ABSTRACT
This chapter examines the state of the art in researchers’ understanding of the triggers that lead to successful cultivation of bacteria—and archaea—from soil. Some bacteria may need particular signal molecules to initiate cell division. Prior to the introduction of modern “omics” techniques in analyses of soil bacterial communities, investigations of bacterial diversity were hampered by the need to dispose of pure cultures of the relevant extant bacteria. As different bacteria have different nutritional requirements in order to grow, variation of nutrient level and range in the growth media may be successful to broaden the scope of isolation. The rationale behind five strategies to recover hitherto-uncultured bacteria is given as follows: reduced nutrient availability and long incubation times; addition of oxidative stress-protective agents; use of alternative solidifying agents; use of increased CO2 tension during incubation; and use of educated-guess-based differences in media compositions. The use of differentially diluted traditional agar media may recover different pools of organisms.
