Antioxidant, Antidiabetic, and Antimicrobial Activities of Bioactive Peptides Derived From Milk Fermented by Multi‐Strain Probiotic Consortium

Milk-derived bioactive peptides (BAPs) generated via microbial fermentation offer significant health benefits. However, the multi-bioactivity potential of BAPs from indigenous probiotic consortia remains largely untapped, limiting therapeutic applications. This study investigated whether fermenting milk with a native probiotic consortium (Bacillus spizizenii BAB 7915 and Bacillus subtilis BAB 7918) augments BAP activities over its constituent single strains. Post-fermentation, BAPs (≤10 kDa) were purified, characterized (RP-HPLC, OHR LCMS/MS), and assessed for α-amylase inhibition, ABTS radical scavenging, and antimicrobial efficacy (MIC). Consortium fermentation markedly enhanced bioactivities. Consortium BAPs showed superior α-amylase inhibition (90.80 ± 1.31%) and ABTS scavenging (54.17 ± 0.39%) over single strains/controls. They also displayed potent antimicrobial activity (MICs 2.5-5 µg/mL) against Pseudomonas aeruginosa MTCC 424, Proteus vulgaris MTCC 1771, Staphylococcus aureus MTCC 737, Streptococcus mutans MTCC 497, and B. subtilis MTCC 441. Indigenous probiotic consortia efficiently produce milk BAPs with augmented multi-bioactivity, promising for managing type 2 diabetes, oxidative stress, and infections. Future studies should isolate and characterize individual peptides to confirm specific contributions, elucidate structure-function relationships, and investigate their in vivo efficacy, bioavailability, and potential for encapsulation.