Analysis of the microbial community of the biocathode of a hydrogen-producing microbial electrolysis cell
Croese, E. ; Pereira, M.A. ; Euverink, G.J.W. ; Stams, A.J.M. ; Geelhoed, J.S. - \ 2011
Applied Microbiology and Biotechnology 92 (2011)5. - ISSN 0175-7598 - p. 1083 - 1093.
desulfovibrio-vulgaris hildenborough - geobacter-sulfurreducens - fuel-cells - exchange membranes - oxide reduction - gene-expression - organic-matter - sequence data - electrodes - electricity
The microbial electrolysis cell (MEC) is a promising system for hydrogen production. Still, expensive catalysts such as platinum are needed for efficient hydrogen evolution at the cathode. Recently, the possibility to use a biocathode as an alternative for platinum was shown. The microorganisms involved in hydrogen evolution in such systems are not yet identified. We analyzed the microbial community of a mixed culture biocathode that was enriched in an MEC bioanode. This biocathode produced 1.1 A m(-2) and 0.63 m3 H2 m(-3) cathode liquid volume per day. The bacterial population consisted of 46% Proteobacteria, 25% Firmicutes, 17% Bacteroidetes, and 12% related to other phyla. The dominant ribotype belonged to the species Desulfovibrio vulgaris. The second major ribotype cluster constituted a novel taxonomic group at the genus level, clustering within uncultured Firmicutes. The third cluster belonged to uncultured Bacteroidetes and grouped in a taxonomic group from which only clones were described before; most of these clones originated from soil samples. The identified novel taxonomic groups developed under environmentally unusual conditions, and this may point to properties that have not been considered before. A pure culture of Desulfovibrio strain G11 inoculated in a cathode of an MEC led to a current development from 0.17 to 0.76 A m(-2) in 9 days, and hydrogen gas formation was observed. On the basis of the known characteristics of Desulfovibrio spp., including its ability to produce hydrogen, we propose a mechanism for hydrogen evolution through Desulfovibrio spp. in a biocathode system
Purification and characterization of a chlorite dismutase from Pseudomonas chloritidismutans
Mehboob, F. ; Wolterink, A.F.W.M. ; Vermeulen, A.J. ; Jiang, B. ; Hagedoorn, P.L. ; Stams, A.J.M. ; Kengen, S.W.M. - \ 2009
FEMS Microbiology Letters 293 (2009)1. - ISSN 0378-1097 - p. 115 - 121.
desulfovibrio-vulgaris hildenborough - (per)chlorate-reducing bacteria - strain gr-1 - reductase - catalase
The chlorite dismutase (Cld) of Pseudomonas chloritidismutans was purified from the periplasmic fraction in one step by hydroxyapatite chromatography. The enzyme has a molecular mass of 110 kDa and consists of four 31-kDa subunits. Enzyme catalysis followed Michaelis-Menten kinetics, with Vmax and K(m) values of 443 U mg(-1) and 84 microM, respectively. A pyridine-NaOH-dithionite-reduced Cld revealed a Soret peak at 418 nm, indicative for protoheme IX. The spectral data indicate the presence of 1.5 mol protoheme IX mol(-1) tetrameric enzyme while metal analysis revealed 2.2 mol iron mol(-1) tetrameric enzyme. High concentrations of chlorite resulted in the disappearance of the Soret peak, which coincided with loss in activity. Electron paramagnetic resonance analyses showed an axial high-spin ferric iron signal. Cld was inhibited by cyanide, azide, but not by hydroxylamine or 3-amino-1,2,3-triazole. Remarkably, the activity was drastically enhanced by kosmotropic salts, and chaotropic salts decreased the activity, in accordance with the Hofmeister series. Chlorite conversion in the presence of 18O-labeled water did not result in the formation of oxygen with a mass of 34 (16O-18O) or a mass of 36 ((18)O-(18)O), indicating that water is not a substrate in the reaction and that both oxygen atoms originate from chlorite
The ecology and biotechnology of sulphate-reducing bacteria
Muyzer, G. ; Stams, A.J.M. - \ 2008
Nature Reviews Microbiology 6 (2008)6. - ISSN 1740-1526 - p. 441 - 454.
16s ribosomal-rna - in-situ hybridization - desulfovibrio-vulgaris hildenborough - out-compete methanogens - citric-acid cycle - rice field soil - real-time pcr - sp-nov. - anaerobic oxidation - gen. nov.
