Membrane-Freeze Concentration Hybrid for Temperature-Sensitive Biomolecules. Investigation, Application, and...

Area of Science:

• Biotechnology and Biochemical Engineering
• Food Science and Technology
• Separation Processes

Background:

• Existing membrane technologies and spray/freeze-drying methods present limitations, particularly concerning thermal stress for sensitive enzyme solutions.
• There is a need for advanced concentration techniques that preserve the integrity and activity of biomolecules.
• Freeze concentration is explored as a potential alternative to overcome thermal degradation issues.

Purpose of the Study:

• To investigate the limits of freeze concentration for concentrating sensitive enzyme solutions.
• To evaluate freeze concentration as a method to bridge the technology gap between membrane processes and spray/freeze-drying.
• To assess the economic feasibility of an integrated freeze concentration system.

Main Methods:

• Laboratory-scale experiments were conducted to determine the operational limits of freeze concentration.
• Investigated were parameters such as crystal size, viscosity, and solids content achievable during ice separation.
• An integrated system combining two-stage freeze concentration, filter-wash column, and ultrafiltration was designed and evaluated.

Main Results:

• Achieved average crystal sizes greater than 300 µm, even with high viscosity solutions.
• Demonstrated successful ice separation up to 42% solids and viscosities exceeding 1000 mm²s⁻¹.
• Confirmed no loss of enzyme activity during the concentration process.

Conclusions:

• Freeze concentration is a viable technology for concentrating enzyme solutions without thermal stress or activity loss.
• A two-stage freeze concentration system integrated with ultrafiltration shows significant potential for industrial application.
• The integrated system was found to be economically feasible in three out of four studied scenarios.