1
|
Allaart MT, Korkontzelos C, Sousa DZ, Kleerebezem R. A novel experimental method to determine substrate uptake kinetics of gaseous substrates applied to the carbon monoxide-fermenting Clostridium autoethanogenum. Biotechnol Bioeng 2024; 121:1325-1335. [PMID: 38265153 DOI: 10.1002/bit.28652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 12/20/2023] [Accepted: 12/22/2023] [Indexed: 01/25/2024]
Abstract
Syngas fermentation has gained momentum over the last decades. The cost-efficient design of industrial-scale bioprocesses is highly dependent on quantitative microbial growth data. Kinetic and stoichiometric models for syngas-converting microbes exist, but accurate experimental validation of the derived parameters is lacking. Here, we describe a novel experimental approach for measuring substrate uptake kinetics of gas-fermenting microbes using the model microorganism Clostridium autoethanogenum. One-hour disturbances of a steady-state chemostat bioreactor with increased CO partial pressures (up to 1.2 bar) allowed for measurement of biomass-specific CO uptake- and CO2 production rates (q CO ${q}_{{CO}}$ ,q CO 2 ${q}_{{{CO}}_{2}}$ ) using off-gas analysis. At a pCO of 1.2 bar, aq CO ${q}_{{CO}}$ of -119 ± 1 mmol g-1 X h-1 was measured. This value is 1.8-3.5-fold higher than previously reported experimental and kinetic modeling results for syngas fermenters. Analysis of the catabolic flux distribution reveals a metabolic shift towards ethanol production at the expense of acetate at pCO ≥ $\ge $ 0.6 atm, likely to be mediated by acetate availability and cellular redox state. We characterized this metabolic shift as acetogenic overflow metabolism. These results provide key mechanistic understanding of the factors steering the product spectrum of CO fermentation in C. autoethanogenum and emphasize the importance of dedicated experimental validation of kinetic parameters.
Collapse
Affiliation(s)
| | | | - Diana Z Sousa
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| |
Collapse
|
2
|
Allaart MT, Fox BB, Nettersheim IHMS, Pabst M, Sousa DZ, Kleerebezem R. Physiological and stoichiometric characterization of ethanol-based chain elongation in the absence of short-chain carboxylic acids. Sci Rep 2023; 13:17370. [PMID: 37833311 PMCID: PMC10576071 DOI: 10.1038/s41598-023-43682-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 09/27/2023] [Indexed: 10/15/2023] Open
Abstract
Hexanoate is a valuable chemical that can be produced by microorganisms that convert short-chain- to medium-chain carboxylic acids through a process called chain elongation. These microorganisms usually produce mixtures of butyrate and hexanoate from ethanol and acetate, but direct conversion of ethanol to hexanoate is theoretically possible. Steering microbial communities to ethanol-only elongation to hexanoate circumvents the need for acetate addition and simplifies product separation. The biological feasibility of ethanol elongation to hexanoate was validated in batch bioreactor experiments with a Clostridium kluyveri-dominated enrichment culture incubated with ethanol, acetate and butyrate in different ratios. Frequent liquid sampling combined with high-resolution off-gas measurements allowed to monitor metabolic behavior. In experiments with an initial ethanol-to-acetate ratio of 6:1, acetate depletion occurred after ± 35 h of fermentation, which triggered a metabolic shift to direct conversion of ethanol to hexanoate despite the availability of butyrate (± 40 mCmol L-1). When only ethanol and no external electron acceptor was supplied, stable ethanol to hexanoate conversion could be maintained until 60-90 mCmol L-1 of hexanoate was produced. After this, transient production of either acetate and butyrate or butyrate and hexanoate was observed, requiring a putative reversal of the Rnf complex. This was not observed before acetate depletion or in presence of low concentrations (40-60 mCmol L-1) of butyrate, suggesting a stabilizing or regulatory role of butyrate or butyrate-related catabolic intermediates. This study sheds light on previously unknown versatility of chain elongating microbes and provides new avenues for optimizing (waste) bioconversion for hexanoate production.
Collapse
Affiliation(s)
| | - Bartholomeus B Fox
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | | | - Martin Pabst
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Diana Z Sousa
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| |
Collapse
|
3
|
Pei R, Vicente-Venegas G, Tomaszewska-Porada A, Van Loosdrecht MCM, Kleerebezem R, Werker A. Visualization of Polyhydroxyalkanoate Accumulated in Waste Activated Sludge. Environ Sci Technol 2023. [PMID: 37474498 PMCID: PMC10399201 DOI: 10.1021/acs.est.3c02381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 07/22/2023]
Abstract
Polyhydroxyalkanoates (PHAs) can be produced with municipal waste activated sludge from biological wastewater treatment processes. Methods of selective fluorescent staining with confocal laser scanning microscopy (CLSM) were developed and optimized to evaluate the distribution of PHA storage activity in this mixed culture activated sludge microbial communities. Selective staining methods were applied to a municipal activated sludge during pilot scale PHA accumulation in replicate experiments. Visualization of stained flocs revealed that a significant but limited fraction of the biomass was engaged with PHA accumulation. Accumulated PHA granules were furthermore heterogeneously distributed within and between flocs. These observations suggested that the PHA content for the bacteria storing PHAs was significantly higher than the average PHA content measured for the biomass as a whole. Optimized staining methods provided high acuity for imaging of PHA distribution when compared to other methods reported in the literature. Selective staining methods were sufficient to resolve and distinguish between distinctly different morphotypes in the biomass, and these observations of distinctions have interpreted implications for PHA recovery methods. Visualization tools facilitate meaningful insights for advancements of activated sludge processes where systematic observations, as applied in the present work, can reveal underlying details of structure-function relationships.
Collapse
Affiliation(s)
- Ruizhe Pei
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA Leeuwarden, The Netherlands
| | - Gerard Vicente-Venegas
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA Leeuwarden, The Netherlands
| | - Agnieszka Tomaszewska-Porada
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA Leeuwarden, The Netherlands
| | - Mark C M Van Loosdrecht
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Alan Werker
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA Leeuwarden, The Netherlands
| |
Collapse
|
4
|
Pei R, Tarek-Bahgat N, Van Loosdrecht MCM, Kleerebezem R, Werker AG. Influence of environmental conditions on accumulated polyhydroxybutyrate in municipal activated sludge. Water Res 2023; 232:119653. [PMID: 36758350 DOI: 10.1016/j.watres.2023.119653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 01/14/2023] [Accepted: 01/19/2023] [Indexed: 06/18/2023]
Abstract
Poly(3-hydroxybutyrate) (PHB) was accumulated in full-scale municipal waste activated sludge at pilot scale. After accumulation, the fate of the PHB-rich biomass was evaluated over two weeks as a function of initial pH (5.5, 7.0 and 10), and incubation temperature (25, 37 and 55°C), with or without aeration. PHB became consumed under aerobic conditions as expected with first order rate constants in the range of 0.19 to 0.55 d-1. Under anaerobic conditions, up to 63 percent of the PHB became consumed within the first day (initial pH 7, 55°C). Subsequently, with continued anaerobic conditions, the polymer content remained stable in the biomass. Degradation rates were lower for acidic anaerobic incubation conditions at a lower temperature (25°C). Polymer thermal properties were measured in the dried PHB-rich biomass and for the polymer recovered by solvent extraction using dimethyl carbonate. PHB quality changes in dried biomass, indicated by differences in polymer melt enthalpy, correlated to differences in the extent of PHB extractability. Differences in the expressed PHB-in-biomass melt enthalpy that correlated to the polymer extractability suggested that yields of polymer recovery by extraction can be influenced by the state or quality of the polymer generated during downstream processing. Different post-accumulation process biomass management environments were found to influence the polymer quality and can also influence the extraction of non-polymer biomass. An acidic post-accumulation environment resulted in higher melt enthalpies in the biomass and, consequently, higher extraction efficiencies. Overall, acidic environmental conditions were found to be favourable for preserving both quantity and quality after PHB accumulation in activated sludge.
Collapse
Affiliation(s)
- R Pei
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, The Netherlands; Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, The Netherlands.
| | - N Tarek-Bahgat
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, The Netherlands
| | - M C M Van Loosdrecht
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| | - R Kleerebezem
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| | - A G Werker
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, The Netherlands
| |
Collapse
|
5
|
Allaart MT, Diender M, Sousa DZ, Kleerebezem R. Overflow metabolism at the thermodynamic limit of life: How carboxydotrophic acetogens mitigate carbon monoxide toxicity. Microb Biotechnol 2023; 16:697-705. [PMID: 36632026 PMCID: PMC10034630 DOI: 10.1111/1751-7915.14212] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 11/29/2022] [Accepted: 01/01/2023] [Indexed: 01/13/2023] Open
Abstract
Carboxydotrophic metabolism is gaining interest due to its applications in gas fermentation technology, enabling the conversion of carbon monoxide to fuels and commodities. Acetogenic carboxydotrophs play a central role in current gas fermentation processes. In contrast to other energy-rich microbial substrates, CO is highly toxic, which makes it a challenging substrate to utilize. Instantaneous scavenging of CO upon entering the cell is required to mitigate its toxicity. Experiments conducted with Clostridium autoethanogenum at different biomass-specific growth rates show that elevated ethanol production occurs at increasing growth rates. The increased allocation of electrons towards ethanol at higher growth rates strongly suggests that C. autoethanogenum employs a form of overflow metabolism to cope with high dissolved CO concentrations. We argue that this overflow branch enables acetogens to efficiently use CO at highly variable substrate influxes by increasing the conversion rate almost instantaneously when required to remove toxic substrate and promote growth. In this perspective, we will address the case study of C. autoethanogenum grown solely on CO and syngas mixtures to assess how it employs acetate reduction to ethanol as a form of overflow metabolism.
Collapse
Affiliation(s)
| | - Martijn Diender
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Diana Z Sousa
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| |
Collapse
|
6
|
Vermeer CM, Depaz L, van den Berg E, Koelmans T, Kleerebezem R. Production of medium-chain-length PHA in octanoate-fed enrichments dominated by Sphaerotilus sp. Biotechnol Bioeng 2023; 120:687-701. [PMID: 36515096 DOI: 10.1002/bit.28306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 12/01/2022] [Accepted: 12/12/2022] [Indexed: 12/15/2022]
Abstract
Medium-chain-length polyhydroxyalkanoate (mcl-PHA) production by using microbial enrichments is a promising but largely unexplored approach to obtain elastomeric biomaterials from secondary resources. In this study, several enrichment strategies were tested to select a community with a high mcl-PHA storage capacity when feeding octanoate. On the basis of analysis of the metabolic pathways, the hypothesis was formulated that mcl-PHA production is more favorable under oxygen-limited conditions than short-chain-length PHA (scl-PHA). This hypothesis was confirmed by bioreactor experiments showing that oxygen limitation during the PHA accumulation experiments resulted in a higher fraction of mcl-PHA over scl-PHA (i.e., a PHA content of 76 wt% with an mcl fraction of 0.79 with oxygen limitation, compared to a PHA content of 72 wt% with an mcl-fraction of 0.62 without oxygen limitation). Physicochemical analysis revealed that the extracted PHA could be separated efficiently into a hydroxybutyrate-rich fraction with a higher Mw and a hydroxyhexanoate/hydroxyoctanoate-rich fraction with a lower Mw . The ratio between the two fractions could be adjusted by changing the environmental conditions, such as oxygen availability and pH. Almost all enrichments were dominated by Sphaerotilus sp. This is the first scientific report that links this genus to mcl-PHA production, demonstrating that microbial enrichments can be a powerful tool to explore mcl-PHA biodiversity and to discover novel industrially relevant strains.
