Sulfate reduction in a hydrogen fed bioreactor operated at haloalkaline conditions
Sousa, J.A.B. ; Plugge, C.M. ; Stams, A.J.M. ; Bijmans, M.F.M. - \ 2015
Water Research 68 (2015). - ISSN 0043-1354 - p. 67 - 76.
gas-lift reactor - sp-nov. - reducing bacteria - high salinity - soda lakes - uasb reactors - waste-water - gen. nov. - sp. nov - bed
Biological sulfate reduction is used as a biotechnological process to treat sulfate rich streams. However, application of biological sulfate reduction at high pH and high salinity using H2 was not thoroughly investigated before. In this work the sulfate reduction activity, biomass growth, microbial community and biomass aggregation were investigated in a H2-fed gas lift bioreactor at haloalkaline conditions. The process was characterized by low sulfate reduction volumetric rates due to slow growth and lack of biomass aggregation. Apparently, the extreme conditions and absence of organic compounds prevented the formation of stable aggregates. The microbial community analysis revealed a low abundance of known haloalkaliphilic sulfate reducers and presence of a Tindallia sp. The identified archaea were related to Methanobacterium alcaliphilum and Methanocalculus sp. The biomass did not attach to metal sulfides, calcite and magnesite crystals. However, biofilm formation on the glass bioreactor walls showed that attachment to glass occurs.
Sulfate Reduction at Low Ph To Remediate Acid Mine Drainage
Sánchez-Andrea, I. ; Sanz, J.L. ; Bijmans, M.F.M. ; Stams, A.J.M. - \ 2014
Journal of Hazardous Materials 269 (2014). - ISSN 0304-3894 - p. 98 - 109.
fluidized-bed reactor - metal-contaminated water - rate-determining step - reducing bacteria - waste-water - microbial community - sp-nov - biological treatment - constructed wetland - passive treatment
Industrial activities and the natural oxidation of metallic sulfide-ores produce sulfate-rich waters with low pH and high heavy metals content, generally termed acid mine drainage (AMD). This is of great environmental concern as some heavy metals are highly toxic. Within a number of possibilities, biological treatment applying sulfate-reducing bacteria (SRB) is an attractive option to treat AMD and to recover metals. The process produces alkalinity, neutralizing the AMD. Simultaneously. The sulfide that is produced react with the metal in solution and precipitates them as metal sulfides. Here, important factors for biotechnological application of SRB such as the inocula, the pH of the process, the substrates and the reactor design are discussed. Microbial communities of sulfidogenic reactors treating AMD which comprise fermentative-, acetogenic- and SRB as well as methanogenic archaea are reviewed
Metabolic response of Alicycliphilus denitrificans strain BC towards electron acceptor variation
Oosterkamp, M.J. ; Boeren, S. ; Plugge, C.M. ; Schaap, P.J. ; Stams, A.J.M. - \ 2013
Proteomics 13 (2013)18-19. - ISSN 1615-9853 - p. 2886 - 2894.
microbial perchlorate reduction - pseudomonas-chloritidismutans - phylogenetic analysis - nitrate reductases - chlorite dismutase - reducing bacteria - anaerobic growth - chlorate - genes - identification
Alicycliphilus denitrificans is a versatile, ubiquitous, facultative anaerobic bacterium. A. denitrificans strain BC can use chlorate, nitrate and oxygen as electron acceptor for growth. Cells display a prolonged lag-phase when transferred from nitrate to chlorate and vice versa. Furthermore, cells adapted to aerobic growth do not easily use nitrate or chlorate as electron acceptor. We further investigated these responses of strain BC by differential proteomics, transcript analysis and enzyme activity assays. In nitrate-adapted cells transferred to chlorate and vice versa, appropriate electron acceptor reduction pathways need to be activated. In oxygen-adapted cells, adaptation to the use of chlorate or nitrate is likely difficult due to the poorly active nitrate reduction pathway and low active chlorate reduction pathway. We deduce that the Nar-type nitrate reductase of strain BC also reduces chlorate, which may result in toxic levels of chlorite if cells are transferred to chlorate. Furthermore, the activities of nitrate reductase and nitrite reductase appear to be not balanced when oxygen-adapted cells a shifted to nitrate as electron acceptor, leading to the production of a toxic amount of nitrite. These data suggest that strain BC encounters metabolic challenges in environments with fluctuations in the availability of electron acceptors
Genome Analysis and Physiological Comparison of Alicycliphilus denitrificans Strains BC and K601(T.)
