1
|
Antunes E, Cintra B, Bredel M, Temmink H, Schuur B. Fractionation of Extracellular Polymeric Substances by Aqueous Three-Phase Partitioning Systems. Ind Eng Chem Res 2024; 63:10748-10760. [PMID: 38911146 PMCID: PMC11191973 DOI: 10.1021/acs.iecr.4c00840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2024] [Revised: 05/12/2024] [Accepted: 05/14/2024] [Indexed: 06/25/2024]
Abstract
Extracellular polymeric substances (EPS) are natural polymers secreted by microorganisms and represent a key chemical for the development of a range of circular economy applications. The production of EPS comes with notable challenges such as downstream processing. In this work, a three-phase partitioning (TPP) system was investigated as a fractionation technique for the separation of polysaccharides and proteins, both present in the EPS culture broth. The effect of the type of phase-forming compounds (alcohol, polymer, or ionic liquid, in combination with salt) and its concentration were evaluated and compared to the results previously obtained with model systems. The recyclability of phase-forming compounds used to form the fractionation platform was assessed by ultrafiltration. The best fractionation of EPS was achieved using a TPP system composed of 23 wt % ethanol and 25% K3C6H5O7 as 82% EPS-PS partitioned to the salt-rich/bottom phase, and 76% EPS-PN was recovered as an interfacial precipitate, which could be readily resolubilized in water. This represented an increase of 1.24 and 2.83-fold in the purity of EPS-PS and EPS-PN, respectively, in relation to the initial feed concentration. Finally, high recovery yields of phase-forming compounds (>99%) and fractionated EPS (>80%) were obtained using ultrafiltration/diafiltration (UF/DF) as the regeneration technique. The substantial fractionation yields, selectivity, and recyclability of the phase-forming compounds confirm the potential of TPP systems in combination with UF/DF as the separation method for real biopolymer mixtures. Key contributions of this study include the demonstration of the applicability of a readily scalable and cost-effective separation technique for the fractionation of EPS from real EPS-containing broths, while also the limitations of prescreening with model systems became clear through the observed deviating trends between model system studies and real broth studies.
Collapse
Affiliation(s)
- Evelyn
C. Antunes
- Wetsus—European
Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911MA Leeuwarden, The Netherlands
- Sustainable
Process Technology Group, Department of Chemical Engineering, Faculty
of Science and Technology, University of
Twente, Drienerlolaan 5, 7522 Enschede, The Netherlands
| | - Bruna Cintra
- Wetsus—European
Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911MA Leeuwarden, The Netherlands
| | - Matthieu Bredel
- Wetsus—European
Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911MA Leeuwarden, The Netherlands
| | - Hardy Temmink
- Wetsus—European
Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911MA Leeuwarden, The Netherlands
- Department
of Environmental Technology, Wageningen
University and Research, Bornse Weilanden 9, 6708 Wageningen, The Netherlands
| | - Boelo Schuur
- Sustainable
Process Technology Group, Department of Chemical Engineering, Faculty
of Science and Technology, University of
Twente, Drienerlolaan 5, 7522 Enschede, The Netherlands
| |
Collapse
|
2
|
Sun H, Qin J, Yu W, Zhao H, Wang H. Impacts of micron-sized aeration bubble on sludge properties and hydraulic dynamics in relation to membrane fouling alleviation. CHEMOSPHERE 2024; 362:142582. [PMID: 38871192 DOI: 10.1016/j.chemosphere.2024.142582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 06/06/2024] [Accepted: 06/09/2024] [Indexed: 06/15/2024]
Abstract
This investigation elucidates the influence of micron-scale aeration bubbles on the improvement of anti-fouling characteristics within submerged membrane bioreactors (sMBRs). A systematic examination of sludge properties, hydraulic dynamics, and fouling tendencies revealed that the application of microbubble aeration, specifically at dimensions of 100 μm, 80 μm, and 30 μm, significantly reduced sludge electrostatic repulsion and augmented particle size distribution, as opposed to the utilization of coarse bubble aeration of 1 mm. Notably, the employment of 100 μm bubbles achieved a significant reduction in the proportion of smaller particles (<10 μm) and sludge viscosity, thereby facilitating a more homogenous and vigorous turbulence at the membrane interface. These optimized conditions were instrumental in the substantial reduction of membrane fouling, which was corroborated by the diminished rate of fouling, reduced resistance accumulation, and lesser foulant deposition. The investigation identified sludge particle size, turbulent kinetic energy, and shear stress as the predominant factors influencing the development of membrane fouling. The findings underscore the pronounced advantages of employing 100 μm-sized bubbles in aeration strategies, providing enhanced understanding for the optimization of aeration parameters to improve sMBR efficiency and maintenance.