Collapse
Affiliation(s)
- Chris M Vermeer
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Lena Depaz
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Emily van den Berg
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Tom Koelmans
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| |
Collapse
|
7
|
Estévez-Alonso Á, Arias-Buendía M, Pei R, van Veelen HPJ, van Loosdrecht MCM, Kleerebezem R, Werker A. Calcium enhances polyhydroxyalkanoate production and promotes selective growth of the polyhydroxyalkanoate-storing biomass in municipal activated sludge. Water Res 2022; 226:119259. [PMID: 36323202 DOI: 10.1016/j.watres.2022.119259] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 10/05/2022] [Accepted: 10/14/2022] [Indexed: 06/16/2023]
Abstract
Activated sludge from municipal wastewater treatment processes can be used directly for the production of biodegradable polyesters from the family of polyhydroxyalkanoates (PHAs). However, municipal activated sludge typically cannot accumulate PHAs to very high levels and often low yields of polymer produced on substrate are observed. In the present work, it was found that the presence of calcium promotes selective growth and enrichment of the PHA-storing biomass fraction and significantly improved both PHA contents and yields. Calcium addition resulted in PHA contents of 0.60 ± 0.03 gPHA/gVSS and average PHA yields on substrate of 0.49 ± 0.03 gCODPHA/gCODHAc compared to 0.35 ± 0.01 gPHA/gVSS and 0.19 ± 0.01 gCODPHA/gCODHAc without calcium addition. After 48 h, three times more PHA was produced compared to control experiments without calcium addition. Higher PHA content and selective biomass production is proposed to be a consequence of calcium dependent increased levels of passive acetate uptake. Such more efficient substrate uptake could be related to a formation of calcium acetate complexes. Findings lead to bioprocess methods to stimulate a short-term selective growth of PHA-storing microorganisms and this enables improvements to the techno-economic feasibility for municipal waste activated sludge to become a generic resource for industrial scale PHA production.
Collapse
Affiliation(s)
- Ángel Estévez-Alonso
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands; Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, The Netherlands.
| | - María Arias-Buendía
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, The Netherlands
| | - Ruizhe Pei
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands; Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, The Netherlands
| | - H Pieter J van Veelen
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, The Netherlands
| | - Mark C M van Loosdrecht
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Alan Werker
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, The Netherlands
| |
Collapse
|
8
|
Estévez-Alonso Á, Altamira-Algarra B, Arnau-Segarra C, van Loosdrecht MCM, Kleerebezem R, Werker A. Process conditions affect properties and outcomes of polyhydroxyalkanoate accumulation in municipal activated sludge. Bioresour Technol 2022; 364:128035. [PMID: 36182016 DOI: 10.1016/j.biortech.2022.128035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 09/19/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
The developments of mixed culture polyhydroxyalkanoate production has been directed to maximize the biomass PHA content with limited attention to polymer quality. Direct comparison of PHA accumulation literature is challenging, and even regularly contradicting in reported results, due to underlying differences that are not well expressed. A study was undertaken to systematically compare the commonly reported process conditions for PHA accumulation by full-scale municipal activated sludge. A biomass acclimation step combined with a pulse-wise feeding strategy resulted in maximum average PHA contents and product yields. pH control and active nitrification did not result in observable effects on the PHA productivity. Under these conditions a high molecular weight polymer (1536 ± 221 kDa) can be produced. Polymer extraction recoveries were influenced by the PHA molecular weight. A standard protocol for an activated sludge PHA accumulation test including downstream processing and standardized extraction has been developed and is available as supplementary material.
Collapse
Affiliation(s)
- Ángel Estévez-Alonso
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands; Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911, MA, Leeuwarden, The Netherlands.
| | - Beatriz Altamira-Algarra
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911, MA, Leeuwarden, The Netherlands
| | - César Arnau-Segarra
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911, MA, Leeuwarden, The Netherlands
| | - Mark C M van Loosdrecht
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Alan Werker
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911, MA, Leeuwarden, The Netherlands
| |
Collapse
|
9
|
Pei R, Estévez-Alonso Á, Ortiz-Seco L, van Loosdrecht MCM, Kleerebezem R, Werker A. Exploring the Limits of Polyhydroxyalkanoate Production by Municipal Activated Sludge. Environ Sci Technol 2022; 56:11729-11738. [PMID: 35900322 PMCID: PMC9387092 DOI: 10.1021/acs.est.2c03043] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 07/18/2022] [Accepted: 07/19/2022] [Indexed: 06/01/2023]
Abstract
Municipal activated sludge can be used for polyhydroxyalkanoate (PHA) production, when supplied with volatile fatty acids. In this work, standardized PHA accumulation assays were performed with different activated sludge to determine (1) the maximum biomass PHA content, (2) the degree of enrichment (or volume-to-volume ratio of PHA-accumulating bacteria with respect to the total biomass), and (3) the average PHA content in the PHA-storing biomass fraction. The maximum attained biomass PHA content with different activated sludge ranged from 0.18 to 0.42 gPHA/gVSS, and the degree of enrichment ranged from 0.16 to 0.51 volume/volume. The average PHA content within the PHA-accumulating biomass fraction was relatively constant and independent of activated sludge source, with an average value of 0.58 ± 0.07 gPHA/gVSS. The degree of enrichment for PHA-accumulating bacteria was identified as the key factor to maximize PHA content when municipal activated sludge is directly used for PHA accumulation. Future optimization should focus on obtaining a higher degree of enrichment of PHA-accumulating biomass, either through selection during wastewater treatment or by selective growth during PHA accumulation. A PHA content in the order of 0.6 g PHA/g VSS is a realistic target to be achieved when using municipal activated sludge for PHA production.
Collapse
Affiliation(s)
- Ruizhe Pei
- Department
of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
- Wetsus, European
Centre of Excellence for Sustainable Water
Technology, Oostergoweg 9, 8911 MA Leeuwarden, The Netherlands
| | - Ángel Estévez-Alonso
- Department
of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
- Wetsus, European
Centre of Excellence for Sustainable Water
Technology, Oostergoweg 9, 8911 MA Leeuwarden, The Netherlands
| | - Laura Ortiz-Seco
- Wetsus, European
Centre of Excellence for Sustainable Water
Technology, Oostergoweg 9, 8911 MA Leeuwarden, The Netherlands
| | - Mark C. M. van Loosdrecht
- Department
of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Robbert Kleerebezem
- Department
of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Alan Werker
- Wetsus, European
Centre of Excellence for Sustainable Water
Technology, Oostergoweg 9, 8911 MA Leeuwarden, The Netherlands
| |
Collapse
|
10
|
Pei R, Vicente-Venegas G, Van Loosdrecht MCM, Kleerebezem R, Werker A. Quantification of polyhydroxyalkanoate accumulated in waste activated sludge. Water Res 2022; 221:118795. [PMID: 35785696 DOI: 10.1016/j.watres.2022.118795] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 06/23/2022] [Accepted: 06/24/2022] [Indexed: 06/15/2023]
Abstract
Polyhydroxyalkanoate accumulation experiments at pilot scale were performed with fullscale municipal waste activated sludge. Development of biomass PHA content was quantified by thermogravimetric analysis. Over 48 h the biomass reached up to 0.49 ± 0.03 gPHA/gVSS (n=4). Samples were processed in parallel to characterise the distribution of PHA in the biomass. Selective staining methods and image analysis were performed by Confocal Laser Scanning Microscopy. The image analysis indicated that nominally 55% of this waste activated sludge was engaged in PHA storage activity. Thus even if the biomass PHA content reached 0.49gPHA/gVSS, the accumulating fraction of the biomass was estimated to have attained about 0.64gPHA/gVSS. The combination of quantitative microscopy and polymer mass assessment enabled to distinguish the effect of level of enrichment in PHA storing bacteria and the average PHA storage capacity of the accumulating bacteria. The distribution of microbial 16S rRNA levels did not follow a measurable trend during PHA accumulation.
Collapse
Affiliation(s)
- Ruizhe Pei
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, Delft 2629 HZ, the Netherlands; Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, Leeuwarden 8911 MA, the Netherlands.
| | - Gerard Vicente-Venegas
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, Leeuwarden 8911 MA, the Netherlands
| | - Mark C M Van Loosdrecht
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, Delft 2629 HZ, the Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, Delft 2629 HZ, the Netherlands
| | - Alan Werker
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, Leeuwarden 8911 MA, the Netherlands
| |
Collapse
|
11
|
Vermeer CM, Bons LJ, Kleerebezem R. Production of a newly discovered PHA family member with an isobutyrate-fed enrichment culture. Appl Microbiol Biotechnol 2022; 106:605-618. [PMID: 34985570 PMCID: PMC8763783 DOI: 10.1007/s00253-021-11742-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 12/07/2021] [Accepted: 12/12/2021] [Indexed: 11/26/2022]
Abstract
Abstract Using microbial enrichment cultures for the production of waste-derived polyhydroxyalkanoates (PHAs) is a promising technology to recover secondary resources. Volatile fatty acids (VFAs) form the preferred substrate for PHA production. Isobutyrate is a VFA appearing in multiple waste valorization routes, such as anaerobic fermentation, chain elongation, and microbial electrosynthesis, but has never been assessed individually on its PHA production potential. This research investigates isobutyrate as sole carbon source for a microbial enrichment culture in comparison to its structural isomer butyrate. The results reveal that the enrichment of isobutyrate has a very distinct character regarding microbial community development, PHA productivity, and even PHA composition. Although butyrate is a superior substrate in almost every aspect, this research shows that isobutyrate-rich waste streams have a noteworthy PHA-producing potential. The main finding is that the dominant microorganism, a Comamonas sp., is linked to the production of a unique PHA family member, poly(3-hydroxyisobutyrate) (PHiB), up to 37% of the cell dry weight. This is the first scientific report identifying microbial PHiB production, demonstrating that mixed microbial communities can be a powerful tool for discovery of new metabolic pathways and new types of polymers. Key points • PHiB production is a successful storage strategy in an isobutyrate-fed SBR • Isomers isobutyrate and butyrate reveal a very distinct PHA production behavior • Enrichments can be a tool for discovery of new metabolic pathways and polymers Graphical abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1007/s00253-021-11742-9.
Collapse
Affiliation(s)
- Chris M Vermeer
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, The Netherlands.
| | - Larissa J Bons
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| |
Collapse
|
12
|
Estévez-Alonso Á, van Loosdrecht MCM, Kleerebezem R, Werker A. Simultaneous nitrification and denitrification in microbial community-based polyhydroxyalkanoate production. Bioresour Technol 2021; 337:125420. [PMID: 34175767 DOI: 10.1016/j.biortech.2021.125420] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 06/11/2021] [Accepted: 06/12/2021] [Indexed: 06/13/2023]
Abstract
Microbial community-based polyhydroxyalkanoate (PHA) production has been demonstrated repeatedly at pilot scale. Ammonium, normally present in waste streams, might be oxidized by nitrifying bacteria resulting in additional aeration energy demand. The use of low dissolved oxygen (DO) concentrations allowed to reduce nitrifying rates by up to 70% compared to non-oxygen limiting conditions. At lower DO concentrations nitrate was used as alternative electron acceptor for PHA production and therefore, a constant PHA production rate could only be maintained if nitrate was sufficiently available. An optimum DO concentration (0.9 mgO2/L) was found for which nitrification was mitigated but also exploited to supply requisite heterotrophic nitrate requirements that maintained maximum PHA production rates. PHA accumulations with such DO control was estimated to reduce oxygen demand by about 18%. This work contributes to establish fundamental insight towards viable industrial practice with the control and exploitation of nitrifying bacteria in microbial community-based PHA production.
