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Author |
Ilgrande, C.; Mastroleo, F.; Christiaens, M.E.R.; Lindeboom, R.E.F.; Prat, D.; Van Hoey, O.; Ambrozova, I.; Coninx, I.; Heylen, W.; Pommerening-Roser, A.; Spieck, E.; Boon, N.; Vlaeminck, S.E.; Leys, N.; Clauwaert, P. |
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Title |
Reactivation of microbial strains and synthetic communities after a spaceflight to the International Space Station : corroborating the feasibility of essential conversions in the MELiSSA Loop |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
Astrobiology |
Abbreviated Journal |
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Volume |
19 |
Issue |
9 |
Pages |
1167-1176 |
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Keywords |
A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
To sustain human deep space exploration or extra-terrestrial settlements where no resupply from the Earth or other planets is possible, technologies for in situ food production, water, air, and waste recovery need to be developed. The Micro-Ecological Life Support System Alternative (MELiSSA) is such a Regenerative Life Support System (RLSS) and it builds on several bacterial bioprocesses. However, alterations in gravity, temperature, and radiation associated with the space environment can affect survival and functionality of the microorganisms. In this study, representative strains of different carbon and nitrogen metabolisms with application in the MELiSSA were selected for launch and Low Earth Orbit (LEO) exposure. An edible photoautotrophic strain (Arthrospira sp. PCC 8005), a photoheterotrophic strain (Rhodospirillum rubrum S1H), a ureolytic heterotrophic strain (Cupriavidus pinatubonensis 1245), and combinations of C. pinatubonensis 1245 and autotrophic ammonia and nitrite oxidizing strains (Nitrosomonas europaea ATCC19718, Nitrosomonas ureae Nm10, and Nitrobacter winogradskyi Nb255) were sent to the International Space Station (ISS) for 7 days. There, the samples were exposed to 2.8 mGy, a dose 140 times higher than on the Earth, and a temperature of 22 degrees C +/- 1 degrees C. On return to the Earth, the cultures were reactivated and their growth and activity were compared with terrestrial controls stored under refrigerated (5 degrees C +/- 2 degrees C) or room temperature (22 degrees C +/- 1 degrees C and 21 degrees C +/- 0 degrees C) conditions. Overall, no difference was observed between terrestrial and ISS samples. Most cultures presented lower cell viability after the test, regardless of the type of exposure, indicating a harsher effect of the storage and sample preparation than the spaceflight itself. Postmission analysis revealed the successful survival and proliferation of all cultures except for Arthrospira, which suffered from the premission depressurization test. These observations validate the possibility of launching, storing, and reactivating bacteria with essential functionalities for microbial bioprocesses in RLSS. |
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Wos |
000475278300001 |
Publication Date |
2019-06-04 |
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Series Issue |
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Edition |
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ISSN |
1557-8070; 1531-1074 |
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UA library record; WoS full record; WoS citing articles |
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no |
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Call Number  |
UA @ admin @ c:irua:161342 |
Serial |
8456 |
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Author |
Christiaens, M.E.R.; De Paepe, J.; Ilgrande, C.; De Vrieze, J.; Barys, J.; Teirlinck, P.; Meerbergen, K.; Lievens, B.; Boon, N.; Clauwaert, P.; Vlaeminck, S.E. |
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Title |
Urine nitrification with a synthetic microbial community |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
Systematic and applied microbiology |
Abbreviated Journal |
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Volume |
42 |
Issue |
6 |
Pages |
Unsp 126021 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
During long-term extra-terrestrial missions, food is limited and waste is generated. By recycling valuable nutrients from this waste via regenerative life support systems, food can be produced in space. Astronauts' urine can, for instance, be nitrified by micro-organisms into a liquid nitrate fertilizer for plant growth in space. Due to stringent conditions in space, microbial communities need to be be defined (gnotobiotic); therefore, synthetic rather than mixed microbial communities are preferred. For urine nitrification, synthetic communities face challenges, such as from salinity, ureolysis, and organics. In this study, a synthetic microbial community containing an AOB (Nitrosomonas europaea), NOB (Nitrobacter winogradskyi), and three ureolytic heterotrophs (Pseudomonas fluorescens, Acidovorax delafieldii, and Delftia acidovorans) was compiled and evaluated for these challenges. In reactor 1, salt adaptation of the ammonium-fed AOB and NOB co-culture was possible up to 45 mS cm(-1), which resembled undiluted nitrified urine, while maintaining a 44 +/- 10 mg NH4+-N L-1 d(-1) removal rate. In reactor 2, the nitrifiers and ureolytic heterotrophs were fed with urine and achieved a 15 +/- 6 mg NO3--N L-1 d(-1) production rate for 1% and 10% synthetic and fresh real urine, respectively. Batch activity tests with this community using fresh real urine even reached 29 +/- 3 mg N L-1 d(-1). Organics removal in the reactor (69 +/- 15%) should be optimized to generate a nitrate fertilizer for future space applications. (C) 2019 Elsevier GmbH. All rights reserved. |
