Spectroscopic profiling of cell free supernatant from Lactocaseibacillus rhamnosus and Limosilactobacillus fermentum and evaluation of their antibacterial activity against Gram-positive and Gram-negative bacteria under varying conditions

Abstract

Spoilage microorganisms and food borne pathogens are major public health concerns causing enormous economic losses globally. The organoleptic qualities of food products are frequently altered in an undesired way by conventional food preservation techniques. Lactic acid bacteria (LAB), on the other hand, naturally synthesise antimicrobial substances that successfully prevent the growth of harmful and spoilage microorganisms without lowering the quality of food. Owing to these traits, LAB-derived compounds like bacteriocins are commonly utilised in food and dairy processing industries. In the present study, Lacticaseibacillus rhamnosus and Limosilactobacillus fermentum were isolated from curd from commercially available brand and evaluated for their antimicrobial efficacy under a range of environmental conditions. Integrated spectroscopic profiling of antimicrobial metabolites present in crude supernatant of LAB reveal that glycosylated molecules featuring ester or peptide could play a key role in the inhibitory effects seen against both Gram-positive and Gram-negative bacteria.