## 4 Discussion
Therefore, the higher soil enzymatic activity of _A. bisporus_ treatment with respect to the other treatments could be a combination of the positive effects of the SMS in soil microbiota and the reduction in soil toxicity because of the high effectivity of this treatment to biodegrade TPHs. The hydrolase and dehydrogenase activities for _P. erygii_, _L. edodes_ and _P. ostreatus_ treatments were not significantly higher than the control, probably because a combination of multiple factors such as the low nutrient status of these SMSs and their lignocellulosic base does not promote the biostimulation of soil microbiota at long lasting. or antagonistic interactions between autochthonous soil microbiota and SMS microbiota and finally, the lower effectivity to reclaim and detoxify the soil than _A. bisporus_ SMS. In this regard, [PERSON] et al. [48] described very low TPHs degradation by _P. ostreatus_ inoculated from SMS. In addition, these authors found that despite the bacterial community of the SMS was competent to degrade TPHs, the bacteria prioritized the transformation of the more biodegradable SMS organic matter. Despite the different visual colonization of the four fungi (Figure 1), the ergosterol content was not different between treatments (Table 2). _P. erygii_ and _A. bisporus_ were the ones with the highest colonization. While _P. ostreatus_ and _L. edodes_ only showed colonization at the end of the experiment, but not as vigorous as the other two species. Ergosterol variesi depending on some factors such as the growth medium, the culture conditions and the growth phase in which it is found [36]. For this mycoremediation test, each microcosm presented a different culture phase of each fungus after 40 days of incubation and the growth medium was also different since each one had a different SMS. The low ability of _P. ostreatus_ to colonize this soil was not expected. There are multiple works that reported good performance of this fungus for the mycoremediation of soil [4; 49; 50]. There are also abundant works about the potential of _P. erygii_, _L. edodes_ and _A. bisporus_ to colonize contaminated soils by PAHs, PCBs or pesticides; however, there is limited or even zero information on the fungal colonization of TPHs contaminated soil by these fungi [20]. The inoculation of lignin-degrading fungi by SMS is a valuable source of ligninolytic enzymes such as lactose and different peroxididases [21]. Many transforming interactions between fungi and different pollutants depend on a variety of extracellular excreted substances and metabolites. Fungi are capable of degrading petroleum hydrocarbons by secreting enzymes [51]. For example, [PERSON] et al. [26] reported the increment of Laccase, MnP and Lignin peroxidase of PAH-polluted soils incubated with SMS of _P. ostreatus_, _P. erygii_ and _Auricularia auricular_ and [PERSON] et al. [24; 52] reported laccase and MnP activity in PAH and PAH-Pb contaminated soils using _A. bisporus_ SMS. In this work, the species _P. erygii_ and _A. bisporus_ were the only ones with laccase activity at the end of the assay. Laccase is a nonspecific enzyme with a high redox potential that can oxidize different compounds such as phenols and polyphenols [53]. This enzyme uses O\({}_{2}\) as an electron acceptor, while for peroxidase it uses H\({}_{2}\)O\({}_{2}\). Despite both fungi, _P. erygii_ and _A. bisporus_, showing laccase activity, the highest laccase activity was measured for _A. bisporus_ treatment. This agrees with the visual colonization of the microcosms that was more vigorous for _A. bisporus_ and _P. erygii_ than for the other fungi. MnP has a high redox potential and is characterized by oxidizing phenolic structures [54]. It was observed that all the bioaugmented treatments showed a relatively higher value than the control,highlighting again _P. eryngii_ and _A. bisporus_. A possible explanation for these better results is, once again, that they were the fungi that better colonized the soil and these enzymes were indicators of fungal activity [41]. Both for _P.