Enzymes are biological components produced from amino acids by digesting food proteins. They play major role in control of major chemical reactions occurring in our body. Many enzymes are produced by microorganisms. Researchers have isolated specific microorganisms from extreme sources under extreme culture conditions, with the objective that such isolated microbes would possess the capability to synthesize special enzymes. The microbial enzymes act as biocatalysts to perform reactions in bio-processes in an economical and environmentally-friendly way as opposed to the use of chemical catalysts. Such enzymes have proven their utility in industries such as food, leather, textiles, animal feed, and in bio-conversions and bioremediations. Microbial enzymes play an important role in the diagnosis, cure and monitoring of different diseases. In this review, we have discussed the main properties of enzymes, types of enzymes including proteases, amylases and many others along with their screening methods and their known biotechnological applications.