Collapse
Affiliation(s)
- Ángel Estévez-Alonso
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands; Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, The Netherlands.
| | - Mark C M van Loosdrecht
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Alan Werker
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, The Netherlands
| |
Collapse
|
13
|
Mulders M, Tamis J, Stouten GR, Kleerebezem R. Simultaneous growth and poly(3-hydroxybutyrate) (PHB) accumulation in a Plasticicumulans acidivorans dominated enrichment culture. J Biotechnol 2021; 324S:100027. [PMID: 34154735 DOI: 10.1016/j.btecx.2020.100027] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 09/20/2020] [Accepted: 10/06/2020] [Indexed: 11/29/2022]
Abstract
The wide variety of organic carbon to nitrogen and phosphorous ratios that are encountered in different wastewaters has a major impact on the poly(3-hydroxybutyrate) (PHB) accumulation potential of microbial communities. In this study we investigated the influence of the substrate composition in terms of the carbon to nitrogen (C/N) or phosphorus (C/P) ratio on the PHB accumulation performance. A multi-reactor set-up was used, enabling parallel experiments using identical inoculum of an enrichment culture dominated by Plasticicumulans acidivorans. In all experiments simultaneous PHB production and growth was observed. Generally, when trace amounts of growth nutrients were present the PHB production yield on substrate remained high for at least 12 h. Interestingly, from the carbon to nutrient ratio in the substrate, the PHB wt% could be accurately predicted in the accumulations. This study demonstrates that strict uncoupling of microbial growth and PHA accumulation is not required for achieving high cellular PHA-contents. Herewith the range of wastewaters that enable a cellular PHA content of 80 % or higher for at least 12 h is expanded to C:N and C:P-ratios exceeding COD:N of 26 gCOD:gNH4-N and COD:P of 511 gCOD:gPO4-P respectively.
Collapse
Affiliation(s)
- Michel Mulders
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands.
| | - Jelmer Tamis
- Paques BV, Tjalke de Boerstritte 24, 8561 EL, Balk, the Netherlands
| | - Gerben Roelandt Stouten
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands
| |
Collapse
|
14
|
Allaart MT, Stouten GR, Sousa DZ, Kleerebezem R. Product Inhibition and pH Affect Stoichiometry and Kinetics of Chain Elongating Microbial Communities in Sequencing Batch Bioreactors. Front Bioeng Biotechnol 2021; 9:693030. [PMID: 34235138 PMCID: PMC8256265 DOI: 10.3389/fbioe.2021.693030] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 05/25/2021] [Indexed: 11/13/2022] Open
Abstract
Anaerobic microbial communities can produce carboxylic acids of medium chain length (e.g., caproate, caprylate) by elongating short chain fatty acids through reversed β-oxidation. Ethanol is a common electron donor for this process. The influence of environmental conditions on the stoichiometry and kinetics of ethanol-based chain elongation remains elusive. Here, a sequencing batch bioreactor setup with high-resolution off-gas measurements was used to identify the physiological characteristics of chain elongating microbial communities enriched on acetate and ethanol at pH 7.0 ± 0.2 and 5.5 ± 0.2. Operation at both pH-values led to the development of communities that were highly enriched (>50%, based on 16S rRNA gene amplicon sequencing) in Clostridium kluyveri related species. At both pH-values, stably performing cultures were characterized by incomplete substrate conversion and decreasing biomass-specific hydrogen production rates during an operational cycle. The process stoichiometries obtained at both pH-values were different: at pH 7.0, 71 ± 6% of the consumed electrons were converted to caproate, compared to only 30 ± 5% at pH 5.5. Operating at pH 5.5 led to a decrease in the biomass yield, but a significant increase in the biomass-specific substrate uptake rate, suggesting that the organisms employ catabolic overcapacity to deal with energy losses associated to product inhibition. These results highlight that chain elongating conversions rely on a delicate balance between substrate uptake- and product inhibition kinetics.
Collapse
Affiliation(s)
| | | | - Diana Z Sousa
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands
| |
Collapse
|
15
|
Estévez-Alonso Á, Pei R, van Loosdrecht MCM, Kleerebezem R, Werker A. Scaling-up microbial community-based polyhydroxyalkanoate production: status and challenges. Bioresour Technol 2021; 327:124790. [PMID: 33582521 DOI: 10.1016/j.biortech.2021.124790] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/22/2021] [Accepted: 01/23/2021] [Indexed: 06/12/2023]
Abstract
Conversion of organic waste and wastewater to polyhydroxyalkanoates (PHAs) offers a potential to recover valuable resources from organic waste. Microbial community-based PHA production systems have been successfully applied in the last decade at lab- and pilot-scales, with a total of 19 pilot installations reported in the scientific literature. In this review, research at pilot-scale on microbial community-based PHA production is categorized and subsequently analyzed with focus on feedstocks, enrichment strategies, yields of PHA on substrate, biomass PHA content and polymer characterization. From this assessment, the challenges for further scaling-up of microbial community-based PHA production are identified.
Collapse
Affiliation(s)
- Ángel Estévez-Alonso
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands; Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, The Netherlands
| | - Ruizhe Pei
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands; Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, The Netherlands
| | - Mark C M van Loosdrecht
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands.
| | - Alan Werker
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, The Netherlands
| |
Collapse
|
16
|
Kleerebezem R, Sousa DZ. Editorial overview: Microbial community engineering. Curr Opin Biotechnol 2021; 67:vi-ix. [PMID: 33745678 DOI: 10.1016/j.copbio.2021.02.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ Delft, The Netherlands.
| | - Diana Z Sousa
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708WE Wageningen, The Netherlands.
| |
Collapse
|
17
|
Stouten GR, Hamers K, van Tatenhove-Pel RJ, van der Knaap E, Kleerebezem R. Seemingly trivial secondary factors may determine microbial competition: a cautionary tale on the impact of iron supplementation through corrosion. FEMS Microbiol Ecol 2021; 97:6081106. [PMID: 33428722 PMCID: PMC7878175 DOI: 10.1093/femsec/fiab002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 01/08/2021] [Indexed: 11/13/2022] Open
Abstract
Microbial community engineering aims for enrichment of a specific microbial trait by imposing specific cultivation conditions. This work demonstrates that things may be more complicated than typically presumed and that microbial competition can be affected by seemingly insignificant variables, like in this case the type of acid used for pH control. Aerobic bioreactors pulse fed with acetate operated with hydrochloric acid resulted in the enrichment of Plasticicumulans acidivorans, and changing the pH controlling agent to sulfuric acid shifted the community towards Zoogloea sp. Further research demonstrated that the change in community structure was not directly caused by the change in acid used for pH control, but resulted from the difference in corrosive strength of both acids and the related iron leaching from the bioreactor piping. Neither system was iron deficient, suggesting that the biological availability of iron is affected by the leaching process. Our results demonstrate that microbial competition and process development can be affected dramatically by secondary factors related to nutrient supply and bioavailability, and is way more complex than generally assumed in a single carbon substrate limited process.
Collapse
Affiliation(s)
- Gerben R Stouten
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| | - Kelly Hamers
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| | - Rinke J van Tatenhove-Pel
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ, Delft, The Netherlands.,Amsterdam Institute for Molecules, Medicines and Systems, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Eline van der Knaap
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| |
Collapse
|
18
|
Abstract
The cyclic nature of specific conversions in the nitrogen cycle imposes strict limitations to the conversions observed in nature and explains for example why anaerobic ammonium oxidation (anammox) bacteria can only use nitrite – and not nitrate – as electron acceptor in catabolism, and why nitrite is required as additional electron donor for inorganic carbon fixation in anabolism. Furthermore, the biochemistry involved in nitrite-dependent anaerobic methane oxidation excludes the feasibility of using nitrate as electron acceptor. Based on the cyclic nature of these nitrogen conversions, we propose two scenarios that may explain the ecological role of recently discovered complete ammonia-oxidizing (comammox) Nitrospira spp., some of which were initially found in a strongly oxygen limited environment: (i) comammox Nitrospira spp. may actually catalyze an anammox-like metabolism using a biochemistry similar to intra-oxic nitrite-dependent methane oxidation, or (ii) scavenge all available oxygen for ammonia activation and use nitrate as terminal electron acceptor. Both scenarios require the presence of the biochemical machinery for ammonia oxidation to nitrate, potentially explaining a specific ecological niche for the occurrence of comammox bacteria in nature.
Collapse
Affiliation(s)
- Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands
| | - Sebastian Lücker
- Department of Microbiology, IWWR, Radboud University, Nijmegen, Netherlands
| |
Collapse
|
19
|
Tamis J, Joosse B, de Leeuw K, Kleerebezem R. High-rate ethanol production at low pH using the anaerobic granular sludge process. Biotechnol Bioeng 2021; 118:1943-1950. [PMID: 33547801 PMCID: PMC8251524 DOI: 10.1002/bit.27708] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 01/15/2021] [Accepted: 01/21/2021] [Indexed: 11/09/2022]
Abstract
In this study, we investigated the operational performance and product spectrum of glucose-fermenting anaerobic granular sludge reactor at pH 4. A selective environment for the growth of granules was implemented by the introduction of a 2 min settling phase, a hydraulic retention time of 6 h and a solid retention time of 12 ± 3 days. The fermentation products were ethanol, lactate, and volatile fatty acids (VFA) with yields of 0.55 ± 0.03, 0.15 ± 0.02, and 0.20 ± 0.04 gram chemical oxygen demand (gCOD)/gCOD glucose, respectively. The obtained product spectrum was remarkably different from the VFA-dominated product spectrum reported in a previous study when the same system was operated at higher pH (4.5-5.5). The shift in product spectrum coincided with a shift in the microbial community structure with the dominance of eukaryotic Candida tropicalis, Pichia jaroonii, and prokaryotic Lactobacillus species instead of the Clostridia species obtained at higher pH-values. The control of the microbiomes and the associated product spectra provides bioprocess engineers with the option to tailor a suitable precursor compound mixture for subsequent chain elongation fermentation or PHA biopolymer production.
Collapse
Affiliation(s)
- Jelmer Tamis
- Department of Emerging Technologies, Paques BV, Balk, The Netherlands.,Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Bart Joosse
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Kasper de Leeuw
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| |
Collapse
|
20
|
Kleerebezem R, Stouten G, Koehorst J, Langenhoff A, Schaap P, Smidt H. Experimental infrastructure requirements for quantitative research on microbial communities. Curr Opin Biotechnol 2021; 67:158-165. [PMID: 33596519 DOI: 10.1016/j.copbio.2021.01.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 01/21/2021] [Indexed: 01/27/2023]
Abstract
Natural microbial communities are composed of a large diversity of interacting microorganisms, each with a specific role in the functional properties of the ecosystem. The objectives in microbial ecology research are related to identifying, understanding and exploring the role of these different microorganisms. Because of the rapidly increasing power of DNA sequencing and the rapid increase of genomic data, main attention of microbial ecology research shifted from cultivation-oriented studies towards metagenomic studies. Despite these efforts, the direct link between the molecular properties and the measurable changes in the functional performance of the ecosystem is often poorly documented. A quantitative understanding of functional properties in relation to the molecular changes requires effective integration, standardization, and parallelization of experiments. High-resolution functional characterization is a prerequisite for interpretation of changes in metagenomic properties, and will improve our understanding of microbial communities and facilitate their exploration for health and circular economy related objectives.
Collapse
Affiliation(s)
- Robbert Kleerebezem
- Delft University of Technology, Department of Biotechnology, Delft, The Netherlands.
| | - Gerben Stouten
- Delft University of Technology, Department of Biotechnology, Delft, The Netherlands
| | - Jasper Koehorst
- Wageningen University and Research, Laboratory of Systems and Synthetic Biology, Wageningen, The Netherlands
| | - Alette Langenhoff
- Wageningen University and Research, Department of Environmental Technology, Wageningen, The Netherlands
| | - Peter Schaap
- Wageningen University and Research, Laboratory of Systems and Synthetic Biology, Wageningen, The Netherlands
| | - Hauke Smidt
- Wageningen University and Research, Laboratory of Microbiology, Wageningen, The Netherlands
| |
Collapse
|
21
|
Moscoviz R, Kleerebezem R, Rombouts JL. Directing carbohydrates toward ethanol using mesophilic microbial communities. Curr Opin Biotechnol 2021; 67:175-183. [PMID: 33588238 DOI: 10.1016/j.copbio.2021.01.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Revised: 01/12/2021] [Accepted: 01/20/2021] [Indexed: 12/14/2022]
Abstract
Bioethanol production is an established biotechnological process. Margins are low which prevent a larger scale production of bioethanol. As a large part of the production cost is due to the feedstock, the use of low value unsterile feedstocks fermented by microbial communities will enable a more cost-competitive bioethanol production. To select for high yield ethanol producing communities, three selective conditions are proposed: acid washing of the cells after fermentation, a low pH (<5) during the fermentation and microaerobiosis at the start of the fermentation. Ethanol producers, such as Zymomonas species and yeasts, compete for carbohydrates with volatile fatty acid and lactic acid producing bacteria. Creating effective consortia of lactic acid bacteria and homo-ethanol producers at low pH will lead to robust and competitive ethanol yields and titres. A conceptual design of an ecology-based bioethanol production process is proposed using food waste to produce bioethanol, electricity, digestate and heat.
