Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Review
. 2016 Oct 12;17(10):1701.
doi: 10.3390/ijms17101701.

New Insights into Various Production Characteristics of Streptococcus thermophilus Strains

Affiliations
Review

New Insights into Various Production Characteristics of Streptococcus thermophilus Strains

Yanhua Cui et al. Int J Mol Sci. .

Abstract

Streptococcus thermophilus is one of the most valuable homo-fermentative lactic acid bacteria, which, for a long time, has been widely used as a starter for the production of fermented dairy products. The key production characteristics of S. thermophilus, for example the production of extracellular polysaccharide, proteolytic enzymes and flavor substances as well as acidifying capacity etc., have an important effect on the quality of dairy products. The acidification capacity of the strains determines the manufacturing time and quality of dairy products. It depends on the sugar utilization ability of strains. The production of extracellular polysaccharide is beneficial for improving the texture of dairy products. Flavor substances increase the acceptability of dairy products. The proteolytic activity of the strain influences not only the absorption of the nitrogen source, but also the formation of flavor substances. Different strains have obvious differences in production characteristics via long-time evolution and adaptation to environment. Gaining new strains with novel and desirable characteristics is an important long-term goal for researchers and the fermenting industry. The understanding of the potential molecular mechanisms behind important characteristics of different strains will promote the screening and breeding of excellent strains. In this paper, key technological and functional properties of different S. thermophilus strains are discussed, including sugar metabolism, proteolytic system and amino acid metabolism, and polysaccharide and flavor substance biosynthesis. At the same time, diversity of genomes and plasmids of S. thermophilus are presented. Advances in research on key production characteristics and molecular levels of S. thermophilus will increase understanding of molecular mechanisms of different strains with different important characteristics, and improve the industrialization control level for fermented foods.

Keywords: Streptococcus thermophilus; genomics; plasmid; production characteristics.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Pathways of sugar metabolism and exopolysaccharide (EPS) biosynthesis in S. thermophilus. FK: fructokinase; G6PD: glucose-6-phosphate dehydrogenase; GalE: UDP-galactose-4-epimerase; UGDH: UDP-glucose 6-dehydrogenase; GalK: galactokinase; GalT: galactose-1-phosphate uridylyltransferase; GalTF: galactosyltransferase; GalU: UDP-glucose pyrophosphorylase; GK: glucokinase; GlcTF: glucosyltransferase; GLMU: N-acetylglucosamine-1-phosphate uridyltransferase; GPD: glucosamine-6-phosphate deaminase; GPI: glucose-6-phosphate isomerase; GPN: glucosamine-1-phosphate N-acetyltransferase; GTF: glycosyltransferase; HMP pathway: pentose phosphate pathway; LacZ: β-glalactosidase; MPI: mannose-6 phosphate isomerase; NDP sugars, nucleotide sugars; PEP: phosphoenolpyruvate; PFK1: phosphofructokinase; PGM: α-phosphoglucomutase; PLMM: phosphoglucosamine mutase; PM: phosphomutase; PTS: sugar phosphotransferase system; RmlB: dTDP-glucose 4, 6-dehydratase; RTF: rhamnosyltransferase; SPH: sucrose-6-phosphate hydrolase; TGP: dTDP-glucose pyrophosphorylase; TKT: transketolase; TRS: dTDP-4-dehydrorhamnose 3,5-epimerase; UDP-GalNAc: UDP-N-acetylgalactosamine; UDP-GlcNAc: UDP-N-acetylglucosamine; UGT: UDP-glucuronosyltransferase. Double headed arrow indicates the bidirectional reaction; dashed arrows indicate a part pathway; arrow indicates a reaction; red fonts indicates enzyme; words with red background color indicate the NDP sugars.
Figure 2
Figure 2
Proteolytic system and amino acid metabolism in S. thermophilus. AHSH: O-acetylhomoserine sulfhydrylase; AK: acyl kinase; AlcDH: alcohol dehydrogenase; AldDH: acetaldehyde dehydrogenase; AraT: aromatic aminotransferase; Asp: aspartate; AspAT: aspartate transaminase; AT: aminotransferase; BcAT: branched-chain aminotransferase; CBL: cystathionine γ lysase; CBS: cystathionine β synthase; CGL: cystathionine β lysase; CGS: cystathionine γ synthase; Cys: cysteine; CysE: serine O-acetyltransferase; CysK: O-acetylserine sulfhydrylase; GDH: glutamate dehydrogenase; Glu: glutamate; HSDH: homoserine dehydrogenase; HSK: homoserine kinase; HSST: homoserine O-succinyltransferase; Iso: isoleucine; KadABCD: keto acid dehydrogenase complex; KdcA: keto acid decarboxylase; Leu: leucine; l-HycDH: l-hydroxyacid dehydrogenase; Met: methionine; MetE: homocysteine methyltransferase; MetH: homocysteine S-methyltransferase; Phe: phenylalanine; PTA: phosophotransacylase; Ser: serine; Trp: tryptophan; Tyr: tyrosine; Val: valine. Double headed arrow indicates the bidirectional reaction; arrow indicates a reaction; red fonts indicates enzyme; words with red background color indicate the important intermediate products (α-keto acids).

Similar articles

Cited by

References

    1. Adolfsson O., Meydani S.N., Russell R.M. Yogurt and gut function. Am. J. Clin. Nutr. 2004;80:245–256. - PubMed
    1. Iyer R., Tomar S.K., Maheswari T.U., Singh R. Streptococcus thermophilus strains: Multifunctional lactic acid bacteria. Int. Dairy J. 2010;20:133–141. doi: 10.1016/j.idairyj.2009.10.005. - DOI
    1. Vaningelgem F., Zamfir M., Mozzi F., Adriany T., Vancanneyt M. Biodiversity of exopolysaccharides produced by Streptococcus thermophilus strains is reflected in their production and their molecular and functional characteristics. Appl. Environ. Microbiol. 2004;70:900–912. doi: 10.1128/AEM.70.2.900-912.2004. - DOI - PMC - PubMed
    1. Hols P., Hancy F., Fontaine L., Grossiord B., Prozzi D. New insights in the molecular biology and physiology of Streptococcus thermophilus revealed by comparative genomics. FEMS Microbiol. Rev. 2005;29:435–463. - PubMed
    1. Zotta T., Ricciardi A., CiociaI F., Rossano R., Parente E. Diversity of stress responses in dairy thermophilic streptococci. Int. J. Food Microbiol. 2008;124:34–42. doi: 10.1016/j.ijfoodmicro.2008.02.024. - DOI - PubMed

MeSH terms