Foam Fractionation Techniques for Wastewater Protein Recovery

Foam fractionation is a separation process that exploits the adsorption of surface‐active proteins at gas–liquid interfaces to concentrate and recover dilute biomolecules from aqueous streams. This methodology is particularly well suited to wastewater protein recovery, where feed streams are often of low protein concentration and contain complex mixtures of organic matter. The process can be operated in discrete or continuous modes, using rising‐foam columns or batch spargers, and may employ surfactants to enhance foam stability or resort to surfactant‐free strategies to preserve protein activity. Key performance metrics include recovery yield, enrichment ratio and selectivity, which are influenced by parameters such as pH, ionic strength, gas flow rate and bubble size. Adjusting pH to the protein’s isoelectric point, for example, minimises aggregation at the interface and maximises foamability. Recent engineered solutions include the use of genetically encoded foam‐stabilising tags to facilitate selective adsorption without additional chemicals. Foam fractionation offers a low‐energy, scalable and sustainable route to transform wastewater from a liability into a resource, yielding proteins for animal feed, fertiliser or industrial enzymes while reducing environmental impact.

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Foam Fractionation Techniques for Wastewater Protein Recovery publication trend

The graph below shows the total number of articles in foam fractionation techniques for wastewater protein recovery across all publications each year (not limited to Nature Index journals).

Technical terms

Foam fractionation: A technique using rising bubbles to adsorb and separate surface‐active proteins from liquid mixtures.

Gas–liquid interface: The boundary between gas bubbles and the surrounding liquid where proteins accumulate.

Enrichment ratio: The concentration of target protein in the foamate relative to its concentration in the feed solution.

Surfactant: A compound that lowers surface tension and stabilises foam, used to enhance or inhibit protein adsorption.

Isoelectric point: The pH at which a protein carries no net electrical charge, often correlating with minimal solubility and interfacial aggregation.

References

1. Foam fractionation Tags (F-Tags) enabling surfactant-free, activity-preserving recovery of enzymes. Applied Microbiology and Biotechnology (2024).
2. Role of pH-induced structural change in protein aggregation in foam fractionation of bovine serum albumin. Biotechnology Reports (2016).
3. Competitive adsorption of surfactant–protein mixtures in a continuous stripping mode foam fractionation column. Chemical Engineering Science (2016).