## 4 Discussion  
The colonization of this polluted soil confirmed the ability of _P. ergngi_, _L. edodes_, _P. ostreatus_ and _A. bisporus_ to adapt to highly contaminated environments. This fact is also more relevant because the fungi were inoculated from SMSs. This agricultural waste is generated after the industrial culture of edible fungi when the culture of more mushrooms is not economically viable. SMSs are characterized by their low level of nutrients for fungi such as cellulose and hemicellulose which were consumed during the culture of mushrooms [41]. However, they still contained the living organism, including mycelium that can be used for soil bioremediation between other possibilities [18; 21; 26]. Hence, SMSs are organic wastes with a wide variety of microorganisms [26; 41]. The use of these wastes in soil bioremediation provides multiple benefits such as their recycling, the alleviation of the disposal problem and the cost decrease in waste treatment [42], possible bioaugmentation of hydrocarbon-elastic bacteria in contaminated soils [26] and inoculation of lignin-degrading fungi [24; 25; 43], biostimulation of autochthonous soil microbiota by adding nutrients and organic matter and serving as a bulking agent increasing oxygen diffusion [26; 42]. One of the key factors for bioremediation processes is microbial activity since it is an indicator of the ability of the microbiota to grow and degrade the pollutants under certain environmental conditions [44]. The soil biological activity of the microcosms was determined by dehydrogenase and total hydrolase activities (Table 2). Dehydrogenase is an oxidoreductase that is related to the abundance and metabolic activity of soil microorganisms and catalyzed the biological oxidation of organic compounds [45]. It is the most representative soil enzyme among soil oxidoreductase, and its activity is one of the most used parameters for evaluating the microbiological status of the soil [46]. This enzymatic activity is clearly related to the degradation of TPHs in soil and was purposed as an indicator of the potential of soil microbiota to degrade TPHs [44]. Hydrolases are enzymes capable of catalyzing the hydrolysis of a chemical bond using water. In the soil, these enzymes are used for the degradation of complex organic matter, generating molecules that are more easily accessible to soil organisms [47]. It is clear in Table 2 the positive impact of _A. bisporus_ SMS on soil microbial activity. This SMS was the only one that include chicken  
Figure 2: Principal component analysis of the control microcosms (C) and the bioaugmented microcosms with SMS of _P. ergngi_ (P.e. ), _L. edodes_ (L.e. ), _P. ostreatus_ (P.o. ), and _A. bisporus_ (A.b.) showing loading scores of the residual concentration of TPHs and their aliphatic (C\({}_{10}\)–C\({}_{12}\), C\({}_{12}\)–C\({}_{16}\), C\({}_{16}\)–C\({}_{21}\), C\({}_{21}\)–C\({}_{35}\) and \(>\)C\({}_{35}\)) and aromatic (EC\({}_{10}\)–EC\({}_{12}\), EC\({}_{12}\)–EC\({}_{16}\), EC\({}_{16}\)–EC\({}_{21}\), EC\({}_{21}\)–EC\({}_{35}\) and \(>\)EC\({}_{35}\)) fractions. manure in its composition because _A. bisporus_ is a secondary decomposer that requires materials with a lower C/N ratio and higher cellulose, hemicellulose and nitrogen contents (manure and compost) than primary decomposers such as the rest of fungi tested in this work who required high C/N ratio and lignin content [18]. Hence, _A. bisporus_ SMS had the highest nutritional content of the four SMSs tested [20], and therefore, the SMS with the highest biostimulation capacity of the soil microbiota. Simultaneously to soil biostimulation, the inherent microbiota of SMS can colonize the soil and produce bioaugmentation of the soil microbiota with microorganisms able to degrade organic pollutants [24]. The other important factor that could enhance the hydrolase and dehydrogenase activity at the end of the incubation period was the lower TPHs concentration of this microcosm. Low activities of these enzymes are indicators of soil toxicity [1; 34].