Fermentation of moso bamboo (Phyllostachys edulis) shoots by giant panda-derived Bacillus altitudinis ICBR-C01 induces release of multifunctional bioactive peptides

The therapeutic potential of multifunctional bioactive peptide derived from food fermentation to alleviate chronic diseases has attracted considerable research interest. The objective of this study was to investigate the biological activities of peptides produced by the fermentation of moso bamboo (Phyllostachys edulis) shoots with Bacillus altitudinis ICBR-C01, a microbial strain isolated from the feces of giant pandas (Ailuropoda melanoleuca). The peptidomics profiles were analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS), and the potential biological activities of the newly generated peptides after the fermentation were predicted with the aid of bioinformatics tools. The angiotensin-I-converting enzyme (ACE) inhibitory, dipeptidyl peptidase-IV (DPP-IV) inhibitory, and antioxidant activities were validated in vitro, and their mechanisms of action were further studied through the use of molecular docking simulations. The stability of the peptides was assessed by hydrothermal treatment and simulated gastrointestinal digestion. The yield of peptides was (16.93 ± 0.19) mg/g bamboo shoot (raw material, RM) by the fermentation of moso bamboo shoots with Bacillus altitudinis ICBR-C01, and the process resulted in a notable alteration of the peptide composition. Among the 53 peptides identified in the fermented moso bamboo shoots, 30 were newly formed, of which six were predicted to possess multifunctional bioactivities. The in vitro experiments and in silico analysis demonstrated that the peptides GGLAGPPGS (IC₅₀: 13.52 μmol/L), SIHKVPL (IC₅₀: 11.48 μmol/L), and EEHPVLL (IC₅₀: 11.79 μmol/L) exhibited potent ACE inhibitory activity. All three peptides were observed to bind to the key amino residues in the S1 active pocket of the ACE protein via multiple interaction forces. Peptides FAGDDAPR, GFAGDDAPR, GGLAGPPGS, and GLAGPPGS were shown to exhibit DPP-IV inhibitory activity, with IC₅₀ values of 495.17 μmol/L, 541.79 μmol/L, 305.19 μmol/L, and 367.24 μmol/L, respectively. Moreover, EEHPVLL exhibited a moderate 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, with an IC₅₀ value of 4.33 mmol/L. The percentage of SIHKVPL and GGLAGPPGS remaining exceeded 90% after being heated for up to 2 h in a water bath at 100 ℃. The percentage remaining after simulated gastrointestinal digestion was over 85% for all four peptides tested. The results of this study provide a basis for the utilization of the giant panda-derived Bacillus altitudinis ICBR-C01 in the fermentation of bamboo shoots, with the aim of preparing multifunctional bioactive peptide.