Purification of proteins from fermentation broth using membrane filtration
(2026) METM01 20261Chemical Engineering (M.Sc.Eng.)
- Abstract
- Protein recovery from fermentation broths remains a challenge in downstream bioprocessing due to the complex composition of fermentation media. This study investigated a cascade microfiltration–ultrafiltration (MF–UF) process for protein clarification and concentration from a whey protein-based model fermentation broth. The work evaluated membrane performance, fouling behavior, cleaning efficiency, and the potential for process scale-up.
MF and UF experiments were performed using model solutions containing whey protein, salts, and yeast cells. Ceramic MF membranes with pore sizes of 0.2 µm and 0.8 µm were evaluated for broth clarification, while polymeric UF membranes with molecular weight cut-offs of 100 kDa and 10 kDa were... (More) - Protein recovery from fermentation broths remains a challenge in downstream bioprocessing due to the complex composition of fermentation media. This study investigated a cascade microfiltration–ultrafiltration (MF–UF) process for protein clarification and concentration from a whey protein-based model fermentation broth. The work evaluated membrane performance, fouling behavior, cleaning efficiency, and the potential for process scale-up.
MF and UF experiments were performed using model solutions containing whey protein, salts, and yeast cells. Ceramic MF membranes with pore sizes of 0.2 µm and 0.8 µm were evaluated for broth clarification, while polymeric UF membranes with molecular weight cut-offs of 100 kDa and 10 kDa were investigated for protein concentration. Membrane performance was assessed based on permeate flux, cell retention, and protein retention. Protein concentration was determined using Bradford assay, while membrane fouling and cleaning behavior were evaluated through pure water flux measurements.
Both MF membranes effectively clarified the model fermentation broth, although membrane performance depended on pore size, yeast concentration, and transmembrane pressure. At lower yeast concentrations, the 0.8 µm membrane achieved higher permeate flux, whereas the 0.2 µm membrane performed better at higher yeast concentrations. During UF, both membranes exhibited similar flux behavior and approached limiting flux conditions at elevated pressures. High flux recovery after cleaning indicated that a large proportion of membrane fouling was reversible. The 10 kDa membrane showed higher protein retention at low TMPs, while retention became comparable for both membranes at higher pressures.
The UF concentration study demonstrated stable filtration performance, achieving an average permeate flux of approximately 26 LMH and an average protein retention of 98.1% up to 70% volume reduction. A preliminary process design and scale-up assessment was further performed, demonstrating how laboratory-scale filtration data can be translated into an industrial UF membrane process design. (Less) - Popular Abstract
- Protein production through fermentation is becoming increasingly important in the food and biotechnology industries. During fermentation, microorganisms produce valuable proteins that can be used in products such as food ingredients, enzymes, and biopharmaceuticals. However, separating these proteins from the fermentation broth is difficult because the broth contains a complex mixture of cells, salts, nutrients, and other biological compounds. Efficient purification methods are therefore necessary to recover proteins while maintaining product quality and reducing processing costs.
One promising alternative for protein purification is membrane filtration. Membranes act as selective barriers that separate particles and molecules based on... (More) - Protein production through fermentation is becoming increasingly important in the food and biotechnology industries. During fermentation, microorganisms produce valuable proteins that can be used in products such as food ingredients, enzymes, and biopharmaceuticals. However, separating these proteins from the fermentation broth is difficult because the broth contains a complex mixture of cells, salts, nutrients, and other biological compounds. Efficient purification methods are therefore necessary to recover proteins while maintaining product quality and reducing processing costs.
One promising alternative for protein purification is membrane filtration. Membranes act as selective barriers that separate particles and molecules based on their size. In this study, microfiltration was used to remove yeast cells and clarify the fermentation broth, while ultrafiltration was used to concentrate proteins. Compared with some conventional purification methods, membrane processes can operate continuously, require lower energy consumption, and are relatively simple to scale up for industrial applications.
Different membrane materials and operating conditions were tested to evaluate how they influenced filtration performance. The study investigated how membrane pore size, operating pressure, and yeast concentration affected fermentation broth clarification, protein retention, and membrane fouling behavior. In addition, the ability of the ultrafiltration membrane system to concentrate proteins during progressive volume reduction was evaluated.
The results showed that membrane behavior depended on membrane pore size, operating pressure, and the concentration of yeast in the fermentation broth. The microfiltration experiments demonstrated how different ceramic membranes influenced clarification performance and fouling behavior under different broth conditions. In the ultrafiltration experiments, the two membranes tested showed similar filtration behavior, while the tighter membrane achieved better protein retention during concentration. Membrane fouling occurred during filtration, but a large portion of the permeability could be recovered after chemical cleaning.
This work shows the potential of membrane filtration as a separation method for future biotechnology and sustainable protein production processes. Improved understanding of membrane fouling, clarification behavior, and protein concentration can contribute to the development of more efficient downstream processing systems with lower energy and chemical consumption. The findings of this study may also support future optimization and scale-up of membrane-based protein recovery processes for industrial fermentation applications.
The experimental results were also used to develop a preliminary industrial-scale membrane process design, illustrating how laboratory findings can be translated into practical protein recovery applications. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/student-papers/record/9242582
- author
- Haileslassie, Tsegazeab Gebreslassie LU
- supervisor
- organization
- course
- METM01 20261
- year
- 2026
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- Fermentation broth, Protein purification, Downstream processing, Microfiltration, Ultrafiltration, Parametric study, Concentration study, Membrane engineering
- language
- English
- id
- 9242582
- date added to LUP
- 2026-06-24 09:01:43
- date last changed
- 2026-09-24 09:02:04
@misc{9242582,
abstract = {{Protein recovery from fermentation broths remains a challenge in downstream bioprocessing due to the complex composition of fermentation media. This study investigated a cascade microfiltration–ultrafiltration (MF–UF) process for protein clarification and concentration from a whey protein-based model fermentation broth. The work evaluated membrane performance, fouling behavior, cleaning efficiency, and the potential for process scale-up.
MF and UF experiments were performed using model solutions containing whey protein, salts, and yeast cells. Ceramic MF membranes with pore sizes of 0.2 µm and 0.8 µm were evaluated for broth clarification, while polymeric UF membranes with molecular weight cut-offs of 100 kDa and 10 kDa were investigated for protein concentration. Membrane performance was assessed based on permeate flux, cell retention, and protein retention. Protein concentration was determined using Bradford assay, while membrane fouling and cleaning behavior were evaluated through pure water flux measurements.
Both MF membranes effectively clarified the model fermentation broth, although membrane performance depended on pore size, yeast concentration, and transmembrane pressure. At lower yeast concentrations, the 0.8 µm membrane achieved higher permeate flux, whereas the 0.2 µm membrane performed better at higher yeast concentrations. During UF, both membranes exhibited similar flux behavior and approached limiting flux conditions at elevated pressures. High flux recovery after cleaning indicated that a large proportion of membrane fouling was reversible. The 10 kDa membrane showed higher protein retention at low TMPs, while retention became comparable for both membranes at higher pressures.
The UF concentration study demonstrated stable filtration performance, achieving an average permeate flux of approximately 26 LMH and an average protein retention of 98.1% up to 70% volume reduction. A preliminary process design and scale-up assessment was further performed, demonstrating how laboratory-scale filtration data can be translated into an industrial UF membrane process design.}},
author = {{Haileslassie, Tsegazeab Gebreslassie}},
language = {{eng}},
note = {{Student Paper}},
title = {{Purification of proteins from fermentation broth using membrane filtration}},
year = {{2026}},
}