Enrichment of zinc in Lactobacillus plantarum DNZ-4: Impact on its characteristics, metabolites and antioxidant activity

The current study was conducted to investigate the effects of zinc enrichment on the characteristics, metabolites and antioxidant activity of L. plantarum DNZ-4. Electron microscopy analysis showed that the ultrastructure of the zinc-enriched strain changed greatly both for surface and inside as compared to the control strain. The zinc-enriched strain showed higher acid production ability resulting in lower pH value. Resistance assays demonstrated that the zinc-enriched strain has stronger tolerance ability to acid, bile salt and H2O2 than that of the control strain. Metabolites analysis indicated that the various metabolites in the zinc-enriched strain were altered significantly as a result of amino acids, energy and fatty acid metabolism affected by zinc enrichment. Furthermore, the antioxidant properties of the zinc-enriched strain, including radical scavenging capacity and the antioxidative enzyme activity increased significantly. These results suggest that zinc addition had a positive effect on the physiologic function of L. plantarum DNZ-4.