Profiles of <i>Streptococcus thermophilus </i><scp>MN</scp>‐<scp>ZLW</scp>‐002 nutrient requirements in controlled <scp>pH</scp> batch fermentations

Liu, Gefei; Qiao, Yali; Leng, Cong; Sun, Jiahui; Chen, Hongyu; Zhang, Yan; Li, Aili; Feng, Zhen

doi:10.1002/mbo3.633

Cited by 12 publications

(11 citation statements)

References 43 publications

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“…Tyrosine can be converted to a biogenic amine via the tyrosine decarboxylase activity of LAB (Christensen et al, 1999). In this study, tyrosine was highly consumed, consistent with the previous work (Liu et al, 2018). The consumption of tyrosine could be associated with regulation of intracellular pH.…”

Section: Discussionsupporting

confidence: 90%

“…S. thermophilus is currently produced in cultures in which the extracellular pH is controlled at 6.25 through the continuous addition of sodium hydroxide. The previous study demonstrated that the extracellular concentration of sodium lactate in ST-MZ-2 increased from 2.61 to 47.67 mmol/L during the pH-controlled fermentation (Liu et al, 2018). The gradual accumulation of extracellular sodium lactate was an important factor for osmotic stress in S. thermophilus.…”

Section: Discussionmentioning

confidence: 93%

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Metabolic Pathway Profiling in Intracellular and Extracellular Environments of Streptococcus thermophilus During pH-Controlled Batch Fermentations

Qiao

Liu

et al. 2020

Front. Microbiol.

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Elucidating the metabolite profiles during the growth of Streptococcus thermophilus is beneficial for understanding its growth characteristics. The changes in the intracellular and extracellular concentrations of carbohydrates, nucleotides, amino sugars, nucleoside sugars, fatty acids, and amino acids, as well as their metabolites over time, were investigated by metabolomics technology. Most metabolites of nucleotides were highly accumulated in the intracellular environment after the mid-exponential phase. Increases in the intracellular unsaturated fatty acids and N-acetyl-glucosamine and N-acetyl-muramoate recycling provided potential evidence that cell envelope remodeling occurred after the mid-exponential phase. At the later fermentation stages, potentially functional metabolite produced by glycine was highly accumulated in the intracellular environment. Additionally, potential toxic metabolites produced by phenylalanine and tyrosine could not be excreted into the extracellular environment in a timely basis. The accumulation of large amounts of these metabolites might be the primary cause of the overconsumption of amino acids and influence the growth of S. thermophilus.

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Section: Discussionsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 93%

Metabolic Pathway Profiling in Intracellular and Extracellular Environments of Streptococcus thermophilus During pH-Controlled Batch Fermentations

Qiao

Liu

et al. 2020

Front. Microbiol.

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“…All STH strains with complete genome sequence have incomplete de novo thiamin (vitamin B1), ribo avin (vitamin B2), pantothenate (B5), pyridoxine (vitamin B6) and biotin (vitamin B8) biosynthesis pathways (data not shown). This analysis con rms at a larger scale vitamin B2 and B5 auxotrophy of STH determined by single omission experiments (66,96). However, the presence of parts of the biosynthetic pathways suggests that STH can produce certain vitamins from extracellular intermediates provided by other bacteria in mixed cultures.…”

