Measurement of bacterial surface protonation constants for two species at elevated temperatures

Wightman, Peter G.; Fein, Jeremy B.; Wesolowski, David J.; Phelps, Tommy J.; Bénézeth, Pascale; Palmer, Donald A.

doi:10.1016/s0016-7037(01)00763-3

Cited by 34 publications

(28 citation statements)

References 39 publications

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“…Some of the model parameters are similar to previously published results (Table 3), although the diversity of biosorbants and modeling approaches described in the literature somewhat limit the comparisons that can be made. The deprotonation constant pK values determined for site 2 and site 3 for both Geobacillus strains are in good agreement with recent results reported for the thermophilic species TOR-39 (42) and Anoxybacillus flavithermus (11), the mesophilic bacterium Bacillus subtilis (16), and five natural bacterial consortia (5). The pK values of site 1 for G. stearothermophilus and G. thermocatenulatus are considerably lower than those reported for the other bacteria and may indicate that a different type of functional group is involved in complexation reactions for species of the genus Geobacillus.…”

Section: Discussionsupporting

confidence: 91%

“…2B) cell mass of bacteria to allow direct visual comparison between the two tested species. In comparison to titrated electrolyte solution without bacteria (data not shown), G. stearothermophilus and G. thermocatenulatus cells significantly buffered pH over the entire range studied in this investigation, which is in agreement with published data for mesophilic microorganisms (13,14,19) and one thermophilic bacterium (42). G. thermocatenulatus, when compared to G. stearothermophilus, shows a slightly higher buffering capacity against addition of the base when titration data are normalized to dry cell mass (Fig.…”

Section: Cadmium Ion Susceptibility Tests the Values Of The Mics Of CDsupporting

confidence: 91%

“…The thermodynamic stability constant K for cadmium ion binding are not as high for the Geobacillus strains as for the other bacteria described in the literature (5,11,16,42,43). We acknowledge that the differences may be due to different modeling approaches employed.…”

Section: Discussionmentioning

confidence: 89%

“…2B). The difference is due to the different bacterial dry-to-wet mass ratios, which were 1:15 and 1:8 for G. thermocatenulatus and G. stearothermophilus, respectively ( (42).…”

Section: Cadmium Ion Susceptibility Tests the Values Of The Mics Of CDmentioning

confidence: 99%

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Cadmium Ion Biosorption by the Thermophilic Bacteria Geobacillus stearothermophilus and G. thermocatenulatus

Hetzer

Daughney

Morgan

2006

Appl Environ Microbiol

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This study reports surface complexation models (SCMs) for quantifying metal ion adsorption by thermophilic microorganisms. In initial cadmium ion toxicity tests, members of the genus Geobacillus displayed the highest tolerance to CdCl 2 (as high as 400 to 3,200 M). The thermophilic, gram-positive bacteria Geobacillus stearothermophilus and G. thermocatenulatus were selected for further electrophoretic mobility, potentiometric titration, and Cd 2؉ adsorption experiments to characterize Cd 2؉ complexation by functional groups within and on the cell wall. Distinct one-site SCMs described the extent of cadmium ion adsorption by both studied Geobacillus sp. strains over a range of pH values and metal/bacteria concentration ratios. The results indicate that a functional group with a deprotonation constant pK value of approximately 3.8 accounts for 66% and 80% of all titratable sites for G. thermocatenulatus and G. stearothermophilus, respectively, and is dominant in Cd 2؉ adsorption reactions. The results suggest a different type of functional group may be involved in cadmium biosorption for both thermophilic strains investigated here, compared to previous reports for mesophilic bacteria.Various metal compounds can be either essential or toxic for living organisms, depending on the form and concentration. In important physiological catalytic reactions, many enzymes require metal ions as central atoms. In order to generate energy, several microorganisms depend on metal compounds that act as final electron acceptors during anaerobic respiration and as electron donors in chemolithotrophic metabolism. In contrast, nonessential metal ions, in particular, and metal ions (both nonessential and essential) at high concentrations, in general, harm the living cell by potentially displacing essential metal ions (in enzymes), competing with structurally related nonmetals in cell reactions and blocking functional groups in biomolecules (29). Therefore, organisms have developed several metal homeostasis and detoxification strategies, including an active efflux system, changes in ion permeability, adsorption, and intra-and extracellular complexation, biotransformation, and compartmentation (10,21,27,31,36).Adsorption of metals by cell wall components is one of the more important interaction mechanisms, and it has been the subject of many studies (for review, see references 3, 15, 20, 34, 35, and 40). Several recent investigations have used surface complexation models (SCMs) to describe the extent of metal adsorption by bacteria as important physical, chemical, and biological parameters are independently varied (5,8,14,16,19,23,43). These SCMs are based upon a set of molecular-scale thermodynamic reactions, each describing adsorption of a particular dissolved chemical species to a particular type of cell wall functional group using a single stability constant, K. Some previous investigations indicate that different bacterial species display similar types of reactive surface functional groups (e.g., carboxyl, phosphoryl, hydroxyl, or ...

