DIN ISO/TS 29843-1:2011-07

This part of ISO/TS 29843 specifies an extended method for the extraction and determination of both phospholipid fatty acids (PLFA) and phospholipid ether lipids (PLEL) from soils. ISO/TS 29843-2 describes a simple method for the extraction of only PLFA from soils. Phospholipids are essential components of membranes of all living cells, and their fatty acids (PLFA: phospholipid fatty acids) or ether-linked isoprenoid side chains (PLEL: phospholipid ether lipid) allow for taxonomic differentiation within complex microbial communities. This approach is now well established in soil ecology and serves as a phenotypic and thus complementary tool to genotypic (= molecular genetic) approaches for determining microbial diversity. Different methodologies for determination of soil fatty acids are available. These methodologies present different levels of complexity when applied and provide different levels of resolution in the description of soil microbial communities. The determination of total PLFA and PLEL provides a quantitative measure of the viable biomass of soil: microorganisms of all three domains of the biosphere (bacteria, fungi and archaebacteria). Viable microbes have an intact membrane, which contains phospholipids. Cellular enzymes hydrolyze and release the phosphate group within minutes or hours following cell death. Apart from taxonomic descriptions, the PLFA technique enables the determination of physiological changes within microbial consortia. The Committee responsible for this document is NA 119-01-02-04 UA "Biologische Verfahren" ("Biological methods") at DIN.