Microbial reduction of metals and radionuclides

May combine two claims.

Anaerobic conditions are generally required to induce maximum Cr(VI) reduction activity, but some enzyme systems operate under aerobic conditions.

“Anaerobic con-ditions are generally required to induce maximum activity against Cr(VI), but some enzyme systems operate under aerobic conditions, for examples the soluble NAD(P)Hdependent reductases of Pseudomonas ambigua G-1, [61] and Pseudomonas putida [62].”

• cites [61] Suzuki T. Miyata H. Horitsu K. Kawai K. Takamizawa Y. Tai Y. Okazaki M. (1992) NAD(P)H-dependent chromium (VI) reductase of Pseudomonas ambigua G-1: a Cr(V) intermediate is formed during the reduction of Cr(VI) to Cr(III). J. Bacteriol. 174, 5340–5345. sourceNot checked — no full text of the source
• cites [62] sourcePartly supported

  The Abstract describes a soluble Pseudomonas putida chromate reductase dependent on NADH or NADPH, supporting its identification as an example of that enzyme system. Neither the Abstract nor the chromate reductase assays section establishes that it operates under aerobic conditions; the paper also does not substantiate the broader statement that anaerobic conditions are generally required for maximum activity. (LLM, conf=0.82)

  Experimental — accuracy not yet measured

May combine two claims.

Hg(II) is transported into the cell via the MerT transporter protein and detoxified by reduction to relatively nontoxic volatile elemental mercury by an intracellular mercuric reductase (MerA).

“Here, Hg(II) is transported into the cell via the MerT transporter protein, and detoxi¢ed by reduction to relatively nontoxic volatile elemental mercury by an intracellular mercuric reductase (MerA).”

• cites [5] sourceSupported

May combine two claims.

The PpcA protein was able to reduce U(VI) in vitro, while a ppcA deletion mutant supplied with acetate as an electron donor had lower activity against U(VI).

“The protein was able to reduce U(VI) in vitro, while a ppcA deletion mutant supplied with acetate as an electron donor had lower activity against U(VI) [42].”

• cites [42] Lloyd, J.R., Leang, C., Hodges Myerson, A.L., Ciufo, S., Sandler, S.J., Methe, B., Lovley, D.R. Biochemical and genetic characterization of PpcA, periplasmic cytochrome in Geobacter sulfurreducens. Biochem. J. 2003. 153–161 sourcePartly supported

  The Physiological role of PpcA section reports that deleting ppcA inhibited U(VI) reduction in cell suspensions when acetate was the electron donor. But the Role of PpcA in the reduction of U(VI) and humics section treats direct U(VI) reduction by PpcA as a possibility, not an established result; our copy does not report an in-vitro demonstration that the purified protein reduces U(VI). Page numbers were not available in the indexed passages. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

May combine two claims.

In these examples, Se(VI) reduction does not support growth, and seems to be incidental to the physiology of the organism.

“In these examples, Se(VI) reduction does not support growth, and seems to be incidental to the physiology of the organism.”

• cites [104] sourceNot checked — no full text of the source
• cites [105] sourceSupported
• cites [106] Lortie L. Gould W.D. Rajan W. McCready R.G.L. Cheng K.-J. (1992) Reduction of selenate and selenite to elemental selenium by a Pseudomonas stutzeri isolate. Appl. Environ. Microbiol. 58, 4042–4044. sourceNot checked — no full text of the source

May combine two claims.

In vivo studies using a cytochrome c3 mutant of D. desulfuricans strain G20 confirmed a role for cytochrome c3 in hydrogen-dependent U(VI) reduction, but suggested additional pathways from organic electron donors to U(VI) that bypassed the cytochrome.

“In vivo studies using a cytochrome c 3 mutant of the close relative D. desulfuricans strain G20 con¢rmed a role for cytochrome c 3 in hydrogen-dependent U(VI) reduction, but suggested additional pathways from organic electron donors to U(VI), that bypassed the cytochrome [122].”

• cites [122] sourceSupported

May combine two claims.

Tc(VII) reduction has not been shown to support growth in any of these studies, and seems to be a fortuitous biochemical side reaction in the organisms studied to date.

“It should be stressed that Tc(VII) reduction has not been shown to support growth in any of these studies, and seems to be a fortuitous biochemical side reaction in the organisms studied to date.”

• cites [131] Lloyd J.R. Macaskie L.E. (1996) A novel phosphorImager based technique for monitoring the microbial reduction of technetium. Appl. Environ. Microbiol. 62, 578–582.Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites [48] sourceNot checked — no full text of the source
• cites [89] Lloyd J.R. Cole J.A. Macaskie L.E. (1997) Reduction and removal of heptavalent technetium from solution by Escherichia coli . J. Bacteriol. 179, 2014–2021. sourceCould not verify

  The available paper passages report Tc(VII) reduction by E. coli and identify the hydrogenase III component of formate hydrogenlyase as responsible. They do not assess whether Tc(VII) reduction supports growth or characterize it as a fortuitous side reaction, including across the other studies mentioned in the claim. Searches for growth coupling and physiological role found no passage addressing those points. (LLM, conf=0.70)

  Experimental — accuracy not yet measured

May combine two claims.

