A method of repeated sampling of static headspace above anaerobic bacterial cultures with fluorine-induced chemiluminescence detection

Stalder, Verena; Bernard, Nicole F.; Hanselmann, Kurt; Bachofen, Reinhard; Chasteen, Thomas G.

doi:10.1016/0003-2670(94)00258-n

Cited by 9 publications

(3 citation statements)

References 14 publications

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“…Sterile controls yielded no organosulfur or organoselenium, and Se-free bacterial cultures produced only volatile organosulfur (Table 2), mirroring previous work with this microbial strain (21,23). The relative amounts of added Se that were converted to the volatile forms reported in Table 2 take into account the amount of the organoselenium compounds detected in the gas phase and an adjustment based on Henry's law (10,24) to estimate the amount of the volatile species that remains in solution at a specific temperature.…”

Section: Resultssupporting

confidence: 78%

“…Though growth rates were somewhat decreased, five phototrophic species grown on Sistrom minimal medium were shown to exhibit overall stationary-phase biomass production similar to that of controls. Methylated organosulfur, organoselenium, and dimethyl selenenyl sulfide have been detected in anaerobic culture headspace, and elemental Se was produced in some cultures (13,21,23). This reduction to the elemental form may be an important process in the biosphere, since soils from an evaporation pond in the Kesterson Reservoir show that, nearest the surface, Se 0 is the most prominent selenium species (16).…”

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confidence: 99%

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Fate of Selenate and Selenite Metabolized by Rhodobacter sphaeroides

Fleet-Stalder

Chasteen

Pickering

et al. 2000

Appl Environ Microbiol

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Cultures of a purple nonsulfur bacterium, Rhodobacter sphaeroides, amended with ϳ1 or ϳ100 ppm selenate or selenite, were grown phototrophically to stationary phase. Analyses of culture headspace, separated cells, and filtered culture supernatant were carried out using gas chromatography, X-ray absorption spectroscopy, and inductively coupled plasma spectroscopy-mass spectrometry, respectively. While selenium-amended cultures showed much higher amounts of SeO 3 2؊ bioconversion than did analogous selenate experiments (94% uptake for SeO 3 2؊ as compared to 9.6% for SeO 4 2؊ -amended cultures from 100-ppm solutions), the chemical forms of selenium in the microbial cells were not very different except at exposure to high concentrations of selenite. Volatilization accounted for only a very small portion of the accumulated selenium; most was present in organic forms and the red elemental form.The roles of selenium in the biosphere, both beneficial and deleterious, are gradually being determined (2,5,7,15), and it is becoming apparent that bacteria play a major role in the global selenium cycle. Selenate (SeO 4 2Ϫ ) and selenite (SeO 3 2Ϫ ) seem to be the most abundant forms of bioavailable selenium in the environment, and both can serve as electron acceptors for many microorganisms, including some phototrophic bacteria. These organisms are widespread and exhibit enormous metabolic and ecological diversity, and some are known to be able to use selenium oxyanions in their anaerobic metabolism (12,13,14,24). Rhodobacter sphaeroides is a purple nonsulfur bacterium that often serves as a model species for the group. It can tolerate high concentrations of selenite and selenate (13,14) and can reduce and/or methylate these compounds (24).Recent work with phototrophic bacteria has shown that some can grow in the presence of 0.1, 1.0, even 10 mM selenate or selenite. Though growth rates were somewhat decreased, five phototrophic species grown on Sistrom minimal medium were shown to exhibit overall stationary-phase biomass production similar to that of controls. Methylated organosulfur, organoselenium, and dimethyl selenenyl sulfide have been detected in anaerobic culture headspace, and elemental Se was produced in some cultures (13,21,23). This reduction to the elemental form may be an important process in the biosphere, since soils from an evaporation pond in the Kesterson Reservoir show that, nearest the surface, Se 0 is the most prominent selenium species (16).Although it is relatively clear that phototrophic bacteria can grow in the presence of selenium oxyanions and that small amounts are reduced and/or methylated, little is known of the extent and path of this process. Here we report the results of quantifying and speciating selenium in the culture medium, the bacteria, and the gaseous headspace above the culture after R. sphaeroides was grown phototrophically in the presence of different concentrations of selenite and selenate to stationary phase. Cell supernatants were analyzed for total selenium using inductively co...

