**Appendix G**

Additional information about the application of post-growth treatments is presented here. Post-growth treatments (drying, baking, compacting then drying, or compacting then baking) were applied to the fully grown specimens in two locations: the Biodesign lab at the University of Akron and redhouse studio's warehouse where the specimens were grown. The relative humidity and presence of contaminants was lower in the Biodesign lab than at the warehouse. For instance, no growth of contaminants was observed on the panels brought to the Biodesign lab, whereas some contaminants started to grow on the panels kept at redhouse studio's warehouse throughout the post-growth treatment procedure. Therefore, non-compacted panels were baked or dried at the University of Akron to reduce the exposure to humid air and contaminants from the warehouse. The rest of the specimens were compacted, and dried or baked at redhouse studio's facility due to equipment availability. With the post-growth treatments applied, materials were moved to the Biodesign lab at the University of Akron for storage and mechanical testing.

To compact materials from the first batch, layers of aluminum foil were placed between the specimen and the metal plates to prevent the myceliated specimens from sticking to the metal plates. After the baking or drying process, some of the aluminum foil remained stuck to the myceliated specimens and metal plates. Separating the specimens from the aluminum foil and metal plates damaged some specimens. For the second batch, the aluminum foil was replaced with a polyester film, called mylar or biaxially-oriented polyethylene terephthalate (BoPET). In addition to its resistance to temperatures up to 100 ◦C, this material did not stick to the myceliated specimens. Once the compaction load was removed, the specimen recovered thickness. Therefore, the panel specimens (i.e.,

grown for bending testing) were kept compacted with metallic clamps. These clamps were only removed after the full drying or baking process. To avoid lateral expansion upon compaction, cylindrical specimens (i.e., grown for compression testing) were compacted inside of their respective growth environments (i.e., PVC pipes). However, clamps could not be placed until the specimens were taken out of the tubes. The load was kept on the specimen for a minimum of 5 min. Then, the specimens were removed from the pipes and kept compacted with clamps to maintain the desired thickness. *Biomimetics* **2022**, *7*, x FOR PEER REVIEW 31 of 36
