ABSTRACT
Soil microbial communities are incredibly complex, with estimates of more than 4000
bacterial genomes in a single soil sample (Torsvik et al. 1990; Amann et al. 1995). However,
evidence has shown that less than 1% of soil bacteria are cultivable using common laboratory
media under standard conditions (Torsvik et al. 1990; Ovreas and Torsvik 1998). Therefore,
it is important to choose a method of community analysis that does not rely on isolation and
cultivation techniques. Methods that extract cellular components that are representative of
most bacterial species directly from soils have become popular. These methods are based on
the characterization of bacterial cell constituents such as lipids and nucleic acids that can be
directly extracted from a soil sample without the need for isolating bacterial cells
(Drenovsky et al. 2004). This chapter will focus on lipid-based community analysis, while
nucleic acid based methods are described in Chapter 43.
