The Shape of Native Plant Cellulose Microfibrils

Area of Science:

• Plant biology
• Biophysics
• Materials science

Background:

• Plant cellulose microfibrils are fundamental components of plant cell walls.
• Understanding microfibril structure is key to optimizing cellulose conversion for biofuels.
• Recent findings indicate microfibrils comprise 18 cellulose chains, not 36.

Purpose of the Study:

• To model and evaluate potential shapes of the 18-chain plant cellulose microfibril.
• To determine the most probable structural arrangement using computational methods.
• To correlate theoretical models with experimental data.

Main Methods:

• Utilizing density functional theory (DFT) calculations.
• Modeling three distinct structural arrangements (habits) for the 18-chain microfibril.
• Comparing calculated energies, structures, 13C NMR chemical shifts, and WAXS diffractograms.

Main Results:

• All three modeled habits partially reproduced experimental data.
• A 5-layer, 34443 arrangement showed the highest theoretical energy favorability.
• A 234432 arrangement was less favored, and a 6x3 arrangement was improbable.

Conclusions:

• The 5-layer, 34443 arrangement is the most probable structure for the 18-chain cellulose microfibril.
• Computational modeling provides valuable insights into plant cellulose microfibril architecture.
• This refined understanding aids in improving biofuel production efficiency.