ABSTRACT

Determining the community structure of a microbial assemblage is one of the greatest challenges facing microbial ecologists. Unlike eukaryotes, the morphology of prokaryotes often yields little or no information concerning the phylogenetic affiliation or the ecological role of the organisms. Classical approaches utilize enrichment and isolation of microorganisms. These approaches are suitable for biochemical, taxonomic, or autecological studies, but it is clear that most microorganisms in the environment are viable but not culturable and that these methods will not produce a quantitative description of microbial assemblages. Lipid analysis offers an alternative method for the quantification of microbial community structure that does not rely upon the cultivation of microorganisms and that is free of potential selections of the biochemical compounds to be analyzed. This chapter reviews methodology for the quantitative recovery of phospholipid fatty acids from environmental samples and illustrates the interpretation of fatty acid profiles and their usefulness in determining microbial community structure.