be seen on the bottom. But the 2-3mm thick extruded parts remained relatively the same.
As a side experiment, I rehydrated one and then remolded & dried it again. That actually worked besides a darkening of the color (oxidation?). So that could be an interesting property.
I have some more sheets growing and drying to see how high you can “build” with this to determine how it can be suitable for 3D-printing. But also to study stability, recommended wall thickness, recommended water percentage and shrinkage that can be expected. The current quantity was too low to evaluate that.
If someone here knows any other binding agents that could work, let me know! Since methylcellulose -although not toxic to my knowledge- is not naturally occuring, I don’t yet consider it bioproduced.
I’ll update this SCOBY-mâché experiment once my new sheets are thick and dried