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Wos |
000494650600006 |
Publication Date |
2019-09-23 |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0723-2020; 1618-0984 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Open Access |
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no |
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Call Number |
UA @ admin @ c:irua:164650 |
Serial |
8717 |
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Author |
Ilgrande, C.; Defoirdt, T.; Vlaeminck, S.E.; Boon, N.; Clauwaert, P. |
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Title |
Media optimization, strain compatibility, and low-shear modeled microgravity exposure of synthetic microbial communities for urine nitrification in regenerative life-support systems |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
Astrobiology |
Abbreviated Journal |
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Volume |
19 |
Issue |
11 |
Pages |
1353-1362 |
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Keywords |
A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
Urine is a major waste product of human metabolism and contains essential macro- and micronutrients to produce edible microorganisms and crops. Its biological conversion into a stable form can be obtained through urea hydrolysis, subsequent nitrification, and organics removal, to recover a nitrate-enriched stream, free of oxygen demand. In this study, the utilization of a microbial community for urine nitrification was optimized with the focus for space application. To assess the role of selected parameters that can impact ureolysis in urine, the activity of six ureolytic heterotrophs (Acidovorax delafieldii, Comamonas testosteroni, Cupriavidus necator, Delftia acidovorans, Pseudomonas fluorescens, and Vibrio campbellii) was tested at different salinities, urea, and amino acid concentrations. The interaction of the ureolytic heterotrophs with a nitrifying consortium (Nitrosomonas europaea ATCC 19718 and Nitrobacter winogradskyi ATCC 25931) was also tested. Lastly, microgravity was simulated in a clinostat utilizing hardware for in-flight experiments with active microbial cultures. The results indicate salt inhibition of the ureolysis at 30 mS cm(-1), while amino acid nitrogen inhibits ureolysis in a strain-dependent manner. The combination of the nitrifiers with C. necator and V. campbellii resulted in a complete halt of the urea hydrolysis process, while in the case of A. delafieldii incomplete nitrification was observed, and nitrite was not oxidized further to nitrate. Nitrate production was confirmed in all the other communities; however, the other heterotrophic strains most likely induced oxygen competition in the test setup, and nitrite accumulation was observed. Samples exposed to low-shear modeled microgravity through clinorotation behaved similarly to the static controls. Overall, nitrate production from urea was successfully demonstrated with synthetic microbial communities under terrestrial and simulated space gravity conditions, corroborating the application of this process in space. |
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Wos |
000492817700004 |
Publication Date |
2019-10-28 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1557-8070; 1531-1074 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:164663 |
Serial |
8215 |
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Author |
Vandekerckhove, T.G.L.; Props, R.; Carvajal-Arroyo, J.M.; Boon, N.; Vlaeminck, S.E. |
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Title |
Adaptation and characterization of thermophilic anammox in bioreactors |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Water Research |
Abbreviated Journal |
Water Res |
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Volume |
172 |
Issue |
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Pages |
115462 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
