Macroporous Resin–Based Adsorption Separation of Ginsenosides From American Ginseng Fibrous Roots: Process Optimization and Mechanistic Insights

American ginseng fibrous roots, often discarded as bioprocessing waste, constitute a valuable source of ginsenosides with high recovery potential. This study established a systematic strategy to enrich ginsenosides from the fibrous roots using macroporous adsorption resins and to investigate the adsorption mechanisms. Among the nine resins tested, the non-polar HPD100 resin, characterized by its styrene-divinylbenzene copolymer matrix and high specific surface area, exhibited superior performance, with an adsorption capacity of 194.1 ± 5.8 mg/g and desorption efficiency above 98.0 ± 1.9%. Dynamic column experiments optimized the operating conditions, achieving 74.9 ± 3.0% purity and 84.9 ± 3.7% recovery at a flow rate of 3 bed volumes per hour, 2.3 ± 0.2 mg/mL sample concentration, and 80% ethanol eluent. The resin maintained stable performance over five adsorption-desorption cycles. Kinetic and thermodynamic analyses revealed that adsorption followed a pseudo-second-order model and Langmuir isotherm, with spontaneous and endothermic characteristics. Structural analyses, including scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy, revealed hydrogen bonding, van der Waals forces, and π-π stacking as key interactions. Molecular dynamics simulations revealed a thermally enhanced binding effect, demonstrating that elevated temperatures strengthen ginsenoside-resin interactions by increasing binding energy even as hydrogen bonding diminishes. This work elucidates the fundamental adsorption mechanism and establishes a theoretical basis for the high-value valorization of American ginseng by-products through a rationally designed, temperature-controlled strategy.