Use of Vegetable Waste as a Culture Medium Ingredient Improves the Antimicrobial and Immunomodulatory Activities of Lactiplantibacillus plantarum WiKim0125 Isolated from Kimchi

Lactic acid bacteria (LAB) isolated from kimchi (a traditional Korean dish typically made of fermented cabbage) can provide various health benefits, including anti-obesity, antioxidant, anti-inflammatory, anticancer, and antimicrobial effects. In this study, we examined the antimicrobial and immunomodulatory effects of Lactiplantibacillus plantarum WiKim0125 cultured in de Man, Rogosa, and Sharpe (MRS) medium containing vegetable waste. Live bacterial cells were eliminated via supernatant filtration or heat treatment. The cell-free supernatant (CFS) obtained from culture broth containing kimchi cabbage waste (KCW), cabbage waste (CW), or onion waste (OW) showed significantly higher antimicrobial activity against skin pathogens (Propionibacterium acnes and Staphylococcus aureus) and foodborne pathogens (Escherichia coli and Salmonella typhimurium), with inhibition zones ranging between 4.4 and 8.5 mm, compared to that in conventional MRS medium (4.0–7.3 mm). In lipopolysaccharide-stimulated RAW264.7 cells, both supernatant and heat-inactivated Lb. plantarum WiKim0125 from culture media containing KCW and CW suppressed the production of inflammatory cytokines (72.8% and 49.6%, respectively) and nitric oxide (62.2% and 66.7%, respectively) without affecting cell viability. These results indicate that vegetable waste can potentially increase the antimicrobial and immunoregulatory potency of LAB while presenting a molecular basis for applying postbiotics to health products.