Exploring the impact of Mg-doped ZnO nanoparticles on a model soil microorganism Bacillus subtilis

Abstract The environmental contamination of soil by metal oxide nanomaterials is a growing global concern because of their potential toxicity. We investigated the effects of Mg doped ZnO (Mg- n ZnO) nanoparticles on a model soil microorganism Bacillus subtilis . Mg- n ZnO exhibited only a moderate toxic effect on B. subtilis vegetative cells but was able to prevent biofilm formation and destroy already formed biofilms. Similarly, Mg- n ZnO (≤1 mg/mL) was moderately toxic towards Listeria monocytogenes, Staphylococcus aureus , Escherichia coli , Salmonella enterica , Saccharomyces cerevisiae and murine macrophages. Engineered Mg- n ZnO produced H 2 O 2 and O 2 •− radicals in solutions of various salt and organic molecule compositions. A quantitative proteomic analysis of B. subtilis membrane proteins showed that Mg- n ZnO increased the expression of proteins involved in detoxification of ROS, translation and biofilm formation. Overall, our results suggest that Mg- n ZnO released into the environment may hinder the spreading, colonization and biofilm formation by B. subtilis but also induce a mechanism of bacterial adaptation .