A novel phosphorimager technique was used to confirm reduction of Tc(VII) by S. putrefaciens and G. metallireducens, with similar activities subsequently detected in laboratory cultures of R. sphaeroides, Paracoccus denitrificans, some pseudomonads, E. coli and a range of sulfate-reducing bacteria.

“In this study, a novel phosphorimager technique was used to con¢rm reduction of the radionuclide by S. putrefaciens and G. metallireducens, with similar activities subsequently detected in laboratory cultures of R. sphaeroides, Paracoccus denitri¢cans, some pseudomonads [48], E. coli [89] and a range of sulfate-reducing bacteria [64,132,133].”

• cites [48] sourceNot checked — no full text of the source
• cites [89] Lloyd J.R. Cole J.A. Macaskie L.E. (1997) Reduction and removal of heptavalent technetium from solution by Escherichia coli . J. Bacteriol. 179, 2014–2021. sourceSupported
• cites [64] sourceNot checked — no full text of the source
• cites [132] Lloyd J.R. Ridley J. Khizniak T. Lyalikova N.N. Macaskie L.E. (1999) Reduction of technetium by Desulfovibrio desulfuricans: biocatalyst characterisation and use in a flow-through bioreactor. Appl. Environ. Microbiol. 65, 2691–2696. sourceNot checked — no full text of the source
• cites [133] Lloyd J.R. Nolting H.-F. Solé V.A. Bosecker K. Macaskie L.E. (1998) Technetium reduction and precipitation by sulphate-reducing bacteria. Geomicrobiol. J. 15, 43–56. sourceNot checked — no full text of the source

May combine two claims.

Evidence was presented to suggest that the mechanism of U(VI) reduction by a S. putrefaciens strain was distinct from those of Fe(III) and Mn(IV) reduction, but may share components of the nitrite-reducing pathway.

“Evidence was presented to suggest that the mech-anism of U(VI) reduction was distinct from those of Fe(III) and Mn(IV) reduction, but may share components of the nitrite-reducing pathway [123].”

• cites [123] sourceSupported

May combine two claims.

Initial studies demonstrated that anaerobic, but not aerobic, cultures of E. coli reduced Tc(VII) with the reduced radionuclide precipitated within the cell.

“Initial studies demonstrated that anaerobic, but not aerobic, cultures of E. coli reduced Tc(VII) with the reduced radionuclide precipitated within the cell [89].”

• cites [89] Lloyd J.R. Cole J.A. Macaskie L.E. (1997) Reduction and removal of heptavalent technetium from solution by Escherichia coli . J. Bacteriol. 179, 2014–2021. sourceSupported

May combine two claims.

Se(VI) reduction is inhibited by chromate and tungstate, but not by molybdate, an inhibitor of sulfate reducers.

“Se(VI) reduction is also inhibited by chromate and tungstate, but not by molybdate, an inhibitor of sulfate reducers [101,102].”

• cites [101] Steinberg N.A. Oremland R.S. (1990) Dissimilatory selenate reduction potentials in a diversity of sediment types. Appl. Environ. Microbiol. 56, 3550–3557.Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites [102] Oremland R.S. Hollibaugh J.T. Maest A.S. Presser T.S. Miller L.G. Culbertson C.W. (1989) Selenate reduction to elemental selenium by anaerobic bacteria in sediments and culture: Biogeochemical significance of a novel, sulfate-independent respiration. Appl. Environ. Microbiol. 55, 2333–2343. sourceNot checked — no full text of the source

May combine two claims.

Se(VI) is not reduced chemically under physiological conditions of pH and temperature, and Se(VI) reduction is inhibited by autoclaving of sediments.

“Also, Se(VI) is not reduced chemically under physiological conditions of pH and temperature, and Se(VI) reduction is inhibited by autoclaving of sediments.”

• cites [101] Steinberg N.A. Oremland R.S. (1990) Dissimilatory selenate reduction potentials in a diversity of sediment types. Appl. Environ. Microbiol. 56, 3550–3557.Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

The ability to reduce Se(VI) is widespread in sediments, with biological reduction unequivocally demonstrated in 10 out of 11 sediment types.

“For example, the ability to reduce Se(VI) is widespread in sediments, with biological reduction unequivocally demonstrated in 10 out of 11 sediment types [101].”

• cites [101] Steinberg N.A. Oremland R.S. (1990) Dissimilatory selenate reduction potentials in a diversity of sediment types. Appl. Environ. Microbiol. 56, 3550–3557.Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Probably not a substantial claim: may not pass S3 (load-bearing).

In no cases has the reduction of Hg(II) been shown to support microbial growth.

“In no cases, however, has the reduction of Hg(II) been shown to support microbial growth.”

Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

To date there have been no reports of microbial growth coupled to the reduction of Te(IV) by non-genetically engineered micro-organisms.

“To date there have been no reports of microbial growth coupled to the reduction of Te(IV) by non-genetically engineered micro-organisms.”

May combine two claims.

Specificity for Se(VI) is high, with a Km of 16 μM.

“Speci¢city for Se(VI) is high, with a K m of 16 WM.”

• cites [103] sourceNot checked — no full text of the source

May combine two claims.

Growth using Te(IV) as an electron acceptor was reported in an engineered strain overexpressing nitrate reductase, but was not thought to be physiologically relevant in wild-type cells of E. coli.

“Growth using Te(IV) as an electron acceptor was also reported in an engineered strain overexpressing nitrate reductase, but was not thought to be physiologically relevant in wild-type cells of E. coli [108].”