Collapse
Affiliation(s)
- Huifang Sun
- Institute of Resources and Environmental Engineering, Shanxi University, Taiyuan, 030006, China
| | - Jiawen Qin
- College of Environment and Resource Sciences, Shanxi University, Taiyuan, 030006, China
| | - Wei Yu
- Institute of Resources and Environmental Engineering, Shanxi University, Taiyuan, 030006, China
| | - Huazhang Zhao
- College of Environment and Resource Sciences, Shanxi University, Taiyuan, 030006, China
| | - Haibo Wang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
| |
Collapse
|
3
|
Recovery Techniques Enabling Circular Chemistry from Wastewater. Molecules 2022; 27:molecules27041389. [PMID: 35209179 PMCID: PMC8877087 DOI: 10.3390/molecules27041389] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 02/10/2022] [Accepted: 02/11/2022] [Indexed: 12/04/2022] Open
Abstract
In an era where it becomes less and less accepted to just send waste to landfills and release wastewater into the environment without treatment, numerous initiatives are pursued to facilitate chemical production from waste. This includes microbial conversions of waste in digesters, and with this type of approach, a variety of chemicals can be produced. Typical for digestion systems is that the products are present only in (very) dilute amounts. For such productions to be technically and economically interesting to pursue, it is of key importance that effective product recovery strategies are being developed. In this review, we focus on the recovery of biologically produced carboxylic acids, including volatile fatty acids (VFAs), medium-chain carboxylic acids (MCCAs), long-chain dicarboxylic acids (LCDAs) being directly produced by microorganisms, and indirectly produced unsaturated short-chain acids (USCA), as well as polymers. Key recovery techniques for carboxylic acids in solution include liquid-liquid extraction, adsorption, and membrane separations. The route toward USCA is discussed, including their production by thermal treatment of intracellular polyhydroxyalkanoates (PHA) polymers and the downstream separations. Polymers included in this review are extracellular polymeric substances (EPS). Strategies for fractionation of the different fractions of EPS are discussed, aiming at the valorization of both polysaccharides and proteins. It is concluded that several separation strategies have the potential to further develop the wastewater valorization chains.
Collapse
|
4
|
Pereira J, Mediayati Y, van Veelen HPJ, Temmink H, Sleutels T, Hamelers B, Heijne AT. The effect of intermittent anode potential regimes on the morphology and extracellular matrix composition of electro-active bacteria. Biofilm 2022; 4:100064. [PMID: 34984335 PMCID: PMC8693015 DOI: 10.1016/j.bioflm.2021.100064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 11/01/2021] [Accepted: 12/08/2021] [Indexed: 11/25/2022] Open
Abstract
Electro-active bacteria (EAB) can form biofilms on an anode (so-called bioanodes), and use the electrode as electron acceptor for oxidation of organics in wastewater. So far, bioanodes have mainly been investigated under a continuous anode potential, but intermittent anode potential has resulted in higher currents and different biofilm morphologies. However, little is known about how intermittent potential influences the electron balance in the anode compartment. In this study, we investigated electron balances of bioanodes at intermittent anode potential regimes. We used a transparent non-capacitive electrode that also allowed for in-situ quantification of the EAB using optical coherence tomography (OCT). We observed comparable current densities between continuous and intermittent bioanodes, and stored charge was similar for all the applied intermittent times (5 mC). Electron balances were further investigated by quantifying Extracellular Polymeric Substances (EPS), by analyzing the elemental composition of biomass, and by quantifying biofilm and planktonic cells. For all tested conditions, a charge balance of the anode compartment showed that more electrons were diverted to planktonic cells than biofilm. Besides, 27–43% of the total charge was detected as soluble EPS in intermittent bioanodes, whereas only 15% was found as soluble EPS in continuous bioanodes. The amount of proteins in the EPS of biofilms was higher for intermittent operated bioanodes (0.21 mg COD proteins mg COD biofilm−1) than for continuous operated bioanodes (0.05 mg COD proteins mg COD biofilm−1). OCT revealed patchy morphologies for biofilms under intermittent anode potential. Overall, this study helped understanding that the use of a non-capacitive electrode and intermittent anode potential deviated electrons to other processes other than electric current at the electrode by identifying electron sinks in the anolyte and quantifying the accumulation of electrons in the form of EPS. Continuous acetate feeding and intermittent anode potential lead to EPS production in electro-active bacteria. A charge balance was made including soluble EPS and planktonic cells. Patchy biofilm morphologies and more planktonic cells were observed when intermittent anode potential was applied. Biofilms grown under intermittent anode potential had more EPS and more proteins.
