β-Galactosidase from strains isolated from breast milk and infant saliva: characterization and participation in absorption of different oligosaccharides

Abstract

Lactobacillus are Gram-positive anaerobic bacteria that naturally occur in the human intestinal tract. They are considered to be beneficial commensals for human health because they prevent the growth of pathogenic bacteria by lowering the intestinal pH and stimulate the host’s immune system to enhance antipathogenic and anticarcinogenic activities. The intestines of breastfed infants are colonized by Lactobacillus  within a week after birth, in comparison with those of bottle-fed infants. 

In our study, we have isolated bacterial strains of breast milk and infants saliva. The isolates were identified by 16S RNA and API identification. This report details the ability of the isolated strain to metabolized human milk oligosaccharides and we clarified that HMOs was sequentially degraded by different glycosidases. We studied the potential of β-galactosidases from studied strains to metabolize carbohydrates from breast milk.

We investigated the β-galactosidase activity after cultivation of medium containing different concentration HMOs,  lactose and some oligosaccharides.