Screening for bacteriocins production in enteric bifidobacterium isolates and study of some production affecting factors

الملخص EN

Enteric Bifidobacterium isolates were screened for bacteriocins production against food–born Listeria monocytogenes by agar– well diffusion assay.

Bifidobacterium longum B1 and Bifidobacterium bifidum B2 was potent producer of antilisterial bacteriocins.

Maximum bacteriocins production was achieved using MRS broth medium.

The antilisterial activity appeared to be pronounced in mid logarithmic growth phase after 6h, 9 h in B1 and B2 respectively.

The optimum temperature and initial pH for bacteriocins production was 35°C and 6.5 respectively.

Bacteriocin production decreased by the addition of NaCl to MRS broth.

Glucose as a carbon source stimulated bacteriocin production in isolate B1 (12.8 mm inhibition zone), while supplementation of MRS with fructose doubled bacteriocin production in isolate B2 (13 mm inhibition zone).

Inclusion of peptone to MRS broth clearly enhanced bacteriocins production in the two tested isolates, comparison to other tested nitrogen sources.