Stress tolerant bifidobacteria

Abstract

The present invention relates in general to the field of Bifidobacteria. In particular, the present invention relates to the field of Bifidobacteria with a modulated stress resistance. One embodiment of the present invention is a Bifidobacterium with a constitutively modulated DnaK, GrpE and/or CIpB expression.

The invention is claimed as follows: 
     
         1 . A method to increase the stress resistance of a  Bifidobacterium  comprising the step of constitutively upregulating an expression of a gene selected from the group consisting of DnaK, DnaJ, GrpE, C1pB and combinations thereof, by introducing at least one point mutation in the hspR gene of the  Bifidobacterium  so that a characteristic selected from the group consisting of HspR expression, HspR functioning and a combination thereof is hindered. 
     
     
         2 . The method of  claim 1 , wherein the  Bifidobacterium  is selected from the group consisting of  Bifidobacterium longum  NCC2912,  Bifidobacterium longum  NCC2913,  Bifidobacterium longum  NCC2923 and combinations thereof. 
     
     
         3 . The method of  claim 1 , wherein the  Bifidobacterium  is  Bifidobacterium longum  NCC2913. 
     
     
         4 . The method of  claim 1 , wherein the hspR gene comprises a DNA sequence selected from the group consisting of SEQ ID NO: 3, 5, 7, 9 and 11.