• cites [108] sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

An additional Te(IV) reductase was detected in the soluble fraction of anaerobically grown cells.

“An additional Te(IV) reductase was detected in the soluble fraction of anaerobically grown cells.”

• cites [108] sourceNot checked — no full text of the source

May combine two claims.

Additional evidence linking the activity of this periplasmic protein with U(VI) reduction in vitro included the precipitation of the reduced product U(IV) in the periplasm, and the lack of impact of protease treatment of whole cells on the ability to reduce U(VI).

“Additional (if indirect) evidence linking the activity of this periplasmic protein with U(VI) reduction in vitro included the precipitation of the reduced product U(IV) in the periplasm (see Fig. 4), and the lack of impact of protease treatment of whole cells on the ability to reduce U(VI) [48].”

• cites [48] sourceNot checked — no full text of the source

Classified as probably not a substantial claim. May combine two claims.

This hypothesis is based on the observed differential cytochrome content and cytochrome activity when grown on alternative electron acceptors; at least three different b-type and two different c-type cytochromes have been detected.

“This hypothesis is based on the observed di¡erential cytochrome content and cytochrome activity when grown on alternative electron acceptors; at least three di¡erent b-type and two di¡erent c-type cytochromes have been detected [110].”

• cites [110] sourceNot checked — no full text of the source

May combine two claims.

Te(IV) (and Se(VI)/Se(IV)) reduction and precipitation by sulfate-reducing bacteria have been reported, in the order Te(IV) > S(VI) > Se(IV), which is in contrast to that predicted by the redox potentials alone.

“Finally, Te(IV) (and Se(VI)/Se(IV)) reduction and precipitation by sulfate-reducing bacteria have also been reported, in the order Te(IV) s S(VI) s Se(IV), which is in contrast to that predicted by the redox potentials alone [64].”

• cites [64] sourceNot checked — no full text of the source

May combine two claims.

Highly soluble Np(V) was reduced to soluble Np(IV) by S. putrefaciens, with the Np(IV) removed as an insoluble phosphate biomineral by a phosphate-liberating Citrobacter sp.

“This is illustrated when considering highly soluble Np(V) (NpO þ 2 ), which was reduced to soluble Np(IV) by S. putrefaciens, with the Np(IV) removed as an insoluble phosphate biomineral by a phosphate-liberating Citrobacter sp.”

• cites [126] sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

The biochemical basis of these transformations remains uncharacterised.

“The biochemical basis of these transformations remains uncharacterised.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Micro-organisms have evolved metal resistance processes that often incorporate changes in the oxidation state of toxic metals.

“Micro-organisms have also evolved metal resistance processes that often incorporate changes in the oxidation state of toxic metals.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Generation of electricity from sediments is a possible biotechnological application of microbial metal reduction.

“and even the generation of electricity from sediments [11]”

• cites [11] sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing), S4 (based). The quote only partly states this claim.

Many Fe(III)-reducing organisms are also able to grow through the reduction of Mn(IV) to Mn(II).

“Many of these organisms are also able to grow through the reduction of Mn(VI) to Mn(II).”

May combine two claims.

Micro-organisms can reduce Cr(VI) efficiently at circumneutral pH and could be used to treat Cr(VI)-contaminated water.

“Recent studies, however, have shown that micro-organisms can also reduce Cr(VI) e⁄ciently at circumneutral pH, and could be used to treat Cr(VI)-contaminated water.”

May combine two claims.

Fe(III)- and Mn(IV)-reducing micro-organisms can impact the fate of other high-valency contaminant metals through direct enzymatic reduction and indirect reduction catalysed by biogenic Fe(II).

“Finally, Fe(III)and Mn(IV)-reducing micro-organisms can also impact on the fate of other high-valency contaminant metals through direct enzymatic reduction, and also via indirect reduction catalysed by biogenic Fe(II).”

Probably not a substantial claim: may not pass S3 (load-bearing).

V(V) reduction by Micrococcus lactilyticus, Desulfovibrio desulfuricans and Clostridium pasteurianum has been shown.

“Despite an early study that showed V(V) reduction by Micrococcus lactilyticus, Desulfovibrio desulfuricans and Clostridium pasteurianum [57]”

• cites [57] Woolfolk C.A. Whiteley H.R. (1962) Reduction of inorganic compounds with molecular hydrogen by Micrococcus lactilyticus . J. Bacteriol. 84, 647–658. sourceNot checked — no full text of the source

May combine two claims.

P. vanadiumreductans and P. isachenkovii can reduce V(V) to blue-coloured V(IV), and possibly further to V(III).

“V(V) was reduced to blue-coloured V(IV), and possibly further reduced to V(III); the latter indicated by the formation of a black precipitate and by its reaction with the reagent tairon [59].”

• cites [59] Yurkova N.A. Lyalikova N.N. (1991) New vanadate-reducing facultative chemolithotrophic bacteria. Microbiology 59, 672–677.Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Probably not a substantial claim: may not pass S3 (load-bearing).

Pseudomonas guillermondii and a Micrococcus species can reduce Mo(VI) to molybdenum blue.

“Early work suggested that Pseudomonas guillermondii and a Micrococcus species could reduce Mo(VI) to molybdenum blue [58].”