Collapse
Affiliation(s)
- João Pereira
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911MA, Leeuwarden, the Netherlands.,Environmental Technology, Wageningen University, Bornse Weilanden 9, P.O. Box 17, 6700, AA, Wageningen, the Netherlands
| | - Yuniki Mediayati
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911MA, Leeuwarden, the Netherlands.,Environmental Technology, Wageningen University, Bornse Weilanden 9, P.O. Box 17, 6700, AA, Wageningen, the Netherlands
| | - H Pieter J van Veelen
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911MA, Leeuwarden, the Netherlands
| | - Hardy Temmink
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911MA, Leeuwarden, the Netherlands.,Environmental Technology, Wageningen University, Bornse Weilanden 9, P.O. Box 17, 6700, AA, Wageningen, the Netherlands
| | - Tom Sleutels
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911MA, Leeuwarden, the Netherlands
| | - Bert Hamelers
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911MA, Leeuwarden, the Netherlands.,Environmental Technology, Wageningen University, Bornse Weilanden 9, P.O. Box 17, 6700, AA, Wageningen, the Netherlands
| | - Annemiek Ter Heijne
- Environmental Technology, Wageningen University, Bornse Weilanden 9, P.O. Box 17, 6700, AA, Wageningen, the Netherlands
| |
Collapse
|
5
|
Paria K, Pyne S, Chakraborty SK. Optimization of heavy metal (lead) remedial activities of fungi Aspergillus penicillioides (F12) through extra cellular polymeric substances. CHEMOSPHERE 2022; 286:131874. [PMID: 34426280 DOI: 10.1016/j.chemosphere.2021.131874] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 08/08/2021] [Accepted: 08/10/2021] [Indexed: 06/13/2023]
Abstract
Wastewater imposes a great threat to any ecosystem across the world, especially the aquatic one because of the different anthropogenic activities of human beings. The present study emphasizes the optimization of ecological parameters [pH, time (h) and temperature (°C)] employing Box-Behnken design (BBD) to achieve better bio-adsorption of a selected heavy metal [lead (Pb II)] from the wastewater through an extracellular polymeric substance (EPS) of a benthic fungus, Aspergillus penicillioides (F12) (MN210327). The relevant statistical analysis (ANOVA) has enabled to record of the optimized bio-adsorption (73.14 %) of lead (Pb II) by fungal EPS at pH (8.85) and temperature (32 °C) for a duration of 5.74 h. Besides that, at the concentration of 0.5 mg/L of EPS, the flocculating rate was noted to be highest (88.4 %) in kaolin clay and the 50 % emulsifying activity. This investigation has also opened up new vistas on the possibility of the development of an alternative method of eco-sustainable bioremediation of heavy metals by fungal EPS on an industrial scale.
Collapse
Affiliation(s)
- Kishalay Paria
- Department of Zoology, Vidyasagar University, Medinipur, 721102, West Bengal, India.
