# Bioremediation of Persistent Organic Pollutant--Oxybenzene with _Pleurotus diamor_
## 3 Results  
### Profile of Organic Compounds with Health Benefits  
The chemical profile of biomass obtained from in vitro cultures of _P. djamor_ supplemented with oxygenzone was analyzed, with particular emphasis on selected organic compounds with potential health benefits. For comparative purposes, the chemical composition of biomass obtained under standard cultivation conditions was also examined. The results are presented in Table 2.  
A comparison of the quantified ergothioneine content in _P. djamor_ biomass cultivated under standard conditions (3.96 mg/100 g dry weight) and in the presence of oxygenzone (1.58 mg/100 g dry weight) revealed a significant reduction in the levels of this compound. This decline suggests that oxygenzone may influence fungal metabolic activity, particularly the biosynthetic pathways of ergothioneine. Oxygenzone is known to generate reactive oxygen species (ROS) and disrupt oxidative homeostasis. Studies have demonstrated that increased ROS levels may lead to reduced ergothioneine production as this compound serves as an antioxidant protecting cells from oxidative stress. However, as ROS levels were not measured in this study, this remains a hypothesis requiring further verification. Additionally, the observed reduction in ergothioneine may be linked to metabolic shifts favoring the synthesis of alternative protective compounds [26]. The reduction in ergothioneine content may also result from a metabolic shift towards the biosynthesis of alternative protective compounds. Studies on another Pleurotus species, Pleurotus citrinopileatus, have demonstrated that stress factors can lead to increased production of polyphenols, terpenoids, or other antioxidants. It is conceivable that in response to oxygenzone exposure, _P. djamor_ mycelium undergoes adaptive metabolic modifications, compensating for the decrease in ergothioneine with other bioactive compounds. However, the specific compounds involved in this compensation require further investigation [27]. The comparison of ergosterol content in _P. djamor_ biomass revealed a substantial increase from 0.15 mg/100 g to 8.88 mg/100 g following oxygenzone supplementation. Ergosterol is a crucial sterol in fungal cell membranes, affecting their fluidity and integrity. Its biosynthesis is a complex process requiring multiple enzymatic steps. Various factors, such as oxygen availability, inhibitors, and precursor accessibility, have been reported to influence this process. However, there are no direct studies on the effect of oxygenzone on ergosterol biosynthesis in _P. djamor_. It is plausible that oxygenzone modulates the expression of sterol biosynthesis-related genes, alters precursor availability, or induces stress \begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**Analyzed Compounds**} & **Mycelium from In Vitro Cultures** & **Mycelium from In Vitro Cultures with BP-3** \\ \hline \hline Indole compounds & & \\ L-Tryptophan & – & 8.47 \(\pm\) 0.34 * \\
6-metylo-D,L-tryptophan & 1.52 \(\pm\) 0.06 & 4.56 \(\pm\) 0.55 * \\ Phenolic compounds & & \\ p-Hydroxybenzoic acid & – & 5.90 \(\pm\) 0.08 * \\ Sterols & & \\ Ergosterol & 0.15 \(\pm\) 0.03 & 8.88 \(\pm\) 0.11 * \\ Other organic compounds & & \\ Lovastatin & – & – \\ Ergothioneine & 3.96 \(\pm\) 0.17 & 1.58 \(\pm\) 0.11 * \\ L-Phenylalanine & 54.03 \(\pm\) 4.3 & 176.33 \(\pm\) 5.85 * \\ \hline \hline \end{tabular} Values in a row followed by * are significantly different at \(p\leq\) 0.05 (statistical analysis: one-way analysis of variance (ANOVA), followed by Tukey’s test). Each value represents the mean of three replicates \(\pm\) standard deviation.  
\end{table} 
Table 2: Antioxidant compounds determined in mycelium from in vitro cultures of _Pleurotus djamor_ [mg/100 g dry weight]. responses that lead to increased ergosterol production. Nevertheless, these mechanisms require further experimental confirmation [28; 29]. A significant increase in L-phenylalanine content in _P.