Oosterkamp, M.J. ; Veuskens, T. ; Talarico Saia, F. ; Weelink, S.A.B. ; Goodwin, L.A. ; Daligault, H.E. ; Bruce, D.C. ; Detter, J.C. ; Tapia, R. ; Han, C.S. ; Land, M. ; Hauser, L. ; Langenhoff, A.A.M. ; Gerritse, J. ; Berkel, W.J.H. van; Pieper, D.H. ; Junca, H. ; Smidt, H. ; Schraa, G. ; Davids, M. ; Schaap, P.J. ; Plugge, C.M. ; Stams, A.J.M. - \ 2013
PLoS ONE 8 (2013)6. - ISSN 1932-6203
periplasmic nitrate reductase - anaerobic benzene degradation - cytochrome-c-oxidase - aromatic-compounds - perchlorate reduction - chlorite dismutase - reducing bacteria - rna genes - 1st step - metabolism
The genomes of the Betaproteobacteria Alicycliphilus denitrificans strains BC and K601(T) have been sequenced to get insight into the physiology of the two strains. Strain BC degrades benzene with chlorate as electron acceptor. The cyclohexanol-degrading denitrifying strain K601(T) is not able to use chlorate as electron acceptor, while strain BC cannot degrade cyclohexanol. The 16S rRNA sequences of strains BC and K601(T) are identical and the fatty acid methyl ester patterns of the strains are similar. Basic Local Alignment Search Tool (BLAST) analysis of predicted open reading frames of both strains showed most hits with Acidovorax sp. JS42, a bacterium that degrades nitro-aromatics. The genomes include strain-specific plasmids (pAlide201 in strain K601(T) and pAlide01 and pAlide02 in strain BC). Key genes of chlorate reduction in strain BC were located on a 120 kb megaplasmid (pAlide01), which was absent in strain K601(T). Genes involved in cyclohexanol degradation were only found in strain K601(T). Benzene and toluene are degraded via oxygenase-mediated pathways in both strains. Genes involved in the meta-cleavage pathway of catechol are present in the genomes of both strains. Strain BC also contains all genes of the ortho-cleavage pathway. The large number of mono- and dioxygenase genes in the genomes suggests that the two strains have a broader substrate range than known thus far
Hydrogenotrophic Sulfate Reduction in a Gas-Lift Bioreactor Operated at 9 degrees C
Nevatalo, L.M. ; Bijmans, M.F.M. ; Lens, P.N.L. ; Kaksonen, A.H. ; Puhakka, J.A. - \ 2010
Journal of Microbiology and Biotechnology 20 (2010)3. - ISSN 1017-7825 - p. 615 - 621.
reducing bacteria - retention time - carbon-dioxide - growth-rate - sp-nov - reactor - temperature - methanogenesis - oxidation - sulfide
The viability of low-temperature sulfate reduction with hydrogen as electron donor was studied with a bench-scale gas-lift bioreactor (GLB) operated at 9 degrees C. Prior to the GLB experiment, the temperature range of sulfate reduction of the inoculum was assayed. The results of the temperature gradient assay indicated that the inoculum was a psychrotolerant mesophilic enrichment culture that had an optimal temperature for sulfate reduction of 31 degrees C, and minimum and maximum temperatures of 7 degrees C and 41 degrees C, respectively. In the GLB experiment at 9 degrees C, a sulfate reduction rate of 500-600 mg l(-1) d(-1), corresponding to a specific activity of 173 mg SO42- g VSS-1 d(-1), was obtained. The electron flow from the consumed H-2-gas to sulfate reduction varied between 27% and 52%, whereas the electron flow to acetate production decreased steadily from 15% to 5%. No methane was produced. Acetate was produced from CO2 and H-2 by homoacetogenic bacteria. Acetate supported the growth of some heterotrophic sulfate-reducing bacteria. The sulfate reduction rate in the GLB was limited by the slow biomass growth rate at 9 degrees C and low biomass retention in the reactor. Nevertheless, this study demonstrated the potential sulfate reduction rate of psychrotolerant sulfate-reducing mesophiles at suboptimal temperature.