| | - Smritikana Pyne
- Department of Food Technology and Biochemical Engineering, Jadavpur University, Kolkata, 700032, West Bengal, India
| | | |
Collapse
|
6
|
Costa-Gutierrez SB, Saez JM, Aparicio JD, Raimondo EE, Benimeli CS, Polti MA. Glycerol as a substrate for actinobacteria of biotechnological interest: Advantages and perspectives in circular economy systems. CHEMOSPHERE 2021; 279:130505. [PMID: 33865166 DOI: 10.1016/j.chemosphere.2021.130505] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 03/25/2021] [Accepted: 04/03/2021] [Indexed: 06/12/2023]
Abstract
Actinobacteria represent a ubiquitous group of microorganisms widely distributed in ecosystems. They have diverse physiological and metabolic properties, including the production of extracellular enzymes and a variety of secondary bioactive metabolites, such as antibiotics, immunosuppressants, and other compounds of industrial interest. Therefore, actinobacteria have been used for biotechnological purposes for more than three decades. The development of a biotechnological process requires the evaluation of its cost/benefit ratio, including the search for economic and efficient substrates for microorganisms development. Biodiesel is a clean, renewable, quality and economically viable source of energy, which also contributes to the conservation of the environment. Crude glycerol is the main by-product of biodiesel production and has many properties, so it has a commercial value that can be used to finance the biofuel production process. Actinobacteria can use glycerol as a source of carbon and energy, either pure o crude. A circular economy system aims to eliminate waste and pollution, keep products and materials in use, and regenerate natural systems. Although these principles are not yet met, some approaches are being made in this direction; the transformation of crude glycerol by actinobacteria is a process with great potential to be scaled on an industrial level. This review discusses the reports on glycerol as a promising source of carbon and energy for obtaining biomass and high-added value products by actinobacteria. Also, the factors influencing the biomass and secondary metabolites production in bioreactors are analyzed, and the tools available to overcome those that generate the main problems are discussed.
Collapse
Affiliation(s)
- Stefanie B Costa-Gutierrez
- Planta Piloto de Procesos Industriales Microbiológicos (PROIMI-CONICET), Avenida Belgrano y Pasaje Caseros, 4000, San Miguel de Tucumán, Tucumán, Argentina
| | - Juliana Maria Saez
- Planta Piloto de Procesos Industriales Microbiológicos (PROIMI-CONICET), Avenida Belgrano y Pasaje Caseros, 4000, San Miguel de Tucumán, Tucumán, Argentina; Facultad de Ciencias Naturales e Instituto Miguel Lillo, Universidad Nacional de Tucumán, Miguel Lillo 205, 4000, Tucumán, Argentina
| | - Juan Daniel Aparicio
- Planta Piloto de Procesos Industriales Microbiológicos (PROIMI-CONICET), Avenida Belgrano y Pasaje Caseros, 4000, San Miguel de Tucumán, Tucumán, Argentina; Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Ayacucho 491, 4000, Tucumán, Argentina
| | - Enzo E Raimondo
- Planta Piloto de Procesos Industriales Microbiológicos (PROIMI-CONICET), Avenida Belgrano y Pasaje Caseros, 4000, San Miguel de Tucumán, Tucumán, Argentina; Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Ayacucho 491, 4000, Tucumán, Argentina
| | - Claudia S Benimeli
- Planta Piloto de Procesos Industriales Microbiológicos (PROIMI-CONICET), Avenida Belgrano y Pasaje Caseros, 4000, San Miguel de Tucumán, Tucumán, Argentina; Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Catamarca, Belgrano 300, 4700, Catamarca, Argentina
| | - Marta A Polti
- Planta Piloto de Procesos Industriales Microbiológicos (PROIMI-CONICET), Avenida Belgrano y Pasaje Caseros, 4000, San Miguel de Tucumán, Tucumán, Argentina; Facultad de Ciencias Naturales e Instituto Miguel Lillo, Universidad Nacional de Tucumán, Miguel Lillo 205, 4000, Tucumán, Argentina.
| |
Collapse
|
7
|
Ajao V, Fokkink R, Leermakers F, Bruning H, Rijnaarts H, Temmink H. Bioflocculants from wastewater: Insights into adsorption affinity, flocculation mechanisms and mixed particle flocculation based on biopolymer size-fractionation. J Colloid Interface Sci 2021; 581:533-544. [PMID: 32814184 DOI: 10.1016/j.jcis.2020.07.146] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 07/29/2020] [Accepted: 07/30/2020] [Indexed: 11/30/2022]
Abstract
HYPOTHESIS Microbial extracellular polymeric substances (EPS) produced from wastewater are generally heterodispersed, which is expected to influence their flocculation performances and mechanism, particularly in mixed particle systems. The different molecular weight (MW) fractions should contribute to the overall adsorption affinity and flocculation mechanism of EPS in single and dual clay systems. EXPERIMENTS EPS harvested from bioreactors were size-fractionated into high, medium and low MW fractions (HMW, MMW, LMW, respectively). The harvested mixed EPS and its fractions were characterised by diverse analytical techniques coupled with optical reflectometry to investigate the role of each EPS fraction in the overall flocculation mechanism of EPS in kaolinite and montmorillonite clay systems. FINDINGS In single clay systems, both the harvested mixed EPS and the HMW-EPS fraction showed comparable flocculation performances. However, mixed EPS proved to be more efficient than the HMW-EPS fraction for dual clay flocculation. Site blocking effects were observed in mixed EPS: the LMW and MMW EPS first adsorbed to the surface due to higher diffusivities and faster mass transfer to the interface, while the HMW-EPS were slowly transported but were attached to the surface irreversibly and stronger than the LMW/MMW-EPS. We propose from this, a mixed EPS adsorption mechanism: extended anionic polymer tails in solution, thereby enhancing particle flocculation.
