23. Breaking Down Plant Materials for Energy
Jocelyn Rose
Jocelyn Rose, Plant Biology, and his research team discovered a class of plant enzymes that allows plant materials to be broken down more efficiently and at less cost than current technologies. The enzymes may make the production of cellulosic ethanol less expensive than corn-based ethanol. Despite its low cost, corn-based ethanol is not a long-term solution as an alternative energy source, so cellulose has become an increasingly key area of research. Producing cellulosic ethanol requires breaking down a plant’s cell wall material and fermenting the sugars that are released. Current technologies use microbial enzymes, cellulases, to digest the cellulose in grasses and rapidly growing trees such as poplars. The microbial enzymes have a structure that makes them very efficient at binding to and digesting plant cell wall material called lignocellulose. The new class of plant enzymes discovered by Rose’s group has a similar structure, while offering researchers new properties for producing ethanol even more efficiently. This is the first example of a cellulose-binding domain in a plant cell wall enzyme—enabling the enzyme to digest cellulose effectively. Although the new type of enzyme was first isolated in a tomato plant, Rose’s group has evidence that these plant proteins exist in many species that could be used for biofuel production. Biofuel research may also uncover new uses for these enzymes. The researchers now aim to understand how plants use this class of enzymes.