Human interactions with microbes
Human interactions with microbes include both practical and symbolic uses of microbes, and negative interactions in the form of human, domestic animal, and crop diseases. Practical use of microbes began in ancient times with fermentation in food processing; bread, beer and wine have been produced by yeasts from the dawn of civilisation, such as in ancient Egypt. More recently, microbes have been used in activities from biological warfare to the production of chemicals by fermentation, as industrial chemists discover how to manufacture a widening variety of organic chemicals including enzymes and bioactive molecules such as hormones and competitive inhibitors for use as medicines. Fermentation is used, too, to produce substitutes for fossil fuels in forms such as ethanol and methane; fuels may also be produced by algae. Anaerobic microorganisms are important in sewage treatment.