Collapse
Affiliation(s)
- Victor Ajao
- Wetsus - European Centre of Excellence for Sustainable Water Technology, P.O. Box 1113, 8911 CC Leeuwarden, Netherlands; Department of Environmental Technology, Wageningen University and Research, P.O. Box 8129, 6700 EV Wageningen, Netherlands.
| | - Remco Fokkink
- Physical Chemistry and Soft Matter, Wageningen University and Research, P.O. Box 8038, 6700 Wageningen, Netherlands.
| | - Frans Leermakers
- Physical Chemistry and Soft Matter, Wageningen University and Research, P.O. Box 8038, 6700 Wageningen, Netherlands.
| | - Harry Bruning
- Department of Environmental Technology, Wageningen University and Research, P.O. Box 8129, 6700 EV Wageningen, Netherlands.
| | - Huub Rijnaarts
- Department of Environmental Technology, Wageningen University and Research, P.O. Box 8129, 6700 EV Wageningen, Netherlands.
| | - Hardy Temmink
- Wetsus - European Centre of Excellence for Sustainable Water Technology, P.O. Box 1113, 8911 CC Leeuwarden, Netherlands; Department of Environmental Technology, Wageningen University and Research, P.O. Box 8129, 6700 EV Wageningen, Netherlands.
| |
Collapse
|
8
|
Saha P, Bruning H, Wagner TV, Rijnaarts HHM. Removal of organic compounds from cooling tower blowdown by electrochemical oxidation: Role of electrodes and operational parameters. CHEMOSPHERE 2020; 259:127491. [PMID: 32650167 DOI: 10.1016/j.chemosphere.2020.127491] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 06/16/2020] [Accepted: 06/18/2020] [Indexed: 06/11/2023]
Abstract
The reuse of cooling tower blowdown (CTBD) in the cooling tower itself requires CTBD deionization and a pre-treatment before deionization to remove organic compounds (OCs) that induce membrane fouling. This study assesses the potential of electrochemical oxidation (EO) with a boron-doped diamond (BDD) and a Ti/RuO2 mixed-metal oxide (MMO) anode for CTBD pre-treatment. Also, the influence of the applied current density (j), initial pH, hydrodynamic conditions, and supporting electrolyte on the process performance was evaluated. Results show that COD and TOC removal were 85 and 51%, respectively, with the BDD-anode; however, they were 50 and 12% with MMO-anode at a j-value of 8.7 mA cm-2 and neutral pH. An increased j-value increased the COD and TOC removal; however, different pHs, hydrodynamic conditions, and the addition of supporting electrolytes had a minor impact on the removal with both anodes. Liquid chromatography-organic carbon detection analysis showed that the OC in CTBD mainly consisted of humic substances (HS). EO with the BDD-anode resulted in 35% HS mineralization, while the rest of the HS were partially oxidized into low molecular weight compounds and building blocks. However, HS mineralization was limited with the MMO-anode. The mineralization and oxidation were accompanied by the formation of organic and inorganic chlorinated species. These species increased the toxicity to Vibrio fischeri 20-fold compared to the initially low-toxic CTBD. Thus, EO with a BDD-anode is a promising pre-treatment technology for the removal of OCs before CTBD deionization, but measures to minimize the chlorinated species formation are required before its application.
