Improvements in the extraction of bacterial ATP from soil with field application

Abstract

An improved procedure for the preparation of an extractant and a demonstration of field applicability of that extractant for extracting microbial ATP from soil samples are reported. Precipitation difficulties that occurred during application of the six-component extractant developed in this laboratory [Webster et al. (1984) Soil Biol. Biochem., 16, 335] have been eliminated by division of the extractant into two mixes. Separate additions of phosphoric acid and/or EDTA at the time of extraction prevented the unwanted precipitation. Although a precipitate formed in the completed extractant, it did not affect ATP extraction from soil samples. A substitute detergent for Lubrol (which is no longer readily available) was selected; it is polyoxyethylene 10 lauryl ether and it functioned as well as Lubrol in the extraction of ATP from soil. Extraction procedures done using either a Brinkmann Polytron and wrist-action shaker (in the laboratory procedure) or a Waring blendor (for the field procedure) extracted equivalent amounts of ATP from soil. A detailed protocol is described that works well in the field. The procedure was made field-applicable by using a portable generator, desktop high speed centrifuge, and a normal laboratory luminometer.