• cites [58] Bautista E.M. Alexander M. (1972) Reduction of inorganic compounds by soil microorganisms. Soil Sci. Soc. Am. Proc. 36, 918–920. sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

Cr(III) is considered 1000 times less mutagenic than Cr(VI).

“Indeed, Cr(III) is considered 1000 times less mutagenic than Cr(VI) [60].”

• cites [60] Wang, Y.-T. (2000) in: Environmental Microbe-Metal Interactions (Lovley, D.R., Ed.), pp. 225–235. ASM Press, Washington, DC. sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

Microbial Mo(VI) reduction could play a role in the Mo cycle, leading to the concentration of insoluble Mo in anaerobic marine sediments and reduction spots in rocks.

“Although microbial Mo(VI) reduction could play a role in the Mo cycle, for example leading to the concentration of insoluble Mo in anaerobic marine sediments and reduction spots in rocks [17]”

• cites [17] sourceNot checked — no full text of the source

May combine two claims.

Cr(VI) is the most toxic and mobile form commonly encountered, with Cr(III) less soluble and less toxic.

“Two oxidation states dominate: Cr(VI) is the most toxic and mobile form commonly encountered, with Cr(III) less soluble and less toxic.”

May combine two claims.

Geobacter species sense when soluble electron acceptors are depleted and synthesise appendages that allow movement to Fe(III) and Mn(IV) minerals and subsequent attachment.

“These results suggest that Geobacter species sense when soluble electron acceptors are depleted and synthesise the appropriate appendages that allow movement to Fe(III) and Mn(IV) minerals and subsequent attachment.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Microbial reduction of V(V) could be responsible for the precipitation of vanadium in anaerobic environments.

“It has been suggested that the microbial reduction of V(V) could be responsible for the precipitation of the element in anaerobic environments and could also be used to remediate vanadium-contaminated ore-processing waste streams [17].”

• cites [17] sourceNot checked — no full text of the source

May combine two claims.

Environmental factors affecting Cr(VI) reduction include competing electron acceptors, pH, temperature, redox potential and the presence of other metals.

“Environmental factors that a¡ect Cr(VI) reduction were reviewed recently and include competing electron accep- tors, pH, temperature, redox potential and the presence of other metals [60].”

• cites [60] Wang, Y.-T. (2000) in: Environmental Microbe-Metal Interactions (Lovley, D.R., Ed.), pp. 225–235. ASM Press, Washington, DC. sourceNot checked — no full text of the source

May combine two claims.

Humics and other extracellular quinones are utilised as electron acceptors by Fe(III)-reducing bacteria, and reduced hydroquinone moieties can abiotically transfer electrons to Fe(III) minerals.

“For example, humics and other extracellular quinones are utilised as electron acceptors by Fe(III)reducing bacteria [51], and the reduced hydroquinone moieties are able to abiotically transfer electrons to Fe(III) minerals.”

• cites [51] sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

Microbial reduction of V(V) could be used to remediate vanadium-contaminated ore-processing waste streams.

“It has been suggested that the microbial reduction of V(V) could be responsible for the precipitation of the element in anaerobic environments and could also be used to remediate vanadium-contaminated ore-processing waste streams [17].”

• cites [17] sourceNot checked — no full text of the source

May combine two claims.

A molybdenum-resistant Enterobacter species can reduce Mo(VI), with Mo(V) formed and complexed with phosphate to form methylene blue.

“More recently, similar activities have been identi¢ed in cultures of a molybdenum-resistant Enterobacter species [78].”

• Also stated in: § 3.3. Reduction of Mo(VI) · plain

  “Reduction of Mo(VI) was accompanied by a change in colour, as Mo(V) formed and complexed with phosphate in the medium to form methylene blue [78].”

• cites [78] Ghani B. Takai M. Hisham N.Z. Kishimoto N. Ismail A.K. Tano T. Sugio T. (1993) Isolation and characterization of a Mo6+-reducing bacterium. App. Environ. Microbiol. 59, 1176–1180. sourceNot checked — no full text of the source

May combine two claims.

A novel Fe2+-dependent mechanism for mercury reduction has been characterised in the membrane fraction of T. ferrooxidans, which may involve cytochrome c oxidase.

“A novel Fe 2þ -dependent mechanism for mercury reduction has been characterised in the membrane fraction of T. ferrooxidans, which may involve cytochrome c oxidase [93]”

• cites [93] sourceNot checked — no full text of the source

May combine two claims.

S. arsenophilum is a very close relative of S. barnesii which can also reduce As(V), and has a broad activity against metals including Fe(III) and Se(VI).

“It is a very close relative of S. barnesii which can also reduce As(V), and has a broad activity against metals including Fe(III) and Se(VI) (see Sections 2.1 and 4.2).”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Sulfurospirillum arsenophilum is a Gram-negative vibroid microaerobic sulfur-reducing bacterium isolated from arsenic-contaminated watershed sediments in eastern Massachusetts.

“Sulfurospirillum arsenophilum (previously strain MIT-13) is a Gram-negative vibroid microaerobic sulfur-reducing bacterium isolated from arsenic-contaminated watershed sediments in eastern Massachusetts.”

Probably not a substantial claim: may not pass S3 (load-bearing).

c-type cytochromes of G. metallireducens can transfer electrons to soluble Au(III).

“Early studies suggested that c-type cytochromes of the Fe(III)-reducing bacterium G. metallireducens were able to transfer electrons to soluble Au(III) [28].”

