Chemistry: molecular biology and microbiology – Micro-organism – tissue cell culture or enzyme using process... – Recombinant dna technique included in method of making a...
Patent
1995-05-01
1997-11-04
Degen, Nancy
Chemistry: molecular biology and microbiology
Micro-organism, tissue cell culture or enzyme using process...
Recombinant dna technique included in method of making a...
426 34, 435 713, 4352534, 435885, 530300, 536 231, 536 237, C12P 2102, C07H 2104, C07K 14315, A23C 9123
Patent
active
056838905
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The subject of the present invention is two bacteriocins from Streptococcus (S.) thermophilus, a strain of S. thermophilus which produces these bacteriocins, a process for producing these bacteriocins from this strain, as well as uses of these bacteriocins and/or of this strain in the preparation of food products or cosmetic products.
STATE OF THE ART
A bacteriocin is an antibacterial substance or an agent which is active against bacteria comprising a protein portion which is involved in the antibacterial effect or antibiotic effect. A bacteriocin generally has a narrow activity spectrum or inhibition spectrum often limited to species close to the species of the bacterium which produces it.
Currently, four S. thermophilus bacteriocins are known.
The first has, in particular, a molecular weight of 10 to 20 kD, exhibits thermolability at 90.degree. C. and sensitivity to pepsin (Smaczny et al., Deutsche Molkerei-Zeitung, 105: 15, 460-464, 1984).
The second, which is described mainly by its bacteria inhibition spectrum in EP 443543, has especially the capacity to inhibit the growth of bacteria of the genus Staphylococcus and Pseudomonas, and the inability to inhibit the growth of bacteria of the genus Lactococcus and Enterococcus, and of the species Bacillus cereus.
The third, which is described by Pulusani et al. (J. of Food Science, 44:2, 575-578, 1979), strongly inhibits Pseudomonas, is not sensitive to pepsin, and contains sugar residues.
Finally, the fourth, described by Gilano et al. (Microbiologie-Aliment-Nutrition, 8, 21-30, 1990), is not sensitive to pepsin, contains sugar residues and does not pass across a membrane with a porosity of 100 kD.
Now, S. thermophilus is of major importance in the food sector, being especially involved in the preparation of dairy products such as yogurts and some cheeses for example. Furthermore, very few bacteriocins exist which are active at the same time against Bacillus, Clostridium and Listeria. It may therefore be more useful, in other words there is a need for a broader range of bacteriocins produced by representatives of this species in order to have especially a broader antibacterial activity spectrum, in particular in the context of this type of product.
The aim of the present invention is to respond to this need.
SUMMARY OF THE INVENTION
One of the subjects of the present invention is the characterization of the amino acid sequence of two new S. thermophilus bacteriocins, as well as their signal peptide which permits their excretion.
The nucleotide sequences encoding these two bacteriocins are also another subject of the invention.
The Streptococcus thermophilus strains producing at least one of the bacteriocins according to the invention are also another subject of the invention, especially the strain CNCM I-1351 of S. thermophilus described below, which is capable of producing the two bacteriocins according to the invention.
The process for producing an extract of at least one bacteriocin according to the present invention is also another subject of the present invention.
Finally, the last subject of the present invention is the use of the bacteriocins according to the invention and the use of their nucleic sequence, as well as their signal sequence.
DETAILED DESCRIPTION OF THE INVENTION
A strain CNCM I-1351 of S. thermophilus was isolated from a fermented dairy product from Czechoslovakia and it was observed, surprisingly, that it has the remarkable property of inhibiting the growth of a broad range of bacteria. This strain was deposited on May 8, 1993, according to the Budapest Treaty, at the Collection Nationale de Cultures de Microorganismes, PASTEUR INSTITUTE, 25, Rue du Docteur Roux, F-75724 PARIS CEDEX 15, France where it was thus assigned the No. I-1351. Any and all restrictions on the availability to the public of the material so deposited will be irrevocably removed upon the granting of a patent for the present invention.
Details on this strain relating especially to its morphology, the fermentation of sugars and the like a
REFERENCES:
patent: 5338682 (1994-08-01), Sasaki et al.
patent: 5482723 (1996-01-01), Sasaki et al.
Smaczny, T. et al.; "Sauerungstorungen in der Joghurt-, Biohurt -und Biogarde -Produktion, bedingt durch Bacteriocn und Bakteriophagen von Streptococcus thermophilus"; Deutsche Molkerei-Zeitung, vol. 105, No. 15, 1984, pp.460-464.
Ward, D. J. et al.; "Bacteriocin production in Streptococcus thermophilus"; Abstracts of the Annual Meeting of the American Society for Micorbiology, May 1993, Washington U.S., p. 344.
Muriana et al. "Cloning, Phenotypic Expression & DNA Sequence of the Gene for Lactacin F . . . " J Bacteriol. 173(5) 1779-1788 1991.
Germond Jacques Edouard
Marciset Olivier
Mollet Beat
Degen Nancy
Nestec S.A.
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