Gas Chromatography-Mass Spectrometry Profiling of Volatile Metabolites Produced by Some spp. and Evaluation of Their Antibacterial and Antibiotic Activities.

species produce different classes of antimicrobial and antioxidant substances: peptides or proteins with different structural compositions and molecular masses and a broad range of volatile organic compounds (VOCs), some of which may serve as biomarkers for microorganism identification. The aim of this study is the identification of biologically active compounds synthesized by five species using gas chromatography coupled to mass spectrometry (GC-MS). The current study profoundly enhances the knowledge of antibacterial and antioxidant metabolites ensuring the unambiguous identification of VOCs produced by some species, which were isolated from vegetable samples of potato, carrot, and tomato. Phylogenetic and biochemical studies were used to identify the bacterial isolates after culturing. Phylogenetic analysis proved that five bacterial isolates BSS12, BSS13, BSS16, BSS21, and BSS25 showed 99% nucleotide sequence similarities with AS-08, WAB2133, NiuFun, FORT 102, and F3, respectively. The crude extract was prepared from bacterial isolates to assess the antibiotic resistance potency and the antimicrobial potential against various targeted multidrug-resistant strains, including yeast strains such as , , and bacterial strains of , , , , , , group B, , , , , , and . GC-MS analysis of bacterial strains found that VOCs from species come in a variety of chemical forms, such as ketones, alcohols, terpenoids, alkenes, etc. Overall, 69 volatile organic compounds were identified from five species, and all five were found to share different chemical classes of volatile organic components, which have a variety of pharmacological applications. However, eight antibacterial compounds with different concentrations were commonly found in all five species: acetoin, acetic acid, butanoic acid, 2-methyl-, oxime-, methoxy-phenyl, phenol, 1,2-benzenedicarboxylic acid, bis(2-methylpropyl) ester, nonanoic acid, and hexadecanoic acid, methyl. The present study has demonstrated that bacterial isolates BSS25, BSS21, and BSS16 display potent inhibitory effects against , while BSS25, BSS21, and BSS13 exhibit the ability to restrain the growth and activity of . Notably, BSS25 and BSS21 are the only isolates that demonstrate substantial inhibitory activity against . This disparity in inhibitory effects could be attributed to the higher concentrations of acetoin in BSS25 and BSS21, whereas BSS16 and BSS13 have relatively elevated levels of butanoic acid, 2-methyl-. Certainly, the presence of acetoin and butanoic acid, 2-methyl-, contributes to the enhanced antibacterial potential of these bacterial strains, in conjunction with other organic volatile compounds and peptides, among other factors. The biology and physiology of can be better understood using these results, which can also be used to create novel biotechnological procedures and applications. Moreover, because of its exceptional ability to synthesize and produce a variety of different antibacterial compounds, species can serve as natural and universal carriers for antibiotic compounds in the form of probiotic cultures and strains to fight different pathogens, including mycobacteria.