Location: Cotton Structure and Quality ResearchTitle: Unraveling cellulose microfibrils: a twisted tale Author
|French, Alfred - Al|
Submitted to: Biopolymers
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/3/2013
Publication Date: 10/1/2013
Publication URL: http://handle.nal.usda.gov/10113/57725
Citation: Hadden, J.A., French, A.D., Woods, R.J. 2013. Unraveling cellulose microfibrils: a twisted tale. Biopolymers. 99(10):746-756. Interpretive Summary: There are several levels of structure in the cotton fiber, but at one very important level, cotton is seen to be composed mostly of microfibrils that are very small crystals of the molecule cellulose. These crystals play important roles in the chemical and physical properties of cotton, including interaction with water, various other chemicals, and enzymes that are used in finishing cotton. It has been very difficult to understand the nature of these particles from purely experimental methods so it has been interesting to study them by computerized molecular modeling. However, the results from these studies have been confusing and in disagreement with the experimental findings, especially in regard to a twist that is observed in the models but seldom in the experiments. The present study examines many of the assumptions that are inherent in the computerized modeling work in regard to the twisting. As more sophisticated treatments were used in the modeling, the degree of twist was reduced. This information is primarily of interest to scientists studying the structure and properties of cotton and various other cellulosic materials, including biomass being prepared for various types of biorefining.
Technical Abstract: Molecular dynamics (MD) simulations of hydrated cellulose microfibrils are attractive to the textiles industry for their capacity to characterize water interactions with cotton fiber, as well as to the biofuels industry for their potential to provide insight toward efficient mechanisms for conversion of cellulose to ethanol. Previous studies of microfibrils based on high resolution X-ray and neutron diffraction data found that these linearly oriented structures tend to adopt a right-handed twist when subjected to MD simulation, suggesting possible limitations in the underlying computational methodology. This work aims to elucidate the driving forces of microfibril twisting, as well as to identify possible artifacts introduced by system design and parameterization in order to enhance general understanding of hydrated microfibril behavior and shed light on how best to apply MD simulation for its study in broader contexts.