Dataset Information

Streptococcus thermophilus JM905-Strain Carbon Source Utilization and Its Fermented Milk Metabolic Profile at Different Fermentation Stages.

ABSTRACT: The metabolic utilization of different carbon sources by Streptococcus thermophilus JM905(S. thermophilus JM905) was determined using a high-throughput microbial phenotyping system, and changes in fermentation characteristics of S. thermophilus JM905 fermented milk were investigated at different fermentation periods, with changes in pH, water-holding capacity, viscosity, nuisance odor, and viable bacteria count being used to define the fermentation characteristics of the strain. Changes in the key metabolites, 2-hydroxybutyric acid, folic acid, L-lactic acid, D-glycerol-D-galactose-heptanol, (R)-leucine, L-aspartic acid, L-proline, D-arginine, L-isoleucine, hydra starch, L-lysine, L-tryptophan, and D-galactose, were clarified. Correspondingly, the fermented milk protein, amino acid, and fermented milk fat quality nutrient contents were determined to be 3.78 ± 0.054 g per 100 g, 3.405 ± 0.0234 g per 100 mL, and 0.161 ± 0.0030 g per 100 g, respectively. This study addressed strain carbon source utilization, changes in fermentation characteristics and metabolites during fermentation, with the aim of investigating the link between fermentation characteristics and metabolite quality components of Streptococcus thermophilus JM905 and its fermented milk with fermentation potential and to provide a useful reference for the screening of superior fermentation strains.

SUBMITTER: Li Y

PROVIDER: S-EPMC10572528 | biostudies-literature | 2023 Oct

REPOSITORIES: biostudies-literature

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Streptococcus thermophilus JM905-Strain Carbon Source Utilization and Its Fermented Milk Metabolic Profile at Different Fermentation Stages.

Li Yu Y Wang Ye Y Li Baolei B Hou Baochao B Hung Weilian W He Jian J Jiang Yujun Y Zhang Yu Y Man Chaoxin C

Foods (Basel, Switzerland) 20231008 19

The metabolic utilization of different carbon sources by Streptococcus thermophilus JM905(S. thermophilus JM905) was determined using a high-throughput microbial phenotyping system, and changes in fermentation characteristics of S. thermophilus JM905 fermented milk were investigated at different fermentation periods, with changes in pH, water-holding capacity, viscosity, nuisance odor, and viable bacteria count being used to define the fermentation characteristics of the str ...[more]

PMID: 37835343

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Project description:Streptococcus thermophilus plays important roles in the dairy industry and is widely used as a dairy starter in the production of fermented dairy products. The genomes of S. thermophilus strains CS5, CS9, CS18, and CS20 from fermented milk in China were sequenced and used for biodiversity analysis. In the present study, the phylogenetic analysis of all 34 S. thermophilus genomes publicly available including these four strains reveals that the phylogenetic reconstruction does not match geographic distribution as strains isolated from the same continent are not even clustered on the nearby branches. The core and variable genes were also identified, which vary among strains from 0 to 202. CS9 strain contained 127 unique genes from a variety of distantly related species. It was speculated that CS9 had undergone horizontal gene transfer (HGT) during the long evolutionary process. The safety evaluation of these four strains indicated that none of them contains antibiotic resistance genes and that they are all sensitive to multiple antibiotics. In addition, the strains do not contain any pathogenic virulence factors or plasmids and thus can be considered safe. Furthermore, these strains were investigated in terms of their technological properties including milk acidification, exopolysaccharide (EPS) and γ-aminobutyric acid (GABA) production, and in vitro survival capacity in the gastrointestinal tract. CS9 possesses a special eps gene cluster containing significant traces of HGT, while the eps gene clusters of CS5, CS18, and CS20 are almost the same. The monosaccharide compositional analysis indicated that crude EPS-CS5, EPS-CS9, EPS-CS18, and EPS-CS20 contain similar monosaccharide compositions with different ratios. Furthermore, CS9 was one of a few GABA-producing strains that could ferment glutamate to produce GABA, which is beneficial for improving the acid tolerance of the strain. CS18 has the most potential for the production of fermented food among these four strains because of its fast growth rate, rapid acidifying capacity, and stronger acid and bile salt resistance capacity. This study focused on the genome analysis of the four new S. thermophilus strains to investigate the diversity of strains and provides a reference for selecting excellent strains by use of the genome data.

Project description:The immunomodulatory properties of exopolysaccharides (EPSs) produced by Streptococcus thermophilus have not been explored in depth. In addition, there are no comparative studies of the functional properties of EPSs produced by streptococci in different food matrices. In this work, EPSs from S. thermophilus SBC8781 were isolated after soy milk (EPS-s) or cow milk (EPS-m) fermentation, identified, and characterized in their abilities to modulate immunity in porcine intestinal epithelial cells. Fresh soy milk and cow milk were inoculated with S. thermophilus SBC8781 (7 log CFU/mL) and incubated at 37 °C for 24 h. The extraction of EPSs was performed by the ethanol precipitation method. Analytical techniques, including NMR, UV-vis spectroscopy, and chromatography, identified and characterized both biopolymer samples as polysaccharides with high purity levels and similar Mw. EPS-s and EPS-m had heteropolysaccharide structures formed by galactose, glucose, rhamnose, ribose, and mannose, although with different monomer proportions. On the other hand, EPS-s had higher quantities of acidic polymer than EPS-m. The biopolymer production of the SBC8781 strain from the vegetable culture broth was 200-240 mg/L, which was higher than that produced in milk, which reached concentrations of 50-70 mg/L. For immunomodulatory assays, intestinal epithelial cells were stimulated with 100 µg/mL of EPS-s or EPS-m for 48 h and then stimulated with the Toll-like receptor 3 agonist poly(I:C). EPS-s significantly reduced the expression of IL-6, IFN-β, IL-8, and MCP-1 and increased the negative regulator A20 in intestinal epithelial cells. Similarly, EPS-m induced a significant reduction of IL-6 and IL-8 expressions, but its effect was less remarkable than that caused by EPS-s. Results indicate that the structure and the immunomodulatory activity of EPSs produced by the SBC8781 strain vary according to the fermentation substrate. Soy milk fermented with S. thermophilus SBC8781 could be a new immunomodulatory functional food, which should be further evaluated in preclinical trials.

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Dataset Information

Streptococcus thermophilus JM905-Strain Carbon Source Utilization and Its Fermented Milk Metabolic Profile at Different Fermentation Stages.

Publications

<i>Streptococcus thermophilus</i> JM905-Strain Carbon Source Utilization and Its Fermented Milk Metabolic Profile at Different Fermentation Stages.

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