A SIMPLIFIED METHOD FOR EXTRACTION OF ERGOSTEROL FROM SOIL

Ergosterol is a sterol common to many fungi and may be useful for esti mating fungal biomass in soil. Our objective was to compare three diff erent methods for extracting ergosterol from soil. These included: (i) a published method that involves extraction with methanol, saponifica tion with KOH, and separation with hexane before analysis using high-p ressure liquid chromatography (HPLC); (ii) a recently published superc ritical fluid extraction (SFE) method; and (iii) a simplified extracti on method developed in our laboratory that is similar to method (i) bu t requires 80 to 90% less reagents. Similar quantities of ergosterol w ere extracted from both prairie and cropland soil with method (i) and with simplified method (iii). In contrast, the SFE method (ii) did not recover naturally occurring ergosterol from soil. Extraction effcienc ies of ergosterol standards added to soil were between 75 and 88% for the three procedures, with coefficients of variation of <15% for all m ethods. Our simplified method substantially reduced cost, extraction t ime, and chemical waste per sample. Results of this study indicate tha t the simplified method was the most efficient technique for extractio n of ergosterol from soil.