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Assessing adsorbent-biomass interactions during expanded bed adsorption onto ion exchangers utilizing surface
RamiReddy Vennapusa1, Sara M Hunegnaw, Rosa B Cabrera
1Downstream Processing Laboratory, Jacobs University, Campus Ring 1, D-28759 Bremen, Germany.
Journal of Chromatography. A
|January 18, 2008
Summary
Understanding biomass adhesion to adsorbents is key for bioproduct purification. Surface energetics and the extended Derjaguin, Landau, Verwey, Overbeek (XDLVO) theory predict cell interaction, guiding optimized chromatography and material design.
Area of Science:
- Biochemical Engineering
- Surface Science
- Separation Science
Background:
- Biomass adhesion and aggregation negatively impact bioproduct downstream processing.
- Quantitative understanding of biomass-adsorbent interactions is crucial for process optimization.
Purpose of the Study:
- To quantitatively describe biomass-adsorbent interactions using surface energetics.
- To predict biomass adhesion behavior on various surfaces relevant to biochemical and environmental applications.
- To provide a universal methodological approach for process and material design.
Main Methods:
- Utilized an indirect thermodynamic approach with contact angle and zeta potential measurements.
- Employed intact yeast cells, yeast homogenates, and disrupted bacterial paste as model systems.
- Applied the extended Derjaguin, Landau, Verwey, Overbeek (XDLVO) theory to model biomass adhesion.
Main Results:
- The extended XDLVO theory successfully predicted biomass adhesion behavior.
- Cell attachment to anion-exchange supports involves strong secondary minimum interactions and aggregation.
- Cell interaction with cation-exchange materials occurs in a reversible secondary minimum at longer distances.
Conclusions:
- Established process buffer conductivity windows for anion-exchange chromatography (AEX) and cation-exchange chromatography (CEX).
- Determined that increased hydrodynamic shear is needed to prevent biomass attachment to AEX compared to CEX.
- Demonstrated that biomass aggregation is dependent on contact time and concentration, informing expanded bed adsorption methods.
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