Work

Bare magnetic iron oxides for binding and selective elution of lactoferrin from acid whey

Year: 2025

Type: article

Abstract: Bare iron oxide nanoparticles (BIONs) can isolate the dilute but valuable protein lactoferrin (LF) from dairy by-products through magnetic separation. While BIONs can be produced in large quantities at a reasonable price and can act as ion-exchanging material, the binding behaviors of biomolecules to BIONs in complex mixtures need to be better understood. Using a combination of static binding studies and zeta potential measurements, we investigated how whey salts and the whey proteins β-lactoglobulin, bovine serum albumin, and α-lactalbumin influence the binding of LF to BIONs. Zeta potential measurements revealed that whey salts induce a surface charge reversal on BIONs, enabling them to function as cation exchangers at acidic pH. The cationic LF exhibited preferential binding to BIONs in single- and multicomponent binding experiments. Even in native acid whey, where LF accounted for less than 3 % of the whey protein, it constituted over 43 % of surface-bound whey protein on BIONs. By selectively controlling whey protein elution with simple salt buffers, we achieved complete LF elution with over 84 % purity. This study represents the first in-depth analysis of BIONs for the selective isolation of an untagged natural protein from a complex mixture, demonstrating their reusability over multiple cycles. Our findings enhance the understanding of bio-nano interactions and demonstrate the potential of magnetic separation with BIONs as a scalable and cost-effective solution for recovering valuable biomolecules from industrial by-products. • Bare iron oxide nanoparticles (BIONs) can isolate lactoferrin from acid whey. • BIONs enable magnetic lactoferrin recovery across multiple reuse cycles. • Whey salts induce charge reversal on BIONs, facilitating protein elution. • Complete lactoferrin recovery from BIONs achieves > 84 % purity. • Scalable, cost-effective process enables integrated capture and purification.

Source: Colloids and Surfaces A Physicochemical and Engineering Aspects

DOI: 10.1016/j.colsurfa.2025.136654

Authors: Eva Krolitzki, Wiebke Winkler, Sebastian Schwaminger, Sonja Berensmeier

Institutions: Technical University of Munich, Medical University of Graz, BioTechMed-Graz

Language: English

Topic: Protein purification and stability

Subfield: Molecular Biology

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

SDG: Responsible consumption and production

Open Access status: hybrid

Estimated APC paid: $3,200