Exploring the unknown

Comparing shape and development has permitted biologists to classify all known animals and plants into more than one million and some half a million species, respectively. For micro‐organisms, however, such morphological criteria are much less suited. Complemented by biochemical criteria, taxonomists were at least able to order the micro‐organisms responsible for infectious diseases in humans, plants and animals. But only about 5000 prokaryotic organisms have so far been formally described, which represents barely one percent of the existing bacterial species (Pace, 1997). This situation will probably change as soon as it is accepted that micro‐organisms produce substances beneficial in the therapy of human diseases or for industrial applications.> The interest in microbiology will grow as soon as expectations become confirmed that micro‐organisms produce substances beneficial in the therapy of human diseases or in industrial applicationsThe biomass of micro‐organisms on our planet is estimated to be much more important than that of plants. Prokaryotes are the basis of every food chain on this planet. They still dwell where higher organisms cannot survive, not only on the surface, but also deep in the oceans and in the earth. But even today, the popular view of micro‐organisms is focused nearly exclusively on those that cause disease. Few are aware of their additional benefits, namely in the fermentation of dairy products, sausages and beverages. But their indispensable presence and necessity in natural biotopes—which includes our digestive tract for instance—is still not commonly accepted. During an excursion to a Swiss lake, I recently heard a perfect exposition of aquatic food chains by a young biologist: to my great surprise he started with the plankton and completely omitted the important role of micro‐organisms in feeding and thus sustaining it. This narrow view has certainly something to do with the obsolete taxonomy, which, as we have …