Abstract
Oyster mushrooms (Pleurotus ostreatus) are a white rot fungus known to biodegrade and metabolize recalcitrant molecules such as polycyclic aromatic hydrocarbons (PAH) in petroleum crude oil, which can be toxic and lethal to organisms in the environment. Restoration efforts for oil spills in estuarine environments impose complex problems due to the sensitivity of the environmental resources at risk, leading to response and restoration methods that have limitations that induce harm to ecosystems. This work aimed to assess the tolerance of P. ostreatus mycelium to varying salinity conditions commonly found in southeastern estuaries. In vitro experiments using different nutrient amendments based on P. ostreatus C:N:P ratio were conducted to optimize mycelium growth and potential biodegradation efficiencies in altering the saturate, aromatic, resin, and asphaltene (SARA) fractions constituting fresh and weathered Louisiana Sweet Crude (LSC) crude oil. We used image analysis in FIJI to track mycelium growth rates in response to LSC and nutrients, and then applied SARA analysis to the oil extractions. A predator-prey relationship between P. ostreatus mycelium and the eastern mud snail (Tritia obsoleta) was demonstrated through both microscopy and grazing rate analyses. Furthermore, a potential trophic transfer of polycyclic aromatic hydrocarbons (PAHs) from oiled mycelium to mud snails was investigated. Oil spills in estuarine ecosystems can negatively impact the blue economy and human health. Thus, this study provides insights into the adaptability of P. ostreatus to estuarine conditions, its response to nutrient amendments, and its role in potential bioremediation strategies for oil-contaminated environments. Oyster mushrooms, based on the results of this study, may be used in the future as an effective and noninvasive remediation tool for estuarine environments.