Living mycelium filters for removal of pyrene from water

The release of toxic chemicals from industrial and agricultural activities degrades ecosystems and depletes natural resources [1]. Polycyclic aromatic hydrocarbons (PAHs) naturally occur in the environment as by-products of incomplete organic matter combustion. However, their increased emissions and elevated concentrations due to anthropogenic activities, pose significant threats to both terrestrial and aquatic ecosystems [2]. This study presents initial data in the development of a novel filtration approach targeting the removal of pyrene utilizing biofilters composed of pure living fungal mycelium. White-rot fungi demonstrate remarkable capabilities in remediating organic pollutants through their enzymatic activities [3]. We investigate the filtration efficiency of mycelium-based filters by analysing the potential of three species; Ganoderma lucidum, Pleurotus ostreatus, and Schizophyllum commune, to separate pyrene from water through fungal cell wall interactions. <br/><br/>The experimental plan consists of three main phases. First, pure fungal filters were made using vacuum filtration with a custom-designed funnel. Second, testing of six specimens per specie through a three-step sequence. Here, fungal filters were washed with demineralized water to remove easily eluted molecules that can confound the measurement of pyrene in later stages (first wash). Then, a 0.139 mg/L pyrene solution was passed over the fungal filters. Lastly, a final wash with distilled water to determine pyrene elution rate from the fungal filter. Samples collected from each phase were analysed using fluorescence spectroscopy and compared against control samples of distilled water and a 0.139 mg/L pyrene solution.<br/><br/>Results demonstrate effective pyrene removal by all three fungal species. After exposure to the pyrene water solution, fungal filters originating from G. lucidum and S. commune biomass sorbed 97.9% of pyrene, while fungal filters made from P. ostreatus biomass achieved a 96.7% removal of pyrene from the solution. During the final wash, pyrene elution was 4.0%, 9.6%, and 5.3% for fungal filters made from G. lucidum, S. commune and P. ostreatus biomass, respectively. No difference in pyrene removal from the pyrene solution that was passed over the fungal filters was observed between fungal filters originating from the different species (p= 0.1911). Additionally, no differences in elution rates were observed between fungal filters originating from the different species(p = 0.5287). Together, this means that pyrene is easily filtered out of solution by all filters made from fungal biomass and difficult to remove once sorbed. The next phase of exploration comprises testing the filter’s elution in subsequent washes in order to determine the efficiency and durability of the material.