Sulfate Reduction at pH 4.0 for Treatment of Process and Wastewaters
Bijmans, M.F.M. ; Vries, E. de; Yang, C.H. ; Buisman, C.J.N. ; Lens, P.N.L. ; Dopson, M. - \ 2010
Biotechnology Progress 26 (2010)4. - ISSN 8756-7938 - p. 1029 - 1037.
acid-mine drainage - gradient gel-electrophoresis - reducing bacteria - anaerobic reactor - bioreactor - hydrogen - sulfide - growth - water - removal
Acidic industrial process and wastewaters often contain high sulfate and metal concentrations and their direct biological treatment is thus far not possible as biological processes at pH <5 have been neglected. Sulfate-reducing bacteria convert sulfate to sulfide that can subsequently be used to recover metals as metal-sulfides precipitate. This study reports on high-rate sulfate reduction with a mixed microbial community at pH 4.0 and 4.5 with hydrogen and/or formate as electron donors. The maximum sulfate reducing activity at pH 4.0 was sustained for over 40 days with a specific activity 500-fold greater than previously reported values: 151 mmol sulfate reduced/L reactor liquid per day with a maximum specific activity of 84 mmol sulfate per gram of volatile suspended solids per day. The biomass yield gradually decreased from 38 to 0.4 g volatile suspended solids per kilogram of sulfate when decreasing the reactor pH from pH 6 to 4. The microorganisms had a high maintenance requirement probably due maintaining pH homeostasis and the toxicity of sulfide at low pH. The microbial community diversity in the pH 4.0 membrane bioreactor decreased over time, while the diversity of the sulfate reducing community increased. Thus, a specialized microbial community containing a lower proportion of microorganisms capable of activity at pH 4 developed in the reactor compared with those present at the start of the experiment. The 16S rRNA genes identified from the pH 4.0 grown mixed culture were most similar to those of Desulfovibrio species and Desulfosporosinus sp. M1. (C) 2010 American Institute of Chemical Engineers Biotechnol. Prog., 26: 1029-1037, 2010
Sulfate reduction during the acidification of sucrose at pH 5 under thermophilic (55 degrees C) conditions. II: Effect of sulfide and COD/SO42- ratio
Lopes, S.I.C. ; Capela, M.I. ; Lens, P.N.L. - \ 2010
Bioresource Technology 101 (2010)12. - ISSN 0960-8524 - p. 4278 - 4284.
granular sludge reactors - anaerobic-digestion - reducing bacteria - acidogenic phase - waste-water - toxicity - systems - degradation - performance - propionate
This work studied the effect of the sulfide concentration and COD/SO42- ratios (4 and 1) on sulfate reduction and acidification in a thermophilic (55 degrees C) UASB reactor fed with sucrose (4 g COD (I-reactor d)(-1)) operated at a reactor mixed liquor pH controlled at 5 for a period of 301 days. When implementing N-2 stripping, sulfate reduction efficiencies up to 95%, corresponding to volumetric sulfate reduction rates of 0.87 and 4.2 g (I-reactor d)(-1) at the COD/SO42- ratios of 4 and 1, respectively, were achieved. Sulfide was toxic to sulfate reduction at a total dissolved sulfide concentration of 100 mg l(-1). Acidification was always complete and acetate was the only form of substrate in the effluent at a COD/SO42- ratio of 1. The sludge was well retained in the reactor and kept its granular shape throughout the reactor run.
Stability of the total and functional microbial communities in river sediment mesocosms exposed to anthropogenic disturbances
Zaan, B.M. van der; Smidt, H. ; Vos, W.M. de; Rijnaarts, H. ; Gerritse, J. - \ 2010
FEMS microbiology ecology 74 (2010)1. - ISSN 0168-6496 - p. 72 - 82.
