Comparison of Methods for Extracting Adenosine Triphosphate from Three High-Latitude Soils

Abstract

Adenosine triphosphate (ATP) in soil has been used as an index of soil microbial biomass, but efficient extraction of ATP from soil is often a problem. The objective of this study was to find an ATP extraction procedure which is simple, can be readily adapted to routine extraction of ATP at remote field locations, and is efficient at extracting ATP from soils, especially high-latitude soils. None of the six methods tested was ideally suited for all of the soils used. The boiling tris, butanol-octanol, and sodium bicarbonate-chloroform procedures could be easily adapted for use at remote field sites but gave very poor recoveries of added ATP for at least some of the soils tested. Measurement of ATP after extraction with the trichloroacetic acid-phosphate-paraquat method was impossible due to very high quenching of emitted light. For added cellular ATP, the phosphoric acid-urea-DMSO-adenosine-EDTA-Zwittergent (Web) procedure gave the highest recoveries, 77 and 64%, respectively, for a subarctic agricultural soil and an arctic tundra organic horizon, but only 10% for a crude-oil-contaminated subarctic forest soil, while the benzalkonium chloride-sulfuric acid-phosphate (BCl-S-P) procedure gave recoveries of 13, 10, and 20% from the agricultural soil, oiled soil, and tundra soil, respectively. The Web method could not be easily adapted for remote-field extractions but the latter could, and for studies in which low recoveries of ATP are acceptable, the BCl-S-P procedure would be the most suitable procedure of those tested.