ABSTRACT
Enzymes are natural catalysts, usually proteins, capable of rapidly converting a substance into another by means of lowering the activation energy of the reaction involved. The source of an enzyme influences its availability, cost and degree of purity. Common sources of enzymes are animals, plants and microorganisms. Microbial enzymes are preferred for large scale biotechnological applications owing to the higher growth rate of microorganisms, generating large quantities of enzyme in short times, easy scale up and strain manipulation for over-expression. One aspect that deserves attention is the genetic improvement of the enzyme producing strain based on recombinant DNA technology. Whilst the role of microorganisms in fermentation processes was well described by Pasteur in 1876, the enzymatic mechanisms, on the other hand, have gained a better understanding only at the beginning of the 20th century. A general classification refers to industrial and special enzymes.
