Extraction and quantification of ergosterol as a measure of fungal biomass in leaf litter

Homogenization in methanol, two hours of refluxing in methanol, and direct saponification in alcoholic KOH were equally efficient at extracting ergosterol from fungally colonized leaf litter. A 25-cm Li-Chrosphere RP18 HPLC column gave excellent resolution of ergosterol in leaf extracts. Recovery of ergosterol added to leaf powder and methylcellulose ranged between 88 and 97%, but differences among leaf species were not significant. Conditions for liquid-liquid extraction from saponified extracts are critical in ergosterol analysis. Dark storage of samples does not lead to dramatic losses of ergosterol. Extensive sample clean up before HPLC injection is nonessential.