In Silico Prediction of Bioactive Peptides From Lactococcus lactis SwR14: Evaluation of a Potential Probiotic...

Lactic acid bacteria (LABs) are widely recognized for their nutritional and therapeutic potential, primarily due to their ability to produce bioactive peptides during fermentation. In this study, Lactococcus lactis strains, potential probiotics from Sui Wu'u, a traditional fermented meat from Bajawa, East Nusa Tenggara, Indonesia, were evaluated for folate biosynthesis, cholesterol-lowering activity, α-glucosidase inhibition, and antioxidant capacity, and their association with bioactive peptide production in milk was investigated. Among the isolates, SwR14 and SwR16 were able to grow under folate-depleted conditions, indicating folate autotrophy, with SwR14 producing the highest extracellular folate concentration in folate-free medium (12.40 ng/mL). All isolates exhibited moderate in vitro cholesterol reduction (14.28%-20.94%) and α-glucosidase inhibitory activity (25.94%-33.96%), with no significant interstrain differences. Antioxidant activity assessed using DPPH, ABTS, and FRAP assays showed assay-dependent variability, with SwR14 demonstrating the most efficient DPPH radical scavenging activity based on the lowest IC₅₀ value. Peptides from milk fermented by L. lactis SwR14 were then identified via liquid chromatography-high-resolution tandem mass spectrometry (LC-HRMS/MS) and profiled using the BIOPEP-UWM database, revealing 49 peptide sequences with 47 distinct biological activities. ACE and DPP-IV inhibitory activities were detected in all sequences, whereas α-glucosidase inhibitory and antioxidant activities were predicted in 33 and 31 sequences, respectively, consistent with the in vitro results. Several peptide sequences emerged as promising candidates for antioxidant and α-glucosidase inhibitory activity on the basis of their molecular weight and hydrophobic amino acid composition, suggesting that milk fermentation by L. lactis SwR14 promotes bioactive peptide generation despite its weak proteolytic phenotype. These findings highlight L. lactis SwR14 as a promising functional strain for the development of bioactive peptide-enriched dairy products. Future studies should explore peptide bioactivity mechanisms and validate their efficacy through in vivo studies.