Optimization of batch processes involving simultaneous enzymatic and microbial reactions.

Area of Science:

• Biochemical Engineering
• Biotechnology
• Process Optimization

Background:

• Simultaneous enzymatic and microbial reaction (SEMR) processes are crucial in biotechnology.
• Enzyme denaturation is a key factor affecting SEMR process efficiency.
• Optimizing enzyme addition strategies can significantly impact fermentation outcomes.

Purpose of the Study:

• To develop and present two general models for batch SEMR processes.
• To analyze the impact of enzyme addition rate strategies on fermentation performance.
• To determine optimal enzyme feeding strategies for ethanol and citric acid fermentations.

Main Methods:

• Development of two SEMR models, with the second accounting for enzyme denaturation.
• Simulation studies using literature-derived parameter values.
• Examination of linear enzyme addition rate strategies as a function of time.

Main Results:

• For ethanol fermentation using cellulose, optimal strategy is to add all enzyme at the beginning.
• For citric acid fermentation using cellulose, a linearly decreasing enzyme addition rate is superior to batch or constant feed.
• A small initial enzyme fraction combined with a decreasing rate enhanced citric acid production.

Conclusions:

• Enzyme addition strategy significantly influences SEMR process economics and efficiency.
• Optimal enzyme feeding varies depending on the specific fermentation (e.g., ethanol vs. citric acid).
• The developed models provide a framework for optimizing SEMR processes with enzyme denaturation.