Metabolite Profiling and Molecular Docking of Candidate Fungal Postbiotics Derived from Rhizopus oligosporus

Abstract

Fungal postbiotics have gained increasing attention as a source of bioactive metabolites with potential applications in food preservation. Previous studies have demonstrated that candidate fungal postbiotics produced by Rhizopus oligosporus cultivated on edamame husks (Glycine max L. Merrill) contain phenolic compounds and exhibit antioxidant activity. Building on these findings, this study aimed to characterize the metabolites present in candidate postbiotics and evaluate their antibacterial potential using molecular docking. Candidate postbiotics were produced by submerged fermentation and analyzed using gas chromatography-mass spectrometry (GC-MS). The major metabolites were docked to Staphylococcus aureus DNA gyrase subunit B (PDB ID: 4URM). GC-MS revealed a diverse metabolite profile dominated by 2,3-butanediol, followed by glycerin, dianhydromannitol, benzoic acid, and n-hexadecanoic acid. All selected metabolites exhibited negative predicted docking score, indicating thermodynamically favorable interactions with the target protein. Among them, n-hexadecanoic acid showed the strongest predicted binding affinity, followed by benzoic acid. These findings suggest that candidate fungal postbiotics derived from R. oligosporus-fermented edamame husks are promising natural bioactive ingredients for food biopreservation and active food packaging. Future molecular dynamics simulations and experimental validation are needed to confirm these computational predictions.