Lactobacillus helveticus heterogeneity in natural cheese starters: the diversity in phenotypic characteristics

Fortina, María Grazia; Nicastro, G.; Carminati, Domenico; Neviani, Erasmo; Manachini, P. L.

doi:10.1046/j.1365-2672.1997.00312.x

Cited by 69 publications

(63 citation statements)

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“…This confirmed that the genetic differences between Grana and Provolone cheese isolates not only depend on the differences in the conserved 16S rDNA region or in the plasmid profiles observed previously (14) but also are more widely distributed along the genome. This result is very interesting because it confirms at a genetic level the extensive phenotypic differences between the two groups of L. helveticus isolates reported previously (9,10). Sequencing data for L. helveticus isolates did not reveal extensive differences between the 16S rRNA gene sequences and the sequences of the species included in the GenBank database.…”

Section: Discussionsupporting

confidence: 89%

“…lactis, and Lactobacillus fermentum, and many biotypes (13, 27) of these species. Substantial differences in several technologically important characteristics have been found among L. helveticus strains isolated from natural dairy starter cultures (1,2,8,9,11,16,18,19,21,28,31).Because of the widespread use of L. helveticus in cheese technology, information concerning genotypic heterogeneity in this species is accumulating rapidly (6,7,14,17). A variety of genotypic and phenotypic methods have been used to show that the dominant L. helveticus communities in various dairy starters are composed of different biotypes, which sometimes may be associated with the source of isolation (2,6,9,12,14,20,22).…”

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confidence: 99%

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confidence: 99%

“…A variety of genotypic and phenotypic methods have been used to show that the dominant L. helveticus communities in various dairy starters are composed of different biotypes, which sometimes may be associated with the source of isolation (2,6,9,12,14,20,22).…”

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confidence: 99%

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Molecular Diversity within Lactobacillus helveticus as Revealed by Genotypic Characterization

Giraffa

Gatti

Rossetti

et al. 2000

Appl Environ Microbiol

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Lactobacillus helveticus is a homofermentative thermophilic lactic acid bacterium that is used in the manufacture of Swiss type and long-ripened Italian cheeses, such as Emmental, Grana, and Provolone cheeses. Substantial differences in several technologically important characteristics are found among L. helveticus strains isolated from natural dairy starter cultures. In the present study we investigated the genotypic diversity of 74 strains isolated from different dairy cultures used for manufacturing Grana and Provolone cheeses and six collection strains. A restriction fragment length polymorphism analysis of both total genomic DNA and the 16S rRNA gene (ribotyping) was used as genotypic fingerprinting. A multivariate statistical analysis of the data enabled us to identify significant genotypic heterogeneity in L. helveticus. We found that genotypic fingerprinting could be used to distinguish strains; in particular, it was possible to associate the presence of specific strain genotypes with dairy ecosystem sources (e.g., Grana or Provolone cheese). Our data contribute to the description of microbial heterogeneity in L. helveticus and provide a more solid basis for understanding the functional and ecological significance of the presence of different L. helveticus biotypes in natural dairy starter cultures.Lactobacillus helveticus is a homofermentative thermophilic lactic acid bacterium (LAB) that is used in the manufacture of Swiss type and long-ripened Italian cheeses, such as Emmental, Grana, and Provolone cheeses. In particular, L. helveticus is the most prevalent species recovered from natural lactic starter cultures used to produce typical Italian cheeses. Such cultures represent complex microbial associations of LAB that are characterized by the presence of various species and subspecies, such as L. helveticus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus delbrueckii subsp. lactis, and Lactobacillus fermentum, and many biotypes (13, 27) of these species. Substantial differences in several technologically important characteristics have been found among L. helveticus strains isolated from natural dairy starter cultures (1,2,8,9,11,16,18,19,21,28,31).Because of the widespread use of L. helveticus in cheese technology, information concerning genotypic heterogeneity in this species is accumulating rapidly (6,7,14,17). A variety of genotypic and phenotypic methods have been used to show that the dominant L. helveticus communities in various dairy starters are composed of different biotypes, which sometimes may be associated with the source of isolation (2,6,9,12,14,20,22).In a previous study, 74 L. helveticus strains that were isolated from Grana and Provolone cheese natural whey starters were distinguished according to their origins by using both cell wall protein profiles and chemometric evaluation of some phenotypic parameters (10). The cell wall protein patterns allowed the researchers to distinguish L. helveticus strains according to their sources of isolation. Good discrimination between the...

