Distinct mechanisms of N-glycolylneuraminic acid reduction by Lactiplantibacillus plantarum R2 and Staphylococcus carnosus C1: Adsorption versus biodegradation

N -glycolylneuraminic acid (Neu5Gc) is a potential pathogenic factor for chronic diseases associated with red meat intake, but there was little research on its biological reduction methods. This study screened microorganisms capable of reducing Neu5Gc and explored their underlying mechanisms in a simulated system using comprehensive approaches, including cellular fractionation, Fourier transform infrared (FTIR) spectroscopy, and enzymatic activity assays. Among six tested species, Lactiplantibacillus plantarum R2 and Staphylococcus carnosus C1 showed the strongest Neu5Gc reduction abilities (from 32.53 μg/mL to 22.75 μg/mL, 30.06 % and from 32.53 μg/mL to 21.79 μg/mL, 33.01 %, respectively). Whole cell suspensions of the both species exhibited higher Neu5Gc reduction efficiency (from 32.53 μg/mL to 25.68 μg/mL, 21.06 % and from 32.53 μg/mL to 24.79 μg/mL, 23.79 % of L. plantarum R2 and S. carnosus C1, respectively) compared to other cellular components ( P  < 0.05). Notably, heat treatment significantly reduced the Neu5Gc reduction rate of L. plantarum R2 ( P  < 0.05), whereas no significant change was observed for S. carnosus C1 ( P  > 0.05). In addition, FTIR analysis revealed physical adsorption involving hydroxyl, carbonyl, and amine groups in both species. Moreover, pronase treatment and enzymatic assays confirmed that L. plantarum R2 degraded Neu5Gc via N -acetylneuraminate lyase and β-galactosidase. Collectively, L. plantarum R2 reduced Neu5Gc via both physical adsorption and enzymatic biodegradation pathways, whereas S. carnosus C1 primarily relied on physical adsorption. This study provided theoretical support for the biological elimination strategy of Neu5Gc.