Anammox, the oxidation of ammonium with nitrite, is a key microbial process in the nitrogen cycle. Under mesophilic conditions (below 40 °C), it is widely implemented to remove nitrogen from wastewaters lacking organic carbon. Despite evidence of the presence of anammox bacteria in high-temperature environments, reports on the cultivation of thermophilic anammox bacteria are limited to a short-term experiment of 2 weeks. This study showcases the adaptation of a mesophilic inoculum to thermophilic conditions, and its characterization. First, an attached growth technology was chosen to obtain the process. In an anoxic fixed-bed biofilm bioreactor (FBBR), a slow linear temperature increase from 38 to over 48 °C (0.05–0.07 °C d−1) was imposed to the community over 220 days, after which the reactor was operated at 48 °C for over 200 days. Maximum total nitrogen removal rates reached up to 0.62 g N L−1 d−1. Given this promising performance, a suspended growth system was tested. The obtained enrichment culture served as inoculum for membrane bioreactors (MBR) operated at 50 °C, reaching a maximum total nitrogen removal rate of 1.7 g N L−1 d−1 after 35 days. The biomass in the MBR had a maximum specific anammox activity of 1.1 ± 0.1 g NH4+-N g−1 VSS d−1, and the growth rate was estimated at 0.075–0.19 d−1. The thermophilic cultures displayed nitrogen stoichiometry ratios typical for mesophilic anammox: 0.93–1.42 g NO2--Nremoved g−1 NH4+-Nremoved and 0.16–0.35 g NO3--Nproduced g−1 NH4+-Nremoved. Amplicon and Sanger sequencing of the 16S rRNA genes revealed a disappearance of the original “Ca. Brocadia” and “Ca. Jettenia” taxa, yielding Planctomycetes members with only 94–95% similarity to “Ca. Brocadia anammoxidans” and “Ca. B. caroliniensis”, accounting for 45% of the bacterial FBBR community. The long-term operation of thermophilic anammox reactors and snapshot views on the nitrogen stoichiometry, kinetics and microbial community open up the development path of thermophilic partial nitritation/anammox. A first economic assessment highlighted that treatment of sludge reject water from thermophilic anaerobic digestion of sewage sludge may become attractive. |
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Wos |
000517663600014 |
Publication Date |
2020-01-10 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0043-1354 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
12.8 |
Times cited |
5 |
Open Access |
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Notes |
; The authors acknowledge (i) the Agency for Innovation by Science and Technology (IWT Flanders) [grant number SB-141205] for funding T.G.L.V., (ii) Ghent University (BOFDOC2015000601) and the Belgian Nuclear Research Centre (SCK.CEN) for funding R.P., (iii) Bart De Gusseme from Farys/UGent for providing the hollow fiber membranes, (iv) Tim Lacoere for performing the DNA extraction and data processing of the Sanger sequencing and 16S rRNA gene amplicon sequencing data, (v) Tim Hendrickx from Paques BV for providing the inoculum, (vi) Bert Bundervoet and Wim Groen in 't Woud from Colsen for the valuable input on the economic assessment and (vii) Joop Colsen, Stijn Van Hulle, Mark Van Loosdrecht, Erik Smolders and Leen De Gelder for their constructive discussions on this work. ; |
Approved |
Most recent IF: 12.8; 2020 IF: 6.942 |
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Call Number |
UA @ admin @ c:irua:165392 |
Serial |
6449 |
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| Permanent link to this record |
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Author |
Vandekerckhove, T.G.L.; Boon, N.; Vlaeminck, S.E. |
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Title |
Pioneering on single-sludge nitrification/denitrification at 50 °C |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Chemosphere |
Abbreviated Journal |
Chemosphere |
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Volume |
252 |
Issue |
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Pages |
126527-10 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
Thermophilic nitrification has been proven in lab-scale bioreactors at 50 °C. The challenge is now to develop a solution for thermophilic nitrogen removal, integrating nitrification with denitrification and aerobic carbon removal. This pioneering study aimed at a single-sludge nitrification/denitrification process at 50 °C, through exposing nitrification in a step by step approach to anoxia and/or organics. Firstly, recurrent anoxia was tolerated by a nitrifying community during long-term membrane bioreactor (MBR) operation (85 days), with high ammonium oxidation efficiencies (>98%). Secondly, five organic carbon sources did not affect thermophilic ammonium and nitrite oxidation rates in three-day aerobic batch flask incubations. Moving to long-term tests with sequencing batch reactors (SBR) and MBR (>250 days), good nitrification performance was obtained at increasing COD/Ninfluent ratios (0, 0.5, 1, 2 and 3). Thirdly, combining nitrification, recurrent anoxia and presence of organic carbon resulted in a nitrogen removal efficiency of 92–100%, with a COD/Nremoved of 4.8 ± 0.6 and a nitrogen removal rate of 50 ± 14 mg N g−1 VSS d−1. Overall, this is the first proof of principle thermophilic nitrifiers can cope with redox fluctuations (aerobic/anoxic) and the aerobic or anoxic presence of organic carbon, can functionally co-exist with heterotrophs and that single-sludge nitrification/denitrification can be achieved. |