Section: Biosynthesis Of Folate and B-vitaminssupporting

confidence: 56%

The Genomic Basis of the Streptococcus Thermophilus Health-Promoting Properties

Roux

Nicolas

Valence

et al. 2021

Preprint

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BackgroundStreptococcus thermophilus is a Gram-positive bacterium widely used as starter in the dairy industry as well as in many traditional fermented products. In addition to its technological importance, it has also gained interest in recent years as beneficial bacterium due to human health-promoting functionalities. The objective of this study was to inventory the main health-promoting properties of S. thermophilus and to study their intra-species diversity at the genomic and genetic level within a collection of representative strains. ResultsIn this study various health-related functions were analyzed at the genome level from 79 genome sequences of strains isolated over a long time period from diverse products and different geographic locations. While some functions are widely conserved among isolates (e.g., degradation of lactose, and folate production) suggesting their central physiological and ecological role for the species, others including the tagatose-6-phosphate pathway involved in the catabolism of galactose, and the production of bioactive peptides and g-aminobutyric acid are strain-specific. Most of these strain-specific health-promoting properties seems to have been acquired via horizontal gene transfer events. The genetic basis for the phenotypic diversity between strains for some health related traits have also been investigated. For instance, substitutions in the galK and gadBC promoter region correlate with the ability of some strains to catabolize galactose via the Leloir pathway and to produce high level of g-aminobutyric acid, respectively. Finally, the low occurrence in S. thermophilus genomes of genes coding for biogenic amine production and antibiotic resistance is also a contributing factor to its safety status.ConclusionsThe natural intra-species diversity of S. thermophilus, therefore, represents an interesting source for innovation in the field of fermented products enriched for healthy components that can be exploited to improve human health. A better knowledge of the health-promoting properties and their genomic and genetic diversity within the species may facilitate the selection and application of strains for specific biotechnological and human health-promoting purpose. Moreover, by pointing out that a substantial part of its functional potential still defies us, our work opens the way to uncover additional health-related functions through the intra-species diversity exploration of S. thermophilus by comparative genomics approaches.

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“…For the high glycolytic carbon flux, a high NADH/NAD + ratio activated the activity of LDH and inhibited the activity of GADPH. The intracellular NADH/NAD + ratio was highest at the lag phase during the culture of ST-MZ-2 (Liu et al, 2018). The results showed that the concentration of lactic acid increased rapidly and the high expression levels of related genes were detected from the end-lag phase.…”

Section: Discussionmentioning

confidence: 89%

Metabolic Profiles of Carbohydrates in Streptococcus thermophilus During pH-Controlled Batch Fermentation

et al. 2020

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Revealing the metabolic profiles of carbohydrates with their regulatory genes and metabolites is conducive to understanding their mechanism of utilization in Streptococcus thermophilus MN-ZLW-002 during pH-controlled batch fermentation. Transcriptomics and metabolomics were used to study carbohydrate metabolism. More than 200 unigenes were involved in carbohydrate transport. Of these unigenes, 55 were involved in the phosphotransferase system (PTS), which had higher expression levels than those involved in ABC protein-dependent systems, permeases, and symporters. The expression levels of the genes involved in the carbohydrate transport systems and phosphate transport system were high at the end-lag and end-exponential growth phases, respectively. In addition, 166 differentially expressed genes (DEGs) associated with carbohydrate metabolism were identified. Most genes had their highest expression levels at the end-lag phase. The pfk, ldh, zwf, and E3.2.1.21 genes involved in the glycolytic pathway had higher expression levels at the end-exponential growth phase than the mid-exponential growth phase. The results showed high expression levels of lacZ and galKTM genes and reabsorption of extracellular galactose. S. thermophilus MN-ZLW-002 can metabolize and utilize galactose. Overall, this comprehensive network of carbohydrate metabolism is useful for further studies of the control of glycolytic pathway during the high-density culture of S. thermophilus.

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Profiles of Streptococcus thermophilus MN‐ZLW‐002 nutrient requirements in controlled pH batch fermentations

Abstract: This study aimed to evaluate the profiles of Streptococcus thermophilus nutrient requirements to guide the design of media for high cell density culturing.

Cited by 12 publications

References 43 publications

Metabolic Pathway Profiling in Intracellular and Extracellular Environments of Streptococcus thermophilus During pH-Controlled Batch Fermentations

Metabolic Pathway Profiling in Intracellular and Extracellular Environments of Streptococcus thermophilus During pH-Controlled Batch Fermentations

The Genomic Basis of the Streptococcus Thermophilus Health-Promoting Properties

Metabolic Profiles of Carbohydrates in Streptococcus thermophilus During pH-Controlled Batch Fermentation

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