Peptidomics‐based identification of an antimicrobial peptide derived from goat milk fermented by Lactobacillus rhamnosus ( C25 )

Abstract

Antimicrobial peptides (AMPs) are emerging as promising novel drug applicants. In the present study, goat milk was fermented using Lactobacillus rhamnosus C25 to generate bioactive peptides (BAPs). The peptide fractions generated were separated using ultrafiltration membranes with molecular weight cut‐offs of 3, 5, and 10 kDa, and their antimicrobial activity toward Gram‐positive and Gram‐negative bacteria was investigated. Isolated AMPs were characterized using RP‐HPLC and identified by LC–MS/MS. A total of 569 sequences of peptides were identified by mass spectrometry. Out of the 569, 36 were predicted as AMPs, 21 were predicted as cationic, and out of 21, 6 AMPs were helical peptides. In silico analysis indicated that the majority of peptides were antimicrobial and cationic in nature, an important factor for peptide interaction with the negative charge membrane of bacteria. The results showed that the peptides of <5 kDa exhibited maximum antibacterial activity against E. faecalis, E. coli, and S. typhi. Further, molecular docking was used to evaluate the potent MurD ligase inhibitors. On the basis of ligand binding energy, six predicted AMPs were selected and then analyzed by AutoDock tools. Among the six AMPs, peptides IGHFKLIFSLLRV (−7.5 kcal/mol) and KSFCPAPVAPPPPT (−7.6 kcal/mol), were predicted as a high‐potent antimicrobial. Based on these findings, in silico investigations reveal that proteins of goat milk are a potential source of AMPs. This is for the first time that the antimicrobial peptides produced by Lactobacillus rhamnosus (C25) fermentation of goat milk have been identified via LC–MS/MS and predicted as AMPs, cationic charges, helical structure in nature, and potent MurD ligase inhibitors. These peptides can be synthesized and improved for use as antimicrobial agents. Practical applications Goat milk is considered a high‐quality source of milk protein. According to this study, goat milk protein is a potential source of AMPs, Fermentation can yield goat milk‐derived peptides with a broad antibacterial activity spectrum at a low cost. The approach described here could be beneficial in that the significant AMPs can be synthesized and used in the pharmaceutical and food industries.

In vitro biosafety and bioactivity assessment of the goat milk protein derived hydrolysates peptides

“…This suggests that the hydrolysates produced peptides with varying hydrophobicity and molecular weight, as observed in previous studies conducted by Kamal et al (2018) and Mudgil et al (2018). In a separate study by Iram, Kindarlae et al (2022), it was found that hydrolysis of goat milk by Lactobacillus rhamnosus (C25) resulted in small peak retention times on RP‐HPLC, ranging from 5 to 30 min, as previously reported by Panchal et al (2020). The chromatograms of both CPH and WPH peptides showed the presence of peaks across areas with retention times ranging from 5.31 to 24.21 min.…”

Microbial Biosurfactant as an Alternate to Chemical Surfactants for Application in Cosmetics Industries in Personal and Skin Care Products: A Critical Review

“…Moreover, Iram et al [ 118 ] and Liu et al [ 119 ] reported that L. fermentum , L. pentosus , and L. acidophilus , which were isolated from human milk, fruits, milk products, and fermented shrimps in Malaysia, have the ability to produce cell-free biosurfactants that exhibit antibacterial properties. Haakensen et al [ 120 ] identified Pediococcus dextrinicus SHU1593 as another bacterium capable of producing biosurfactants.…”

Advances in separation and identification of biologically important milk proteins and peptides

“…For example, most predominant plasmin (secreted in milk as plasminogen) causes proteolysis of α S1 -CN, α S2 -CN, and β-casein (β-CN) into γ-CN [50], and it can have beneficial or detrimental results depending on the extent of hydrolysis [51]. Further, hydrolysis of milk proteins and release of bioactive peptides can occur via various processes, for example, naturally, by digestive enzymes and/or microbial enzymes, by enzymatic hydrolysis in laboratories [3,52], and by fermentation of milk [32]. After protein hydrolysis, the bioactive peptides are isolated and validated for their activities.…”

“…Peptidomic-based analyses have been carried out to search for the peptides with potential antimicrobial activities. The goat milk was fermented by Lactobacillus rhamnosus C25 (2%) at 37 • C for 48 h [32] to generate the peptides from milk proteins. The peptides were subjected to ultrafiltration with the MWCO membranes of 3, 5, and 10 kDa, and each resulting peptide fraction was evaluated for microbial activities against gram-positive/negative bacteria.…”

“…Related to the field of medicine, bioactive milk proteins/peptides have been shown to have many beneficial effects and possess an array of biological activities. They have antioxidant [31], antimicrobial/antiviral properties [16,31,32], and have been shown to have antihypertensive [16,31], anticarcinogenic [33][34][35], antithrombotic [36], and immunomodulatory/anti-inflammatory [37][38][39] activities. The peptides from milk casein can ameliorate high-glucose-induced insulin resistance [40].…”