real-time pcr - reducing bacteria - soil bacterial - pollution - dehalococcoides - diversity - nitrogen - genes - water - mineralization
River systems are exposed to anthropogenic disturbances, including chemical pollution and eutrophication. This may affect the phylogenetic diversity as well as the abundance of various functional groups within sediment-associated microbial communities. To address such potential effects, mesocosms filled with Ebro delta sediment covered with river water were exposed to chlorinated organic compounds or to a high nutrient concentration as used for fertilization. Changes in the abundance of selected functional microbial groups, i.e. total aerobes, nitrate, sulfate and iron reducers, organohalide-respiring microorganisms as well as methanogens, were examined using culture-dependent most probable number and culture-independent PCR methods targeting phylogenetic as well as functional gene markers. It was concluded that the abundance of functional groups was neither affected by pollution with 1,2-dichloroethane and tetrachloroethene nor by elevated nutrient loads, although changes in the bacterial community composition were observed using 16S rRNA gene-targeted fingerprint techniques. This study reinforced the notion that complementary culture-dependent and molecular methods, focusing on different fractions of the microbial community (cultivable, active or total), should be used in combination for a comprehensive description of phylogenetic diversity and functional potential
Trace methane oxidation and the methane dependency of sulfate reduction in anaerobic granular sludge
Meulepas, R.J.W. ; Jagersma, C.G. ; Zhang, Y. ; Petrillo, M. ; Cai, H. ; Buisman, C.J.N. ; Stams, A.J.M. ; Lens, P.N.L. - \ 2010
FEMS microbiology ecology 72 (2010)2. - ISSN 0168-6496 - p. 261 - 271.
reducing bacteria - marine-sediments - methanotrophic archaea - metabolic interactions - thermophilic sulfate - oxidizing archaea - skagerrak denmark - carbon-monoxide - microbial mats - waste-water
This study investigates the oxidation of labeled methane (CH(4)) and the CH(4) dependence of sulfate reduction in three types of anaerobic granular sludge. In all samples, (13)C-labeled CH(4) was anaerobically oxidized to (13)C-labeled CO(2), while net endogenous CH(4) production was observed. Labeled-CH(4) oxidation rates followed CH(4) production rates, and the presence of sulfate hampered both labeled-CH(4) oxidation and methanogenesis. Labeled-CH(4) oxidation was therefore linked to methanogenesis. This process is referred to as trace CH(4) oxidation and has been demonstrated in methanogenic pure cultures. This study shows that the ratio between labeled-CH(4) oxidation and methanogenesis is positively affected by the CH(4) partial pressure and that this ratio is in methanogenic granular sludge more than 40 times higher than that in pure cultures of methanogens. The CH(4) partial pressure also positively affected sulfate reduction and negatively affected methanogenesis: a repression of methanogenesis at elevated CH(4) partial pressures confers an advantage to sulfate reducers that compete with methanogens for common substrates, formed from endogenous material. The oxidation of labeled CH(4) and the CH(4) dependence of sulfate reduction are thus not necessarily evidence of anaerobic oxidation of CH(4) coupled to sulfate reduction
Effect of methanogenic substrates on anaerobic oxidation of methane and sulfate reduction by an anaerobic methanotrophic enrichment
Meulepas, R.J.W. ; Jagersma, C.G. ; Khadem, A.F. ; Buisman, C.J.N. ; Stams, A.J.M. ; Lens, P.N.L. - \ 2010
Applied Microbiology and Biotechnology 87 (2010)4. - ISSN 0175-7598 - p. 1499 - 1506.
anoxic marine sediment - microbial communities - electron-transfer - reducing bacteria - carbon-monoxide - archaea - energy - requirements - consumption - consortium
Anaerobic oxidation of methane (AOM) coupled to sulfate reduction (SR) is assumed to be a syntrophic process, in which methanotrophic archaea produce an interspecies electron carrier (IEC), which is subsequently utilized by sulfate-reducing bacteria. In this paper, six methanogenic substrates are tested as candidate-IECs by assessing their effect on AOM and SR by an anaerobic methanotrophic enrichment. The presence of acetate, formate or hydrogen enhanced SR, but did not inhibit AOM, nor did these substrates trigger methanogenesis. Carbon monoxide also enhanced SR but slightly inhibited AOM. Methanol did not enhance SR nor did it inhibit AOM, and methanethiol inhibited both SR and AOM completely. Subsequently, it was calculated at which candidate-IEC concentrations no more Gibbs free energy can be conserved from their production from methane at the applied conditions. These concentrations were at least 1,000 times lower can the final candidate-IEC concentration in the bulk liquid. Therefore, the tested candidate-IECs could not have been produced from methane during the incubations. Hence, acetate, formate, methanol, carbon monoxide, and hydrogen can be excluded as sole IEC in AOM coupled to SR. Methanethiol did inhibit AOM and can therefore not be excluded as IEC by this study
Endogenous and bioaugmented sulphate reduction in calcareous gypsiferous soils
Alfaya, F. ; Cuenca-Sanchez, M. ; Garcia-Orenes, F. ; Lens, P.N.L. - \ 2009
Environmental Technology 30 (2009)12. - ISSN 0959-3330 - p. 1305 - 1312.
