Effects of Different Nutritional Zinc Forms on the Proliferation of Beneficial Commensal Microorganisms

Abstract

This study compared the minimal inhibition concentrations (MICs) and their effects on the growth kinetics of seven different types of zinc (Zn) compounds and Na2EDTA in the case of three typical commensal beneficial microorganisms (Bacillus subtilis, Lactococcus lactis, and Saccharomyces cerevisiae). The seven Zn compounds included ZnSO4, four Zn–amino acid chelates, and two Zn–EDTA complexes. Both MICs and growth kinetic parameters indicated that different microorganisms show different sensitivities; for example, B. subtilis, L. lactis, and S. cerevisiae were most sensitive to ZnSO4, Na2EDTA, and Zn(NH3)2(Gly)2, respectively. Both ZnEDTA and Zn(NH3)2(Lys)2 improved the growth rate of all beneficial commensal intestinal microorganisms at low concentrations (5–10 mg/L) and showed low toxicity towards all tested strains. At higher concentrations (100–500 mg/L), all compounds decreased the growth rate and increased the lag phase. In conclusion, both growth kinetic parameters and MICs tested effectively measured the inhibitory effects of the test materials; however, growth kinetics provides a more detailed picture of the concentration-dependent effects and those on the mechanisms of microbial growth inhibition.

Antimicrobial and anti-biofilm efficacy of different inorganic and organic zinc forms against multidrug-resistant Escherichia, Klebsiella, Staphylococcus and Pseudomonas

“…Therefore, the search for new zinc (Zn) antimicrobials is still a great challenge (Abendrot and Kalinowska 2018 ). Previous in vivo studies demonstrated many beneficial impacts of supplemental Zn (organic or inorganic) on different physiological and immunological functions, positive impact on animal health and performance, and some of them deal with the effect on the gut bacterial composition (Bujňáková et al 2023 ), since Zn in appropriate concentration is essential for microorganisms, although conversely, the antimicrobial effect of excess Zn is well-known (Molnar-Nagy et al 2022 ). The most common used inorganic Zn derivatives are Zn(II) sulphates.…”