Fermentation uses microorganisms to convert raw materials to product.
Strictly speaking, fermentation is microorganism metabolism on a carbon. Fermentation processes include chemical reactions such as oxidations, reductions, polymerizations, and hydrolysis, as well as biosynthesis and the formation of cells. The rate of fermentation depends on the concentration of microorganisms, cells, cellular components, and enzymes as well as temperature and pH. Product recovery always involves the concentration of the dilute solution. Products may be excreted into the broth whether or not products are excreted by the micoorganisms. In the conventional batch process, the reactor is filled with a sterile nutrient substrate and inoculated with the microorganism.