sludge bed reactors - granular sludge - reducing bacteria - anaerobic reactor - electron-donors - methanol - bioreactor - acetate - ethanol - sucrose
Gypsiferous soils have a high agricultural value, but their utilization is limited by the presence of gypsum that can induce hardpan and vertical crusting. This paper reports on sulphate reduction in this soil type as a basis of a bioremediation technology to remove the gypsum content of calcareous gypsiferous soils. Both the endogenous and bioaugmented sulphate-reducing potential of the soil was assessed in anaerobic batch tests. An endogenous population of sulphate-reducing bacteria was found to be present in the calcareous gypsiferous soil investigated, which could form the basis of both in situ and ex situ bioremediation schemes for this soil type.
Acceleration of the Fe(III)EDTA(-) reduction rate in BioDeNO(x) reactors by dosing electron mediating compounds
Maas, P.M.F. van der; Brink, P. van den; Klapwijk, A. ; Lens, P.N.L. - \ 2009
Chemosphere 75 (2009)2. - ISSN 0045-6535 - p. 243 - 249.
methanogenic bacteria - hydrogen-sulfide - reducing bacteria - nitrogen-oxides - chelated iron - nitric-oxide - fatty-acids - flue-gas - edta - absorption
BioDeNO(x), a novel technique to remove NOx from industrial flue gases, is based on absorption of gaseous nitric oxide into an aqueous Fe(II)EDTA(2-) solution, followed by the biological reduction of Fe(II)EDTA(2-) complexed NO to N-2. Besides NO reduction, high rate biological Fe(III)EDTA(-) reduction is a crucial factor for a succesful application of the BioDeNO(x) technology, as it determines the Fe(II)EDTA(2-) concentration in the scrubber liquor and thus the efficiency of NO removal from the gas phase. This paper investigates the mechanism and kinetics of biological Fe(III)EDTA(-) reduction by unadapted anaerobic methanogenic sludge and BioDeNO(x) reactor mixed liquor. The influence of different electron donors, electron mediating compounds and CaSO3 on the Fe(III)EDTA(-) reduction rate was determined in batch experiments (21 mM Fe(III)EDTA(-), 55 degrees C, pH 7.2 +/- 0.2). The Fe(III)EDTA(-) reduction rate depended on the type of electron donor, the highest rate (13.9 mM h(-1)) was observed with glucose, followed by ethanol, acetate and hydrogen. Fe(III)EDTA(-) reduction occurred at a relatively slow (4.1 mM h(-1)) rate with methanol as the electron donor. Small amounts (0.5 mM) of sulfide, cysteine or elemental sulfur accelerated the Fe(III)EDTA(-) reduction. The amount of iron reduced significantly exceeded the amount that can be formed by the chemical reaction of sulfide with Fe(III)EDTA(-), suggesting that the Fe(III)EDTA(-) reduction was accelerated via an auto-catalytic process with an unidentified electron mediating compound, presumably polysulfides. formed out of the sulfur additives, Using ethanol as electron donor, the specific Fe(III)EDTA(-) reduction rate was linearly related to the amount of sulfide supplied. CaSO3 (0.5-100 mM) inhibited Fe(III)EDTA(-) reduction, probably because SO32- scavenged the electron mediating compound. 3
|Sulfate Reduction at pH 5 in a High-Rate Membrane Bioreactor: Reactor Performance and Microbial Community Analyses
Bijmans, M.F.M. ; Dopson, M. ; Peeters, T.W.T. ; Lens, P.N.L. ; Buisman, C.J.N. - \ 2009
Journal of Microbiology and Biotechnology 19 (2009)7. - ISSN 1017-7825 - p. 698 - 708.
acid-mine drainage - gradient gel-electrophoresis - containing waste-water - anaerobic bioreactor - reducing bacteria - carbon-dioxide - paper-mill - metal - hydrogen - removal
High rate sulfate reduction under acidic conditions opens possibilities for new process flow sheets that allow the selective recovery of metals from mining and metallurgical waste and process water. However, knowledge about high-rate sulfate reduction under acidic conditions is limited. This paper investigates sulfate reduction in a membrane bioreactor at a controlled pH of 5. Sulfate and formate were dosed using a pH-auxostat system while formate was converted into hydrogen, which was used for sulfate reduction. Sulfide was removed from the gas phase to prevent sulfide inhibition. This study shows a high-rate sulfate-reducing bioreactor system for the first time at pH 5, with a volumetric activity of 188 mmol SO42-/I/d and a specific activity of 81 mmol SO42- volatile suspended solids/d. The microbial community at the end of the reactor run consisted of a diverse mixed population including sulfate-reducing bacteria.
