Cellulose hydrolysis in evolving substrate morphologies I: A general modeling formalism

Area of Science:

• Biomass Conversion
• Biochemical Engineering
• Enzyme Kinetics

Background:

• Cellulose hydrolysis is crucial for biofuel production but complex to model.
• Existing models often neglect substrate structural changes during enzymatic attack.
• Realistic modeling requires integrating substrate morphology evolution with enzyme kinetics.

Purpose of the Study:

• To develop a general, realistic rate equation modeling framework for cellulose hydrolysis.
• To explicitly account for the time evolution of substrate morphology during hydrolysis.
• To integrate novel geometrical concepts and site number representation for improved accuracy.

Main Methods:

• Developed a coupled morphology-plus-kinetics rate equation approach.
• Integrated novel geometrical concepts to capture time-dependent random substrate morphology.
• Introduced an innovative site number representation tracking available beta(1,4) glucosidic bonds.
• Formulated a reduced ordinary differential equation (ODE) system.

Main Results:

• The formalism quantitatively simulates hydrolytically evolving substrate morphology.
• It captures the significant effects of morphology on hydrolysis kinetics.
• The model provides a framework for simulating the entire solubilization process realistically.
• Reduced ODE system size compared to previous chain fragmentation kinetics approaches.

Conclusions:

• The developed framework enables realistic modeling of cellulose hydrolysis beyond the short-time limit.
• It accounts for substrate morphology changes, a previously neglected factor.
• This approach offers a more comprehensive understanding of the enzymatic cellulose conversion process.