After learning about cellulose in early high school, my vegetarian mind often wondered how much more energy I could have potentially obtained if humans had the ability to digest cellulose. Of course, with cellulose being the most common biopolymer on Earth, it seemed inevitable that one day, a scientist with a bold plan would develop a means of digesting cellulose, the component that builds the sturdy cell walls of plant. Since cellulose makes up 35-50% of a plant’s dry weight, the efficiency of eating plants would drastically increase if cellulose could be digested. Cellulose digestion can therefore have grand implications in the field of agriculture, as ranchers with livestock could feed their animals nearly 50% less under optimal circumstances.

However, the road to digesting cellulose is a long one. Before current research on cellulose, only one enzyme, cellulose synthase (CESA), of the cellulose constructing protein complex was known. Recently, researchers at Max Planck Institute of Molecular Plant Physiology in Potsdam, working with colleagues in the USA, identified another enzyme that may play a crucial role in the synthesis of cellulose. When researchers tested plants that could not form this newly identified protein, cellulose synthase-interactive protein (CSI1), they found that a much lower amount of cellulose was produced. This, of course, led to structural malformations in the plant.

Although the scientists have not completely ascertained the full scope of CSI1’s function, the identification of the protein remains a large step forward for the pursuit of cellulose digestion. Understanding the formation of cellulose and plant cell walls could prove to be key in increasing the digestibility of cellulose in animal feed, and could, in turn, spur agricultural production in the midst of a global food crisis.

Discussion Question: Can you foresee any problems if livestock or humans could digest cellulose?

News Article: http://www.sciencedaily.com/releases/2010/07/100720083254.htm

Journal Article: http://dx.doi.org/10.1073/pnas.1007092107