Effect of environmental conditions on sulfate reduction with methane as electron donor by an Eckemförde Bay enrichment
Meulepas, R.J.W. ; Jagersma, C.G. ; Khadem, A.F. ; Buisman, C.J.N. ; Stams, A.J.M. ; Lens, P.N.L. - \ 2009
Environmental Science and Technology 43 (2009)17. - ISSN 0013-936X - p. 6553 - 6559.
coenzyme-m reductase - anaerobic oxidation - marine-sediments - methanotrophic archaea - oxidizing archaea - reducing bacteria - skagerrak denmark - microbial mats - black-sea - consumption
Sulfate reduction (SR) coupled to anaerobic oxidation of methane (AOM) is meditated by marine microorganisms and forms an important process in the global sulfur and carbon cycle. In this research, the possibility to use this process for the removal and recovery of sulfur and metal compounds from waste streams was investigated. A membrane bioreactor was used to enrich for a community of methane-oxidizing sulfate-reducing microorganisms from Eckernförde Bay sediment The AOM and SR rate of the obtained enrichment were 1.0 mmol gvss(-1) d(-1). The operational window and optimal environmental conditions for SR with methane as electron donor were assessed. The optimum pH, salinity, and temperature were 7.5, 30% per hundred and 20 degrees C, respectively. The enrichment had a good affinity for sulfate (Km <0.5 mM) and a low affinity for methane (Kn > 0.075 MPa). A0M coupled to SR was completely inhibited at 2.4 (L0.1) mM sulfide. AOM occurred with sulfate, thiosulfate, and sulfite as electron accepters. Sulfate reduction with methane as electron donor can be applied for the removal of sulfate or for the production of sulfide,for metal precipitation. However, the low optimal temperature and the high salt requirement limit the operational window of the process
Citric acid wastewater as electron donor for biological sulfate reduction
Stams, A.J.M. ; Huisman, J. ; Garcia Encina, P.A. ; Muyzer, G. - \ 2009
Applied Microbiology and Biotechnology 83 (2009)5. - ISSN 0175-7598 - p. 957 - 963.
sp-nov. - lactosphaera-pasteurii - ruminococcus-palustris - citrate metabolism - reducing bacteria - comb-nov - gen-nov - reactor - veillonella - reclassification
Citrate-containing wastewater is used as electron donor for sulfate reduction in a biological treatment plant for the removal of sulfate. The pathway of citrate conversion coupled to sulfate reduction and the microorganisms involved were investigated. Citrate was not a direct electron donor for the sulfate-reducing bacteria. Instead, citrate was fermented to mainly acetate and formate. These fermentation products served as electron donors for the sulfate-reducing bacteria. Sulfate reduction activities of the reactor biomass with acetate and formate were sufficiently high to explain the sulfate reduction rates that are required for the process. Two citrate-fermenting bacteria were isolated. Strain R210 was closest related to Trichococcus pasteurii (99.5% ribosomal RNA (rRNA) gene sequence similarity). The closest relative of strain S101 was Veillonella montepellierensis with an rRNA gene sequence similarity of 96.7%. Both strains had a complementary substrate range
Effect of Sulfide Removal on Sulfate Reduction at pH 5 in a Hydrogen fed Gas-Lift Bioreactor
Bijmans, M.F.M. ; Dopson, M. ; Lens, P.N.L. ; Buisman, C.J.N. - \ 2008
Journal of Microbiology and Biotechnology 18 (2008)11. - ISSN 1017-7825 - p. 1809 - 1818.
