Microbial manufacture of chalcogenide-based nanoparticles via the reduction of selenite usingVeillonella atypica: anin situEXAFS study

Abstract

The ability of metal-reducing bacteria to produce nanoparticles, and their precursors, can be harnessed for the biological manufacture of fluorescent, semiconducting nanomaterials. The anaerobic bacterium Veillonella atypica can reduce selenium oxyanions to form nanospheres of elemental selenium. These selenium nanospheres are then further reduced by the bacterium to form reactive selenide which could be precipitated with a suitable metal cation to produce nanoscale chalcogenide precipitates, such as zinc selenide, with optical and semiconducting properties. The whole cells used hydrogen as the electron donor for selenite reduction and an enhancement of the reduction rate was observed with the addition of a redox mediator (anthraquinone disulfonic acid). A novel synchrotron-based in situ time-resolved x-ray absorption spectroscopy technique was used, in conjunction with ion chromatography and inductively coupled plasma-atomic emission spectroscopy, to study the mechanisms and kinetics of the microbial reduction of selenite to selenide. The products of this biotransformation were also assessed using electron microscopy, energy-dispersive spectroscopy, x-ray diffraction and fluorescence spectroscopy. This process offers the potential to prepare chalcogenide-based nanocrystals, for application in optoelectronic devices and biological labelling, from more environmentally benign precursors than those used in conventional organometallic synthesis.

Ecology and Biotechnology of Selenium-Respiring Bacteria

“…High-rate SeO 3 2Ϫ reduction was achieved when Veillonella atypica cells were supplemented with H 2 as the electron donor (53). Interestingly, little reduction was observed using lactate as the electron donor, and no reduction at all was achieved using acetate or formate as the electron donor (53 reduction.…”

“…Interestingly, little reduction was observed using lactate as the electron donor, and no reduction at all was achieved using acetate or formate as the electron donor (53 reduction. Until now, detailed investigation of SeO 3 2Ϫ reduction via respiratory electron transport pathways was limited to a single study using S. oneidensis MR-1 (55).…”

“…Selenium methylation by the members of the Gammaproteobacteria was observed in freshwater sediments (52). Microbial methylation of selenium forms volatile compounds, such as dimethyl selenide, dimethyl diselenide, dimethyl selenyl sulfide, hydrogen selenide, and methaneselenol (53,57). Microbial selenium methylation is significant in environmental settings, although it is a slow process (54).…”

Bacillus cereus, selenite-reducing bacterium from contaminated lake of an industrial area: a renewable nanofactory for the synthesis of selenium nanoparticles

“…It is significant to note that, in the literature, selenium nanoparticle producing bacteria are reported in wide range of environments under aerobic and anaerobic conditions including in sludge and sewerage (Mishra et al 2011). The anaerobic/anoxic bacteria include strains such as Selenihalanaerobacter shriftii DSSE1, Sulfurospirillum barnesii (Oremland et al 2004), Rhodopseudomonas palustris N (Li et al 2014), Veillonella atypica (Pearce et al 2008), Shewanella putrefaciens 200 (Jiang et al 2012), Shewanella sp. HN-41 (Lee et al 2007), etc.…”

“…In addition, from the soil of a antimony mine from Lengshuijiang, southern China (Zheng et al 2014), soil of a magnesite mine from Salem, India (Ramya et al 2015), soil of a coal mine from West Bengal, India (Dhanjal and Cameotra 2010), selenium laden agricultural soil of North-East Punjab, India (Bajaj et al 2012), soil of mangrove forest from Bhitarkanika, Orissa, India (Mishra et al 2011), rhizosphere soil of a selenium hyperaccumulator legume grown in seleniferous mine from Sardina, Italy (Lampis et al 2014), rhizosphere of wheat grown in herbicide contaminated soil (Dwivedi et al 2013), and rhizosphere of cereal plants grown in ash-derived volcanic soil of southern Chile (Durán et al 2015). Others include rock fragments of black oil shale from Haenam, Korea (Tam et al 2010), food wastes collected from local market of Giza, Egypt (Khiralla and El-Deeb 2015), sub gingival dental plaque (Pearce et al 2008) etc. Thus, a large number of selenite-reducing bacteria have been known to produce selenium nanoparticles under both aerobic and anaerobic conditions (Husen and Siddiqi 2014).…”