Sulphate-reducing bacteria (SRB) are anaerobic microorganisms that use sulphate as a terminal electron acceptor in, for example, the degradation of organic compounds. They are ubiquitous in anoxic habitats, where they have an important role in both the sulphur and carbon cycles. SRB can cause a serious problem for industries, such as the offshore oil industry, because of the production of sulphide, which is highly reactive, corrosive and toxic. However, these organisms can also be beneficial by removing sulphate and heavy metals from waste streams. Although SRB have been studied for more than a century, it is only with the recent emergence of new molecular biological and genomic techniques that we have begun to obtain detailed information on their way of life
Carbon monoxide conversion by thermophilic sulfate-reducing bacteria in pure culture and in co-culture with Carboxydothermus hydrogenoformans
Parshina, S.N. ; Kijlstra, S. ; Henstra, A.M. ; Sipma, J. ; Plugge, C.M. ; Stams, A.J.M. - \ 2005
Applied Microbiology and Biotechnology 68 (2005)3. - ISSN 0175-7598 - p. 390 - 396.
desulfovibrio-vulgaris hildenborough - anaerobic bioreactor sludges - sp-nov - gen.-nov. - methanogenic bacteria - growth - reduction - energy - gas - hydrogenases
Biological sulfate (SO4) reduction with carbon monoxide (CO) as electron donor was investigated. Four thermophilic SO4-reducing bacteria, Desulfotomaculum thermoacetoxidans (DSM 5813), Thermodesulfovibrio yellowstonii (ATCC 51303), Desulfotomaculum kuznetsovii (DSM 6115; VKM B-1805), and Desulfotomaculum thermobenzoicum subsp. thermosyntrophicum (DSM 14055), were studied in pure culture and in co-culture with the thermophilic carboxydotrophic bacterium Carboxydothermus hydrogenoformans (DSM 6008). D. thermoacetoxidans and T. yellowstonii were extremely sensitive to CO: their growth on pyruvate was completely inhibited at CO concentrations above 2% in the gas phase. D. kuznetsovii and D. thermobenzoicum subsp. thermosyntrophicum were less sensitive to CO. In pure culture, D. kuznetsovii and D. thermobenzoicum subsp. thermosyntrophicum were able to grow on CO as the only electron donor and, in particular in the presence of hydrogen/carbon dioxide, at CO concentrations as high as 50-70%. The latter SO4 reducers coupled CO oxidation to SO4 reduction, but a large part of the CO was converted to acetate. In co-culture with C. hydrogenoformans, D. kuznetsovii and D. thermobenzoicum subsp. thermosyntrophicum could even grow with 100% CO (P CO=120 kPa).
A crystallographic study of Cys69Ala flavodoxin II from Azotobacter vinelandii: Structural determinants of redox potential
Alagaratnam, S. ; Pouderoyen, G. van; Pijning, T. ; Dijkstra, B.W. ; Cavazzini, D. ; Rossi, G.L. ; Dongen, W.M.A.M. van; Mierlo, C.P.M. van; Berkel, W.J.H. van; Canters, G.W. - \ 2005
Protein Science 14 (2005)9. - ISSN 0961-8368 - p. 2284 - 2295.
desulfovibrio-vulgaris hildenborough - mononucleotide binding-site - oxidation-reduction potentials - long-chain flavodoxin - oxidized flavodoxin - electron-transfer - megasphaera-elsdenii - anacystis-nidulans - crystal-structures - flavin-binding
Flavodoxin II from Azotobacter vinelandii is a "long-chain" flavodoxin and has one of the lowest E1 midpoint potentials found within the flavodoxin family. To better understand the relationship between structural features and redox potentials, the oxidized form of the C69A mutant of this flavodoxin was crystallized and its three-dimensional structure determined to a resolution of 2.25 A¿ by molecular replacement. Its overall fold is similar to that of other flavodoxins, with a central five-stranded parallel ß-sheet flanked on either side by ¿-helices. An eight-residue insertion, compared with other long-chain flavodoxins, forms a short 310 helix preceding the start of the ¿3 helix. The flavin mononucleotide (FMN) cofactor is flanked by a leucine on its re face instead of the more conserved tryptophan, resulting in a more solvent-accessible FMN binding site and stabilization of the hydroquinone (hq) state. In particular the absence of a hydrogen bond to the N5 atom of the oxidized FMN was identified, which destabilizes the ox form, as well as an exceptionally large patch of acidic residues in the vicinity of the FMN N1 atom, which destabilizes the hq form. It is also argued that the presence of a Gly at position 58 in the sequence stabilizes the semiquinone (sq) form, as a result, raising the E2 value in particular
Characterization of the chlorate reductase from Pseudomonas chloritidismutans
Wolterink, A.F.W.M. ; Schiltz, E. ; Hagedoorn, P.L. ; Hagen, W.R. ; Kengen, S.W.M. ; Stams, A.J.M. - \ 2003
Journal of Bacteriology 185 (2003)10. - ISSN 0021-9193 - p. 3210 - 3213.
desulfovibrio-vulgaris hildenborough - nitrate reductase - paracoccus-denitrificans - haloarcula-marismortui - energy transduction - oxide reductase - purification - dehydrogenase - (per)chlorate - enzymes
A chlorate reductase has been purified from the chlorate-reducing strain Pseudomonas chloritidismutans. Comparison with the periplasmic (per)chlorate reductase of strain GR-1 showed that the cytoplasmic chlorate reductase of P. chloritidismutans reduced only chlorate and bromate. Differences were also found in N-terminal sequences, molecular weight, and subunit composition. Metal analysis and electron paramagnetic resonance measurements showed the presence of iron and molybdenum, which are also found in other dissimilatory oxyanion reductases