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Wos |
000534377000121 |
Publication Date |
2020-03-17 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0045-6535; 1879-1298 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
8.8 |
Times cited |
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Open Access |
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Notes |
; The authors acknowledge (i) the Agency for Innovation by Science and Technology (IWT Flanders) [grant number SB-141205] for funding Tom G.L. Vandekerckhove, (ii) Wouter Peleman and Zoe Pesonen for practical support during their master thesis, (iii) Jolien De Paepe for assisting in the reactor operation, and (iv) Jo De Vrieze and Tim Lacoere for their help with qPCR and 16S rRNA gene amplicon sequencing. ; |
Approved |
Most recent IF: 8.8; 2020 IF: 4.208 |
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Call Number |
UA @ admin @ c:irua:167324 |
Serial |
6581 |
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| Permanent link to this record |
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Author |
Seuntjens, D.; Carvajal Arroyo, J.M.; Van Tendeloo, M.; Chatzigiannidou, I.; Molina, J.; Nop, S.; Boon, N.; Vlaeminck, S.E. |
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Title |
Mainstream partial nitritation/anammox with integrated fixed-film activated sludge : combined aeration and floc retention time control strategies limit nitrate production |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Bioresource Technology |
Abbreviated Journal |
Bioresource Technol |
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Volume |
314 |
Issue |
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Pages |
123711-10 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
Implementation of mainstream partial nitritation/anammox (PN/A) can lead to more sustainable and cost-effective sewage treatment. For mainstream PN/A reactor, an integrated fixed-film activated sludge (IFAS) was operated (26 °C). The effects of floccular aerobic sludge retention time (AerSRT_floc), a novel aeration strategy, and N-loading rate were tested to optimize the operational strategy. The best performance was observed with a low, but sufficient AerSRTfloc (~7d) and continuous aeration with two alternating dissolved oxygen setpoints: 10 min at 0.07–0.13 mg O2 L−1 and 5 min at 0.27–0.43 mg O2 L−1. Nitrogen removal rates were 122 ± 23 mg N L−1 d−1, and removal efficiencies 73 ± 13%. These conditions enabled flocs to act as nitrite sources while the carriers were nitrite sinks, with low abundance of nitrite oxidizing bacteria. The operational strategies in the source-sink framework can serve as a guideline for successful operation of mainstream PN/A reactors. |
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Place of Publication |
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Wos |
000558601200004 |
Publication Date |
2020-06-24 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0960-8524 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
11.4 |
Times cited |
3 |
Open Access |
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Notes |
; D.S. was supported by a Ph.D. grant from the Institute for the Promotion of Innovation by Science and Technology in Flanders (IWTVlaanderen, SB-131769). M.V.T. was supported by a Ph.D. SB Fellowship from the Research Foundation -Flanders (FWO-Vlaanderen, 1S03218N). ; |
Approved |
Most recent IF: 11.4; 2020 IF: 5.651 |
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Call Number |
UA @ admin @ c:irua:170054 |
Serial |
6559 |
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| Permanent link to this record |
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Author |
Kerckhof, F.-M.; Sakarika, M.; Van Giel, M.; Muys, M.; Vermeir, P.; De Vrieze, J.; Vlaeminck, S.E.; Rabaey, K.; Boon, N. |
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Title |
From biogas and hydrogen to microbial protein through co-cultivation of methane and hydrogen oxidizing bacteria |
Type |
A1 Journal article |
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Year |
2021 |
Publication |
Frontiers in Bioengineering and Biotechnology |
Abbreviated Journal |
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Volume |
9 |
Issue |
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Pages |
733753 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
