Molybdenum in Biology - An Essential Trace Element
Molybdenum in bacteria
Azotobacter vinelandii
Molybdate and iron are metals that are required by the obligately aerobic organism;Azotobacter vinelandii to survive in the nutrient-limited conditions of its natural. soil environment. A high concentration of molybdate (1 mM) affects the formation of A. vinelandii siderophores such that the tricatecholate protochelin is formed to the exclusion of the other catecholate siderophores, azotochelin and aminochelin. Molybdate combines readily with catecholates and interferes with siderophore function. Stable molybdosiderophore complexes were formed but were readily destabilized by Fe3 + . Protochelin accumulates in the presence of molybdate because protochelin uptake and conversion into its component parts, azotochelin and aminochelin, are inhibited by interference with ferric reductase. Molybdate partially inhibited the activity of ferric reductase, an enzyme important in the deferration of ferric siderophores.
Sulfate reducing bacteria including inhibition by Mo
Molybdate is a specific inhibitor for sulfate-reducing bacteria. Sodium molybdate (980 mg/L) added to artificial wastewater decreased sulfate reducing bacteria by a factor of 103 and sulfate reduction
Yamamoto-Ikemoto, R., Matsui, S., Komori, T., Ecological Interactions Among Denitrification, Poly-P Accumulation, Sulfate Reduction, And Filamentous Sulfur Bacteria In Activated-Sludge, Water Science And Technology , 1994, 30 , 201-210.
Mier, J.l., Ballester, A., Gonzalez, F., Blazquez, M.l., Gomez, E.,The Influence Of Metallic-Ions On The Activity Of Sulfolobus BC, Journal Of Chemical Technology And Biotechnology , 1996, 65 , 272-280.
Sodium molybdate inhibited sulfate reduction by human gut sulfate-reducing bacteria causing an accumulation of ethanol and malonate and reducing the rate of utilization of lactate.
Willis, C.L., Cummings, J.H., Neale, G., Gibson, G.R., Nutritional aspects of dissimilatory sulfate reduction in the human large intestine, Current Microbiology , 1997, 35 , 294-298.
When sodium molybdate (20 mmol l -1)was added to a sediment slurry, sulfate reduction was completely stopped and mainly acetate was accumulated. From the third day after the addition of molybdate methane was produced while accumulated acetate was consumed. The maximum rate of methane production was 1.2-1.9 micromol ml -1 day -1.
Fukui, M., Suh, J., Yonezawa, Y., Urushigawa, Y., Major substrates for microbial sulfate reduction in the sediments of Ise Bay, Japan, Ecological Research ,1997, 12 , 201-209.
Gardner, A. W. and Hall-Patch, P. K., J. Nutr. , 1962, 84 , 31.
Biogas produced during anaerobic treatment of sulfate containing wastes, such as distillery waste, invariably contains around 1-3% (v/v) H2S. Sodium molybdate inhibits sulfate reduction and H2S production. A single dose of 3 mM molybdate inhibited production of H2S for 9 days. Continuous dosing of 3 mM molybdate inhibited H2S production for only 11 days. Methane production declined from day 66.
Ranade, DR, Dighe, AS, Bhirangi, SS, Panhalkar, VS, Yeole, TY Evaluation of the use of sodium molybdate to inhibit sulphate reduction during anaerobic digestion of distillery waste, Bioresource Technology , 1999, 68 , 287-291
The culture growth of the sulfate-reducing bacterium Desulfovibrio desulfuricans and the rate of sulfate reduction were reduced in contact with sputter-deposited Mo thin films and Mo powder. Mo formed molybdate, molybdenum disulfide, oxoMo(V) cysteine and thiocyanato complexes.
Chen, G., Ford, T.E., Clayton, C.R., Interaction of sulfate-reducing bacteria with molybdenum dissolved from sputter-deposited molybdenum thin films and pure molybdenum powder, Journal Of Colloid And Interface Science , 1998, 204 , 237-246.
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Lomans, B.P., OpdenCamp, H.J.M., Pol, A., vanderDrift, C., Vogels, G.D., Role of methanogens and other bacteria in degradation of dimethyl sulfide and methanethiol in anoxic freshwater sediments , Applied And Environmental Microbiology , 1999, 65 , 2116-2121.
Sodium nitrite and ammonium molybdate inhibit production of H2 S by sulfate-reducing bacteria. The amounts of inhibitor required to stop production of H2S from water associated with an oil field in containment of sulfate reducing bacteria depends on the composition and metabolic state of the microbial community. a pure culture of the sulfate-reducing bacterium and a consortium of sulfate reducing bacteria, enriched from produced water of a Canadian oil field, were investigated. Addition of 0.1 mM nitrite or 0.024 mM molybdate at the start of growth prevented the production of H 2S by Desulfovibrio sp. strain Lac6. With exponentially growing cultures, higher levels of inhibitors, 0.25 mM nitrite or 0.095 mM molybdate, were required to suppress the production of H2S. Simultaneous addition of nitrite and molybdate had a synergistic effect: at time 0, 0.05 mM nitrite and 0.01 mM molybdate, whereas during the exponential phase, 0.1 mM nitrite and 0.047 mM molybdate were sufficient to stop H2S production. With an exponentially growing consortium of sulfate-reducing bacterium, enriched from produced water of the Coleville oil field, much higher levels of inhibitors, 4 mM nitrite or 0.47 mM molybdate, were needed to stop the production of H2S.
Nemati, M., Mazutinec, T. J., Jenneman, G. E., and Voordouw, G., Control of biogenic H2S production with nitrite and molybdate, Journal of Industrial Microbiology & Biotechnology, 2001, 26, 350-355.
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