New advances in exopolysaccharides production of Streptococcus thermophilus

Abstract

Streptococcus thermophilus is the most important thermophilic dairy starter, and is widely used in the dairy industry. Streptococcus thermophilus exopolysaccharides received wide attention over recent decades, because they can improve the properties of the dairy product and confer beneficial health effects. The understanding of the regulatory and biosynthetic mechanisms of EPS will improve the EPS biosynthesis, increase the productivity of EPSs, and develop EPSs with desirable properties. The structure of EPSs is the focus of this study. Revealing the structure-function relationship can lead to increase the knowledge base and from there to increased research of EPS. The EPS yield is a key limiting factor in the research and utilization of EPS. In the present review, biosynthetic pathways and genetics of S. thermophilus EPSs were described and reviewed. At the same time, functional properties and applications of EPS, and strategies for enhancement of EPS production are discussed.

Genome Analysis and Physiological Characterization of Four Streptococcus thermophilus Strains Isolated From Chinese Traditional Fermented Milk

“…This result further confirmed that three S. thermophilus strains have close relationships. In addition, these eps clusters belonged to a common type and were found in some S. thermophilus strains, including ASCC1275, Sfi39, KLDS MS, MN-BM-A02, DGCC7710, C106, KLDS 3.1003, TH982, FI9186, and MTC310 (Cui et al, 2017). Furthermore, there was also an additional gene unit eps2C-eps2D in the eps clusters of CS5, CS18, and CS20 which could affect the length of the EPS unit.…”

“…(Hols et al, 2005;Cui et al, 2016Cui et al, , 2017. Furthermore, it has been confirmed that S. thermophilus has various health benefits such as antiinflammatory activity, antimicrobial activity, antioxidant activity, as well as immunomodulation (Junjua et al, 2016;Cui et al, 2017;Uriot et al, 2017). These probiotic effects have a close relationship with the biologically active molecules produced by S. thermophilus such as EPS and bacteriocins (Hols et al, 2005;Junjua et al, 2016;Cui et al, 2017;Uriot et al, 2017).…”

“…Meanwhile, this bacterium could synthesize some beneficial molecules, such as exopolysaccharide (EPS), aromatic compounds, and formic and folic acids, which contribute to many desirable production characteristics of dairy products including viscosity, texture, flavor, and water holding capacity, etc. (Hols et al, 2005;Cui et al, 2016Cui et al, , 2017. Furthermore, it has been confirmed that S. thermophilus has various health benefits such as antiinflammatory activity, antimicrobial activity, antioxidant activity, as well as immunomodulation (Junjua et al, 2016;Cui et al, 2017;Uriot et al, 2017).…”

“…The eps gene clusters determining the EPS biosynthesis were found in CS5, CS9, CS18, and CS20 (Figure 7A). They could be divided into four parts: (1) the regulatory genes of EPS production (epsA, epsB); (2) genes for controlling the EPS chain length (epsC, epsD); (3) the EPS repeat units forming genes; (4) the genes related to polymerization and exportation of repeating units (Cui et al, 2017).…”

“…In the last two decades, a number of S. thermophilus genomes have been published, and the whole genome information has improved the understanding of metabolic activities of this bacterium at the molecular level, including the biosynthesis of EPS and folate (Iyer et al, 2010;Cui et al, 2017;Li et al, 2018;Xiong et al, 2019), resistance to bacteriophage (Hao et al, 2018), proteolytic system (Tian et al, 2018), and carbohydrate metabolism (Prajapati et al, 2013), etc. Furthermore, the comparative genomic analysis of different S. thermophilus strains with various technological properties has advanced the development of knowledge about the relationship between genetic characters and phenotypic traits (Rasmussen et al, 2008;Vendramin et al, 2017).…”