acid-mine drainage - reducing bacteria - anaerobic bioreactor - product inhibition - carbon-dioxide - growth - reactor - metal - water - precipitation
UNCORRECTED PROOF J. Microbiol. Biotechnol. (2007), 17(4), ¿ Effect of Sulfide Removal on Sulfate Reduction at pH 5 in a Hydrogen fed Gas-Lift Bioreactor Bijmans, Martijn F. M.1*, Mark Dopson2, Frederick Ennin1, Piet N. L. Lens1, and Cees J. N. Buisman1 1Sub Department of Environmental Technology, Wageningen University and Research Centre, P.O. Box 8129, 6700 EV Wageningen, The Netherlands 2Department of Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden Received: / Accepted: Biotechnological treatment of sulfate- and metal-ionscontaining acidic wastewaters from mining and metallurgical activities utilizes sulfate-reducing bacteria to produce sulfide that can subsequently precipitate metal ions. Reducing sulfate at a low pH has several advantages above neutrophilic sulfate reduction. This study describes the effect of sulfide removal on the reactor performance and microbial community in a high-rate sulfidogenic gas-lift bioreactor fed with hydrogen at a controlled internal pH of 5. Under sulfide removal conditions, 99% of the sulfate was converted at a hydraulic retention time of 24 h, reaching a volumetric activity as high as 51 mmol sulfate/l/d. Under nonsulfide removal conditions,
High rate sulfate reduction at pH 6 in a Ph-auxostat submerged membrane bioreactor fed with formate
Bijmans, M.F.M. ; Peeters, T.W.T. ; Lens, P.N.L. ; Buisman, C.J.N. - \ 2008
Water Research 42 (2008)10-11. - ISSN 0043-1354 - p. 2439 - 2448.
afvalwaterbehandeling - industrieel afval - bioreactoren - membranen - filtratie - sulfaat reducerende bacteriën - sulfaatreductie - waste water treatment - industrial wastes - bioreactors - membranes - filtration - sulfate reducing bacteria - sulfate reduction - gas-lift reactor - reducing bacteria - hydrogen-sulfide - carbon-dioxide - growth - methanogenesis - conversion - removal - sludge - water
Many industrial waste and process waters contain high concentrations of sulfate, which can be removed by sulfate-reducing bacteria (SRB). This paper reports on mesophilic (30 °C) sulfate reduction at pH 6 with formate as electron donor in a membrane bioreactor with a pH-auxostat dosing system. A mixed microbial community from full-scale industrial wastewater treatment bioreactors operated at pH 7 was used as inoculum. The pH-auxostat enabled the bacteria to convert sulfate at a volumetric activity of 302 mmol sulfate reduced per liter per day and a specific activity of 110 mmol sulfate reduced per gram volatile suspended solids per day. Biomass grew in 15 days from 0.2 to 4 g volatile suspended solids per liter. This study shows that it is possible to reduce sulfate at pH 6 with formate as electron donor at a high volumetric and specific activity with inocula from full-scale industrial wastewater treatment bioreactors operated at neutral pH. The combination of a membrane bioreactor and a pH-auxostat is a useful research tool to study processes with unknown growth rates at maximum activities.
Low pH (6, 5, and 4) sulfate reduction during the acidification of sucrose under thermophilic (55°C) conditions
Lopes, S.I.C. ; Sulistyawati, I. ; Capela, M.I. ; Lens, P.N.L. - \ 2007
Process Biochemistry 42 (2007)4. - ISSN 1359-5113 - p. 580 - 591.
propionic-acid accumulation - granular sludge reactors - anaerobic-digestion processes - reducing bacteria - waste-water - acidogenic phase - hydrogen-production - sulfide toxicity - methanol degradation - growth
The effect of a low pH (6, 5 and 4) and different COD/SO42¿ ratios (9 and 3.5) on thermophilic (55 °C) sulfate reduction and acidification of sucrose was investigated using three upflow anaerobic sludge bed reactors fed with sucrose at an organic loading rate of 3.5 gCOD (lreactor d)¿1. The three reactors showed nearly 100% acidification of sucrose for all pH values and COD/SO42¿ ratios investigated. Sulfate reduction was complete at pH 6 and a COD/SO42¿ ratio of 9. At pH 5, sulfate reduction efficiencies were 80¿95% for both COD/SO42¿ ratios (9 and 3.5). At pH 4, sulfate reduction efficiencies further dropped to 55¿65% at a COD/SO42¿ ratio of 9 and 30¿40% at a COD/SO42¿ ratio of 3.5. The pH decrease from 6 to 5 or 4 caused a shift in the acidification products from mainly acetate to butyrate, as well as a higher production of ethanol, especially at pH 4. At pH 4, propionate and methane were not formed and hydrogen concentrations in the biogas reached 50%, equivalent to a hydrogen yield of 1.3 mol H2 (mol glucose)¿1. This study shows that sulfate reduction is possible in the acidification phase of anaerobic wastewater treatment at pH values as low as 6 till 4 and that the pH strongly affects both the acidification pathways and the sulfate reduction efficiencies.
