Xylanases.

Many microbes and fungi that feed off dead and decaying plant material have developed ways of breaking down the abundant sugar polymers found in plant material, to provide a source of carbohydrates for their own needs.  The breakdown of sugar polymers is achieved by enzymes that are secreted by the microbial cells, amongst which are enzymes called xylanases which catalyse the conversion of the the plant polymer xylan to the simple 5-carbon sugar xylose. 

This chemical conversion not only alters the mechanical properties of plant fibres, but can also can increase the amount of sugars that can be obtained from plant material, and xylanases are being used in an increasing variety of biotechnological and industrial applications. Many industrial processes work at high temperatures, conditions in which most enzymes lose their native 3D structures, and consequently their catalytic capabilities. However, certain enzymes are temperature resistant, and may even work best at higher temperatures and these thermostable enzymes are potential candidates for development for industrial uses.  We are exploring the structural basis of thermostability of xylanses by simulating the process of Darwinian natural selection through the application of the powerful technique of directed evolution.