“Rosettazyme”: A Synthetic Cellulosome for Cellulose Ethanol Production

In the production of biofuel ethanol from lignocellulosic biomass, the cellulose molecules are usually broken down ("hydrolyzed" or "saccharified") by enzymes into simple sugars that can be fermented subsequently into ethanol. "Biomass recalcitrance" is the resistance of the cellulose molecules in lignocellulosic biomass to enzymatic hydrolysis, and is often a major bottleneck in the commercialization of cellulose-ethanol production technology. The use of cellulosomes is one research area which attempts to address biomass recalcitrance. The Center for Molecular Biophysics website describes cellulosomes as "large extracellular enzyme complexes that are produced by anaerobic bacteria and can efficiently break down plant cell wall polysaccharides, such as cellulose, hemicellulose and pectin into sugars." Structurally, they consist of a variety of enzymes arranged around a "scaffolding protein". Recently, an international team of scientists reported the construction of a cellulosome where the bound cellulase enzymes were observed to have increased cellulose-degrading ability compared to free enzymes in solution. They called the engineered multi-enzyme structures as "rosettazymes". Details of their study are published in the Journal of Biotechnology (URL above)

Related information on Cellulosomes: http://cmb.ornl.gov/research/cellulosome/cellulosome-design-for-cellulosic-ethanol