Collapse
Affiliation(s)
- Roman Moscoviz
- SUEZ, Centre International de Recherche Sur l'Eau et l'Environnement (CIRSEE), 38 rue du Président Wilson, Le Pecq, France
| | - Robbert Kleerebezem
- Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | | |
Collapse
|
22
|
Regueira A, Rombouts JL, Wahl SA, Mauricio-Iglesias M, Lema JM, Kleerebezem R. Resource allocation explains lactic acid production in mixed-culture anaerobic fermentations. Biotechnol Bioeng 2020; 118:745-758. [PMID: 33073364 DOI: 10.1002/bit.27605] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 09/28/2020] [Accepted: 10/11/2020] [Indexed: 02/04/2023]
Abstract
Lactate production in anaerobic carbohydrate fermentations with mixed cultures of microorganisms is generally observed only in very specific conditions: the reactor should be run discontinuously and peptides and B vitamins must be present in the culture medium as lactic acid bacteria (LAB) are typically auxotrophic for amino acids. State-of-the-art anaerobic fermentation models assume that microorganisms optimise the adenosine triphosphate (ATP) yield on substrate and therefore they do not predict the less ATP efficient lactate production, which limits their application for designing lactate production in mixed-culture fermentations. In this study, a metabolic model taking into account cellular resource allocation and limitation is proposed to predict and analyse under which conditions lactate production from glucose can be beneficial for microorganisms. The model uses a flux balances analysis approach incorporating additional constraints from the resource allocation theory and simulates glucose fermentation in a continuous reactor. This approach predicts lactate production is predicted at high dilution rates, provided that amino acids are in the culture medium. In minimal medium and lower dilution rates, mostly butyrate and no lactate is predicted. Auxotrophy for amino acids of LAB is identified to provide a competitive advantage in rich media because less resources need to be allocated for anabolic machinery and higher specific growth rates can be achieved. The Matlab™ codes required for performing the simulations presented in this study are available at https://doi.org/10.5281/zenodo.4031144.
Collapse
Affiliation(s)
- Alberte Regueira
- CRETUS Institute, Department of Chemical Engineering, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Julius L Rombouts
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - S Aljoscha Wahl
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Miguel Mauricio-Iglesias
- CRETUS Institute, Department of Chemical Engineering, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Juan M Lema
- CRETUS Institute, Department of Chemical Engineering, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| |
Collapse
|
23
|
Ceron-Chafla P, Kleerebezem R, Rabaey K, van Lier JB, Lindeboom REF. Direct and Indirect Effects of Increased CO 2 Partial Pressure on the Bioenergetics of Syntrophic Propionate and Butyrate Conversion. Environ Sci Technol 2020; 54:12583-12592. [PMID: 32845128 PMCID: PMC7547868 DOI: 10.1021/acs.est.0c02022] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Simultaneous digestion and in situ biogas upgrading in high-pressure bioreactors will result in elevated CO2 partial pressure (pCO2). With the concomitant increase in dissolved CO2, microbial conversion processes may be affected beyond the impact of increased acidity. Elevated pCO2 was reported to affect the kinetics and thermodynamics of biochemical conversions because CO2 is an intermediate and end-product of the digestion process and modifies the carbonate equilibrium. Our results showed that increasing pCO2 from 0.3 to 8 bar in lab-scale batch reactors decreased the maximum substrate utilization rate (rsmax) for both syntrophic propionate and butyrate oxidation. These kinetic limitations are linked to an increased overall Gibbs free energy change (ΔGOverall) and a potential biochemical energy redistribution among syntrophic partners, which showed interdependence with hydrogen partial pressure (pH2). The bioenergetics analysis identified a moderate, direct impact of elevated pCO2 on propionate oxidation and a pH-mediated effect on butyrate oxidation. These constraints, combined with physiological limitations on growth exerted by increased acidity and inhibition due to higher concentrations of undissociated volatile fatty acids, help to explain the observed phenomena. Overall, this investigation sheds light on the role of elevated pCO2 in delicate biochemical syntrophic conversions by connecting kinetic, bioenergetic, and physiological effects.
Collapse
Affiliation(s)
- Pamela Ceron-Chafla
- Sanitary
Engineering Section, Department of Water Management, Delft University of Technology, Stevinweg 1, 2628
CN Delft, The Netherlands
| | - Robbert Kleerebezem
- Department
of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, Netherlands
| | - Korneel Rabaey
- Center
for Microbial Ecology and Technology (CMET), Ghent University, Coupure
Links 653, B-9000 Ghent, Belgium
- Center
for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Coupure Links 653, B-9000 Ghent, Belgium
| | - Jules B. van Lier
- Sanitary
Engineering Section, Department of Water Management, Delft University of Technology, Stevinweg 1, 2628
CN Delft, The Netherlands
| | - Ralph E. F. Lindeboom
- Sanitary
Engineering Section, Department of Water Management, Delft University of Technology, Stevinweg 1, 2628
CN Delft, The Netherlands
| |
Collapse
|
24
|
Capson-Tojo G, Batstone DJ, Grassino M, Vlaeminck SE, Puyol D, Verstraete W, Kleerebezem R, Oehmen A, Ghimire A, Pikaar I, Lema JM, Hülsen T. Purple phototrophic bacteria for resource recovery: Challenges and opportunities. Biotechnol Adv 2020; 43:107567. [PMID: 32470594 DOI: 10.1016/j.biotechadv.2020.107567] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 05/11/2020] [Accepted: 05/14/2020] [Indexed: 10/24/2022]
Abstract
Sustainable development is driving a rapid focus shift in the wastewater and organic waste treatment sectors, from a "removal and disposal" approach towards the recovery and reuse of water, energy and materials (e.g. carbon or nutrients). Purple phototrophic bacteria (PPB) are receiving increasing attention due to their capability of growing photoheterotrophically under anaerobic conditions. Using light as energy source, PPB can simultaneously assimilate carbon and nutrients at high efficiencies (with biomass yields close to unity (1 g CODbiomass·g CODremoved-1)), facilitating the maximum recovery of these resources as different value-added products. The effective use of infrared light enables selective PPB enrichment in non-sterile conditions, without competition with other phototrophs such as microalgae if ultraviolet-visible wavelengths are filtered. This review reunites results systematically gathered from over 177 scientific articles, aiming at producing generalized conclusions. The most critical aspects of PPB-based production and valorisation processes are addressed, including: (i) the identification of the main challenges and potentials of different growth strategies, (ii) a critical analysis of the production of value-added compounds, (iii) a comparison of the different value-added products, (iv) insights into the general challenges and opportunities and (v) recommendations for future research and development towards practical implementation. To date, most of the work has not been executed under real-life conditions, relevant for full-scale application. With the savings in wastewater discharge due to removal of organics, nitrogen and phosphorus as an important economic driver, priorities must go to using PPB-enriched cultures and real waste matrices. The costs associated with artificial illumination, followed by centrifugal harvesting/dewatering and drying, are estimated to be 1.9, 0.3-2.2 and 0.1-0.3 $·kgdry biomass-1. At present, these costs are likely to exceed revenues. Future research efforts must be carried out outdoors, using sunlight as energy source. The growth of bulk biomass on relatively clean wastewater streams (e.g. from food processing) and its utilization as a protein-rich feed (e.g. to replace fishmeal, 1.5-2.0 $·kg-1) appears as a promising valorisation route.
Collapse
Affiliation(s)
- Gabriel Capson-Tojo
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD 4072, Australia; CRETUS Institute, Department of Chemical Engineering, School of Engineering, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
| | - Damien J Batstone
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - María Grassino
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - Siegfried E Vlaeminck
- Research Group of Sustainable Energy, Air and Water Technology, Department of Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen, Belgium.
| | - Daniel Puyol
- Department of Chemical and Environmental Technology, ESCET, Rey Juan Carlos University, Móstoles, Spain.
| | - Willy Verstraete
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000 Gent, Belgium; Avecom NV, Industrieweg 122P, 9032 Wondelgem, Belgium.
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, the Netherlands.
| | - Adrian Oehmen
- School of Chemical Engineering, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - Anish Ghimire
- Department of Environmental Science and Engineering, Kathmandu University, Dhulikhel, Nepal.
| | - Ilje Pikaar
- School of Civil Engineering, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - Juan M Lema
- CRETUS Institute, Department of Chemical Engineering, School of Engineering, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
| | - Tim Hülsen
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD 4072, Australia.
| |
Collapse
|
25
|
Rombouts JL, Kranendonk EMM, Regueira A, Weissbrodt DG, Kleerebezem R, van Loosdrecht MCM. Selecting for lactic acid producing and utilising bacteria in anaerobic enrichment cultures. Biotechnol Bioeng 2020; 117:1281-1293. [PMID: 32034763 PMCID: PMC7187302 DOI: 10.1002/bit.27301] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 01/27/2020] [Accepted: 02/07/2020] [Indexed: 01/23/2023]
Abstract
Lactic acid‐producing bacteria are important in many fermentations, such as the production of biobased plastics. Insight in the competitive advantage of lactic acid bacteria over other fermentative bacteria in a mixed culture enables ecology‐based process design and can aid the development of sustainable and energy‐efficient bioprocesses. Here we demonstrate the enrichment of lactic acid bacteria in a controlled sequencing batch bioreactor environment using a glucose‐based medium supplemented with peptides and B vitamins. A mineral medium enrichment operated in parallel was dominated by Ethanoligenens species and fermented glucose to acetate, butyrate and hydrogen. The complex medium enrichment was populated by Lactococcus, Lactobacillus and Megasphaera species and showed a product spectrum of acetate, ethanol, propionate, butyrate and valerate. An intermediate peak of lactate was observed, showing the simultaneous production and consumption of lactate, which is of concern for lactic acid production purposes. This study underlines that the competitive advantage for lactic acid‐producing bacteria primarily lies in their ability to attain a high biomass specific uptake rate of glucose, which was two times higher for the complex medium enrichment when compared to the mineral medium enrichment. The competitive advantage of lactic acid production in rich media can be explained using a resource allocation theory for microbial growth processes.
Collapse
Affiliation(s)
| | | | - Alberte Regueira
- Department of Chemical Engineering, Institute of Technology, Universidade de Santiago Compostela, Santiago de Compostela, Spain
| | | | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | | |
Collapse
|
26
|
Rombouts JL, Mos G, Weissbrodt DG, Kleerebezem R, Van Loosdrecht MCM. The impact of mixtures of xylose and glucose on the microbial diversity and fermentative metabolism of sequencing-batch or continuous enrichment cultures. FEMS Microbiol Ecol 2019; 95:5530754. [PMID: 31291461 DOI: 10.1093/femsec/fiz112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 07/08/2019] [Indexed: 11/14/2022] Open
Abstract
Efficient industrial fermentation of lignocellulosic waste containing a large part of glucose and xylose is desirable to implement a circular economy. Mixed culture biotechnologies can aid in realizing this goal. The effect of feeding equivalent substrates to a microbial community, such a xylose and glucose, is not well understood in terms of the number of dominant species and how these species compete for the substrates. We compared the metabolism and microbial community structure in a continuous-flow stirred tank reactor (CSTR) and a sequencing batch reactor (SBR) fed with a mixture of xylose and glucose, inoculated with bovine rumen at pH 8, 30°C and a hydraulic retention time of 8 h. We hypothesised that a CSTR will select for generalist species, taking up both substrates. We used 16S rRNA gene sequencing and fluorescent in situ hybridisation to accurately determine the microbial community structures. Both enrichments were stoichiometrically and kinetically characterised. The CSTR enrichment culture was dominated by Clostridium intestinale (91% ± 2%). The SBR showed an abundance of Enterobacteriaceae (75% ± 8%), dominated by Citrobacter freundii and a minor fraction of Raoultella ornithinolytica. C. freundii ferments xylose and glucose in a non-diauxic fashion. Clearly, a non-diauxic generalist outcompetes specialists and diauxic generalists in SBR environments.
