ISIS Neutron and Muon Source Data Journal

SANS probing of bacteria-silica-Hg interactions as encapsulation mechanism of mercury

Abstract: High Hg levels, up to 4 ppm, in Amazonian fish indicate significant heavy metal (HM) pollution and stimulate research on bacterial bioremediation of these media. Simultaneous nanoparticles' aggregation and HM-bacterial uptake offer an unmatched test on how both phenomena can limit Hg-species' mobility. Since aggregation is a microstructural phenomenon dependent on time and pH, we propose contrast-matching and time-resolved SANS experiments on the SiO2 nanoparticles (NPs)-HgCl2-HM resistant bacteria system. We hypothesise that silica's aggregation in the presence of HM-resistant bacteria can encapsulate Hg, reducing its levels in the liquid phase. Measurements on 1 and 8 ppm Hg series will comprise ~60% and 100% D2O liquid buffers, pH ~7, pressure and temperature ambient conditions, totaling 4 time-resolved SANS experiments to probe the vector q range from ~0.004 to 0.3 Å^-1 at Larmor beamline. At pH~7, cationic Hg species predominate, raising our expectation to observe aggregates up to 157 nm. A ~60% D2O buffer matches the SLD of SiO2-NPs, which could help observe HgCl2-bacteria interactions. At 100% D2O, bacterial lipids display high squared contrast, providing the best conditions to probe silica?bacteria interactions. This proposal focuses on biosilica initial formation stages and could be important for the bioremediation of Amazonia media where Hg levels largely exceed the Brazilian law's threshold (0.5 Hg ppm).

Principal Investigator: Dr Patricio Montecinos Munoz
Experimenter: Professor CRISTIANO OLIVEIRA
Local Contact: Dr Gregory Smith
Experimenter: Dr Felipe Vasquez
Experimenter: Mr Juscelino Leao
Experimenter: Dr Jan Ilavsky
Experimenter: Dr Lawrence Anovitz

DOI: 10.5286/ISIS.E.RB2420196

ISIS Experiment Number: RB2420196

Publisher: STFC ISIS Neutron and Muon Source

Data format: RAW/Nexus
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Data Citation

The recommended format for citing this dataset in a research publication is as:
[author], [date], [title], [publisher], [doi]

For Example:
Dr Patricio Montecinos Munoz et al; (2024): SANS probing of bacteria-silica-Hg interactions as encapsulation mechanism of mercury, STFC ISIS Neutron and Muon Source, https://doi.org/10.5286/ISIS.E.RB2420196

Data is released under the CC-BY-4.0 license.