The activity of sulfate-reducing bacteria (SRB) intensifies the problems associated to corrosion of metals and the solution entails significant economic costs. Although molybdate can be used to control the negative effects of these organisms, the mechanisms triggered in the cells exposed to Mo-excess are poorly understood. In this work, the effects of molybdate ions on the growth and morphology of the SRB Desulfovibrio alaskensis G20 (DaG20) were investigated. In addition, the cellular localization, ion uptake and regulation of protein expression were studied. We found that molybdate concentrations ranging between 50 and 150 A mu M produce a twofold increase in the doubling time with this effect being more significant at 200 A mu M molybdate (five times increase in the doubling time). It was also observed that 500 A mu M molybdate completely inhibits the cellular growth. On the context of protein regulation, we found that several enzymes involved in energy metabolism, cellular division and metal uptake processes were particularly influenced under the conditions tested. An overall description of some of the mechanisms involved in the DaG20 adaptation to molybdate-stress conditions is discussed
Nair, R. R., Silveira, C. M., Diniz, M. S., Almeida, M. G., Moura, J. J. G., and Rivas, M. G., Changes in metabolic pathways of Desulfovibrio alaskensis G20 cells induced by molybdate excess, Journal of Biological Inorganic Chemistry, 2015, 20, 311-322.
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.
See also
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.
See also
Pareek, S., Azuma, J., Shimizu , Y., and Matsui, S., Hydrolysis of newspaper polysaccharides under sulfate reducing and methane producing conditions, Biodegradation, 2000, 11, 229-237.
Robertson, W.J., Franzmann, P. D., and Mee, B. J., Spore-forming, Desulfosporosinus-like sulphate-reducing bacteria from a shallow aquifer contaminated with gasoline, Journal of Applied Microbiology, 2000, 88, 248-259.
Scholten, J.C.M., Conrad, R., and Stams, A. J. M., Effect of 2-bromo-ethane sulfonate, molybdate and chloroform on acetate consumption by methanogenic and sulfate-reducing populations in freshwater sediment, Fems Microbiology Ecology, 2000, 32, 35-42.
A single dose of 3 mM molybdate inhibited production of H2S for 9 days from distillery waste which had a sulfate content of 10 g /l. Continuous dosing of 3 mM molybdate inhibited H2S production for only 11 days after which H2S was again produced, while methane production declined from day 66.
Ranade, D.R., Dighe, A.S., Bhirangi, S.S., Panhalkar, V.S., Yeole, T.Y. Evaluation of the use of sodium molybdate to inhibit sulphatereduction during anaerobic digestion of distillery waste Bioresource Technology, 1999, 68, 3, 287-291.
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.
Bacteria may reduce molybdate to MoS2 . D. desulfuricans suspended in bicarbonate buffer solution with lactate or dihydrogen as the electron donor reduces molybdenum(VI) in the presence of sulfide to MoS2 , which precipitates. Enzymatic reduction of Mo( VI) by sulfate-reducing bacteria may contribute to the accumulation of Mo(IV) in anaerobic environments. These organisms may be useful for removing soluble Mo from contaminated water.
Tucker M.D., Barton L.L., Thomson B.M., Reduction and immobilization of molybdenum by Desulfovibrio desulfuricans, Journal Of Environmental Quality, 1997, 26, 1146-1152.
The characterization of a novel Mo-Fe protein (MorP) associated with a system that responds to Mo in Desulfovibrio alaskensis is reported. Biochemical characterization shows that MorP is a periplasmic homomultimer of high molecular weight (260 ± 13 kDa) consisting of 16-18 monomers of 15321.1 ± 0.5 Da. The UV/visible absorption spectrum of the as-isolated protein shows absorption peaks around 280, 320, and 570 nm with extinction coefficients of 18700, 12800, and 5000 M-1 cm-1, respectively. Metal content, EXAFS data and DFT calculations support the presence of a Mo-2S-[2Fe-2S]-2S-Mo cluster. Analysis of the available genomes from Desulfovibrio species shows that the MorP encoding gene is located downstream of a sensor and a regulator gene. This type of gene arrangement, called two component system, is used by the cell to regulate diverse physiological processes in response to changes in enviromental conditions. Increase of both gene expression and protein production was observed when cells were cultured in the presence of 45 mu M molybdenum. Involvement of this system in Mo tolerance of sulfate reducing bacteria is proposed.
Rivas, M. G., Carepo, M. S. P., Mota, C. S., Korbas, M., Durand, M. C., Lopes, A. T., Brondino, C. D., Pereira, A. S., George, G. N., Dolla, A., Moura, J. J. G., and Moura, I., Molybdenum Induces the Expression of a Protein Containing a New Heterometallic Mo-Fe Cluster in Desulfovibrio alaskensis, Biochemistry, 2009, 48, 873-882.