Collapse
Affiliation(s)
- Julius L Rombouts
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, the Netherlands
| | - Galvin Mos
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, the Netherlands
| | - David G Weissbrodt
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, the Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, the Netherlands
| | - Mark C M Van Loosdrecht
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, the Netherlands
| |
Collapse
|
27
|
Hoekstra M, Geilvoet SP, Hendrickx TLG, van Erp Taalman Kip CS, Kleerebezem R, van Loosdrecht MCM. Towards mainstream anammox: lessons learned from pilot-scale research at WWTP Dokhaven. Environ Technol 2019; 40:1721-1733. [PMID: 29697015 DOI: 10.1080/09593330.2018.1470204] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 04/16/2018] [Indexed: 05/21/2023]
Abstract
The aim of this research was to study the biological feasibility of the Partial Nitritation/Anammox (PN/A) technology to remove nitrogen from municipal mainstream wastewaters. During stable process operations at summer temperatures (23.2 ± 1.3°C), the total nitrogen removal rate was 0.223 ± 0.029 kg N (m3 d)-1 while at winter temperatures (13.4 ± 1.1°C) the total nitrogen removal rate was 0.097 ± 0.016 kg N (m3 d)-1. Nitrite-oxidizing bacteria (NOB) suppression was successfully achieved at the complete temperature range of municipal mainstream wastewater. Despite the presence of NOB as observed in activity tests, their activity could be successfully suppressed due to a relative low dissolved oxygen concentration. An overcapacity of ammonia-oxidizing bacteria and anammox activity was always present. Long-term stability is a focus point for future research, especially in relation to the stability of the biological oxygen demand removing step, preceding the PN/A reactor.
Collapse
Affiliation(s)
- Maaike Hoekstra
- a Department of Biotechnology, Faculty of Applied Sciences , Delft University of Technology , Delft , Netherlands
| | | | | | | | - Robbert Kleerebezem
- a Department of Biotechnology, Faculty of Applied Sciences , Delft University of Technology , Delft , Netherlands
| | - Mark C M van Loosdrecht
- a Department of Biotechnology, Faculty of Applied Sciences , Delft University of Technology , Delft , Netherlands
| |
Collapse
|
28
|
Conthe M, Lycus P, Arntzen MØ, Ramos da Silva A, Frostegård Å, Bakken LR, Kleerebezem R, van Loosdrecht MCM. Denitrification as an N 2O sink. Water Res 2019; 151:381-387. [PMID: 30616050 DOI: 10.1016/j.watres.2018.11.087] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Revised: 11/29/2018] [Accepted: 11/30/2018] [Indexed: 06/09/2023]
Abstract
The strong greenhouse gas nitrous oxide (N2O) can be emitted from wastewater treatment systems as a byproduct of ammonium oxidation and as the last intermediate in the stepwise reduction of nitrate to N2 by denitrifying organisms. A potential strategy to reduce N2O emissions would be to enhance the activity of N2O reductase (NOS) in the denitrifying microbial community. A survey of existing literature on denitrification in wastewater treatment systems showed that the N2O reducing capacity (VmaxN2O→N2) exceeded the capacity to produce N2O (VmaxNO3→N2O) by a factor of 2-10. This suggests that denitrification can be an effective sink for N2O, potentially scavenging a fraction of the N2O produced by ammonium oxidation or abiotic reactions. We conducted a series of incubation experiments with freshly sampled activated sludge from a wastewater treatment system in Oslo and found that the ratio α = VmaxN2O→N2/VmaxNO3→N2O fluctuated between 2 and 5 in samples taken at intervals over a period of 5 weeks. Adding a cocktail of carbon substrates resulted in increasing rates, but had no significant effect on α. Based on these results - complemented with qPCR and metaproteomic data - we discuss whether the overcapacity to reduce N2O can be ascribed to gene/protein abundance ratios (nosZ/nir), or whether in-cell competition between the reductases for electrons could be of greater importance.
Collapse
Affiliation(s)
- Monica Conthe
- Department of Biotechnology, Delft University of Technology, Delft, the Netherlands
| | - Pawel Lycus
- Faculty of Chemistry, Biotechnology and Food Sciences, Norwegian University of Life Sciences, Ås, Norway
| | - Magnus Ø Arntzen
- Faculty of Chemistry, Biotechnology and Food Sciences, Norwegian University of Life Sciences, Ås, Norway
| | | | - Åsa Frostegård
- Faculty of Chemistry, Biotechnology and Food Sciences, Norwegian University of Life Sciences, Ås, Norway
| | - Lars R Bakken
- Faculty of Chemistry, Biotechnology and Food Sciences, Norwegian University of Life Sciences, Ås, Norway
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Delft, the Netherlands
| | | |
Collapse
|
29
|
Soler-Jofra A, Wang R, Kleerebezem R, van Loosdrecht MCM, Pérez J. Stratification of nitrifier guilds in granular sludge in relation to nitritation. Water Res 2019; 148:479-491. [PMID: 30408734 DOI: 10.1016/j.watres.2018.10.064] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 10/19/2018] [Accepted: 10/22/2018] [Indexed: 06/08/2023]
Abstract
A lab-scale partial nitritation granular sludge air-lift reactor was operated in continuous mode treating low strength synthetic medium (influent ca. 50 mg-N-NH4+/L). Granules were initially stratified with AOB in the external shell and NOB in the inner core at 20 °C. Once temperature was decreased progressively from 20 °C to 15 °C, nitrate production was initially observed during several weeks. However, by maintaining relatively high ammonium concentrations in the liquid (ca. 28 mg-N-NH4+/L), effluent nitrate concentrations in the reactor decreased in time and process performance was recovered. Batch tests were performed in the reactor at different conditions. To understand the experimental results an existing one-dimensional biofilm model was used to simulate batch tests and theoretically assess the impact of stratification, dissolved oxygen (DO) and short-term effects of temperature on time course concentrations of ammonium, nitrite and nitrate. This theoretical assessment served to develop an experimental methodology for the evaluation of in-situ batch tests in the partial nitritation reactor. These batch tests proved to be a powerful tool to easily monitor the extent of stratification of nitrifier guilds in granular sludge and to determine the required bulk ammonium concentration to minimize nitrite oxidation. When nitrifier guilds were stratified in the granular sludge, a higher bulk ammonium concentration was required to efficiently repress NOB at lower temperature (ca. 19 versus 7 mg-N-NH4+/L at 15 and 20 °C, respectively).
Collapse
Affiliation(s)
- Aina Soler-Jofra
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629, HZ, Delft, the Netherlands
| | - Ru Wang
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629, HZ, Delft, the Netherlands; Department of Environment Engineering, College of Environmental & Resource Science, Zhejiang University, Yuhangtang Road 866, 310058, Hangzhou, China
| | - Robbert Kleerebezem
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629, HZ, Delft, the Netherlands
| | - Mark C M van Loosdrecht
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629, HZ, Delft, the Netherlands
| | - Julio Pérez
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629, HZ, Delft, the Netherlands; Department of Chemical, Biological and Environmental Engineering, Universitat Autonoma de Barcelona, 08193, Cerdanyola del Valles, Spain.
| |
Collapse
|
30
|
Timmers PHA, Vavourakis CD, Kleerebezem R, Damsté JSS, Muyzer G, Stams AJM, Sorokin DY, Plugge CM. Metabolism and Occurrence of Methanogenic and Sulfate-Reducing Syntrophic Acetate Oxidizing Communities in Haloalkaline Environments. Front Microbiol 2018; 9:3039. [PMID: 30619130 PMCID: PMC6295475 DOI: 10.3389/fmicb.2018.03039] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 11/26/2018] [Indexed: 01/31/2023] Open
Abstract
Anaerobic syntrophic acetate oxidation (SAO) is a thermodynamically unfavorable process involving a syntrophic acetate oxidizing bacterium (SAOB) that forms interspecies electron carriers (IECs). These IECs are consumed by syntrophic partners, typically hydrogenotrophic methanogenic archaea or sulfate reducing bacteria. In this work, the metabolism and occurrence of SAOB at extremely haloalkaline conditions were investigated, using highly enriched methanogenic (M-SAO) and sulfate-reducing (S-SAO) cultures from south-western Siberian hypersaline soda lakes. Activity tests with the M-SAO and S-SAO cultures and thermodynamic calculations indicated that H2 and formate are important IECs in both SAO cultures. Metagenomic analysis of the M-SAO cultures showed that the dominant SAOB was ‘Candidatus Syntrophonatronum acetioxidans,’ and a near-complete draft genome of this SAOB was reconstructed. ‘Ca. S. acetioxidans’ has all genes necessary for operating the Wood–Ljungdahl pathway, which is likely employed for acetate oxidation. It also encodes several genes essential to thrive at haloalkaline conditions; including a Na+-dependent ATP synthase and marker genes for ‘salt-out‘ strategies for osmotic homeostasis at high soda conditions. Membrane lipid analysis of the M-SAO culture showed the presence of unusual bacterial diether membrane lipids which are presumably beneficial at extreme haloalkaline conditions. To determine the importance of SAO in haloalkaline environments, previously obtained 16S rRNA gene sequencing data and metagenomic data of five different hypersaline soda lake sediment samples were investigated, including the soda lakes where the enrichment cultures originated from. The draft genome of ‘Ca. S. acetioxidans’ showed highest identity with two metagenome-assembled genomes (MAGs) of putative SAOBs that belonged to the highly abundant and diverse Syntrophomonadaceae family present in the soda lake sediments. The 16S rRNA gene amplicon datasets of the soda lake sediments showed a high similarity of reads to ‘Ca. S. acetioxidans’ with abundance as high as 1.3% of all reads, whereas aceticlastic methanogens and acetate oxidizing sulfate-reducers were not abundant (≤0.1%) or could not be detected. These combined results indicate that SAO is the primary anaerobic acetate oxidizing pathway at extreme haloalkaline conditions performed by haloalkaliphilic syntrophic consortia.
