microbiology

Study of micro-organisms, mostly viruses and single-celled organisms such as bacteria, protozoa, and yeasts. The practical applications of microbiology are in medicine (since many micro-organisms cause disease); in brewing, baking, and other food and beverage processes, where the micro-organisms carry out fermentation; and in genetic engineering, which is creating increasing interest in the field of microbiology. This discipline is also crucial for our understanding of the ecology and evolution of life on Earth, which for 2/3 of its history was inhabited exclusively by microbes.