Rapid discrimination of strain-dependent fermentation characteristics among Lactobacillus strains by NMR-based metabolomics of fermented vegetable juice

• Published in: PloS one Vol. 12; no. 7; p. e0182229
• Main Authors: Tomita, Satoru, Saito, Katsuichi, Nakamura, Toshihide, Sekiyama, Yasuyo, Kikuchi, Jun
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 31.07.2017; Public Library of Science (PLoS)
• Subjects: Abundance; Acetic acid; Acetoin; Aroma; Bacteria; Biology and Life Sciences; Chemical properties; Citric acid; Citric Acid - metabolism; Contamination; Ethanol; Fermentation; Fermented food; Fermented foods; Food; Food production; Fruit and Vegetable Juices - microbiology; Fruit juices; Glutamic acid; Lactic acid; Lactic acid bacteria; Lactobacillus; Lactobacillus - classification; Lactobacillus - metabolism; Lactobacillus brevis; Lactobacillus plantarum; Magnetic Resonance Spectroscopy; Mannitol; Metabolites; Metabolome; Metabolomics; Microorganisms; NMR; Nuclear magnetic resonance; Ornithine; Physical Sciences; Principal components analysis; Research and analysis methods; Species; Strains (organisms); Succinic acid; Sucrose; Sucrose - metabolism; Sugar; Tyrosine; Vegetable juices; Vegetables; γ-Aminobutyric acid; Japan
• DOI: 10.1371/journal.pone.0182229
• ISSN: 1932-6203

In this study, we investigated the applicability of NMR-based metabolomics to discriminate strain-dependent fermentation characteristics of lactic acid bacteria (LAB), which are important microorganisms for fermented food production. To evaluate the discrimination capability, six type strains of Lactobacillus species and six additional L. brevis strains were used focusing on i) the difference between homo- and hetero-lactic fermentative species and ii) strain-dependent characteristics within L. brevis. Based on the differences in the metabolite profiles of fermented vegetable juices, non-targeted principal component analysis (PCA) clearly separated the samples into those inoculated with homo- and hetero-lactic fermentative species. The separation was primarily explained by the different levels of dominant metabolites (lactic acid, acetic acid, ethanol, and mannitol). Orthogonal partial least squares discrimination analysis, based on a regions-of-interest (ROIs) approach, revealed the contribution of low-abundance metabolites: acetoin, phenyllactic acid, p-hydroxyphenyllactic acid, glycerophosphocholine, and succinic acid for homolactic fermentation; and ornithine, tyramine, and γ-aminobutyric acid (GABA) for heterolactic fermentation. Furthermore, ROIs-based PCA of seven L. brevis strains separated their strain-dependent fermentation characteristics primarily based on their ability to utilize sucrose and citric acid, and convert glutamic acid and tyrosine into GABA and tyramine, respectively. In conclusion, NMR metabolomics successfully discriminated the fermentation characteristics of the tested strains and provided further information on metabolites responsible for these characteristics, which may impact the taste, aroma, and functional properties of fermented foods.