Screening of New Enzyme Activities

There is a range of techniques for obtaining new enzyme activities  

In the age of recombinant DNA technology and genetic engineering-based methodologies, why is the search for new microorganisms or new enzyme activities still so important  

The criteria for success of a screening process with the goal of are  

The organism must deliver the desired enzyme in good yield and within a reasonably short time frame if possible, in submerged culture. 

The organism must produce the enzyme with inexpensive and accessible nutrients. 

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