New Technique for Studying Enzymes Aids Biofuels Researchers

Researchers from the University of California (UC) Berkeley and Lawrence Berkeley National Laboratory (Berkeley Lab) have developed a technique that can allow them to design better mixtures of cellulase enzymes that are optimally matched with the structure of particular biomass substrates.

The Berkeley researchers reported in the journal Nature Chemical Biology the results of their study that shed new light on the catalytic activity of cellulases, that degrade cellulosic biomass of grass and wood to release fermentable sugars into ethanol. Mixtures of cellulase enzymes are normally used because individual cellulases interact preferentially with cellulose structures based on their distinct structural organizations. Increasing the fermentable sugar yields from cellulosic biomass can boost biofuel production. A key challenge is to reduce the cost of extracting fermentable sugars by optimizing the collective activity of cellulase enzymes.

The researchers employed the technique known as PALM (Photo-Activated Localization Microscopy ) where target enzymes are tagged with molecules that emit light when activated by weak ultraviolet light. By photoactivating individual cellulase enzymes, the researchers were able to track their specific locations as they bind with the cellulose substrates. Their results showed that cellulases exhibit specificities to different cellulose structures, ranging from the highly ordered to the highly disordered. They also developed a means to show that a valuable synergy can be generated by combining cellulases that bind to similar but not identical cellulose structural organizations.

The said technique can be used to determine the optimum combination of cellulases by matching them to the structural organizations of particular biomass substrates. This will increase the efficiency of cellulose breakdown into fermentable sugar, which in turn will help reduce biofuel production costs.