Micro-organisms are the oldest inhabitants of earth. They are masters in versality and adaptability to the changing environment. They will definitely prove to be most cost effective partners in our efforts for sustainable development. The microorganisms influence the man in several ways. The diversity of their activities varies from causing diseases in human and other animals and plants to the production of various useful products. Microbes have a very significant role in the era of biotechnology and hence microbiology has today come forth as one of the most demanding subject in the science stream of graduate and post graduate courses.