Three-dimensional biofilm model with individual cells and continuum EPS matrix

Area of Science:

• Microbial Ecology
• Biophysics
• Computational Biology

Background:

• Biofilms are complex microbial communities encased in an extracellular polymeric substance (EPS) matrix.
• Existing models often simplify either microbial cell behavior or matrix dynamics, limiting realism.
• Understanding biofilm structure and development is crucial for various applications, from medicine to industrial processes.

Purpose of the Study:

• To develop an innovative hybrid biofilm model integrating discrete microbial cells and a continuum matrix representation.
• To realistically simulate the temporal development of biofilm structure in 2D and 3D.
• To investigate biofilm consolidation and micro-colony formation mechanisms.

Main Methods:

• A hybrid modeling approach combining individual-based microbial particle descriptions with continuum matrix representation.
• Incorporation of soluble components (substrates, metabolic products) with diffusion and reaction dynamics.
• Modeling cell growth, division, EPS production, cell movement (pushing and advection), and detachment/attachment processes.

Main Results:

• The hybrid model accurately captures biofilm temporal development and structure.
• Demonstrated biofilm consolidation via EPS and cell degradation, leading to denser cell layers and irregular surfaces under nutrient limitation.
• Investigated micro-colony formation of autotrophic bacteria within an EPS matrix produced by heterotrophic cells, comparing colony size and shape.

Conclusions:

• The hybrid model offers a more realistic description of biofilm dynamics than traditional approaches.
• The model provides insights into biofilm consolidation and micro-colony formation under specific conditions.
• This approach enhances the understanding of complex multispecies biofilm development and structure.