Collapse
Affiliation(s)
- Pradip Saha
- Department of Environmental Technology, Wageningen University and Research, P.O. Box 17, 6700 AA, Wageningen, the Netherlands; Department of Chemical Engineering and Polymer Science, Shahjalal University of Science and Technology, Sylhet, 3114, Bangladesh.
| | - Harry Bruning
- Department of Environmental Technology, Wageningen University and Research, P.O. Box 17, 6700 AA, Wageningen, the Netherlands.
| | - Thomas V Wagner
- Department of Environmental Technology, Wageningen University and Research, P.O. Box 17, 6700 AA, Wageningen, the Netherlands.
| | - Huub H M Rijnaarts
- Department of Environmental Technology, Wageningen University and Research, P.O. Box 17, 6700 AA, Wageningen, the Netherlands.
| |
Collapse
|
9
|
Ter Heijne A, Pereira MA, Pereira J, Sleutels T. Electron Storage in Electroactive Biofilms. Trends Biotechnol 2020; 39:34-42. [PMID: 32646618 DOI: 10.1016/j.tibtech.2020.06.006] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 06/05/2020] [Accepted: 06/09/2020] [Indexed: 10/23/2022]
Abstract
Microbial electrochemical technologies (METs) are promising for sustainable applications. Recently, electron storage during intermittent operation of electroactive biofilms (EABs) has been shown to play an important role in power output and electron efficiencies. Insights into electron storage mechanisms, and the conditions under which these occur, are essential to improve microbial electrochemical conversions and to optimize biotechnological processes. Here, we discuss the two main mechanisms for electron storage in EABs: storage in the form of reduced redox active components in the electron transport chain and in the form of polymers. We review electron storage in EABs and in other microorganisms and will discuss how the mechanisms of electron storage can be influenced.
Collapse
Affiliation(s)
- A Ter Heijne
- Environmental Technology, Wageningen University and Research, Wageningen, The Netherlands.
| | - M A Pereira
- CEB - Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - J Pereira
- Environmental Technology, Wageningen University and Research, Wageningen, The Netherlands; Wetsus, European Centre of Excellence for Sustainable Water Technology, Leeuwarden, The Netherlands
| | - T Sleutels
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Leeuwarden, The Netherlands
| |
Collapse
|
10
|
Ajao V, Nam K, Chatzopoulos P, Spruijt E, Bruning H, Rijnaarts H, Temmink H. Regeneration and reuse of microbial extracellular polymers immobilised on a bed column for heavy metal recovery. WATER RESEARCH 2020; 171:115472. [PMID: 31931379 DOI: 10.1016/j.watres.2020.115472] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 12/20/2019] [Accepted: 01/03/2020] [Indexed: 06/10/2023]
Abstract
Microbial extracellular polymeric substances (EPS) have gained increasing attention for various water treatment applications. In this study, EPS produced from nitrogen-limited glycerol/ethanol-rich wastewater were used to recover Cu2+ and Pb2+ from aqueous solutions. Continuous flow-through tests were conducted on a column packed with silica gel coated with polyethyleneimine, to which EPS were irreversibly attached as shown by optical reflectometry. These immobilised EPS excellently adsorbed Cu2+ and Pb2+, with 99.9% of influent metal adsorbed before the breakthrough points. Metal desorption was achieved with 0.1M HCl, with an average recovery of 86% for Cu2+ and 90% recovery for Pb2+. For the first time, we successfully showed the possibility to regenerate and reuse the immobilised EPS for five adsorption-desorption cycles (using Cu2+ as an example) with no reduction in the adsorbed amount at the breakthrough point (qbp). Based on the mass balance of the associated metal ions participating in the adsorption process, ion exchange was identified as the major mechanism responsible for Cu2+ and Pb2+ adsorption by EPS. The results demonstrate the potential of wastewater-produced EPS as an attractive and perhaps, cost-effective biosorbent for heavy metal removal (to trace effluent concentrations) and recovery (86-99%).
Collapse
Affiliation(s)
- Victor Ajao
- Wetsus - European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, the Netherlands; Sub-department of Environmental Technology, Wageningen University and Research, Bornse Weilanden 9, 6708 WG, Wageningen, the Netherlands.
