Lactic acid bacteria from fermented products: Antimicrobial activity and metabolite production

In the present study, lactic acid bacteria (LAB) isolated from various fermented food sources, were studied on their antimicrobial properties alongside quantifying the production levels of lactic acid and diacetyl. Based on the findings of 16S rRNA sequencing, Pediococcus spp. were identified in 4 out of 11 isolates, Lactiplantibacillus spp. in 2 isolates, Leuconostoc spp. in 2 isolates, and Enterococcus spp. in 3 isolates. Except for isolate 8, all tested isolates demonstrated inhibitory effects against the pathogens used in the antimicrobial activity assays conducted in this study. Isolate F2 exhibited the highest lactic acid production, reaching a concentration of 10.07 mg/mL, while isolate 8 showed the highest diacetyl production at 0.8 µg/mL. Particularly, strains 40, 50, F2, AF1, and AF2 exhibited significant lactic acid production and demonstrated strong antimicrobial effects. Consequently, isolates exhibiting elevated levels of lactic acid production also demonstrated heightened antimicrobial effects, suggesting a contributory role of lactic acid production in antimicrobial activity.