August 1, 2012.
The definitive version is available at http://dx.doi.org/.
Biomass conversion to renewable biofuels provides an alternative to conventional fossil-fuel based transportation fuels and a means to reduce dependence on foreign oil. However, plant cell walls have evolved to be quite resistant to enzymatic deconstruction, a phenomenon generally termed biomass recalcitrance. As enzymes represent a substantial cost in biofuels production, there is significant impetus to understand and improve their efficiency in converting cell wall carbohydrates to fermentable sugars. Much research has been conducted on single "free" enzymes with one catalytic unit per protein and on the much larger, complexed "cellulosomes" with many tens of catalytic units per protein, but little work has been done on multi-domain enzymes that are an interpolation in size between free enzymes and cellulosomes. A bioinformatics study on multi-domain glycoside hydrolases was conducted to gather information on the various ways each family is found and organized in nature. GH61s, GH6s and GH7s in particular have been classified based on order of protein domain, catalytic domain, carbohydrate binding module, linker length, and origin. It is hoped that this will eventually become a complete database of multi-domain enzymes that will aid in the development of cost-effective methods of lignocellulosic biomass conversion.
Biochemistry, Biophysics, and Structural Biology
National Renewable Energy Laboratory (NREL)
This material is based upon work supported by the S.D. Bechtel, Jr. Foundation and by the National Science Foundation under Grant No. 0952013 and Grant No. 0833353. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the S.D. Bechtel, Jr. Foundation or the National Science Foundation. This project has also been made possible with support of the National Marine Sanctuary Foundation. The STAR program is administered by the Cal Poly Center for Excellence in Science and Mathematics Education (CESaME) on behalf of the California State University (CSU).