Effect of COD/SO42- ratio and sulfide on thermophilic (55°C) sulfate reduction during the acidification of sucrose at pH 6
Lopes, S.I.C. ; Wang, X. ; Capela, M.I. ; Lens, P.N.L. - \ 2007
Water Research 41 (2007)11. - ISSN 0043-1354 - p. 2379 - 2392.
granular sludge reactors - volatile fatty-acid - anaerobic-digestion - reducing bacteria - waste-water - acidogenic phase - degradation - propionate - velocity - hydrogen
This study investigated the effect of the COD/SO42¿ ratio (4 and 1) and the sulfide concentration on the performance of thermophilic (55 °C) acidifying (pH 6) upflow anaerobic sludge bed reactors fed with sucrose at an organic loading rate of 4.5 g COD lreactor¿1 day¿1. Sulfate reduction efficiencies amounted to 65% and 25¿35% for the COD/SO42¿ ratios of 4 and 1, respectively. Acidification was complete at all the tested conditions and the electron flow was similar at the two COD/SO42¿ ratios applied. The stepwise decrease of the sulfide concentrations in the reactors with a COD/SO42¿ ratio of 1 by N2 stripping caused an immediate stepwise increase in the sulfate reduction efficiencies, indicating a reversible inhibition by sulfide. The degree of reversibility was, however, affected by the growth conditions of the sludge. Acidifying sludge pre-grown at pH 6, at a COD/SO42¿ ratio of 9 and exposed for 150 days to 115 mg l¿1 sulfide, showed a slower recovery from the sulfide inhibition than a freshly harvested sludge from a full scale treatment plant (pH 7 and COD/SO42¿=9.5) exposed for a 70 days to 200 mg l¿1 sulfide. In the latter case, the decrease of the sulfide concentration from 200 to 45 mg l¿1 (35 mg l¿1 undissociated sulfide) by N2 stripping caused an immediate increase of the sulfate reduction efficiency from 35% to 96%.
H2 enrichment from synthesis gas by Desulfotomaculum carboxydivorans for potential applications in synthesis gas purification and biodesulfurization
Sipma, J. ; Parshina, S.N. ; Osuna, M.B. ; Henstra, A.M. ; Lettinga, G. ; Stams, A.J.M. ; Lens, P.N.L. - \ 2007
Applied Microbiology and Biotechnology 76 (2007)2. - ISSN 0175-7598 - p. 339 - 347.
biological sulfate reduction - carbon-monoxide conversion - thermophilic sulfate - reducing bacteria - hydrogen - reactor - growth - energy - co2 - bioreactor
Desulfotomaculum carboxydivorans, recently isolated from a full-scale anaerobic wastewater treatment facility, is a sulfate reducer capable of hydrogenogenic growth on carbon monoxide (CO). In the presence of sulfate, the hydrogen formed is used for sulfate reduction. The organism grows rapidly at 200 kPa CO, pH 7.0, and 55 degrees C, with a generation time of 100 min, producing nearly equimolar amounts of H-2 and CO2 from CO and H2O. The high specific CO conversion rates, exceeding 0.8 mol CO (g protein)(-1) h(-1), makes this bacterium an interesting candidate for a biological alternative of the currently employed chemical catalytic water-gas shift reaction to purify synthesis gas (contains mainly H-2, CO, and CO2). Furthermore, as D. carboxydivorans is capable of hydrogenotrophic sulfate reduction at partial CO pressures exceeding 100 kPa, it is also a good candidate for biodesulfurization processes using synthesis gas as electron donor at elevated temperatures, e.g., in biological flue gas desulfurization. Although high maximal specific sulfate reduction rates (32 mmol (g protein)(-1) h(-1)) can be obtained, its sulfide tolerance is rather low and pH dependent, i.e., maximally 9 and 5 mM sulfide at pH 7.2 and pH 6.5, respectively.