Does the lack of microbial competition significantly enhance boreal white-rot fungi's capacity to degrade organic pollutants and uptake toxic elements?

Mycoremediation, the application of fungi for pollutant degradation, offers a sustainable solution for bioremediating contaminated environments. In mixed microbial settings, microbial competition can influence the efficiency of fungi by modulating pollutant degradation and nutrient availability. We investigated the bioremediation potential of boreal white-rot fungi (WRF) in fiberbank sediments, targeting organic pollutants such as polycyclic aromatic hydrocarbons (PAHs) and potentially toxic elements (PTEs). Previously isolated and identified thirteen WRF species were screened in sterilized and unsterilized substrates to evaluate the effects of microbial interactions on pollutant degradation and metal uptake. Key findings revealed that unsterilized fiberbank material supported superior PAH degradation, with Trametes hirsuta achieving up to 94% removal, suggesting synergistic interactions between WRF and native microbial communities. Conversely, sterilized substrates enhanced PTE uptake, with Phlebia tremellosa demonstrating significant accumulation of cadmium, bioconcentration factor (BCF) of 5.56 in sterile conditions and 0.85 in unsterile conditions, and lead, BCF of 1.65 under sterile conditions, and 0.38 for unsterile conditions, this enhanced accumulation might be due to reduced microbial competition. Statistical analyses confirmed significant differences (p < 0.001) in pollutant removal and metal uptake between the two substrate conditions. These results underline the importance of tailoring bioremediation strategies to substrate conditions. A dual approach, employing unsterilized substrates for organic pollutant degradation and sterilized substrates for metal accumulation, emerges as a promising framework. Future applications could focus on large-scale implementation of these strategies to rehabilitate industrially contaminated sites like fiberbanks, balancing ecological sustainability with remediation efficacy.