Microalgal kinetics - a guideline for photobioreactor design and process development.

Area of Science:

• Biochemical Engineering
• Photobiology
• Microalgal Biotechnology

Background:

• Traditional microalgal kinetics often borrow from heterotrophs, lacking mechanistic basis, especially for light harvesting.
• Oversimplified kinetic equations fail to capture complex intracellular mechanisms and accurately predict growth behavior.
• Understanding kinetics is crucial for reliable comparisons and simulations in microalgal cultivation.

Purpose of the Study:

• To present a mechanistic modeling approach for photoautotrophic microalgal growth.
• To emphasize the importance of distinguishing fundamental kinetic modules for accurate simulations.
• To guide the application of kinetics in photobioreactor design and process optimization.

Main Methods:

• Developed a modeling approach integrating physical and kinetic modules with literature-derived mechanistic foundations.
• Split the light submodel into distinct modules: light distribution, absorption, and photosynthetic sugar production.
• Incorporated nutrient uptake kinetics and their impact on carbon partitioning and anabolism.

Main Results:

• Demonstrated that a modular approach with independent parameters allows for transfer of kinetics across different reactor designs.
• Highlighted how nutrient uptake kinetics significantly influence carbon partitioning within cellular stoichiometry.
• Showcased applications of mechanistic kinetics for photobioreactor design, gassing, and nutrient optimization.

Conclusions:

• Mechanistic kinetic models are essential for accurate microalgal growth simulations and understanding physiological states.
• The proposed modular framework enhances the reliability and applicability of kinetic models in bioprocess engineering.
• Further comprehensive kinetic measurements are vital for advancing microalgal process development and optimization.