Proteolytic activity of Enterococcus faecalis VB63F for reduction of allergenicity of bovine milk proteins
Résumé
With the aim of screening proteolytic strains of lactic acid bacteria to evaluate their potential for the reduction of allergenicity of the major bovine milk proteins, we isolated a new proteolytic strain of Enterococcus faccalis (Ent. faccalis VB63F) from raw bovine milk. The proteases produced by this strain had strong activity against caseins (alpha(S1)-, alpha(S2)-, and beta-casein), in both skim milk and sodium caseinate. However, only partial hydrolysis of whey proteins was observed. Proteolysis of Na-caseinate and whey proteins, observed after sodium dodecyl sulfate-PAGE, was confirmed by analysis of peptide profiles by reversed-phase HPLC. Inhibition of proteolysis with EDTA indicated that the proteases produced by Eat. faccalis VB63F belonged to the group of metalloproteases. The optimal conditions for their activity were 42 degrees C and pH 6.5. The majority of assessed virulence genes were absent in Ent. faecalis VB63F. The obtained results suggest that Ent. faecolis VB63F could be efficient in reducing the immunoreactivity of bovine milk proteins.