Exopolysaccharide biosynthesis by Lactobacillus helveticus ATCC 15807

Torino, María Inés; Mozzi, Fernanda; Valdez, Graciela Font de

doi:10.1007/s00253-004-1865-2

Cited by 32 publications

(22 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Up to now, no results have been published investigating the regulation of L. reuteri genes involved in EPS production. However, EPS production has been shown to be affected by environmental factors, like temperature and pH, e.g., in Lactobacillus helveticus ATCC 15807 (40,41) and Streptococcus thermophilus 1275 (46). Therefore, it is tempting to speculate that L. reuteri LTH5531 may synthesize EPS in sourdough under control of the transcriptional regulator that we have detected.…”

Section: Discussionmentioning

confidence: 81%

Inducible Gene Expression in Lactobacillus reuteri LTH5531 during Type II Sourdough Fermentation

Bello

Walter

Roos

et al. 2005

Appl Environ Microbiol

View full text Add to dashboard Cite

Lactobacillus reuteri LTH5531 is a dominant member of the microbiota of type II sourdough fermentations. To investigate the genetic background of the ecological performance of LTH5531, in vivo expression technology was used to identify promoters that show elevated levels of expression during growth of this organism in a type II sourdough fermentation. Thirty-eight sourdough-induced fusions were detected, and 29 genes could be identified on the basis of the available sequence information. Four genes encoded stress-related functions (e.g., acid and general stress response), reflecting the harsh conditions prevailing during sourdough fermentation. Further, eight genes were involved in acquisition and synthesis of amino acids and nucleotides, indicating their limited availability in sourdough. The remaining genes were either part of functionally unrelated pathways or encoded hypothetical proteins. The identification of a putative proteinase and a component of the arginine deiminase pathway is of technological interest, as they are potentially involved in the formation of aroma precursors. Our study allowed insight into the transcriptional response of Lactobacillus reuteri to the dough environment, which establishes the molecular basis to investigate bacterial properties that are likely to contribute to the ecological performance of the organism and influence the final outcome of the fermentation.Sourdough is an intermediate product in bread production and contains a microbiota comprised of lactic acid bacteria and yeasts (reviewed in reference 16). Microbiological studies have revealed that 43 species of lactic acid bacteria, mostly species of the genus Lactobacillus, and more than 23 species of yeast occur in this ecological niche. The metabolic activity of these microorganisms leads to an acidification of the dough and the development of aroma precursors and is therefore of major importance for the quality of the final product. Sourdough breads are characterized by their unique flavor and texture, enhanced nutritional value, and favorable technological properties, such as prolonged shelf life and delayed staling (reviewed in reference 15). Type II sourdoughs serve mainly as dough acidifiers and are fermented for long periods (up to 5 days) at temperatures of Ͼ30°C and with high dough yields to permit pumping of the dough. Strains of Lactobacillus reuteri have been shown to be highly competitive in type II sourdough fermentations and persist over several years of continuous propagation in industrial fermentation processes (13,22). Numerous ecological factors affect the competitiveness of lactobacilli in sourdough fermentations, i.e., temperature, ionic strength, dough yield, and microbial products, such as lactate, acetate, CO 2 , and ethanol as well as factors resulting from substrates present in the cereal fraction and from enzymatic reactions (6, 22). The properties and genetic background responsible for the ecological performance of L. reuteri in sourdough fermentation are, however, poorly understood.In vivo ex...

show abstract

Section: Discussionmentioning

confidence: 81%

Inducible Gene Expression in Lactobacillus reuteri LTH5531 during Type II Sourdough Fermentation

Bello

Walter

Roos

et al. 2005

Appl Environ Microbiol

View full text Add to dashboard Cite

show abstract

“…A large biodiversity of HePS from LAB exists regarding their composition and structure, molecular mass (MM), yield, and functionalities (5,7,35). Further, polymer formation is strongly influenced by culture conditions (1,7,22,32). Recently, the molecular genetics of HePS biosynthesis have been studied for different LAB species (6,25).…”

mentioning

confidence: 99%

“…In general, the biodiversity of HePS may be ascribed to the sugar nucleotide biosynthesis routes and the genetic potential of the strains (7). A correlation between the HePS monomers and the activity of glycosyltransferases (17,18,35) and enzymes for sugar nucleotide biosynthesis has been reported (2,21,22,32).…”

mentioning

confidence: 99%

Diversity of Heteropolysaccharide-Producing Lactic Acid Bacterium Strains and Their Biopolymers

