Potential of Pleurotus ostreatus to remediate diesel-contaminated soil in subarctic mesocosms

Abstract

Pleurotus ostreatus, a gilled basidiomycete, has previously been shown to biodegrade petroleum using extracellular enzymes. However, few studies have tested petroleum biodegradation by fungi, known as mycoremediation, in cold temperatures. I conducted mesocosm studies to assess the potential from mycoremediation of diesel-contaminated soil collected from interior Alaska with a cultivated strain of P. ostreatus var. columbinus at 4 ºC, 10 ºC, and 25 ºC. In soil, both uninoculated and inoculated with P. columbinus, diesel range organics (DRO) decreased by 22-28% (p=0.455), 41-55% (p=0.236), and 91-92% (p=0.735) at the three temperatures, respectively. The differences in DRO loss between uninoculated and inoculated mesocosms at each temperature were not statistically significant, most likely due to high soil heterogeneity. However, DRO loss was greater as temperature increased, and was significantly different between the temperatures evaluated. These results indicate that temperature is a more important factor controlling DRO loss than substrate or inoculation with P. columbinus. Inoculation may enhance DRO loss at medium temperatures, but inoculation does not appear to enhance DRO loss at the highest and lowest temperatures in this study. The results also suggest that manipulating the temperature of remediation sites may be more important than inoculating with Pleurotus, and that inoculation might not be needed at sites where temperature can be increased.