Collapse
Affiliation(s)
- Peer H A Timmers
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands.,European Centre of Excellence for Sustainable Water Technology, Wetsus, Leeuwarden, Netherlands
| | - Charlotte D Vavourakis
- Microbial Systems Ecology, Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands
| | - Jaap S Sinninghe Damsté
- Department of Marine Microbiology and Biogeochemistry, NIOZ Netherlands Institute for Sea Research, Utrecht University, Utrecht, Netherlands.,Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, Netherlands
| | - Gerard Muyzer
- Microbial Systems Ecology, Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, Netherlands
| | - Alfons J M Stams
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands.,Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - Dimity Y Sorokin
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands.,Winogradsky Institute of Microbiology, Research Centre of Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Caroline M Plugge
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands.,European Centre of Excellence for Sustainable Water Technology, Wetsus, Leeuwarden, Netherlands
| |
Collapse
|
31
|
Rombouts JL, Mos G, Weissbrodt DG, Kleerebezem R, Van Loosdrecht MCM. Diversity and metabolism of xylose and glucose fermenting microbial communities in sequencing batch or continuous culturing. FEMS Microbiol Ecol 2018; 95:5228722. [DOI: 10.1093/femsec/fiy233] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 11/30/2018] [Indexed: 11/13/2022] Open
Affiliation(s)
- Julius L Rombouts
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, the Netherlands
| | - Galvin Mos
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, the Netherlands
| | - David G Weissbrodt
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, the Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, the Netherlands
| | - Mark C M Van Loosdrecht
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, the Netherlands
| |
Collapse
|
32
|
Conthe M, Wittorf L, Kuenen JG, Kleerebezem R, Hallin S, van Loosdrecht MCM. Growth yield and selection of nosZ clade II types in a continuous enrichment culture of N 2 O respiring bacteria. Environ Microbiol Rep 2018; 10:239-244. [PMID: 29457693 DOI: 10.1111/1758-2229.12630] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 02/13/2018] [Indexed: 06/08/2023]
Abstract
Nitrous oxide (N2 O) reducing microorganisms may be key in the mitigation of N2 O emissions from managed ecosystems. However, there is still no clear understanding of the physiological and bioenergetic implications of microorganisms possessing either of the two N2 O reductase genes (nosZ), clade I and the more recently described clade II type nosZ. It has been suggested that organisms with nosZ clade II have higher growth yields and a lower affinity constant (Ks ) for N2 O. We compared N2 O reducing communities with different nosZI/nosZII ratios selected in chemostat enrichment cultures, inoculated with activated sludge, fed with N2 O as a sole electron acceptor and growth limiting factor and acetate as electron donor. From the sequencing of the 16S rRNA gene, FISH and quantitative PCR of nosZ and nir genes, we concluded that betaproteobacterial denitrifying organisms dominated the enrichments with members within the family Rhodocyclaceae being highly abundant. When comparing cultures with different nosZI/nosZII ratios, we did not find support for (i) a more energy conserving N2 O respiration pathway in nosZ clade II systems, as reflected in the growth yield per mole of substrate, or (ii) a higher affinity for N2 O, defined by μmax /Ks , in organisms with nosZ clade II.
Collapse
Affiliation(s)
- Monica Conthe
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Lea Wittorf
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - J Gijs Kuenen
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Sara Hallin
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | | |
Collapse
|
33
|
Marang L, van Loosdrecht MC, Kleerebezem R. Enrichment of PHA-producing bacteria under continuous substrate supply. N Biotechnol 2018; 41:55-61. [DOI: 10.1016/j.nbt.2017.12.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 08/28/2017] [Accepted: 12/04/2017] [Indexed: 10/18/2022]
|
34
|
Hoekstra M, de Weerd FA, Kleerebezem R, van Loosdrecht MCM. Deterioration of the anammox process at decreasing temperatures and long SRTs. Environ Technol 2018; 39:658-668. [PMID: 28317443 DOI: 10.1080/09593330.2017.1309078] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 03/16/2017] [Indexed: 06/06/2023]
Abstract
The implementation of autotrophic nitrogen removal in the mainstream of a municipal wastewater treatment plant is currently pursued. Among the crucial unknown factors are the kinetic properties of anaerobic ammonium oxidising (anammox) bacteria at low temperatures. In this study we investigated the adaptation of a fast-growing anammox culture to a lower temperature. In a membrane bioreactor a highly enriched anammox community was obtained at 30°C, 25°C and 20°C. This culture was exposed to long- and short-term temperature changes. In short-term experiments the decrease in biomass-specific activity due to decrease in temperature can be described by an activation energy of 64 ± 28 kJ mol-1. Prolonged cultivation (months) implies that cultivation at low temperatures resulted in deterioration of biomass-specific activity (EaLT 239 kJ mol-1). The growth rate and specific anammox activity in the system decreased from 0.33 d-1 and 4.47 g NO2-N g VSS-1 d-1 at 30°C to 0.0011 d-1 and 0.037 g NO2-N g VSS-1 d-1 at 20°C. The reason for the deterioration of the system was related to the required long SRT in the system. The long SRT leads to an increase of non-active and non-anammox cells in the reactor, thereby decreasing the biomass-specific activity.
Collapse
Affiliation(s)
- Maaike Hoekstra
- a Department of Biotechnology, Faculty of Applied Sciences , Delft University of Technology , Delft , The Netherlands
| | - Florence A de Weerd
- a Department of Biotechnology, Faculty of Applied Sciences , Delft University of Technology , Delft , The Netherlands
| | - Robbert Kleerebezem
- a Department of Biotechnology, Faculty of Applied Sciences , Delft University of Technology , Delft , The Netherlands
| | - Mark C M van Loosdrecht
- a Department of Biotechnology, Faculty of Applied Sciences , Delft University of Technology , Delft , The Netherlands
| |
Collapse
|
35
|
Conthe M, Wittorf L, Kuenen JG, Kleerebezem R, van Loosdrecht MCM, Hallin S. Life on N 2O: deciphering the ecophysiology of N 2O respiring bacterial communities in a continuous culture. ISME J 2018; 12:1142-1153. [PMID: 29416125 PMCID: PMC5864245 DOI: 10.1038/s41396-018-0063-7] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 12/19/2017] [Accepted: 12/29/2017] [Indexed: 01/04/2023]
Abstract
Reduction of the greenhouse gas N2O to N2 is a trait among denitrifying and non-denitrifying microorganisms having an N2O reductase, encoded by nosZ. The nosZ phylogeny has two major clades, I and II, and physiological differences among organisms within the clades may affect N2O emissions from ecosystems. To increase our understanding of the ecophysiology of N2O reducers, we determined the thermodynamic growth efficiency of N2O reduction and the selection of N2O reducers under N2O- or acetate-limiting conditions in a continuous culture enriched from a natural community with N2O as electron acceptor and acetate as electron donor. The biomass yields were higher during N2O limitation, irrespective of dilution rate and community composition. The former was corroborated in a continuous culture of Pseudomonas stutzeri and was potentially due to cytotoxic effects of surplus N2O. Denitrifiers were favored over non-denitrifying N2O reducers under all conditions and Proteobacteria harboring clade I nosZ dominated. The abundance of nosZ clade II increased when allowing for lower growth rates, but bacteria with nosZ clade I had a higher affinity for N2O, as defined by μmax/Ks. Thus, the specific growth rate is likely a key factor determining the composition of communities living on N2O respiration under growth-limited conditions.
Collapse
Affiliation(s)
- Monica Conthe
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Lea Wittorf
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - J Gijs Kuenen
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | | | - Sara Hallin
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
| |
Collapse
|
36
|
Conthe M, Kuenen JG, Kleerebezem R, van Loosdrecht MCM. Exploring microbial N 2 O reduction: a continuous enrichment in nitrogen free medium. Environ Microbiol Rep 2018; 10:102-107. [PMID: 29327471 DOI: 10.1111/1758-2229.12615] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 01/06/2018] [Indexed: 06/07/2023]
Abstract
N2 O is a potent greenhouse gas, but also a potent electron acceptor. In search of thermodynamically favourable - yet undescribed - metabolic pathways involving N2 O reduction, we set up a continuous microbial enrichment, inoculated with activated sludge, fed with N2 O as the sole electron acceptor and acetate as an electron donor. A nitrogen-free mineral medium was used with the intention of creating a selective pressure towards organisms that would use N2 O directly as source of nitrogen for cell synthesis. Instead, we obtained a culture dominated by microorganisms of the Rhodocyclaceae family growing by N2 O reduction to N2 coupled to N2 fixation. Biomass yields of this culture were 40% lower than those of a previously reported culture grown under comparable conditions but with an NH4+-amended medium, as expected from the extra energy expense of N2 fixation. Interestingly, we found no significant difference in yields whether N2 O or acetate was the growth-limiting substrate in the chemostat in contrast to the study with NH4+-amended medium, in which biomass yields were roughly 30% lower during acetate limiting conditions.
Collapse
Affiliation(s)
- Monica Conthe
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - J Gijs Kuenen
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | | |
Collapse
|
37
|
Fazeli Danesh A, Mooij P, Ebrahimi S, Kleerebezem R, van Loosdrecht M. Effective role of medium supplementation in microalgal lipid accumulation. Biotechnol Bioeng 2018; 115:1152-1160. [PMID: 29337346 DOI: 10.1002/bit.26548] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 01/07/2018] [Accepted: 01/09/2018] [Indexed: 12/29/2022]
Abstract
The present study investigated the interaction between starch and lipid accumulation in a green microalgae enrichment culture. The objective was to optimize the lipid content by manipulation of the medium in regular batch culture. Two medium designs were evaluated: First a high ortho-P concentration with vitamin supplementary (Pi-vitamins supplemented medium), second normal growth medium (control). Both media contained a low amount of nitrogen which was consumed during batch growth in three days. The batch experiments continued for another 4 days with the absence of soluble nitrogen in the medium. When the mixed microalgal culture was incubated in the Pi-vitamin supplemented medium, the lipid, and starch content of the culture increased within the first 3 days to 102.0 ± 5.2 mg/L (12.7 ± 0.6% of DW) and 31.7 ± 1.6 mg/L (4.0 ± 0.2% of DW), respectively. On the last day of the experiment, the lipid, and starch content in Pi-vitamin medium increased to 663.1 ± 32.5 mg/L (33.4 ± 1.6% of DW) and 127.5 ± 5.2 mg/L (6.4 ± 0.3% of DW). However, the lipid and starch content in the control process, reached to 334.7 ± 16.4 mg/L (20.1 ± 1.0% of DW) and 94.3 ± 4.6 mg/L (5.7 ± 0.3% of DW), respectively. The high Pi-vitamin medium induced storing lipid formation clearly while the starch formation was not affected. The lipid contents reported here are among the high reported in the literature, note that already under full growth conditions significant lipid levels occurred in the algal enrichment culture. The high lipid productivity of the reported mixed microalgae culture provides an efficient route for efficient algal biodiesel production.
Collapse
Affiliation(s)
- Azadeh Fazeli Danesh
- Biotechnology Research Center, Faculty of Chemical Engineering, Sahand University of Technology, Tabriz, Iran.,Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Peter Mooij
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Sirous Ebrahimi
- Biotechnology Research Center, Faculty of Chemical Engineering, Sahand University of Technology, Tabriz, Iran
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Mark van Loosdrecht
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| |
Collapse
|
38
|
van Turnhout AG, Brandstätter C, Kleerebezem R, Fellner J, Heimovaara TJ. Theoretical analysis of municipal solid waste treatment by leachate recirculation under anaerobic and aerobic conditions. Waste Manag 2018; 71:246-254. [PMID: 29017871 DOI: 10.1016/j.wasman.2017.09.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 09/05/2017] [Accepted: 09/27/2017] [Indexed: 06/07/2023]
Abstract
Long-term emissions of Municipal Solid Waste (MSW) landfills are a burden for future generations because of the required long-term aftercare. To shorten aftercare, treatment methods have to be developed that reduce long-term emissions. A treatment method that reduces emissions at a lysimeter scale is re-circulation of leachate. However, its effectiveness at the field scale still needs to be demonstrated. Field scale design can be improved by theoretical understanding of the processes that control the effectiveness of leachate recirculation treatment. In this study, the simplest and most fundamental sets of processes are distilled that describe the emission data measured during aerobic and anaerobic leachate recirculation in lysimeters. A toolbox is used to select essential processes with objective performance criteria produced by Bayesian statistical analysis. The controlling processes indicate that treatment efficiency is mostly affected by how homogeneously important reactants are spread through the MSW during treatment. A more homogeneous spread of i.e. oxygen or methanogens increases the total amount of carbon degraded. Biodegradable carbon removal is highest under aerobic conditions, however, the hydrolysis rate constant is lower which indicates that hydrolysis is not enhanced intrinsically in aerobic conditions. Controlling processes also indicate that nitrogen removal via sequential nitrification and denitrification is plausible under aerobic conditions as long as sufficient biodegradable carbon is present in the MSW. Major removal pathways for carbon and nitrogen are indicated which are important for monitoring treatment effectiveness at a field scale. Optimization strategies for field scale application of treatments are discussed.