• cites [28] sourceNot checked — no full text of the source

May combine two claims.

C. arsenatis contains a periplasmic arsenate reductase consisting of two subunits (masses 87 and 29 kDa) which contain Mo, Fe, S and Zn cofactors.

“This organism contains a periplasmic arsenate reductase consisting of two subunits (masses 87 and 29 kDa) which contain Mo, Fe, S and Zn cofactors [98].”

• cites [98] sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

A new organism has recently been isolated that is able to use As(III) as an electron donor for aerobic growth, closing the biological As cycle.

“Finally, on this note, it is worth mentioning that a new organism has recently been isolated that is able to use As(III) as an electron donor for aerobic growth [100] closing the biological As cycle.”

• cites [100] sourceNot checked — no full text of the source

The quote only partly states this claim.

Soluble Pd(II) can be reduced to insoluble Pd(0) by D. desulfuricans.

“Initial experiments aimed at reducing and recovering Pd were based on the use of D. desulfuricans because it is active against a wide range of metals including Fe(III), Mn(IV), U(VI), Cr(VI), Tc(VII) via hydrogenase or cytochrome c 3 [86].”

• cites [86] Lloyd J.R. Yong P. Macaskie L.E. (1998) Enzymatic recovery of elemental palladium by using sulfate-reducing bacteria. Appl. Environ. Microbiol. 64, 4607–4609.Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Probably not a substantial claim: may not pass S3 (load-bearing).

Inhibition of Pd(II) bioreduction by chloride ions may necessitate optimisation of leaching from catalysts.

“Inhibition by chloride ions was reported and may necessitate optimisation of leaching from catalysts to minimise the formation of PdCl 23 4 prior to bioreduction and recovery.”

• cites [87] sourceNot checked — no full text of the source

May combine two claims.

Desulfotomaculum auripigmentum reduces As(V) followed by sulfate, resulting in the formation of orpiment (As2S3).

“A Gram-positive sulfate-reducing bacterium De-sul¢tomaculum auripigmentum has also been described that reduces As(V) followed by sulfate, resulting in the formation of orpiment (As 2 S 3 ) [99].”

• cites [99] Newman D.K. Kennedy E.K. Coates J.D. Ahmann D. Ellis D.J. Lovley D.R. Morel F.M.M. (1998) Dissimilatory arsenate and sulfate reduction in Desulfotomaculum auripigmentum sp. nov. Arch. Microbiol. 165, 380–388. sourceNot checked — no full text of the source

May combine two claims.

Co(II) formed does not associate strongly with EDTA and absorbs to soils, offering potential for in situ immobilisation.

“The Co(II) formed does not associate strongly with EDTA (it is over 25 orders of magnitude less thermodynamically stable than Co(III)EDTA), and absorbs to soils, o¡ering potential for in situ immobilisation of the metal in contaminated soils.”

May combine two claims.

As(V) reduction is inhibited by air but enhanced by an atmosphere of hydrogen, suggesting the involvement of anaerobic metal-reducing bacteria.

“In addition, As(V) reduction was inhibited by air but enhanced by an atmosphere of hydrogen suggesting the involvement of anaerobic metal-reducing bacteria.”

• cites [96] Oremland, R.S. and Stolz, J. (2000) in: Environmental Microbe-Metal Interactions (Lovley, D.R., Ed.), pp. 199–224. ASM Press, Washington, DC. sourceNot checked — no full text of the source

May combine two claims.

TEM with EDS confirmed Pd precipitation in the periplasm, and X-ray diffraction confirmed reduction to Pd(0).

“Transmission electron microscope studies in combination with energy dispersive X-ray microanalysis (EDS) con¢rmed precipitation in the periplasm, with X-ray di¡raction studies con¢rming reduction to Pd(0) (see Fig. 3).”

• cites [86] Lloyd J.R. Yong P. Macaskie L.E. (1998) Enzymatic recovery of elemental palladium by using sulfate-reducing bacteria. Appl. Environ. Microbiol. 64, 4607–4609.Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Chrysiogenes arsenatis is a strict anaerobe that was isolated from wastewater from a gold mine.

“Chrysiogenes arsenatis is a strict anaerobe that was isolated from wastewater from a gold mine [97].”

• cites [97] sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

A recent review has mentioned the preliminary purification and characterisation of an arsenate reductase from S. arsenophilum, which constituted a trimeric complex of mass 120 kDa, consisting of subunits of 65 kDa, 31 kDa and 22 kDa.

“A recent review has mentioned the preliminary puri¢cation and characterisation of an arsenate reductase from this organism, which constituted a trimeric complex of mass 120 kDa, consisting of subunits of 65 kDa, 31 kDa and 22 kDa [96].”

• cites [96] Oremland, R.S. and Stolz, J. (2000) in: Environmental Microbe-Metal Interactions (Lovley, D.R., Ed.), pp. 199–224. ASM Press, Washington, DC. sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

Other mechanisms of Te(IV) resistance may be important, involving cysteine-metabolising enzymes and methyl transferases.

“Other mechanisms of resistance may be important, however, involving cysteine-metabolising enzymes and methyl transferases [114].”

