Biogenic SeNPs from Bacillus mycoides SelTE01 and Stenotrophomonas maltophilia SelTE02: Characterization with reference to their associated organic coating

Abstract

The exploitation of biological systems (i.e. plants, fungi and bacteria) for the production of nanomaterials relies on their ability to bioconvert toxic metal(loid) ions into their less toxic and bioavailable elemental states forming mainly nanoparticles (NPs) or nanorods (NRs). Further, these methods of nanomaterial production are nowadays recognized as eco-friendly alternatives to the chemical synthesis processes. A common feature among the so-called biogenic nanomaterials is the presence of an organic layer surrounding them. However, we are just learning the existing relation between biogenic nanostructures and their organic material. Our work is focused on the study of bacterial strains for the production of selenium nanoparticles (SeNPs) as end product of selenite (SeO32−) bioconversion. In this context, our previous reports described the ability of two bacteria, namely Bacillus mycoides SelTE01 and Stenotrophomonas maltophilia SelTE02, to generate SeNPs, which were surrounded by organic material. Here, the potential role of this organic material as stabilizing agent of SeNPs was investigated altering both the bacteria cells culturing and the SeNPs extraction procedure, in order to understand the interaction between these two elements in suspension. As a result, SeNPs produced by both bacterial strains showed the tendency to aggregate when subjected to the treatments tested, suggesting an involvement of the surrounding organic material in their stabilization in suspension.