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Section: Discussionsupporting

confidence: 91%

Section: Cadmium Ion Susceptibility Tests the Values Of The Mics Of CDsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 89%

“…2B). The difference is due to the different bacterial dry-to-wet mass ratios, which were 1:15 and 1:8 for G. thermocatenulatus and G. stearothermophilus, respectively ( (42).…”

Section: Cadmium Ion Susceptibility Tests the Values Of The Mics Of CDmentioning

confidence: 99%

See 2 more Smart Citations

Cadmium Ion Biosorption by the Thermophilic Bacteria Geobacillus stearothermophilus and G. thermocatenulatus

Hetzer

Daughney

Morgan

2006

Appl Environ Microbiol

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“…The ratio of wet to dry biomass was determined to be 11.1 to 1. These characteristics of T. zilligii cells are comparable to other microorganisms for which SCMs have been developed (Fein et al, 1997;Wightman et al, 2001;Yee et al, 2004;Burnett et al, 2006a;Hetzer et al, 2006;Heinrich, 2008).…”

Section: Characteristics Of T Zilligii Cellssupporting

confidence: 58%

Proton and cadmium adsorption by the archaeon Thermococcus zilligii: Generalising the contrast between thermophiles and mesophiles as sorbents

et al. 2010

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Adsorption by microorganisms can play a significant role in the fate and transport of metals in natural systems. Surface complexation models (SCMs) have been applied extensively to describe metal adsorption by mesophilic bacteria, and several recent studies have extended this framework to thermophilic bacteria. We conduct acid-base titrations and batch experiments to characterise proton and Cd adsorption onto the thermophilic archaeon Thermococcus zilligii. The experimental data and the derived SCMs indicate that the archaeon displays significantly lower overall sorption site density compared to previously studied thermophilic bacteria such Anoxybacillus flavithermus, Geobacillus stearothermophilus, G. thermocatenulatus, and Thermus thermophilus. The thermophilic bacteria and archaea display lower sorption site densities than the mesophilic microorganisms that have been studied to date, which points to a general pattern of total concentration of cell wall adsorption sites per unit biomass being inversely correlated to growth temperature.

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Metal Bioremediation by Thermophilic Microorganisms

Sar

Kazy

Paul

et al. 2013

Thermophilic Microbes in Environmental and Industrial Biotechnology

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Measurement of bacterial surface protonation constants for two species at elevated temperatures

Cited by 34 publications

References 39 publications

Cadmium Ion Biosorption by the Thermophilic Bacteria Geobacillus stearothermophilus and G. thermocatenulatus

Cadmium Ion Biosorption by the Thermophilic Bacteria Geobacillus stearothermophilus and G. thermocatenulatus

Proton and cadmium adsorption by the archaeon Thermococcus zilligii: Generalising the contrast between thermophiles and mesophiles as sorbents

Metal Bioremediation by Thermophilic Microorganisms

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