The mechanism for microbial CLA production has been elucidated for Propionibacterium and Lactobacillus, employing either a polyunsaturated fatty acid isomerase or a three-enzyme system, respectively. The recently identified linoleic acid isomerase (LAI) of Bifidobacterium breve JKL2022 exhibited isomer-specific conversion of free linoleic acid into cis-9, trans-11 CLA, a distinct enzyme from those of Propionibacterium and Lactobacillus. The bifidobacterial LAI presents numerous advantages for controlled bioactive fatty acid synthesis. Multi-method characterization revealed the membrane-spanning configuration of LAI, which was later cloned in Escherichia coli BL21. Wildtype and recombinant LAI exhibited strong CLA conversion under controlled in vitro reaction with LA as substrate, resulting in ≥99.15% CLA conversion with the cis-9, trans-11 isomer as the major isomer (73.27 ± 3.80%). In combination with Candida rugosa type VII lipase (CRL), grapeseed oil, which contains the TG form of LA, was successfully used as a substrate for specific biosynthesis of cis-9, trans-11 CLA. Thus, the potential for isomer-specific CLA production using plant-derived oils through microbial enzyme reactions is a feasible alternative for chemical-based CLA synthesis, which results in multiple CLA isomers. 

Ligilactobacillus agilis LDTM47, isolated from the gastrointestinal tract contents of broiler, produces Class IIa bacteriocin during the growth. It has demonstrated the ability to inhibit numerous pathogenic Gram-positive bacteria. It also demonstrated inhibition and prevention effects against Listeria monocytogenes strains in raw chicken breast meat and cream cheese. Additionally, whole genome sequencing [1] and in silico analysis using BAGEL4 tool [2] revealed that there was only one bacteriocin identical to LDTM47 bacteriocin, and the presence of core peptide and ABC transporter. This study suggests that the bacteriocin of Ligilactobacillus agilis LDTM47 has potential applicability as a bio-preservative in the animal-derived food industry for foodborne-induced pathogens. 

Silver nanoparticles (AgNPs) were synthesized using the cell-free supernatants (CFS) of two bacteriocin-producing strains, Ligilactobacillus salivarius B4112 and Enterococcus faecalis M157. The green-synthesized AgNPs, prepared using silver nitrate (AgNO₃) as a precursor, were analyzed under various synthesis conditions using ultraviolet–visible spectroscopy to monitor formation and yield. Further characterization was performed using field emission transmission electron microscopy (FE-TEM), energy-dispersive X-ray spectroscopy (EDS), dynamic light scattering (DLS), and Fourier-transform infrared spectroscopy (FT-IR). Antimicrobial activity of the AgNPs was tested against two Gram-positive bacteria (Listeria monocytogenes ATCC 19114 and Staphylococcus aureus ATCC 33591) and two Gram-negative bacteria (Escherichia coli ATCC 25922 and Pseudomonas aeruginosa KCTC 1750T) using the well diffusion assay. In most cases, combined treatment with CFS and AgNPs (CFS+AgNPs) showed stronger antibacterial effects than either component alone. Anti-biofilm activity of the AgNPs was also evaluated against E. coli, S. aureus, and mixed-species biofilms. Similarly, CFS+AgNPs—using B4112+AgNPs (9.03–1.13 µg/mL) and M157+AgNPs (26.53–3.32 µg/mL)—exhibited enhanced anti-biofilm effects. These results suggest that green-synthesized AgNPs, especially when combined with bacteriocin-containing CFS, can broaden the antimicrobial spectrum. A key application is their use in food packaging to reduce microbial contamination. 

Enterococcus faecalis CAUM157, isolated from raw cow's milk, was observed to produce a bacteriocin with a wide range of inhibitory activity against pathogens including Listeria monocytogenes, Staphylococcus aureus, and periodontitis-causing bacteria. Whole-genome analysis revealed that the bacteriocin produced by E. faecalis CAUM157 is a two-peptide bacteriocin with a high degree of amino acid sequence similarity with MR10A and MR10B bacteriocin first described from E. faecalis MRR 10-3 [1]. Furthermore, in silico analysis using BAGEL4 online tool [2] revealed genes encoding for self-immunity and ABC-transport system downstream of the putative bacteriocin gene.