Purification and identification of novel α‐glucosidase inhibitors in okara fermented with Bacillus amyloliquefaciens YP2

Background α ‐Glucosidase inhibitors are established medications for managing type 2 diabetes. In this study, novel inhibitors were identified from okara fermented by Bacillus amyloliquefaciens , and their peptide– α ‐glucosidase interaction mechanism was investigated. Results The inhibition rate of α ‐glucosidase reached 84% ± 2% after eight dilutions when Bacillus amyloliquefaciens YP2 was used for okara fermentation. Metabolite analysis revealed abundant compounds in the fermented okara. Subsequently, 1‐deoxynojirimycin (DNJ) and two additional components were purified using a combination of five types of column chromatography, with DNJ demonstrating a purity of over 95%. A total of 283 peptides were identified, of which seven were predicted as candidates using bioinformatic software and in vitro assays. The half maximal inhibitory concentration (IC 50 ) value of DNJ was 1.62 mM and that of the peptide CKLLL was 6.05 mM. Molecular docking studies indicated strong affinities of both DNJ and CKLLL for α ‐glucosidase, with CKLLL binding a greater number of amino acid residues. Conclusion This study is the first to identify diverse α ‐glucosidase inhibitors in fermented okara. Bacillus amyloliquefaciens YP2 is a promising strain for producing α ‐glucosidase inhibitors and developing hypoglycemic food as a nutritional supplement from okara.