Collapse
Affiliation(s)
- André G van Turnhout
- Geoscience & Engineering Department, Faculty of CiTG, Delft University of Technology, Stevinweg 1, 2628 CN Delft, Netherlands.
| | - Christian Brandstätter
- Institute for Water Quality, Resource and Waste Management, Vienna Technical University, Austria
| | - Robbert Kleerebezem
- Environmental Technology Group, Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, Netherlands
| | - Johann Fellner
- Institute for Water Quality, Resource and Waste Management, Vienna Technical University, Austria
| | - Timo J Heimovaara
- Geoscience & Engineering Department, Faculty of CiTG, Delft University of Technology, Stevinweg 1, 2628 CN Delft, Netherlands
| |
Collapse
|
39
|
Korkakaki E, van Loosdrecht MCM, Kleerebezem R. Impact of phosphate limitation on PHA production in a feast-famine process. Water Res 2017; 126:472-480. [PMID: 29024909 DOI: 10.1016/j.watres.2017.09.031] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 08/27/2017] [Accepted: 09/16/2017] [Indexed: 05/20/2023]
Abstract
Double-limitation systems have shown to induce polyhydroxyalkanoates (PHA) production in chemostat studies limited in e.g. carbon and phosphate. In this work the impact of double substrate limitation on the enrichment of a PHA producing community was studied in a sequencing batch process. Enrichments at different C/P concentration ratios in the influent were established and the effect on the PHA production capacity and the enrichment community structure was investigated. Experimental results demonstrated that when a double substrate limitation is imposed at a C/P ratio in the influent in a range of 150 (C-mol/mol), the P-content of the biomass and the specific substrate uptake rates decreased. Nonetheless, the PHA storage capacity remained high (with a maximum of 84 wt%). At a C/P ratio of 300, competition in the microbial community is based on phosphate uptake, and the PHA production capacity is lost. Biomass specific substrate uptake rates are a linear function of the cellular P-content, offering advantages for scaling-up the PHA production process due to lower oxygen requirements.
Collapse
Affiliation(s)
- Emmanouela Korkakaki
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands.
| | - Mark C M van Loosdrecht
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| |
Collapse
|
40
|
van den Berg EM, Rombouts JL, Kuenen JG, Kleerebezem R, van Loosdrecht MCM. Role of nitrite in the competition between denitrification and DNRA in a chemostat enrichment culture. AMB Express 2017; 7:91. [PMID: 28497287 PMCID: PMC5425655 DOI: 10.1186/s13568-017-0398-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 05/02/2017] [Indexed: 11/10/2022] Open
Abstract
Denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are two microbial processes that compete for oxidized nitrogen compounds in the environment. The objective of this work was to determine the role of nitrite versus nitrate as terminal electron acceptor on the competition between DNRA and denitrification. Initially, a mixed culture chemostat was operated under nitrate limitation and performed DNRA. Stepwise, the influent nitrate was replaced with nitrite until nitrite was the sole electron acceptor and N-source present. Despite changing the electron acceptor from nitrate to nitrite, the dominant process remained DNRA and the same dominant organism closely related to Geobacter lovleyi was identified. Contrary to previous studies conducted with a complex substrate in marine microbial communities, the conclusion of this work is that nitrate versus nitrite as electron acceptor does not generally control the competition between DNRA and denitrification. Our results show that the effect of this ratio must be interpreted in combination with other environmental factors, such as the type and complexity of the electron donor, pH, or sulfide concentrations.
Collapse
|
41
|
van den Berg EM, Elisário MP, Kuenen JG, Kleerebezem R, van Loosdrecht MCM. Fermentative Bacteria Influence the Competition between Denitrifiers and DNRA Bacteria. Front Microbiol 2017; 8:1684. [PMID: 28928722 PMCID: PMC5591879 DOI: 10.3389/fmicb.2017.01684] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 08/21/2017] [Indexed: 11/13/2022] Open
Abstract
Denitrification and dissimilatory reduction to ammonium (DNRA) are competing nitrate-reduction processes that entail important biogeochemical consequences for nitrogen retention/removal in natural and man-made ecosystems. The nature of the available carbon source and electron donor have been suggested to play an important role on the outcome of this microbial competition. In this study, the influence of lactate as fermentable carbon source on the competition for nitrate was investigated for varying ratios of lactate and nitrate in the influent (Lac/N ratio). The study was conducted in an open chemostat culture, enriched from activated sludge, under strict anoxia. The mechanistic explanation of the conversions observed was based on integration of results from specific batch tests with biomass from the chemostat, molecular analysis of the biomass enriched, and a computational model. At high Lac/N ratio (2.97 mol/mol) both fermentative and respiratory nitrate reduction to ammonium occurred, coupled to partial oxidation of lactate to acetate, and to acetate oxidation respectively. Remaining lactate was fermented to propionate and acetate. At a decreased Lac/N ratio (1.15 mol/mol), the molar percentage of nitrate reduced to ammonium decreased to 58%, even though lactate was supplied in adequate amounts for full ammonification and nitrate remained the growth limiting compound. Data evaluation at this Lac/N ratio suggested conversions were comparable to the higher Lac/N ratio, except for lactate oxidation to acetate that was coupled to denitrification instead of ammonification. Respiratory DNRA on acetate was likely catalyzed by two Geobacter species related to G. luticola and G. lovleyi. Two Clostridiales members were likely responsible for lactate fermentation and partial lactate fermentation to acetate coupled to fermentative DNRA. An organism related to Propionivibrio militaris was identified as the organism likely responsible for denitrification. The results of this study clearly show that not only the ratio of available substrates, but also the nature of the electron donor influences the outcome of competition between DNRA and denitrification. Apparently, fermentative bacteria are competitive for the electron donor and thereby alter the ratio of available substrates for nitrate reduction.
Collapse
Affiliation(s)
- Eveline M van den Berg
- Environmental Biotechnology Group, Department of Biotechnology, Delft University of TechnologyDelft, Netherlands
| | - Marina P Elisário
- Environmental Biotechnology Group, Department of Biotechnology, Delft University of TechnologyDelft, Netherlands
| | - J Gijs Kuenen
- Environmental Biotechnology Group, Department of Biotechnology, Delft University of TechnologyDelft, Netherlands
| | - Robbert Kleerebezem
- Environmental Biotechnology Group, Department of Biotechnology, Delft University of TechnologyDelft, Netherlands
| | - Mark C M van Loosdrecht
- Environmental Biotechnology Group, Department of Biotechnology, Delft University of TechnologyDelft, Netherlands
| |
Collapse
|
42
|
van den Berg EM, Boleij M, Kuenen JG, Kleerebezem R, van Loosdrecht MCM. DNRA and Denitrification Coexist over a Broad Range of Acetate/N-NO 3- Ratios, in a Chemostat Enrichment Culture. Front Microbiol 2016; 7:1842. [PMID: 27933040 PMCID: PMC5121219 DOI: 10.3389/fmicb.2016.01842] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 11/02/2016] [Indexed: 11/13/2022] Open
Abstract
Denitrification and dissimilatory nitrate reduction to ammonium (DNRA) compete for nitrate in natural and engineered environments. A known important factor in this microbial competition is the ratio of available electron donor and elector acceptor, here expressed as Ac/N ratio (acetate/nitrate-nitrogen). We studied the impact of the Ac/N ratio on the nitrate reduction pathways in chemostat enrichment cultures, grown on acetate mineral medium. Stepwise, conditions were changed from nitrate limitation to nitrate excess in the system by applying a variable Ac/N ratio in the feed. We observed a clear correlation between Ac/N ratio and DNRA activity and the DNRA population in our reactor. The DNRA bacteria dominated under nitrate limiting conditions in the reactor and were outcompeted by denitrifiers under limitation of acetate. Interestingly, in a broad range of Ac/N ratios a dual limitation of acetate and nitrate occurred with co-occurrence of DNRA bacteria and denitrifiers. To explain these observations, the system was described using a kinetic model. The model illustrates that the Ac/N effect and concomitant broad dual limitation range related to the difference in stoichiometry between both processes, as well as the differences in electron donor and acceptor affinities. Population analysis showed that the presumed DRNA-performing bacteria were the same under nitrate limitation and under dual limiting conditions, whereas the presumed denitrifying population changed under single and dual limitation conditions.
Collapse
Affiliation(s)
- Eveline M van den Berg
- Environmental Biotechnology Group, Department of Biotechnology, Delft University of Technology Delft, Netherlands
| | - Marissa Boleij
- Environmental Biotechnology Group, Department of Biotechnology, Delft University of Technology Delft, Netherlands
| | - J Gijs Kuenen
- Environmental Biotechnology Group, Department of Biotechnology, Delft University of Technology Delft, Netherlands
| | - Robbert Kleerebezem
- Environmental Biotechnology Group, Department of Biotechnology, Delft University of Technology Delft, Netherlands
| | - Mark C M van Loosdrecht
- Environmental Biotechnology Group, Department of Biotechnology, Delft University of Technology Delft, Netherlands
| |
Collapse
|
43
|
Korkakaki E, van Loosdrecht MCM, Kleerebezem R. Survival of the fastest: Selective removal of the side population for enhanced PHA production in a mixed substrate enrichment. Bioresour Technol 2016; 216:1022-1029. [PMID: 27343455 DOI: 10.1016/j.biortech.2016.05.125] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 05/09/2016] [Accepted: 05/28/2016] [Indexed: 06/06/2023]
Abstract
The success of enriching PHA-producers in a feast/famine regime strongly depends on the substrate utilized. A distinction can be made between substrates that select for PHA-producers (e.g. volatile fatty acids) and substrates that select for growing organisms (e.g. methanol). In this study the feasibility of using such a mixed substrate was evaluated. A sedimentation step was introduced in the cycle after acetate depletion and the supernatant containing methanol was discharged. This process configuration resulted in an increased maximum PHA storage capacity of the biomass from 48wt% to 70wt%. A model based on the experimental results indicated that the length of the pre-settling period and the supernatant volume that is discharged play a significant role for the elimination of the side population. However, the kinetic properties of the two different populations determine the success of the proposed strategy.
Collapse
Affiliation(s)
- Emmanouela Korkakaki
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Mark C M van Loosdrecht
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands.
| |
Collapse
|
44
|
Sorokin DY, Abbas B, Geleijnse M, Kolganova TV, Kleerebezem R, van Loosdrecht MCM. Syntrophic associations from hypersaline soda lakes converting organic acids and alcohols to methane at extremely haloalkaline conditions. Environ Microbiol 2016; 18:3189-202. [DOI: 10.1111/1462-2920.13448] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Dimitry Y. Sorokin
- Winogradsky Institute of Microbiology, Research Centre of Biotechnology, Russian Academy of Sciences; Moscow Russia
- Department of Biotechnology; Delft University of Technology; 2628 Delft BC The Netherlands
| | - Ben Abbas
- Department of Biotechnology; Delft University of Technology; 2628 Delft BC The Netherlands
| | - Mitchell Geleijnse
- Department of Biotechnology; Delft University of Technology; 2628 Delft BC The Netherlands
| | - Tatjana V. Kolganova
- Centre Bioengineering; Research Centre of Biotechnology, Russian Academy of Sciences; Moscow Russia
| | - Robbert Kleerebezem
- Department of Biotechnology; Delft University of Technology; 2628 Delft BC The Netherlands
| | | |
Collapse
|
45
|
Korkakaki E, Mulders M, Veeken A, Rozendal R, van Loosdrecht MCM, Kleerebezem R. PHA production from the organic fraction of municipal solid waste (OFMSW): Overcoming the inhibitory matrix. Water Res 2016; 96:74-83. [PMID: 27019467 DOI: 10.1016/j.watres.2016.03.033] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 03/02/2016] [Accepted: 03/13/2016] [Indexed: 05/06/2023]
Abstract
Leachate from the source separated organic fraction of municipal solid waste (OFMSW) was evaluated as a substrate for polyhydroxyalkanoates (PHA) production. Initially, the enrichment step was conducted directly on leachate in a feast-famine regime. Maximization of the cellular PHA content of the enriched biomass yielded to low PHA content (29 wt%), suggesting that the selection for PHA-producers was unsuccessful. When the substrate for the enrichment was switched to a synthetic volatile fatty acid (VFA) mixture -resembling the VFA carbon composition of the leachate-the PHA-producers gained the competitive advantage and dominated. Subsequent accumulation with leachate in nutrient excess conditions resulted in a maximum PHA content of 78 wt%. Based on the experimental results, enriching a PHA-producing community in a "clean" VFA stream, and then accumulating PHA from a stream that does not allow for enrichment but does enable a high cellular PHA content, such as OFMSW leachate, makes the overall process much more economically attractive. The estimated overall process yield can be increased four-fold, in comparison to direct use of the complex matrix for both enrichment and accumulation.
