Schwan's findings also suggested that alcoholic fermentation was due to a fungus or mold, i.e., yeast, and inoculation resulted in quicker fermentation. But microbiology is widely considered to have begun in 1857 when Pasteur reported his studies on lactic acid fermentation, including the microscopic features of the microorganisms and a suitable medium for the process; the scientific basis of industrial microbiology began with this paper.

In 1876, Cohn showed that bacterial spores have a high level of heat resistance and developed the technique of 'intermittent sterilization' for their inactivation. In 1897, Buchner demonstrated alcohol fermentation by cell-free yeast juice; he suggested that a proteinaceous enzyme was responsible for fermentation.
Wildiers demonstrated in 1901 that yeast required growth factors (vitamins) for growth, especially at low inoculum levels; vitamins are used in fermentation even today. In 1929, Alexander Fleming accidentally discovered penicillin produced by Penicillium growing as contaminant in a Petri plate of Staphylococcus.
Fleming developed the technique for assay of antibacterial activity of penicillin using bacteria and showed its low toxicity to man and animals. This was followed by an intensive search for antibiotics during the Second World War leading to the discovery of streptomycin, chloramphenicol, tetracyclines, etc.
Later developments have resulted in the use of metabolically blocked mutants of microorganisms, which accumulate large amounts of metabolic intermediates.