Stable Isotope Probing of Microbial Phospholipid Fatty Acids in Environmental Samples

Methods Mol Biol. 2019:2046:45-55. doi: 10.1007/978-1-4939-9721-3_4.

Abstract

Phospholipid fatty acid (PLFA) extracted from environmental samples describe the microbial community pattern and are sensitive to monitor and quantify shifts in the microbial community. Linkage with the stable isotope technique adds a functional perspective and is frequently used to quantify carbon turnover in microbial communities and detect physiological changes. Here we present a PLFA extraction method by using an organic solvent water mixture, followed by lipid separation based on solid-phase extraction and an alkaline methylation. Finally, we provide a protocol for the carbon stable isotope measurements of the extracted fatty acid methyl esters (FAMEs) by gas chromatograph-isotope ratio mass spectrometer (GC-IRMS) and calculation of concentration and δ13CVPDB values.

Keywords: Alkaline methylation; Environmental samples; Fatty acid methyl ester; GC-IRMS; Lipid extraction; Microorganisms; Phospholipid fatty acid; Separation; Solid-phase extraction; Stable isotope probing.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbon Isotopes / analysis*
  • Fatty Acids / chemistry*
  • Fatty Acids / isolation & purification*
  • Gas Chromatography-Mass Spectrometry / methods
  • Isotope Labeling / methods*
  • Microbiota / physiology
  • Phospholipids / chemistry*
  • Phospholipids / isolation & purification*
  • Soil Microbiology
  • Solid Phase Extraction / methods

Substances

  • Carbon Isotopes
  • Fatty Acids
  • Phospholipids