Mozzi

Vaningelgem

Hébert

et al. 2006

Appl Environ Microbiol

125

102

View full text Add to dashboard Cite

Thirty-one lactic acid bacterial strains from different species were evaluated for exopolysaccharide (EPS) production in milk. Thermophilic strains produced more EPS than mesophilic ones, but EPS yields were generally low. Ropiness or capsular polysaccharide formation was strain dependent. Six strains produced high-molecular-mass EPS. Polymers were classified into nine groups on the basis of their monomer composition. EPS from Enterococcus strains were isolated and characterized.Certain lactic acid bacteria (LAB) produce exopolysaccharides (EPS), either capsular polysaccharides (CPS) that are tightly associated with the cell surface or slime EPS that are secreted into the extracellular environment. EPS from LAB can be divided into homopolysaccharides, which are polymers composed of one type of monosaccharide, and heteropolysaccharides (HePS), which are polymers of repeating units that are composed of two or more types of monosaccharides (5,6,7,11). A large biodiversity of HePS from LAB exists regarding their composition and structure, molecular mass (MM), yield, and functionalities (5,7,35). Further, polymer formation is strongly influenced by culture conditions (1,7,22,32). Recently, the molecular genetics of HePS biosynthesis have been studied for different LAB species (6, 25). Several glycosyltransferases involved in the assemblage of the HePS repeating units have been discovered (17,18,35). EPS can act as viscosifying, stabilizing, gel-forming, and/or water-binding agents in various foods (6, 10). Additionally, they have been claimed to display properties beneficial to health (6, 29). Little attention has been paid to CPS formation by food grade LAB. Exploration of the biodiversity of wild LAB strains is the most suitable approach to search for a desired EPS phenotype (28,33,34). The aims of this study were to seek new EPS-producing LAB strains, to characterize their biopolymers, and to explore their diversity to find novel or interesting HePS or HePS-producing strains.EPS screening, isolation, and characterization. Two hundred one thermophilic (11 strains of Lactobacillus acidophilus, 79 of Lactobacillus delbrueckii subsp. bulgaricus, 1 of L. delbrueckii subsp. lactis, 1 of Streptococcus macedonicus, and 42 of Streptococcus thermophilus) and mesophilic (23 strains of Enterococcus faecalis, 1 of Enterococcus faecium, 5 of Lactobacillus casei, 29 of Lactobacillus paracasei, and 9 of Lactobacillus rhamnosus) LAB strains (CERELA Culture Collection, Tucumán, Argentina) were used throughout this study. All bacteria were stored as previously described (22). Before experimental use, cultures were propagated twice in MRS (Britania, Buenos Aires, Argentina) for lactobacilli or in LAPTg (27) for streptococci and enterococci.Screening for EPS-producing LAB was performed with reconstituted skim milk (10%, wt/vol) at 37°C for 16 h using cultures propagated in milk as the inoculum (1%, vol/vol). Noninoculated medium was used as a control. Cell counts, expressed as numbers of CFU per milliliter, were determined by pour pla...

show abstract

“…The synthesis of EPS by L. casei strain CRL 87 was improved by using galactose as carbon source at a controlled pH of 5.0, and the high EPS production was correlated with high activity level of the enzymes involve in the synthesis of UDP-sugars (Mozzi et al, 2003). Similar approaches were applied for L. helveticus strain ATCC 15807, which produces a higher amount of EPS from lactose at pH 4.5 than at pH 6.2, which was correlated with higher levels of -Pgm activity (Torino et al, 2005). A L. delbrueckii subesp.…”

Section: Exopolysaccharides (Eps) Productionmentioning

confidence: 99%

Genetically Engineered Lactobacilli for Technological and Functional Food Applications

Yebra¹,

Monedero²,

Pérez-Martı́nez³

et al. 2012

Food Industrial Processes - Methods and Equipment

View full text Add to dashboard Cite

Exopolysaccharide biosynthesis by Lactobacillus helveticus ATCC 15807

Cited by 32 publications

References 33 publications

Inducible Gene Expression in Lactobacillus reuteri LTH5531 during Type II Sourdough Fermentation

Inducible Gene Expression in Lactobacillus reuteri LTH5531 during Type II Sourdough Fermentation

Diversity of Heteropolysaccharide-Producing Lactic Acid Bacterium Strains and Their Biopolymers

Genetically Engineered Lactobacilli for Technological and Functional Food Applications

Contact Info

Product

Resources

About