Serial, M. RaquelM. RaquelSerialSchmidt, LucaLucaSchmidtAdrian, MuhammadMuhammadAdrianBrauckmann, GritGritBrauckmannBenders, StefanStefanBendersBueschler, VictoriaVictoriaBueschlerLiese, AndreasAndreasLiesePenn, AlexanderAlexanderPenn2025-09-232025-09-232025-08-29Biochemical Engineering Journal 225: 109909 (2026)https://hdl.handle.net/11420/57458Enzyme immobilization plays a crucial role in enhancing the stability and recyclability of enzymes for industrial applications. However, traditional methods for quantifying enzyme loading within porous carriers are limited by time-consuming workflows, cumulative errors, and the inability to probe enzymes adsorbed inside the pores. In this study, we introduce Time-Domain Nuclear Magnetic Resonance (TD-NMR) relaxometry as a novel, non-invasive technique for directly quantifying enzyme adsorption within porous carriers. Focusing on epoxy methyl acrylate carriers, commonly used in biocatalysis, we correlate changes in T<inf>2</inf> relaxation times with enzyme concentration, leading to the development of an NMR-based pore-filling ratio that quantifies enzyme loading. Validation experiments demonstrate that TD-NMR-derived adsorption curves align closely with traditional photometric measurements, offering a reliable and reproducible alternative for enzyme quantification. The accessibility of tabletop TD-NMR spectrometers makes this technique a practical and cost-effective tool for optimizing biocatalytic processes. Furthermore, the method holds promise for real-time monitoring of adsorption dynamics and could be adapted for a wider range of carrier materials and enzymes.en1369-703X2025Elsevierhttps://creativecommons.org/licenses/by/4.0/Adsorption isothermsEnzyme immobilizationPore-filling ratioPorous carriersTD-NMR relaxometryNatural Sciences and Mathematics::572: BiochemistryTechnology::660: Chemistry; Chemical EngineeringJournal Articlehttps://doi.org/10.15480/882.1590110.1016/j.bej.2025.10990910.15480/882.1590110.15480/882.15837Journal Article