From three-dimensional morphology to effective diffusivity in filamentous fungal pellets

Area of Science:

• Biotechnology
• Bioprocess Engineering
• Mycology

Background:

• Filamentous fungi are vital cell factories in biotechnology, producing valuable compounds.
• Fungal morphology during submerged cultivation significantly influences process productivity.
• Fungal pellets can impede the diffusion of essential substances like oxygen, substrates, and products.

Purpose of the Study:

• To develop a novel approach for determining effective diffusivity within fungal pellets based on their 3D morphology.
• To investigate the relationship between the effective diffusion factor and the hyphal fraction within fungal pellets.
• To provide more accurate data for optimizing fungal pellet morphology in biotechnological applications.

Main Methods:

• Utilized X-ray microcomputed tomography to capture 3D morphology of freeze-dried Aspergillus niger pellets.
• Reconstructed 3D images and processed them to create representative pellet cubes.
• Performed diffusion computations on these cubes using GeoDict software to calculate effective diffusion factor and tortuosity.

Main Results:

• Successfully correlated the effective diffusion factor with the hyphal fraction within fungal pellet cubes.
• Observed significant deviations from previously reported correlations in the literature.
• Generated new, more accurate insights into mass transport within fungal pellets.

Conclusions:

• The developed method provides a more precise understanding of diffusion dynamics within fungal pellets.
• The findings offer valuable data for optimizing fungal pellet morphology to enhance yields in biotechnological processes.
• This research contributes to improving the efficiency of fungal cell factories.