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Section: Resultssupporting

confidence: 78%

mentioning

confidence: 99%

Fate of Selenate and Selenite Metabolized by Rhodobacter sphaeroides

Fleet-Stalder

Chasteen

Pickering

et al. 2000

Appl Environ Microbiol

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“…A 100 mL aliquot of the medium previously described was transferred to a 300‐mL headspace analysis apparatus, described by Stalder et al . in a sterile laminar flow hood. The headspace (∼200 mL) contained about 54 mg of O 2 to support the metabolism of the Gordonia sp.…”

Section: Materials and Methodologiesmentioning

confidence: 99%

A deployable decentralized biofilm system for degrading organic carbon and benzene in wastewater

Chen¹,

Lin²,

Jones

et al. 2012

Env Prog and Sustain Energy

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A fixed biofilm system was explored for decentralized wastewater treatment utilizing laboratory cultivated microorganisms including Gordonia sp. The system is deployable in a 40‐ft ISO container/trailer or on a C‐130 aircraft. Experimental results indicated that pre‐addition of raw wastewater to the microbial culture before inoculation resulted in a significantly higher BOD5 degradation (77 ± 2% in 24 h) than the consortium alone (58 ± 10%) during the startup of the system. After the pilot system was in semi‐continuous operation with an average flow rate of 13.2 L/min, the removal efficiency of BOD5 and total suspended solids (TSS) was 83 ± 9 and 84 ± 9, respectively. As an important supplement to the pilot studies, laboratorial tests by headspace analysis showed that the Gordonia sp. were able to degrade benzene in water. More significant biodegradation of benzene was found in sessile form (57 ± 8%) than in planktonic form (25 ± 11%) with minimal glucose in 26 h. However, no benzene degradation was found in sessile form when no glucose was supplied. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 505–511, 2013

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Geobacillus stearothermophilus V ubiE gene product is involved in the evolution of dimethyl telluride in Escherichia coli K-12 cultures amended with potassium tellurate but not with potassium tellurite

et al. 2004

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A 3.8-kb fragment of chromosomal DNA of Geobacillus stearothermophilus V cloned in pSP72 (p1VH) confers resistance to potassium tellurite (K(2)TeO(3)) and to potassium tellurate (K(2)TeO(4)) when the encoded genes are expressed in Escherichia coli K-12. The nt sequence of the cloned fragment predicts three ORFs of 780, 399, and 600 bp, whose encoded protein products exhibit about 80% similarity with the SUMT methyltransferase and the BtuR protein of Bacillus megaterium, and with the UbiE methyltransferase of Bacillus anthracis A2012, respectively. In addition, E. coli/p1VH cells evolved dimethyl telluride, which was released into the headspace gas above liquid cultures when amended with K(2)TeO(3) or with K(2)TeO(4). After 48 h of growth in the presence of these compounds, a protein of about 25 kDa was found at a significantly higher level when crude extracts were analyzed by SDS-PAGE. The N-terminal amino acid (aa) sequence of this protein, obtained by Edman degradation, matched the deduced aa sequence predicted by the G. stearothermophilus V ubiE gene. This gene was amplified by PCR, subcloned in pET21b, and transformed into E. coli JM109(DE3). Interestingly, DMTe evolution occurred when these modified cells were grown in K(2)TeO(4) - but not in K(2)TeO(3) - amended media. These results may be indicative that the two Te oxyanions could be detoxified in the cell by different metabolic pathways.

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A method of repeated sampling of static headspace above anaerobic bacterial cultures with fluorine-induced chemiluminescence detection

Cited by 9 publications

References 14 publications

Fate of Selenate and Selenite Metabolized by Rhodobacter sphaeroides

Fate of Selenate and Selenite Metabolized by Rhodobacter sphaeroides

A deployable decentralized biofilm system for degrading organic carbon and benzene in wastewater

Geobacillus stearothermophilus V ubiE gene product is involved in the evolution of dimethyl telluride in Escherichia coli K-12 cultures amended with potassium tellurate but not with potassium tellurite

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