Geology topics

C.I. Pearce

Publications and source records attributed to C.I. Pearce.

2 recordsLinked to original sources

USGS2011

Nanoparticles formed from bacterial oxyanion reduction of toxic Group 15 and 16 metalloids

This chapter presents some examples of nanoparticles formed by only a few microbial species that are cultivated in only a handful of laboratories worldwide. The investigations so far have just scratched the surface of the potential of the natural world to yield bionanomineral producers. While future research should involve screening surveys of the prokaryotes for this biomineralizing phenomenon, more detailed investigations are justified. The chapter discusses microbial Interaction with Group 15 and 16 Toxic Metalloids. The toxicity of the metalloids Se, Te, and As is due to the disruption of thiol intracellular biochemistry through the formation of stable, long-lived sulfur complexes. Selenium oxyanion reduction occurs in a wide range of microbes, including representatives of the Wolinella , Pseudomonas , Sulfurospirillum , Enterobacter , Thaurea , Bacillus , Shewanella , and Citrobacter genera. Technological applications of Se(0) and Te(0) nanoparticles include their use in photocopiers, microelectronic circuits, and solar cells as a result of their photo-optical and semiconducting physical properties. Nonetheless, once novel Se, Te, and As bionanoparticles are identified as having significant technical applications, applied research into their practical commercial production will without doubt ensue rapidly.

Book chapter↗

USGS2009

Investigating different mechanisms for biogenic selenite transformations: Geobacter sulfurreducens , Shewanella oneidensis and Veillonella atypica

The metal-reducing bacteria Geobacter sulfurreducens, Shewanella oneidensis and Veillonella atypica, use different mechanisms to transform toxic, bioavailable sodium selenite to less toxic, non-mobile elemental selenium and then to selenide in anaerobic environments, offering the potential for in situ and ex situ bioremediation of contaminated soils, sediments, industrial effluents, and agricultural drainage waters. The products of these reductive transformations depend on both the organism involved and the reduction conditions employed, in terms of electron donor and exogenous extracellular redox mediator. The intermediary phase involves the precipitation of elemental selenium nanospheres and the potential role of proteins in the formation of these structures is discussed. The bionanomineral phases produced during these transformations, including both elemental selenium nanospheres and metal selenide nanoparticles, have catalytic, semiconducting and light-emitting properties, which may have unique applications in the realm of nanophotonics. This research offers the potential to combine remediation of contaminants with the development of environmentally friendly manufacturing pathways for novel bionanominerals. ?? 2009 Taylor & Francis.

Environmental Technology↗