## 3 Results
### Prebiotic Activity  
The mushroom extracts were also tested regarding their prebiotic activity using different probiotic bacteria. The extracts were tested at 2% and 1% (\(m/v\)) (Figure 5). Unfortunately, due to a lack of sufficient extract, it was not possible to determine the _P. eryngii_ M2A prebiotic activity. Observing the results in Figure 5, it is possible to see that the _A. cylindricalacea_ and _P. eryngii_ extracts were able to induce growth in most of the probiotic bacteria. Overall, extract M1 at 1% from A. cylindricalacea stood out since it showed higher prebiotic activity than the other extracts in most of the bacteria studied. This effect on growth was never higher than in the glucose control. In contrast, the _P. ostreatus_ M1 and M2A had a negative effect on the growth of all probiotic bacteria while M2B was able to enhance some of the bacteria growth, especially in _Lactobacillus acidophilus_ Ki and _Bifidobacterium lactis_ BLC. This prebiotic activity aligned with what is reported in other studies. For instance, in a study conducted by [PERSON] et al. [30], it was observed that aqueous extracts from _P. eryngii_ and _P. ostreatus_, rich in \(\beta\)-glucans and proteins, were able to promote probiotic bacteria growth rates, including _Lactobacillus_ and _Bifidobacterium_ strains. In the same study, _P. eryngii_ extract proved to be a better growth source than _P. ostreatus_. For instance, a _Bifidobacterium_ strain grew only with _P. eryngii_ extract, while _P. ostreatus_ was not able to stimulate its growth [18]. In another work, a hydroethanolic extract from _P. ostreatus_ was able to induce the growth of _L. acidophilus_ at 1% (\(m/v\)) [53]. In addition, a different study showed that the abundance of families such as Lactobacillusaceae and Bifidobacteriumaceae was increased in the presence of _P. eryngii_ extracts [54]. _A. cylindtracea_ polysaccharides have also been reported to have prebiotic activity [55]. Figure 4: Heat map of biofilm formation inhibition (%) by _P. ostreatus_, _P. eryngii_, and _A. cylindricalacea_ aqueous extracts against Gram-positive and Gram-negative bacteria. Extract M1—hot extraction (1 g of mushroom dry matter (DM); 20 mL of water; 90 °C, 700 rpm, 1 h); extract M2A—room-temperature extraction (1 g of mushroom DM; 20 mL of water); extract M2B—hot extraction of residue from M2A (1 g of mushroom DM; 20 mL of water; 90 °C, 700 rpm, 1 h). In the present study, among all bacteria, _B. lactis_ BB12 was the one with the worst prebiotic results, with only the _A. cylindracea_ M1 and M2A (2% and 1%) extracts and _P. erygii_ M2B (1%) stimulating its growth. With some exceptions, the highest extract  
Figure 5: The growth curves of selected strains of prebiotic bacteria in MRS broth containing glucose (control) or each of the extracts from _A. cylindracea_, _P. erygii_, and _P. ostreatus_ at 2% and 1% (\(m/v\)). Extract M1—hot extraction (1 g of mushroom dry matter (DM); 20 mL of water; 90 °C, 700 rpm, 1 h); extract M2—room-temperature extraction (1 g of mushroom DM; 20 mL of water); extract M2B—hot extraction of residue from M2A (1 g of mushroom DM; 20 mL of water; 90 °C, 700 rpm, 1 h). concentration of 2% was not as efficient at inducing bacterial growth when compared to the lower concentration. One of the reasons for these results might be that at the highest concentration, as well as at the lower concentration, the extract did not solubilize in MRS. Thus, at 2% concentrations, the solutions were not as homogeneous, and the polysaccharides were not as readily available as in the lower concentrations. Concentrations of 1% appeared more homogeneous, thus providing a better source of energy for the probiotic bacteria. In the case of the _P. ostreatus_ M1 and M2A extracts, the negative effect on the growth of bacteria was more noticeable at the higher concentration. This might be explained by some compounds that were present in the extracts that inhibited the growth of bacteria. With a lower concentration, bacteria growth was not induced.