Inhibition of Foodborne Pathogens by a Bacteriocin-Like Substance Produced by a Novel Strain of Lactobacillus Acidophilus Isolated from Camel Milk

摘要

As increasing demand for eliminating the use of chemical additives in foodstuff, bacteriocins might have significant potential in food preservation. Of 11 strains of Lactobacillus acidophilus isolated from camel milk 3 strains showed inhibitory activity against foodborne pathogens. L. acidophilus AA105 identified by 16S rRNA demonstrated antimicrobial activity of a wide spectrum. The bacteriolytic bacteriocin produced by L. acidophilus AA105 lost no activity after 30 min at 121A degrees C and was sensitive to proteolytic enzymes. This antimicrobial compound produced at logarithm phase of cultivation and extracted with n-butanol was stored at 37A degrees C for at least 70 days without loss of its activity. Native bacteriocin was retained by 5 kDa membrane with full activity. The sequencing of 12 amino acids of the N-terminus was determined as GNPKVAHCASQI. The genes encoding the antimicrobial compound were located on the chromosome but not in plasmid. L. acidophilus AA105 was investigated for susceptibility to available commercially antibiotics. These characteristics classify antimicrobial compound produced by L. acidophilus AA105 as a novel bacteriocin and give this compound an application potential as food biopreservative or antimicrobials.