Bacteriocin producing strain, Enterococcus faecium ST10Bz was isolated from a Bulgarian cereal-based beverage, boza. Previous characterization included the characterization of expressed bacteriocin/s, study of potential probiotic properties and safety of the strain. To further characterize the strain, metabolomic analysis of the cell free supernatant obtained from ST10Bz culture was performed. The metabolomic analysis revealed some potentially beneficial properties of the strain, suggesting that this research approach may be applied in screening of probiotic properties and deeper safety characterization of bacterial cultures.
Based on the metabolomic analysis, E. faecium ST10Bz was found to produce additional antimicrobials, including lactic acid, ß-phenyllactic acid, and phenethylamine, which may play role in the prevention of the colonization in the gut by pathogens, in addition to the previously studied antimicrobial enterocins it could produce. Moreover, increased levels of oleic acid, an anti-inflammatory compound, and ?-hydroxybutyric acid, a precursor of the neurotransmitter GABA, were also recorded. The potential ability of the strain to produce GABA was also supported by the presence of gad gene observed from its bio-molecular analysis of DNA obtained from E. faecium ST10Bz. Conversely, xanthine was consumed by E. faecium ST10Bz. This purine is considered potentially toxic to humans, thus, the metabolism of it may be considered as beneficial to the host, human and/or other animals. Overall, the E. faecium ST10Bz was found out to have additional probiotic properties, particularly expression of metabolites, those that are beneficial to the hosts, as the strain could inhabit the gut. Thus, further studies in vitro on the production and quantification of beneficial metabolites must be performed, and in vivo animal study as the validation experiment.