Understanding photosynthetic biofilm productivity and structure through 2D simulation

Area of Science:

• Biotechnology
• Biophysics
• Mathematical Modeling

Background:

• Microalgae biofilms are complex living systems with applications in biotechnology.
• Understanding their growth dynamics is crucial for optimizing cultivation and harvesting.

Purpose of the Study:

• To develop a spatial model for microalgae biofilm growth.
• To investigate the influence of biological and physical factors on biofilm structure.
• To determine optimal harvesting strategies for maximizing productivity.

Main Methods:

• A 2D spatial model incorporating photosynthesis, carbon accumulation, extracellular matrix production, and mortality.
• Kinetic laws regulated by light, nitrate, oxygen, and inorganic carbon.
• Mixture theory and conservation laws (mass and momentum) to describe component behavior.

Main Results:

• A 75 μm thick active region was identified as the primary driver of biofilm development.
• Optimal biofilm height and harvesting periods were determined for maximum productivity.
• Different harvesting patterns were evaluated, showing varied effects on biofilm structure.

Conclusions:

• The spatial model accurately simulates microalgae biofilm structural dynamics.
• Harvesting strategies must be tailored to specific objectives, such as total biofilm recovery versus algal biomass extraction.