New Dimensions in Microbiology: An Introduction

Microbiology - a century on from Koch's pioneering development of monoculture techniques - is steadily changing from traditional studies of pure cultures and their growth on single substrates to those in which new dimensions are being added. These new dimensions include the analysis of mixed substrates, mixed cultures and multiphase systems in which microorganisms grow on or within solid substrates. While it has long been recognized that metabolism of complex substrate mixtures, such as the contents of the rumen, may require a complex community of microorganisms, a new concept is the metabolism of single substrates, whether complex or simple, by stable communities of different organisms, so stable that some have been handled for years as monocultures and named accordingly. Finally, the widespread occurrence of genetic exchange between microorganisms has introduced an entirely new dimension to the older ideas of stable organisms only altering their metabolic potentialities by rare mutational events.