Assembly, growth and conductive properties of tellurium nanorods produced by Rhodococcus aetherivorans BCP1

Abstract

Tellurite (TeO32−) is a hazardous and toxic oxyanion for living organisms. However, several microorganisms can bioconvert TeO32− into the less toxic form of elemental tellurium (Te0). Here, Rhodococcus aetherivorans BCP1 resting (non-growing) cells showed the proficiency to produce tellurium-based nanoparticles (NPs) and nanorods (NRs) through the bioconversion of TeO32−, depending on the oxyanion initial concentration and time of cellular incubation. Te-nanostructures initially appeared in the cytoplasm of BCP1 cells as spherical NPs, which, as the exposure time increased, were converted into NRs. This observation suggested the existence of an intracellular mechanism of TeNRs assembly and growth that resembled the chemical surfactant-assisted process for NRs synthesis. The TeNRs produced by the BCP1 strain showed an average length (>700 nm) almost doubled compared to those observed in other studies. Further, the biogenic TeNRs displayed a regular single-crystalline structure typically obtained for those chemically synthesized. The chemical-physical characterization of the biogenic TeNRs reflected their thermodynamic stability that is likely derived from amphiphilic biomolecules present in the organic layer surrounding the NRs. Finally, the biogenic TeNRs extract showed good electrical conductivity. Thus, these findings support the suitability of this strain as eco-friendly biocatalyst to produce high quality tellurium-based nanomaterials exploitable for technological purposes.

Superior Antibacterial Activity of Integral Lemon Pectin Extracted via Hydrodynamic Cavitation

“…A non‐challenged bacterial suspension was incubated in parallel and used as control. After 24 h, all cultures were serially diluted and aliquots (20 μL) of opportune dilutions were spotted onto mannitol salt agar plates, recovered at 37 °C under static mode . The number of viable CFU mL −1 is reported (Figure ) in logarithmic (Log 10 ) scale with standard deviation ( n =3).…”

Tunable photoluminescence properties of selenium nanoparticles: biogenic versus chemogenic synthesis

“…Physical-chemical features of the Biogenic SeNP extracts, L-cys SeNPs, OMs and chemogenic SeNPs exposed to the OMs were investigated through a Hitachi H7650 TEM operating at 80 kV. The samples were prepared for TEM imaging as indicated elsewhere [49][50]. To establish the average diameter (expressed in nm with standard deviation) of either biogenic or chemogenic SeNPs, the actual size of 100 randomly chosen NPs was measured by using ImageJ software.…”

A combined physical–chemical and microbiological approach to unveil the fabrication, provenance, and state of conservation of the Kinkarakawa-gami art

“…The presence of microorganisms can also be linked to their tolerance and/or resistance towards a broad spectrum of metal and metalloid compounds 52 , which are the main components of inorganic pigments. For instance, bacteria belonging to the Firmicutes and Actinobacteria phyla can detoxify their surrounding environment from toxic metals or metalloids, even using them as a terminal electron acceptor to produce energy 52,53 . Bacillus, Staphylococcus, and Micrococcus spp.…”