Co-culture affects protein profile and heat tolerance of Lactobacillus delbrueckii subsp. lactis and Bifidobacterium longum

Abstract

Some strains of the genus Bifidobacterium are considered probiotics and can be added as adjunct cultures to functional dairy products. Lactobacillus delbrueckii subsp. lactis is used as a starter in food fermentations. The influence of co-culturing strains Bifidobacterium longum NCIMB 8809 and L. delbrueckii subsp. lactis 193 on the physiology and heat tolerance of these microorganisms was studied. 2DE coupled to MS protein analysis allowed the identification of several proteins from each bacterium whose expression changed when cells were grown in compartmentalized co-cultures compared to mono-cultures. Remarkably, production of stress response chaperones was enhanced in both strains and was related with increased survival to heat shock, a technologically suitable property in the manufacture of some dairy products. This study provides the first insight in understanding communication between B. longum and L. delbrueckii subsp. lactis.