Collapse
Affiliation(s)
- Emmanouela Korkakaki
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC, Delft, The Netherlands.
| | - Michel Mulders
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC, Delft, The Netherlands
| | - Adrie Veeken
- Attero BV, Vamweg 7, 9418 TM, Wijster, The Netherlands
| | - Rene Rozendal
- Paques BV, T. de Boerstraat 24, 8561 EL, Balk, The Netherlands
| | - Mark C M van Loosdrecht
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC, Delft, The Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC, Delft, The Netherlands
| |
Collapse
|
46
|
Mora M, López LR, Lafuente J, Pérez J, Kleerebezem R, van Loosdrecht MCM, Gamisans X, Gabriel D. Respirometric characterization of aerobic sulfide, thiosulfate and elemental sulfur oxidation by S-oxidizing biomass. Water Res 2016; 89:282-292. [PMID: 26704759 DOI: 10.1016/j.watres.2015.11.061] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 11/25/2015] [Accepted: 11/26/2015] [Indexed: 06/05/2023]
Abstract
Respirometry was used to reveal the mechanisms involved in aerobic biological sulfide oxidation and to characterize the kinetics and stoichiometry of a microbial culture obtained from a desulfurizing biotrickling filter. Physical-chemical processes such as stripping and chemical oxidation of hydrogen sulfide were characterized since they contributed significantly to the conversions observed in respirometric tests. Mass transfer coefficient for hydrogen sulfide and the kinetic parameters for chemical oxidation of sulfide with oxygen were estimated. The stoichiometry of the process was determined and the different steps in the sulfide oxidation process were identified. The conversion scheme proposed includes intermediate production of elemental sulfur and thiosulfate and the subsequent oxidation of both compounds to sulfate. A kinetic model describing each of the reactions observed during sulfide oxidation was calibrated and validated. The product selectivity was found to be independent of the dissolved oxygen to hydrogen sulfide concentration ratio in the medium at sulfide concentrations ranging from 3 to 30 mg S L(-1). Sulfide was preferentially consumed (SOURmax = 49.2 mg DO g(-1) VSS min(-1)) and oxidized to elemental sulfur at dissolved oxygen concentrations above 0.8 mg DO L(-1). Substrate inhibition of sulfide oxidation was observed (K(i,S(2-))= 42.4 mg S L(-1)). Intracellular sulfur accumulation also affected negatively the sulfide oxidation rate. The maximum fraction of elemental sulfur accumulated inside cells was estimated (25.6% w/w) and a shrinking particle equation was included in the kinetic model to describe elemental sulfur oxidation. The microbial diversity obtained through pyrosequencing analysis revealed that Thiothrix sp. was the main species present in the culture (>95%).
Collapse
Affiliation(s)
- Mabel Mora
- GENOCOV Research Group, Department of Chemical, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Luis R López
- GENOCOV Research Group, Department of Chemical, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Javier Lafuente
- GENOCOV Research Group, Department of Chemical, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Julio Pérez
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
| | - Mark C M van Loosdrecht
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
| | - Xavier Gamisans
- Department of Mining Engineering and Natural Resources, Universitat Politècnica de Catalunya, Bases de Manresa 61-73, 08240 Manresa, Spain
| | - David Gabriel
- GENOCOV Research Group, Department of Chemical, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
| |
Collapse
|
47
|
Junicke H, van Loosdrecht MCM, Kleerebezem R. Kinetic and thermodynamic control of butyrate conversion in non-defined methanogenic communities. Appl Microbiol Biotechnol 2016; 100:915-25. [PMID: 26403924 PMCID: PMC4703631 DOI: 10.1007/s00253-015-6971-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 08/15/2015] [Accepted: 08/28/2015] [Indexed: 12/01/2022]
Abstract
Many anaerobic conversions proceed close to thermodynamic equilibrium and the microbial groups involved need to share their low energy budget to survive at the thermodynamic boundary of life. This study aimed to investigate the kinetic and thermodynamic control mechanisms of the electron transfer during syntrophic butyrate conversion in non-defined methanogenic communities. Despite the rather low energy content of butyrate, results demonstrate unequal energy sharing between the butyrate-utilizing species (17 %), the hydrogenotrophic methanogens (9-10 %), and the acetoclastic methanogens (73-74 %). As a key finding, the energy disproportion resulted in different growth strategies of the syntrophic partners. Compared to the butyrate-utilizing partner, the hydrogenotrophic methanogens compensated their lower biomass yield per mole of electrons transferred with a 2-fold higher biomass-specific electron transfer rate. Apart from these thermodynamic control mechanisms, experiments revealed a ten times lower hydrogen inhibition constant on butyrate conversion than proposed by the Anaerobic Digestion Model No. 1, suggesting a much stronger inhibitory effect of hydrogen on anaerobic butyrate conversion. At hydrogen partial pressures exceeding 40 Pa and at bicarbonate limited conditions, a shift from methanogenesis to reduced product formation was observed which indicates an important role of the hydrogen partial pressure in redirecting electron fluxes towards reduced products such as butanol. The findings of this study demonstrate that a careful consideration of thermodynamics and kinetics is required to advance our current understanding of flux regulation in energy-limited syntrophic ecosystems.
Collapse
Affiliation(s)
- H Junicke
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628, BC, Delft, The Netherlands.
| | - M C M van Loosdrecht
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628, BC, Delft, The Netherlands
| | - R Kleerebezem
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628, BC, Delft, The Netherlands
| |
Collapse
|
48
|
Jiang Y, Mikova G, Kleerebezem R, van der Wielen LAM, Cuellar MC. Feasibility study of an alkaline-based chemical treatment for the purification of polyhydroxybutyrate produced by a mixed enriched culture. AMB Express 2015; 5:5. [PMID: 25642402 PMCID: PMC4305094 DOI: 10.1186/s13568-015-0096-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Accepted: 01/07/2015] [Indexed: 01/14/2024] Open
Abstract
This study focused on investigating the feasibility of purifying polyhydroxybutyrate (PHB) from mixed culture biomass by alkaline-based chemical treatment. The PHB-containing biomass was enriched on acetate under non-sterile conditions. Alkaline treatment (0.2 M NaOH) together with surfactant SDS (0.2 w/v% SDS) could reach 99% purity, with more than 90% recovery. The lost PHB could be mostly attributed to PHB hydrolysis during the alkaline treatment. PHB hydrolysis could be moderated by increasing the crystallinity of the PHB granules, for example, by biomass pretreatment (e.g. freezing or lyophilization) or by effective cell lysis (e.g. adjusting alkali concentration). The suitability of the purified PHB by alkaline treatment for polymer applications was evaluated by molecular weight and thermal stability. A solvent based purification method was also performed for comparison purposes. As result, PHB produced by mixed enriched cultures was found suitable for thermoplastic applications when purified by the solvent method. While the alkaline method resulted in purity, recovery yield and molecular weight comparable to values reported in literature for PHB produced by pure cultures, it was found unsuitable for thermoplastic applications. Given the potential low cost and favorable environmental impact of this method, it is expected that PHB purified by alkaline method may be suitable for other non-thermal polymer applications, and as a platform chemical.
Collapse
|
49
|
Pronk M, de Kreuk MK, de Bruin B, Kamminga P, Kleerebezem R, van Loosdrecht MCM. Full scale performance of the aerobic granular sludge process for sewage treatment. Water Res 2015; 84:207-217. [PMID: 26233660 DOI: 10.1016/j.watres.2015.07.011] [Citation(s) in RCA: 315] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 06/24/2015] [Accepted: 07/06/2015] [Indexed: 06/04/2023]
Abstract
Recently, aerobic granular sludge technology has been scaled-up and implemented for industrial and municipal wastewater treatment under the trade name Nereda(®). With full-scale references for industrial treatment application since 2006 and domestic sewage since 2009 only limited operating data have been presented in scientific literature so far. In this study performance, granulation and design considerations of an aerobic granular sludge plant on domestic wastewater at the WWTP Garmerwolde, the Netherlands were analysed. After a start-up period of approximately 5 months, a robust and stable granule bed (>8 g L(-1)) was formed and could be maintained thereafter, with a sludge volume index after 5 min settling of 45 mL g(-1). The granular sludge consisted for more than 80% of granules larger than 0.2 mm and more than 60% larger than 1 mm. Effluent requirements (7 mg N L(-1) and 1 mg P L(-1)) were easily met during summer and winter. Maximum volumetric conversion rates for nitrogen and phosphorus were respectively 0.17 and 0.24 kg (m(3) d)(-1). The energy usage was 13.9 kWh (PE150·year)(-1) which is 58-63 % lower than the average conventional activated sludge treatment plant in the Netherlands. Finally, this study demonstrated that aerobic granular sludge technology can effectively be implemented for the treatment of domestic wastewater.
Collapse
Affiliation(s)
- M Pronk
- Department of Biotechnology, Delft University of Technology, The Netherlands.
| | - M K de Kreuk
- Department of Biotechnology, Delft University of Technology, The Netherlands; Department of Water Management, Delft University of Technology, Stevinweg 1, 2628CN, Delft, The Netherlands
| | - B de Bruin
- Royal HaskoningDHV B.V., P.O Box 1132, 3800 BC Amersfoort, The Netherlands
| | - P Kamminga
- Waterschap Noorderzijlvest, Stedumermaar 1, 9735 AC Groningen, The Netherlands
| | - R Kleerebezem
- Department of Biotechnology, Delft University of Technology, The Netherlands
| | | |
Collapse
|
50
|
Lotti T, Kleerebezem R, Abelleira-Pereira JM, Abbas B, van Loosdrecht MCM. Faster through training: The anammox case. Water Res 2015; 81:261-268. [PMID: 26074189 DOI: 10.1016/j.watres.2015.06.001] [Citation(s) in RCA: 114] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 05/30/2015] [Accepted: 06/01/2015] [Indexed: 06/04/2023]
Abstract
Anaerobic ammonium oxidizing (anammox) bacteria based technologies are widely applied for nitrogen removal from warm (25-40 °C) wastewater with high ammonium concentrations (∼1 gNH4-N L(-1)). Extension of the operational window of this energy and resource efficient process is restricted by the "supposed" low growth rate of the responsible microorganisms. Here we demonstrate that the maximum specific growth rate (μ(max)) of anammox bacteria can be increased to a μ(max) value of 0.33 d(-1) by applying a novel selection strategy based on the maximization of the electron transfer capacity in a membrane bioreactor. This value is four times higher than the highest previously reported value. The microbial community was strongly dominated by anammox bacteria closely related (99%) to Candidatus Brocadia sp.40 throughout the experiment. The results described here demonstrate the remarkable capacity of a phylogenetically stable anammox community to adjust its growth rate in response to a change in the cultivation conditions imposed.
Collapse
Affiliation(s)
- T Lotti
- Department of Biotechnology, Delft University of Technology, 2628 BC, Delft, The Netherlands.
| | - R Kleerebezem
- Department of Biotechnology, Delft University of Technology, 2628 BC, Delft, The Netherlands
| | - J M Abelleira-Pereira
- Department of Chemical Engineering and Food Technologies, University of Cádiz, 11510, Puerto Real, Cádiz, Spain
| | - B Abbas
- Department of Biotechnology, Delft University of Technology, 2628 BC, Delft, The Netherlands
| | - M C M van Loosdrecht
- Department of Biotechnology, Delft University of Technology, 2628 BC, Delft, The Netherlands
| |
Collapse
|