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

PLoS One. 2017 Jul 31;12(7):e0182229. doi: 10.1371/journal.pone.0182229. eCollection 2017.

Abstract

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.

MeSH terms

  • Citric Acid / metabolism
  • Fermentation*
  • Fruit and Vegetable Juices / microbiology*
  • Lactobacillus / classification
  • Lactobacillus / metabolism*
  • Magnetic Resonance Spectroscopy
  • Metabolome*
  • Sucrose / metabolism

Substances

  • Citric Acid
  • Sucrose

Grants and funding

The research was supported financially by the Ministry of Agriculture, Forestry and Fisheries of Japan, within the project “The special scheme to deploy highly advanced technology for agriculture forestry and fisheries”. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.