Isolation and characterization of Lactobacillus brevis C23 with ability to secrete antimicrobial substance for the inhibition of a foodborne pathogen Listeria monocytogenes ATCC 7644

ABSTRACT

Aims@#This study aims to isolate lactic acid bacteria (LAB) from various food sources to obtain a potent strain against Listeria monocytogenes. @*Methodology and results@#A total of 68 LAB isolates were selected to evaluate their antimicrobial activity against L. monocytogenes, a foodborne pathogen and a causative agent of listeriosis. The selected isolate was identified and characterized. The isolate C23 from cabbage showed the highest antimicrobial activity against L. monocytogenes ATCC 7644 with inhibition ability of 73.94%. The isolate was closely related to Lactobacillus brevis by 16S rRNA sequencing and subsequently deposited in GenBank with an accession number of MN880215, named as L. brevis C23. The cell free supernatant (CFS) of L. brevis C23 had high tolerance in low pH and was able to withstand up to 60 °C. The proteinaceous nature of the antimicrobial agent was also confirmed through the enzymatic test. The CFS was stable on different detergents as well as bile salts. Under transmission electron microscopy (TEM), the inhibitory effect of CFS against L. monocytogenes was proven by causing cell lysis.@*Conclusion, significance and impact of study@#Bacteriocin-like inhibitory substances (BLIS) of L. brevis C23 showed very promising potential in food industrial application.