Increasing efforts are directed towards the development of sustainable alternative protein sources among which microbial protein (MP) is one of the most promising. Especially when waste streams are used as substrates, the case for MP could become environmentally favorable. The risks of using organic waste streams for MP production–the presence of pathogens or toxicants–can be mitigated by their anaerobic digestion and subsequent aerobic assimilation of the (filter-sterilized) biogas. Even though methane and hydrogen oxidizing bacteria (MOB and HOB) have been intensively studied for MP production, the potential benefits of their co-cultivation remain elusive. Here, we isolated a diverse group of novel HOB (that were capable of autotrophic metabolism), and co-cultured them with a defined set of MOB, which could be grown on a mixture of biogas and H2/O2. The combination of MOB and HOB, apart from the CH4 and CO2 contained in biogas, can also enable the valorization of the CO2 that results from the oxidation of methane by the MOB. Different MOB and HOB combinations were grown in serum vials to identify the best-performing ones. We observed synergistic effects on growth for several combinations, and in all combinations a co-culture consisting out of both HOB and MOB could be maintained during five days of cultivation. Relative to the axenic growth, five out of the ten co-cultures exhibited 1.1–3.8 times higher protein concentration and two combinations presented 2.4–6.1 times higher essential amino acid content. The MP produced in this study generally contained lower amounts of the essential amino acids histidine, lysine and threonine, compared to tofu and fishmeal. The most promising combination in terms of protein concentration and essential amino acid profile was Methyloparacoccus murrelli LMG 27482 with Cupriavidus necator LMG 1201. Microbial protein from M. murrelli and C. necator requires 27–67% less quantity than chicken, whole egg and tofu, while it only requires 15% more quantity than the amino acid-dense soybean to cover the needs of an average adult. In conclusion, while limitations still exist, the co-cultivation of MOB and HOB creates an alternative route for MP production leveraging safe and sustainably-produced gaseous substrates. |
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Wos |
000697897900001 |
Publication Date |
2021-09-06 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2296-4185 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ admin @ c:irua:180591 |
Serial |
7985 |
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Author |
Faust, V.; van Alen, T.A.; Op den Camp, H.J.M.; Vlaeminck, S.E.; Ganigué, R.; Boon, N.; Udert, K.M. |
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Title |
Ammonia oxidation by novel “Candidatus Nitrosacidococcus urinae” is sensitive to process disturbances at low pH and to iron limitation at neutral pH |
Type |
A1 Journal article |
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Year |
2022 |
Publication |
Water Research X |
Abbreviated Journal |
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Volume |
17 |
Issue |
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Pages |
100157-11 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
Acid-tolerant ammonia-oxidizing bacteria (AOB) can open the door to new applications, such as partial nitritation at low pH. However, they can also be problematic because chemical nitrite oxidation occurs at low pH, leading to the release of harmful nitrogen oxide gases. In this publication, the role of acid-tolerant AOB in urine treatment was explored. On the one hand, the technical feasibility of ammonia oxidation under acidic conditions for source-separated urine with total nitrogen concentrations up to 3.5 g-N L−1 was investigated. On the other hand, the abundance and growth of acid-tolerant AOB at more neutral pH was explored. Under acidic conditions (pH of 5), ammonia oxidation rates of 500 mg-N L−1 d−1 and 10 g-N g-VSS-1 d-1 were observed, despite high concentrations of 15 mg-N L−1 of the AOB-inhibiting compound nitrous acid and low concentration of 0.04 mg-N L−1 of the substrate ammonia. However, ammonia oxidation under acidic conditions was very sensitive to process disturbances. Even short periods of less than 12 h without oxygen or without influent resulted in a complete cessation of ammonia oxidation with a recovery time of up to two months, which is a problem for low maintenance applications such as decentralized treatment. Furthermore, undesirable nitrogen losses of about 10% were observed. Under acidic conditions, a novel AOB strain was enriched with a relative abundance of up to 80%, for which the name “Candidatus (Ca.) Nitrosacidococcus urinae” is proposed. While Nitrosacidococcus members were present only to a small extent (0.004%) in urine nitrification reactors operated at pH values between 5.8 and 7, acid-tolerant AOB were always enriched during long periods without influent, resulting in an uncontrolled drop in pH to as low as 2.5. Long-term experiments at different pH values showed that the activity of “Ca. Nitrosacidococcus urinae” decreased strongly at a pH of 7, where they were also outcompeted by the acid-sensitive AOB Nitrosomonas halophila. The experiment results showed that the decreased activity of “Ca. Nitrosacidococcus urinae” correlated with the limited availability of dissolved iron at neutral pH. |
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Place of Publication |
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Wos |
000877925500001 |
Publication Date |
2022-10-04 |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2589-9147 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ admin @ c:irua:190944 |
