Lactic acid bacteria
AssigneeInternational N&H Denmark Aps
InventorsAnais Jedrzejowski, Christophe Fremaux, Sabine Van Dillen, Thomas Desfougeres, Max Charles Jodeau, Damien Lugand
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Abstract
The invention relates to a polynucleotide comprising a lacZ gene (lacZFS) encoding a β-galactosidase characterized by a particular profile regarding its efficiency of hydrolysis of lactose. The invention is also directed to a Streptococcus thermophilus strain comprising a lacZFS allele and bacterial composition thereof, and their use to obtain fermented milk not undergoing post-acidification.
Claims16
A polynucleotide encoding a β-galactosidaseFS, which comprises an amino acid sequence which has at least 95% identity with SEQ ID NO:2;
- and which is defined as a lacZ allele which increases the ratio of the activity of lactose importation of the LacS permease at pH 4.5 over the activity of lactose hydrolysis of the beta-galactosidase at pH 4.5 above 8 in a DGCC715 derivative, said DGCC715 derivative being a strain DGCC715 (deposited at the DSMZ on Feb. 12, 2019 under the accession number DSM33036), into which its lacZ gene was replaced by said polynucleotide encoding a β-galactosidaseFS.
A method to identify a lacZFS allele encoding a β-galactosidaseFS, comprising:
- a) inserting the lacZ allele to be tested in lieu of the allele of the lacZ gene of the strain DGCC715 (deposited at the DSMZ on Feb. 12, 2019 under the accession number DSM33036), to obtain a DGCC715-derivative;
- and
- b) determining the activity of lactose importation of the LacS permease at pH 4.5 (LacSpH4.5) and the activity of lactose hydrolysis of the beta-galactosidase at pH 4.5 (LacZpH4.5);
- wherein a ratio LacSpH4.5 over LacZpH4.5 which is more than 8 is indicative of a lacZ allele which is a lacZFS allele encoding a β-galactosidaseFS.
Dependencies are inferred from the claim text.