*3.1. Quantifying Particle Sizes*

A total of 4004 particles were measured for the large mixture and 7014 for the small mixture. In both mixtures, micro-particles (i.e., size less than 0.01 mm) were detected. Due to reorientation of the particles during the sieving process, a few particles longer than 20 mm were still present in both mixtures. However, there was a clear difference in the lengths and widths of the set of particles from both mixtures (Figure 2). For the large mixture, the mean length of particles was 5.89 ± 4.08 mm, with a length ranging from less than 0.01 to 51.78 mm. The mean width was 0.63 ± 0.69 mm, with values ranging from less than 0.01 to 8.29 mm. For the small mixture, the mean length of particles was 2.99 ± 3.57 mm, with lengths ranging from less than 0.01 to 72.95 mm. The mean width was 1.13 ± 0.80 mm with values ranging from less than 0.01 to 9.50 mm. *Biomimetics* **2022**, *7*, x FOR PEER REVIEW 12 of 36

**Figure 2.** This figure shows the difference between the distribution particles' dimensions in both mixtures (L for large and S for small). The *x*-axis is displayed on a log-scale. Due to the presence of 0s in the data (emerging from micro-particles), which equal -∞ on a log-scale, the data was offset by adding 1 to every value. Particles shown at 1 mm represent any micro-particles detected measuring less than 0.01 mm; (**a**) shows the distribution of particles' length + 1 in both mixtures; (**b**) shows the distribution of particles' width + 1 in both mixtures. **Figure 2.** This figure shows the difference between the distribution particles' dimensions in both mixtures (L for large and S for small). The *x*-axis is displayed on a log-scale. Due to the presence of 0s in the data (emerging from micro-particles), which equal -∞ on a log-scale, the data was offset by adding 1 to every value. Particles shown at 1 mm represent any micro-particles detected measuring less than 0.01 mm; (**a**) shows the distribution of particles' length + 1 in both mixtures; (**b**) shows the distribution of particles' width + 1 in both mixtures.

### *3.2. Growth of Mycelium-Based Materials with Pleurotus ostreatus*  3.2.1. Growth Assessment *3.2. Growth of Mycelium-Based Materials with Pleurotus ostreatus* 3.2.1. Growth Assessment

Appendix I contains information about the evolution of mycelium and contaminants' growth over time. All specimens grown for bending testing, and 65% of those for compression testing, exhibited some contamination by species believed to be *Trichoderma*  Appendix I contains information about the evolution of mycelium and contaminants' growth over time. All specimens grown for bending testing, and 65% of those for compres-

*harzianum* or *Penicillium* sp. In addition, species visually resembling *Rhizopus* sp. (i.e., pin mold), and *Dactylium* sp. or *Hypomyces* sp. (i.e., cobweb mold), were also observed on

quantities of substrate or the mixing and placement in the molds (i.e., warehouse environment). The specimens grown in PVC pipes having a height of 34 cm had more contamination at the bottom of the specimen than the top, which may have resulted from higher humidity. Therefore, the growth of contaminants seems to correlate with high humidity. Throughout the growth and drying periods, fruiting bodies emerged from the specimens. These mushrooms had to be removed regularly as contaminants were growing on them. For the specimens grown for compression testing, the weight of contaminated material removed accounted for 59.16% of the initial weight from mixture L and 63.22% of that from mixture S. For the specimens grown for bending testing, the weight of material removed accounted for 40.99% of the initial weight from mixture L and 21.72% of that from mixture S. Therefore, one particle size did not seem to increase con-

In addition to the contamination, quantities of 805 and 697 g of fruiting bodies were removed from the specimens grown for compression and bending testing, respectively. Therefore, the weight of fruiting bodies collected equaled approximatively 3.07 ± 3.48% and 3.20 ± 2.96% of the initial specimen weight for both compression and bending specimens, respectively. Since the mixture was composed of 67.5wt% of water, the weight of fruiting bodies accounted for 9.45 ± 10.70% and 9.85 ± 9.10% of the initial dry

tamination in all cases (i.e., both compression and bending specimens).

weight of the specimens, respectively.

sion testing, exhibited some contamination by species believed to be *Trichoderma harzianum* or *Penicillium* sp. In addition, species visually resembling *Rhizopus* sp. (i.e., pin mold), and *Dactylium* sp. or *Hypomyces* sp. (i.e., cobweb mold), were also observed on some of the specimens. The contamination may have resulted from autoclaving large quantities of substrate or the mixing and placement in the molds (i.e., warehouse environment). The specimens grown in PVC pipes having a height of 34 cm had more contamination at the bottom of the specimen than the top, which may have resulted from higher humidity. Therefore, the growth of contaminants seems to correlate with high humidity. Throughout the growth and drying periods, fruiting bodies emerged from the specimens. These mushrooms had to be removed regularly as contaminants were growing on them. For the specimens grown for compression testing, the weight of contaminated material removed accounted for 59.16% of the initial weight from mixture L and 63.22% of that from mixture S. For the specimens grown for bending testing, the weight of material removed accounted for 40.99% of the initial weight from mixture L and 21.72% of that from mixture S. Therefore, one particle size did not seem to increase contamination in all cases (i.e., both compression and bending specimens).

In addition to the contamination, quantities of 805 and 697 g of fruiting bodies were removed from the specimens grown for compression and bending testing, respectively. Therefore, the weight of fruiting bodies collected equaled approximatively 3.07 ± 3.48% and 3.20 ± 2.96% of the initial specimen weight for both compression and bending specimens, respectively. Since the mixture was composed of 67.5wt% of water, the weight of fruiting bodies accounted for 9.45 ± 10.70% and 9.85 ± 9.10% of the initial dry weight of the specimens, respectively.