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Section: Discussionsupporting

confidence: 89%

mentioning

confidence: 99%

mentioning

confidence: 99%

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confidence: 99%

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Molecular Diversity within Lactobacillus helveticus as Revealed by Genotypic Characterization

Giraffa

Gatti

Rossetti

et al. 2000

Appl Environ Microbiol

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“…helveticus strains show phenotypic and genotypic variability (7,8,10,11). Fortina et al (7) reported that a wide phenotypic variability exists among L. helveticus strains isolated from natural cheese starters.…”

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Isolation and Characterization of a Slowly Milk-Coagulating Variant of Lactobacillus helveticus Deficient in Purine Biosynthesis

Hébert

Giori

Raya

2001

Appl Environ Microbiol

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A slowly milk-coagulating variant (Fmc ؊ ) of Lactobacillus helveticus CRL 1062, designated S1, was isolated and characterized. Strain S1 possessed all the known essential components required to utilize casein as a nitrogen source, which include functional proteinase and peptidase activities as well as functional amino acid, di-and tripeptide, and oligopeptide transport systems. The amino acid requirements of strain S1 were similar to those of the parental strain. However, on a purine-free, chemically defined medium, the growth rate of the Fmc ؊ strain was threefold lower than that of the wild-type strain. L. helveticus S1 was found to be defective in IMP dehydrogenase activity and therefore was deficient in the ability to synthesize XMP and GMP. This conclusion was further supported by the observation that the addition of guanine or xanthine to milk, a substrate poor in purine compounds, restored the Fmc ؉ phenotype of L. helveticus S1.Lactobacillus helveticus is used in the dairy industry with other lactic acid bacteria (LAB) as starter cultures to produce fermented milk, sour milk, and Swiss-and Italian-type cheeses. A useful guide to the suitability of these bacteria for cheesemaking is their ability to coagulate autoclaved milk within 16 h at 42°C when used as a 1% freshly coagulated inoculum (35), a property which defines a fast milk-coagulating (Fmc ϩ ) strain (an Fmc Ϫ strain requires more than 30 h of incubation for coagulating autoclaved milk at 42°C). Thus, the ideal starter culture should rapidly and dependably produce lactic acid during growth in milk. For this, LAB depend on their ability to metabolize lactose and on the presence of a complete proteolytic system which allows the efficient degradation and utilization of casein, the major milk protein. The specialized proteolytic system of these microorganisms consists of a cell envelope-associated proteinase, transport systems to allow uptake of the resultant amino acids and peptides, and several intracellular peptidases which degrade peptides to amino acids (17).In Lactococcus, the conversion of an Fmc ϩ phenotype to an Fmc Ϫ phenotype has mainly been attributed to loss of either a cell wall-bound proteinase (PrtP) or the enzyme(s) required for lactose utilization and can be due to loss of a plasmid coding for these enzymes (16,20). Yu et al. (36) found that the Fmc Ϫ phenotype in Lactococcus lactis could also be due to loss of a plasmid encoding an oligopeptide permease system. In addition, it was reported that an aminopeptidase (encoded by pepA) is required for optimal growth of L. lactis in milk (19). Recent findings have shown that Lactococcus lactis subsp. lactis C2 deficient in aspartate synthesis exhibited an Fmc Ϫ phenotype (35). When any of these properties are lost from the cells, the ability to synthesize lactic acid is also slowed and the cells are no longer effective starter organisms. Despite the industrial importance of thermophilic lactobacilli (e.g., L. helveticus) as dairy starters, information about the nature of the Fmc Ϫ pheno...

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Exopolysaccharide biosynthesis by Lactobacillus helveticus ATCC 15807

Torino

Mozzi

Valdez

2005

Appl Microbiol Biotechnol

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Exopolysaccharide (EPS) production and the activities of the enzymes involved in sugar nucleotide biosynthesis in Lactobacillus helveticus ATCC 15807 under controlled pH conditions were investigated. Batch fermentations using lactose as energy source showed higher EPS synthesis by L. helveticus ATCC 15807 at pH 4.5 with respect to pH 6.2, the enzyme alpha-phosphoglucomutase (alpha-PGM) being correlated with both total and specific EPS production. When glucose was used as carbon source instead of lactose, the lower EPS synthesis obtained was linked to a decrease in alpha-PGM and galactose 1-phosphate-uridyltransferase (GalT) activities, the reduction of the latter being more pronounced. Higher EPS production by L. helveticus ATCC 15807 at the acidic constant pH of 4.5 requires that both alpha-PGM and GalT activities are high. These enzymes are needed to synthesize UDP-glucose and UDP-galactose for supplying the corresponding monomers for EPS biosynthesis. Although differences are observed in EPS production by this strain regarding the energy source (lactose or glucose), the monomeric composition of the polymers produced is independent of the carbohydrate used. The obtained results contribute to a better understanding of the physiological factors that affect EPS biosynthesis by lactobacilli, which could help in the correct handling of the fermentation parameters within the fermented dairy industry.

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Lactobacillus helveticus heterogeneity in natural cheese starters: the diversity in phenotypic characteristics

Cited by 69 publications

References 2 publications

Molecular Diversity within Lactobacillus helveticus as Revealed by Genotypic Characterization

Molecular Diversity within Lactobacillus helveticus as Revealed by Genotypic Characterization

Isolation and Characterization of a Slowly Milk-Coagulating Variant of Lactobacillus helveticus Deficient in Purine Biosynthesis

Exopolysaccharide biosynthesis by Lactobacillus helveticus ATCC 15807

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