0 avis
Characterization of new strain Lactobacillus paracasei I-N-10 with proteolytic activity: Potential role in decrease in beta-casein immuno-reactivity
Archive ouverte
Edité par CCSD ; Springer Verlag (Germany) -
International audience. The proteolytic activity of thirty-three Lisolates from Mongolian tarag was tested on skimmed milk. The strain displaying the highest proteolytic activity was purified and presented by 16S rDNA sequencing 99.9 % homology with Lactobacillus paracasei 1-4-2A. It was named L. paracasei I-N-10. Proteases of L. paracasei I-N-10 hydrolyze predominately beta-casein and in some level alpha(S2)-casein; hydrolysis of alpha(S1)-casein was not observed. Proteolytic activity was optimal at 42 A degrees C and neutral pH. Proteases of L. paracasei I-N-10 were inhibited by serine- and metalloproteases inhibitors. PCR amplification revealed the presence of prtP gene, which was identical to prtP gene of L. paracasei genus. Mass spectrometry analysis of beta-casein hydrolysate allowed to characterize 7 peptides resulting from proteolysis by L. paracasei I-N-10. The isolated strain was able to cleave beta-casein in different sites including 2 of the major linear epitopes implicated in its allergenicity. Being sensitive to main antibiotics classes, L. paracasei I-N-10 could be considered as safe and used as starter culture with a potential role in decreasing beta-casein immuno-reactivity.