Biotechnology is broadly defined as the application of scientific and engineering principles to produce valuable substances by deploying biological agents. Here, the biological agents are not only limited to microorganisms but animals and plants are also being used for the purpose. The substances referred here are renewable materials produced by the biological agents for food, feed, beverages, pharmaceuticals and industrial uses. Today, scientists can isolate any gene of interest from any organism or part thereof and incorporate it into a small self-replicating extrachromosomal genetic element for multiplication as well as expression of the gene. The recombinant DNA molecule thus produced can be introduced into host cells such as bacteria or yeast to grow large vats or fermenters full of the recombinant organism.