• cites [114] Taylor D.E. (1999) Bacterial tellurite resistance. Trends Biotechnol. 7, 111–115. sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

210Po has attracted recent attention, accounting for all α-emitting activity in some samples of groundwater from the Central Florida Phosphate District, and has been identified as a troublesome isotope contaminating and fouling drilling equipment during oil exploration in areas rich in uranium ores.

“210 Po has attracted recent attention, accounting for all K-emitting activity in some samples of groundwater from the Central Florida Phosphate District [115], and has also been identi¢ed as a troublesome isotope contaminating and fouling drilling equipment during oil exploration in areas rich in uranium ores [116].”

• cites [115] Burnett, W.C., Cowart, J.B. and Chin, P.A. (1987) in: Radon Radium and Other Radioactivity in Groundwater; Hydrogeologic Impact and Application to Indoor Airborne Contamination (Graves, B., Ed.), pp. 251–269. Lewis Publ.Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites [116] Lloyd, J.R. and Macaskie, L.E. (2000) in: Environmental Microbe-Metal Interactions (Lovley, D.R., Ed.), pp. 277–327. ASM Press, Washington, DC. sourceNot checked — no full text of the source

May combine two claims.

Plasmids are known to encode several distinct resistance determinants for Te(IV), and Te(IV) reduction is implicated as the resistance mechanism as elemental Te is laid down in Te-resistant bacteria.

“Finally, plasmids are known to encode several distinct resistance determinants for Te(IV), and again Te(IV) reduction is implicated as the resistance mechanism as elemental Te is laid down in Te-resistant bacteria [114].”

• cites [114] Taylor D.E. (1999) Bacterial tellurite resistance. Trends Biotechnol. 7, 111–115. sourceNot checked — no full text of the source

May combine two claims.

Little is known about the geochemistry of Po, but there is evidence that factors affecting the sulfur cycle may affect Po availability.

“Little is known about the geochemistry of Po, but there is evidence that factors a¡ecting the sulfur cycle may a¡ect Po availability.”

May combine two claims.

Other organisms including a Clostridium sp., D. desulfuricans and Desulfovibrio vulgaris also reduce uranium, but are unable to conserve energy for growth via this transformation.

“Other organisms including a Clostridium sp.[120] and the sulfate-reducing bacteria D. desulfuricans [121] and Desulfovibrio vulgaris [65] also reduce uranium, but are unable to conserve energy for growth via this transformation.”

• cites [120] Francis A.J. (1994) Microbial transformations of radioactive wastes and environmental restoration through bioremediation. J. Alloys Compounds 213/214, 226–231. sourceNot checked — no full text of the source
• cites [121] Lovley D. Phillips E.J. (1992) Reduction of uranium by Desulfovibrio desulfuricans . Appl. Environ. Microbiol. 58, 850–856.Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites [65] Lovley D.R. Phillips E.J.P. (1994) Reduction of chromate by Desulfovibrio vulgaris and its c 3 cytochrome. Appl. Environ. Microbiol. 60, 726–728.Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Probably not a substantial claim: may not pass S3 (load-bearing).

The authors of the S. barnesii study suggest that a suite of specific terminal reductases are required for growth on different electron acceptors.

“the authors of this paper suggest that a suite of speci¢c terminal reductases are required for growth on the di¡erent electron acceptors.”

• cites [110] sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

Earlier studies suggested that the enzyme that catalysed further reduction of Se(IV) to elemental selenium in T. selanatis was a component of the nitrate-respiratory system, possibly a periplasmic nitrite reductase.

“Earlier studies had suggested that the enzyme that catalysed further reduction of Se(IV) (selenite) to elemental selenium in the organism was a component of the nitrate-respiratory system, possibly a periplasmic nitrite reductase [112].”

• cites [112] sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

210Po is the terminal member of the 238U decay series, produced by the decay of 210Pb via 210Bi.

“210 Po is the terminal member of the 238 U decay series, produced by the decay of 210 Pb via 210 Bi.”

May combine two claims.

A periplasmic complex of approximately 180 kDa (with subunits of masses 96, 40 and 23 kDa) has been characterised in T. selanatis, and shown to contain Mo, Fe and acid-labile sulfur.

“A periplasmic complex of approximately 180 kDa (with subunits of masses 96, 40 and 23 kDa) has been characterised, and shown to contain Mo, Fe and acid-labile sulfur.”

• cites [103] sourceNot checked — no full text of the source

May combine two claims.

The first demonstration of dissimilatory U(VI) reduction was by Lovley and coworkers who reported that G. metallireducens and S. oneidensis can conserve energy for anaerobic growth via the reduction of U(VI).

“The ¢rst demonstration of dissimilatory U(VI) reduction was by Lovley and coworkers [3] who reported that the Fe(III)-reducing bacteria G. metallireducens (previously designated strain GS-15) and S. oneidensis (formerly A. putrefaciens and then S. putrefaciens) can conserve energy for anaerobic growth via the reduction of U(VI).”

• cites [3] sourceNot checked — no full text of the source

May combine two claims.

Rhodobacter sphaeroides reduces Te(IV) (as well as oxyanions of Se), with a requirement for a functional photosynthetic electron transfer chain under photosynthetic conditions, or cytochromes bc1 and c2 when grown aerobically.

“Rhodobacter sphaeroides has also been reported to reduce Te(IV) (as well as oxyanions of Se), with a requirement for a functional photosynthetic electron transfer chain under photosynthetic conditions, or cytochromes bc 1 and c 2 when grown aerobically [113].”