| | - Kang Nam
- School of Life Sciences and Environmental Technology, Avans University of Applied Science, Breda, the Netherlands
| | - Paraschos Chatzopoulos
- Wetsus - European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, the Netherlands
| | - Evan Spruijt
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, the Netherlands
| | - Harry Bruning
- Sub-department of Environmental Technology, Wageningen University and Research, Bornse Weilanden 9, 6708 WG, Wageningen, the Netherlands
| | - Huub Rijnaarts
- Sub-department of Environmental Technology, Wageningen University and Research, Bornse Weilanden 9, 6708 WG, Wageningen, the Netherlands
| | - Hardy Temmink
- Wetsus - European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, the Netherlands; Sub-department of Environmental Technology, Wageningen University and Research, Bornse Weilanden 9, 6708 WG, Wageningen, the Netherlands
| |
Collapse
|
11
|
Li H, Wu S, Du C, Zhong Y, Yang C. Preparation, Performances, and Mechanisms of Microbial Flocculants for Wastewater Treatment. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:E1360. [PMID: 32093205 PMCID: PMC7068532 DOI: 10.3390/ijerph17041360] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 02/10/2020] [Accepted: 02/17/2020] [Indexed: 12/15/2022]
Abstract
In recent years, close attention has been paid to microbial flocculants because of their advantages, including safety to humans, environmental friendliness, and acceptable removal performances. In this review, the preparation methods of microbial flocculants were first reviewed. Then, the performances of bioflocculants in the removal of suspended solids, heavy metals, and other organic pollutants from various types of wastewater were described and commented, and the removal mechanisms, including adsorption bridging, charge neutralization, chemical reactions, and charge neutrality, were also discussed. The future research needs on microbial flocculants were also proposed. This review would lead to a better understanding of current status, challenges, and corresponding strategies on microbial flocculants and bioflocculation in wastewater treatment.
Collapse
Affiliation(s)
- Huiru Li
- College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China; (H.L.); (S.W.)
| | - Shaohua Wu
- College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China; (H.L.); (S.W.)
- Guangdong Provincial Key Laboratory of Petrochemical Pollution Processes and Control, School of Environmental Science and Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, China; (C.D.); (Y.Z.)
| | - Cheng Du
- Guangdong Provincial Key Laboratory of Petrochemical Pollution Processes and Control, School of Environmental Science and Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, China; (C.D.); (Y.Z.)
| | - Yuanyuan Zhong
- Guangdong Provincial Key Laboratory of Petrochemical Pollution Processes and Control, School of Environmental Science and Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, China; (C.D.); (Y.Z.)
| | - Chunping Yang
- College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China; (H.L.); (S.W.)
- Guangdong Provincial Key Laboratory of Petrochemical Pollution Processes and Control, School of Environmental Science and Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, China; (C.D.); (Y.Z.)
- Hunan Provincial Environmental Protection Engineering Center for Organic Pollution Control of Urban Water and Wastewater, Changsha 410001, China
| |
Collapse
|
12
|
Evaluation of Fresh Water Actinomycete Bioflocculant and Its Biotechnological Applications in Wastewaters Treatment and Removal of Heavy Metals. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16183337. [PMID: 31510036 PMCID: PMC6765771 DOI: 10.3390/ijerph16183337] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 08/07/2019] [Accepted: 08/14/2019] [Indexed: 11/28/2022]
Abstract
This study evaluated the potential of a biopolymeric flocculant produced by Terrabacter sp. isolated from Sterkfontein Dam, South Africa. Microbial flocculants aid the aggregation of suspended solutes in solutions, thus, suggesting its alternative application to inorganic and synthetic organic flocculants, which are associated with health-related problems. The 16S rDNA analysis revealed the bacteria to have 98% similarity to Terrabacter sp. MUSC78T and the sequence was deposited in the Genbank as Terrabacter sp. with accession number KF682157.1. A series of experimental parameters such as bioflocculant dosage, cations concentrations, pH, and application of the purified bioflocculant in wastewaters treatment were investigated. In the presence of glucose as a sole carbon source, Ca2+ as cation at pH 8, the optimal flocculating activity attained was 85%. Optimum bioflocculant dosage of 0.5 mg/mL was able to remove chemical oxygen demand (COD), biological oxygen demand (BOD), suspended solids (SS), nitrate, and turbidity in dairy wastewater. In addition, the tested bioflocculant exhibited higher flocculating efficiency as compared to polyaluminum chloride, polyethylenime, and alum. Inductible coupled plasma optical emission spectroscopy (ICP-OES) analyses confirmed significant removal of 77.7% Fe, 74.8% Al, 61.9% Mn, and 57.6% Zn as representatives of heavy metals from treated dairy wastewater. Fourier transform infrared spectroscopy (FTIR) indicated the presence of carboxyl, hydroxyl, and amino groups in the purified bioflocculant which could be responsible for flocculation. Findings from this study showed the prospect of the studied bioflocculant as an alternative candidate in wastewater treatment and remediating of heavy metals.
Collapse
|