Microscopic fungi
 

Only microscopic fungi are part of the micro-organisms: they are eukaryotic cells. The most significant group is yeasts' group, first micro-organism which has been used by the Man for the production of alcoholic drinks (since Antiquity). Pasteur's work on the yeast was the first step to the microbiology. Nowadays, those microorganisms are well-used in biomedical research and biotechnology.