• cites [113] Moore M.D. Kaplan S. (1992) Identification of intrinsic high-level resistance to rare-earth oxides and oxyanions in members of the class Proteobacteria: characterization or tellurite, selenite, and rhodium sesquioxide reduction in Rhodobacter sphaeroides . J. Bacteriol. 174, 1505–1514. sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

Tellurite (TeO3^2-) reduction has been studied in several organisms, mainly in the context of resistance to this toxic oxyanion.

“Tellurite (TeO 23 3 ) reduction has also been studied in several organisms, mainly in the context of resistance to this toxic oxyanion.”

May combine two claims.

Cherrier et al. demonstrated the microbial uptake of Po into the cellular pool, indicating the potential for assimilative Po reduction and a biochemical role analogous to that of S.

“Indeed, Cherrier et al. [117] demonstrated the microbial uptake of Po into the cellular pool, indicating the potential for assimilative Po reduction and a biochemical role analogous to that of S.”

• cites [117] Cherrier J. Burnett W.C. LaRock P.A. (1995) Uptake of polonium and sulfur by bacteria. Geomicrobiol. J. 13, 103–115. sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

In S. barnesii, the Se(VI) reductase activity is localised in the membrane fraction and may have a wider substrate specificity than that characterised in T. selanatis.

“Biochemical studies are not so advanced in S. barnesii, although the enzyme activity contrasts with that characterised in T. selanatis as it is localised in the membrane fraction, and may have a wider substrate speci¢city [110].”

• cites [110] sourceNot checked — no full text of the source

May combine two claims.

Subsequent studies on the development of a bioprocess to treat Tc(VII)-contaminated water have focused on the use of immobilised cells of sulfate-reducing bacteria such as D. desulfuricans which are robust and capable of treating low concentrations of Tc(VII) against a high background of contaminating nitrate ions.

“Subsequent studies on the development of a bioprocess to treat Tc(VII)-contaminated water have focused on the use of immobilised cells of sulfate-reducing bacteria such as D. desulfuricans which are robust and capable of treating low concentrations of Tc(VII) against a high background of contaminating nitrate ions, which is often noted in nuclear waste [132,137].”

• cites [132] Lloyd J.R. Ridley J. Khizniak T. Lyalikova N.N. Macaskie L.E. (1999) Reduction of technetium by Desulfovibrio desulfuricans: biocatalyst characterisation and use in a flow-through bioreactor. Appl. Environ. Microbiol. 65, 2691–2696. sourceNot checked — no full text of the source
• cites [137] Lloyd J.R. Thomas G.H. Finlay J.A. Cole J.A. Macaskie L.E. (1999) Microbial reduction of technetium by Escherichia coli and Desulfovibrio desulfuricans: enhancement via the use of high activity strains and effect of process parameters. Biotechnol. Bioeng. 66, 123–130. sourceNot checked — no full text of the source

May combine two claims.

U(VI) would seem to be reduced in the periplasm, while the reduction of insoluble Fe(III) oxides was inhibited dramatically by protease treatment, presumably due to removal of surface-bound cytochromes required for reduction of the extracellular electron acceptor.

“U(VI) would seem to be reduced in the periplasm, while the reduction of insoluble Fe(III) oxides was inhibited dramatically by protease treatment, presumably due to removal of surface-bound cytochromes required for reduction of the extracellular electron acceptor.”

May combine two claims.

The tetravalent actinides are amenable to bioremediation due to their high ligand-complexing abilities, and are also immobilised in sediments containing active biomass.

“This is signi¢cant because the tetravalent actinides are amenable to bioremediation due to their high ligand-complexing abilities [116], and are also immobilised in sediments containing active biomass [125].”

• cites [116] Lloyd, J.R. and Macaskie, L.E. (2000) in: Environmental Microbe-Metal Interactions (Lovley, D.R., Ed.), pp. 277–327. ASM Press, Washington, DC. sourceNot checked — no full text of the source
• cites [125] Peretrukhin V.F. Khizhniak N.N. Lyalikova N.N. German K.E. (1996) Biosorption of technetium-99 and some actinides by bottom sediments of Lake Belsso Kosino of the Moscow region. Radiochemistry 38, 440–443.Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Although this may lead to solubilisation of sediment-bound Pu(IV), it will yield a trivalent actinide that is also amenable to bioremediation using a range of microbially produced ligands.

“Although this may lead to solubilisation of sediment-bound Pu(IV), it will yield a trivalent actinide that is also amenable to bioremediation using a range of microbially produced ligands [116].”

• cites [116] Lloyd, J.R. and Macaskie, L.E. (2000) in: Environmental Microbe-Metal Interactions (Lovley, D.R., Ed.), pp. 277–327. ASM Press, Washington, DC. sourceNot checked — no full text of the source

May combine two claims.

Th(IV) and Am(III) are stable across most Eh values encountered in radionuclide-contaminated waters, but the potentials for Pu(V)/Pu(IV) and Np(V)/Np(IV), in common with that of U(VI)/U(IV), are more electropositive than the standard redox potential of ferrihydrite/Fe2+ (approximately 0 V).

