Abstract:

Bifidobacterium L-SN capable of producing an antimicrobial substance that was effective against Lactobacillus
plantarum PL-2 was screened from 32 strains of Bifidobacterium isolated from the feces of centenarians in Bama county
of Guangxi region. By eliminating the effects of organic acid and H2O2, we confirmed the antimicrobial role because of
bacteriocin. Based on morphological, physiological and biochemical characteristics and 16S rRNA sequence analysis,
the strain L-SN was identified as Bifidobacterium animalis subsp. lactis. We investigated the secretion characteristics of
Bifidobacterium animalis L-SN and established the optimum incubation conditions for producing bacteriocin: 28 h of culture
at 30 ℃ and initial medium pH 6.5. The bacteriocin had a wide spectrum of antibacterial activities against Gram-positive and
Gram-negative bacteria, especially against Staphylococcus aureus, Escherichia coli and Listeria monocytogenes showing a
potential application prospect.

Key words: Bifidobacterium, screening, bacteriocin, secretion characteristics