Mycoremediation of Louisiana sweet crude oil with Pleurotus ostreatus and nutrient amendments.

Oyster mushrooms (Pleurotus ostreatus) are known to metabolize polycyclic aromatic hydrocarbons in petroleum crude oil, making them candidates for oil spill remediation studies. This work aimed to assess P. ostreatus for its hydrocarbon degradation potential in estuarine conditions. In vitro experiments evaluated nutrient amendments based on P. ostreatus carbon: nitrogen: phosphorous (C: N: P) ratios to optimize mycelium growth, increase degradation efficiencies, and reduce potential nutrient runoff in broader applications. Image analysis was used to track mycelium growth response to various salinities, nutrient amendments, and oil types. Subsequent evaluation of alterations within the saturate, aromatic, resin, and asphaltene (SARA) fractions constituting Louisiana sweet crude (LSC) was conducted via SARA analysis. Results indicate that P. ostreatus mycelium tolerates estuarine salinities, with maximum growth between 5 and 15‰. Relative to 0‰, growth was reduced at salinities >25‰, but positive growth was still observed. Nutrient amendments significantly increased growth over 7 days relative to untreated samples (p < 0.0001). The combination of ammonium chloride and potassium phosphate yielded optimal mycelium growth after 7 days. Mycelium and nutrients significantly altered saturate (p = 0.0015) and asphaltene (p = 0.0124) fractions in LSC. This study suggests that mycelium growth is viable under estuarine salinities and can be enhanced with nutrient amendments. Introducing nutrient factors was shown to influence oil degradation. Results also indicate that mycelium can reduce recalcitrant oil fractions. Thus, this study highlights the adaptability of P. ostreatus to estuarine conditions and its response to nutrient amendments, all while offering a promising approach to crude oil bioremediation.