06/02/2011

Solving the Mysteries of Cellobiose Stability Using High-Performance Computing

Summary

Cellobiose, a two glucose basic repeat unit of cellulose, is formed in enzymatic or acidic hydrolysis of plant biomass and is the precursor compound that microbes digest to produce cellulosic biofuels. Because this process happens outside of the microbial cell, understanding the structure and stability of cellobiose in solution provides a framework for improving microbial biofuel production. Interestingly, the low-temperature, gas-phase stable, preferred structure of cellobiose is cis, while the high temperature structure is trans. However, in cellulose itself, cellobiose is always in the trans state. Researchers believe that the stability of trans-cellobiose could be due to the water environment that surrounds it. Now, an international collaborative study has found that water molecules hydrate cellobiose collectively instead of binding to cellobiose separately and sequentially as was previously assumed. The team used DOE’s National Energy Research Scientific Computing Center, a high-performance computing facility, to simulate cellobiose dynamics together with vibrational spectroscopy experiments. Their results suggest that water dynamics could play a critical role in determining the most stable structure of cellobiose. The next step in this research will be to produce a simulation of cellobiose that includes the quantum and dynamically polar nature of water. It is anticipated that this new research will provide insight into how to optimize the hydrolysis of plant-derived cellulose, a key step in the production of biofuels. The computational aspects of the research were funded by DOE’s SciDAC program.

References

Pincu, M., et al. 2011. “Isotopic Hydration of Cellobiose: Vibrational Spectroscopy and Dynamical Simulations,” Journal of Physical Chemistry A, DOI: 10.1021/jp112109p.