“Th(IV) and Am(III) are stable across most E h values encountered in radionuclide-contaminated waters (Fig. 5) but the potentials for Pu(V)/Pu(IV) and Np(V)/Np(IV), in common with that of U(VI)/U(IV), are more electropositive than the standard redox potential of ferrihydrite/Fe 2þ (approximately 0 V [12]).”

• cites [12] sourceNot checked — no full text of the source

May combine two claims.

Several reduced forms of Tc are insoluble, and metal-reducing microorganisms can reduce Tc(VII) and precipitate the radionuclide as a low-valency oxide.

“Several reduced forms of the radionuclide are insoluble, however, and metal-reducing microorganisms can reduce Tc(VII) and precipitate the radionuclide as a low-valency oxide.”

May combine two claims.

Although microbial metabolism was known to decrease the solubility of Tc from earlier studies, Lloyd and Macaskie were the first to unequivocally demonstrate direct enzymatic reduction of Tc(VII) by micro-organisms.

“Although microbial metabolism was known to decrease the solubility of Tc from earlier studies [129,130], Lloyd and Macaskie were the ¢rst to unequivocally demonstrate direct enzymatic reduction of Tc(VII) by micro-organisms [131].”

• cites [129] Henrot J. (1989) Bioaccumulation and chemical modification of Tc by soil bacteria. Health Phys. 57, 239–245. sourceNot checked — no full text of the source
• cites [130] Pignolet L. Fonsny K. Capot F. Moureau Z. (1989) Role of various microorganisms on Tc behaviour in sediments. Health Phys. 57, 791–800. sourceNot checked — no full text of the source
• cites [131] Lloyd J.R. Macaskie L.E. (1996) A novel phosphorImager based technique for monitoring the microbial reduction of technetium. Appl. Environ. Microbiol. 62, 578–582.Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Although 238U remains the priority pollutant in most medium-and low-level radioactive wastes, other actinides including 230Th, 237Np, 241Pu and 241Am can also be present.

“Although 238 U remains the priority pollutant in most medium-and low-level radioactive wastes, other actinides including 230 Th, 237 Np, 241 Pu and 241 Am can also be present [116,124].”

• cites [116] Lloyd, J.R. and Macaskie, L.E. (2000) in: Environmental Microbe-Metal Interactions (Lovley, D.R., Ed.), pp. 277–327. ASM Press, Washington, DC. sourceNot checked — no full text of the source
• cites [124] sourceNot checked — no full text of the source

May combine two claims.

Tc(VII) reduction and precipitation by biogenic Fe(II) is particularly efficient, and may offer a potentially useful mechanism for the remediation of Tc-contaminated sediments containing active concentrations of Fe(III)-reducing bacteria.

“Tc(VII) reduction and precipitation by biogenic Fe(II) is particularly e⁄cient, and may o¡er a potentially useful mechanism for the remediation of Tc-contaminated sediments containing active concentrations of Fe(III)-reducing bacteria [119].”

• cites [119] sourceNot checked — no full text of the source

Classified as probably not a substantial claim. May combine two claims.

Tc(VII) has weak ligand-complexing capabilities and is difficult to remove from solution using conventional 'chemical' approaches.

“Like Np(V), Tc(VII) has weak ligand-complexing capabilities and is di⁄cult to remove from solution using conventional 'chemical' approaches.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The fission product technetium is another long-lived radionuclide that is present in nuclear waste and has attracted considerable recent interest.

“The ¢ssion product technetium is another long-lived radionuclide that is present in nuclear waste and has attracted considerable recent interest.”

May combine two claims.

Fe(III)-reducing bacteria have the metabolic potential to reduce these radionuclides enzymatically, or via Fe(II) produced from the reduction of Fe(III) oxides.

“Thus, Fe(III)reducing bacteria have the metabolic potential to reduce these radionuclides enzymatically, or via Fe(II) produced from the reduction of Fe(III) oxides.”

May combine two claims.

Other workers have used this technique to show that T. ferrooxidans and Thiobacillus thiooxidans and the hyperthermophile P. islandicum are also able to reduce Tc(VII).

“Other workers have used this technique to show that T. ferrooxidans and Thiobacillus thiooxidans [134] and the hyperthermophile P. islandicum [135] are also able to reduce Tc(VII).”

• cites [134] Lyalikova N.N. Khizhnyak T.V. (1996) Reduction of heptavalent technetium by acidophilic bacteria of the genus Thiobacillus . Microbiology 65, 468–473.Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites [135] sourceNot checked — no full text of the source

May combine two claims.

Although it is possible for Fe(III)-reducing bacteria to reduce and precipitate actinides in one step, some transformations do not result in direct formation of an insoluble mineral phase but in the formation of a cation more amenable to bioprecipitation.

“Thus, although it is possible for Fe(III)reducing bacteria to reduce and precipitate actinides in one step, e.g. the reduction of soluble U(VI) to insoluble U(IV) (see above), some transformations do not result in direct formation of an insoluble mineral phase but in the formation of a cation more amenable to bioprecipitation.”

May combine two claims.

Some studies have suggested that the reduction of Pu(IV) to Pu(III) can be achieved by Fe(III)-reducing bacteria, although the Pu(III) was reported to reoxidise spontaneously.

“Also, some studies have suggested that the reduction of Pu(IV) to Pu(III) can be achieved by Fe(III)-reducing bacteria, although the Pu(III) was reported to reoxidise spontaneously [127].”

• cites [127] sourceNot checked — no full text of the source