Enzyme Identification and Screening: Activity-Based Methods

Methods for the identification and characterization of “ideal” enzymes for industrial use in the field of biotechnology have developed rapidly in recent years. The use of activity-based methods for enzyme identification from natural resources such as the metagenome allows the discovery of biocatalysts. The main advantage of activity-based screening is the direct identification of desired enzyme activities completely independent of any knowledge about the sequence or structure of an enzyme. In this way, activity-based screening also enables the identification of new, previously unknown enzymes. This chapter describes current methods for identifying enzyme activities from natural resources. In which resources can new enzymes be searched for? What is the “ideal” enzyme? Why is gene expression so important? Which screening methods are established today? All this is explained in this chapter. The focus is on high- to low-throughput assays such as selective agar plate assays or fluorescence-activated cell sorting, as well as on liquid assays in 96-well plate format or chromatographic methods. By describing the advantages and disadvantages of each method, you will learn when which screening method is appropriate and what requirements must be met to perform an efficient screening.