Premium
Comparison of Fatty Acid Methyl Ester (FAME) Methods for Characterizing Microbial Communities
Author(s) -
Schutter Mary E.,
Dick Richard P.
Publication year - 2000
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2000.6451659x
Subject(s) - soil water , loam , fatty acid , chemistry , extraction (chemistry) , fatty acid methyl ester , food science , botany , biology , chromatography , organic chemistry , ecology , biodiesel , catalysis
Fatty acid profiling is a popular method for characterizing microbial communities of natural systems. Direct extraction of microbial fatty acids in situ would be useful compared with methods that extract lipids first and subsequently release fatty acids from lipids. In this study, two methods for the direct extraction of fatty acids from soils were compared for three cultivated silt loams and one forested sandy clay loam. Fresh soils were analyzed for their fatty acid methyl ester (FAME) profiles by an ester‐linked (EL) method and the method of MIDI (Microbial ID, Inc., Newark, DE). Soils were stored four different ways (moist at 4°C, moist at −20°C, air‐dried at 25°C, and partially dry at 4°C) and analyzed for FAME profile changes after 30 and 90 d of storage. Eleven and 17 FAMEs were unique to the EL and MIDI method, respectively, but unique FAMEs generally were found in only minute amounts. Soils extracted with the MIDI method yielded more hydroxy FAMEs and short‐chain saturated and branched FAMEs. Conversely, EL‐extracted soils generally produced more long‐chain saturated and branched FAMEs, unsaturated FAMEs, and FAMEs with cyclopropane and methyl groups. Both extraction methods were able to differentiate among communities of different soil types, regardless if soils were fresh or stored. Changes in FAME profiles did occur in stored soils, but the effectiveness of each storage protocol for preserving FAME patterns over time was different among the four soils. While community analyses should be conducted on fresh soil, overall effects of storage were slight compared with those of extraction method and soil type.