Serial |
7124 |
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| Permanent link to this record |
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Author |
Faust, V.; Boon, N.; Ganigué, R.; Vlaeminck, S.E.; Udert, K.M. |
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Title |
Optimizing control strategies for urine nitrification : narrow pH control band enhances process stability and reduces nitrous oxide emissions |
Type |
A1 Journal article |
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Year |
2023 |
Publication |
Frontiers in environmental science |
Abbreviated Journal |
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Volume |
11 |
Issue |
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Pages |
1275152-14 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
Nitrification is well-suited for urine stabilization. No base dosage is required if the pH is controlled within an appropriate operating range by urine feeding, producing an ammonium-nitrate fertilizer. However, the process is highly dependent on the selected pH set-points and is susceptible to process failures such as nitrite accumulation or the growth of acid-tolerant ammonia-oxidizing bacteria. To address the need for a robust and reliable process in decentralized applications, two different strategies were tested: operating a two-position pH controller (inflow on/off) with a narrow pH control band at 6.20/6.25 (∆pH = 0.05, narrow-pH) vs. a wider pH control band at 6.00/6.50 (∆pH = 0.50, wide-pH). These variations in pH also cause variations in the chemical speciation of ammonia and nitrite and, as shown, the microbial production of nitrite. It was hypothesized that the higher fluctuations would result in greater microbial diversity and, thus, a more robust process. The diversity of nitrifiers was higher in the wide-pH reactor, while the diversity of the entire microbiome was similar in both systems. However, the wide-pH reactor was more susceptible to tested process disturbances caused by increasing pH or temperature, decreasing dissolved oxygen, or an influent stop. In addition, with an emission factor of 0.47%, the nitrous oxide (N2O) emissions from the wide-pH reactor were twice as high as the N2O emissions from the narrow-pH reactor, most likely due to the nitrite fluctuations. Based on these results, a narrow control band is recommended for pH control in urine nitrification. |
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Publisher |
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Place of Publication |
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Wos |
001087861500001 |
Publication Date |
2023-10-10 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2296-665x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ admin @ c:irua:199585 |
Serial |
8909 |
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| Permanent link to this record |
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Author |
Carballa, M.; Smits, M.; Etchebehere, C.; Boon, N.; Verstraete, W. |
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Title |
Correlations between molecular and operational parameters in continuous lab-scale anaerobic reactors |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Applied microbiology and biotechnology |
Abbreviated Journal |
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Volume |
89 |
Issue |
2 |
Pages |
303-314 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
In this study, the microbial community characteristics in continuous lab-scale anaerobic reactors were correlated to reactor functionality using the microbial resource management (MRM) approach. Two molecular techniques, denaturing gradient gel electrophoresis (DGGE) and terminal-restriction fragment length polymorphism (T-RFLP), were applied to analyze the bacterial and archaeal communities, and the results obtained have been compared. Clustering analyses showed a similar discrimination of samples with DGGE and T-RFLP data, with a clear separation between the meso- and thermophilic communities. Both techniques indicate that bacterial and mesophilic communities were richer and more even than archaeal and thermophilic communities, respectively. Remarkably, the community composition was highly dynamic for both Bacteria and Archaea, with a rate of change between 30% and 75% per 18 days, also in stable performing periods. A hypothesis to explain the latter in the context of the converging metabolism in anaerobic processes is proposed. Finally, a more even and diverse bacterial community was found to be statistically representative for a well-functioning reactor as evidenced by a low Ripley index and high biogas production. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Wos |
000285872500008 |
Publication Date |
2010-09-27 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0175-7598; 1432-0614 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:85202 |
Serial |
7736 |
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| Permanent link to this record |
