*3.2. Cultivation of Materials*

The fungal spawns of *Pleurotus ostreatus* were purchased from local suppliers (Lambert Spawn, Coatesville, PA, USA). Oyster mushroom spawn has been used because 1) it is widely available locally, and 2) satisfactory results have been obtained with similar genera according to the literature [8]. Sterilized substrates were inoculated with the spawns by 7% of the dry weight in a sterilized environment. The bags were then placed in a growth room with environmental control. The temperature was set to 21 ◦C, and the relative humidity to 95%. The room was kept dark to help with the growth process.

To study the effects of different durations of growth on the mechanical behavior of MBC, three different durations of growth for 5, 6, and 7 weeks were selected, regarding the best results from the literature [7]. The growth process of MBC has been divided into two phases: within bags and formworks. To compare the partial growth of MBC in bags and formworks, the substrate mixtures have been placed in formworks at different times. These different substrate mixtures and timeframes made 35 different treatments. The treatments are coded as Xij: X indicates the substrate mixture used for the cultivation, and i and j indicate the cultivation time (weeks) in bags and formworks. The details about the total and partial duration of the treatments are shown in Table A1.
