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Wu H, Zeng W, Wu L, Lu S, Peng Y. Mechanisms of endogenous and exogenous partial denitrification in response to different carbon/nitrogen ratios: Transcript levels, nitrous oxide production, electron transport. BIORESOURCE TECHNOLOGY 2024; 399:130558. [PMID: 38460557 DOI: 10.1016/j.biortech.2024.130558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 03/04/2024] [Accepted: 03/06/2024] [Indexed: 03/11/2024]
Abstract
Nitrite as an important substrate for Anammox can be provided by partial denitrification (PD). In this study, endogenous partial denitrification (EdPD) and exogenous partial denitrification (ExPD) sludge were domesticated and their nitrite transformation rate reached 74.4% and 83.4%, respectively. The impact of four carbon/nitrogen (C/N) ratios (1.5, 3.0, 5.0 and 6.0) on nitrous oxide (N2O) emission and denitrification functional genes expression in both PD systems were investigated. Results showed that elevated C/N ratios enhanced most denitrification genes expression, but in EdPD, high nitrite levels suppressed nosZ genes expression (from 9.4% to 1.4%), leading to increased N2O emission (0 to 3.4%). EdPD also exhibited lower electron transfer system activity, resulting in slower nitrogen oxide conversion efficiency and more stable nitrite accumulation compared to ExPD. These findings offer insights for optimizing PD systems under varying water quality conditions.
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Affiliation(s)
- Hongan Wu
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, China
| | - Wei Zeng
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, China.
| | - Lei Wu
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, China
| | - Sijia Lu
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, China
| | - Yongzhen Peng
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, China
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2
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Botti A, Musmeci E, Negroni A, Capuozzo R, Fava F, Biagi E, Zanaroli G. Site-specific response of sediment microbial community to supplementation of polyhydroxyalkanoates as biostimulants for PCB reductive dechlorination. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 898:165485. [PMID: 37442469 DOI: 10.1016/j.scitotenv.2023.165485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 06/23/2023] [Accepted: 07/10/2023] [Indexed: 07/15/2023]
Abstract
The use of biodegradable plastics is constantly raising, increasing the likeliness for these polymers to end up in the environment. Environmental applications foreseeing the intentional release of biodegradable plastics have been also recently proposed, e.g., for polyhydroxyalkanoates (PHAs) acting as slow hydrogen releasing compounds to stimulate microbial reductive dehalogenation processes. However, the effects of their release into the environment on the ecosystems still need to be thoroughly explored. In this work, the use of PHAs to enhance the microbial reductive dechlorination of polychlorobiphenyls (PCBs) and their impact on the metabolic and compositional features of the resident microbial community have been investigated in laboratory microcosms of a polluted marine sediment from Mar Piccolo (Taranto, Italy), and compared with recent findings on a different contaminated marine sediment from Pialassa della Baiona (Ravenna, Italy). A decreased biostimulation efficiency of PHAs on PCBs reductive dechlorination was observed in the sediment from Mar Piccolo, with respect to the sediment from Pialassa della Baiona, suggesting that the sediments' physical-chemical characteristics and/or the biodiversity and composition of its microbial community might play a key role in determining the outcome of this biostimulation strategy. Regardless of the sediment origin, PHAs were found to have a specific and pervasive effect on the sediment microbial community, reducing its biodiversity, defining a newly arranged microbial core of primary degraders and consequently affecting, in a site-specific way, the abundance of subdominant bacteria, possibly cross-feeders. Such potential to dramatically change the structure of autochthonous microbial communities should be carefully considered, since it might have secondary effects, e.g., on the natural biogeochemical cycles.
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Affiliation(s)
- Alberto Botti
- Dept. of Civil, Chemical, Environmental and Material Engineering (DICAM), Alma Mater Studiorum University of Bologna, Via Terracini 28, 40131 Bologna, Italy
| | - Eliana Musmeci
- Dept. of Civil, Chemical, Environmental and Material Engineering (DICAM), Alma Mater Studiorum University of Bologna, Via Terracini 28, 40131 Bologna, Italy
| | - Andrea Negroni
- Dept. of Civil, Chemical, Environmental and Material Engineering (DICAM), Alma Mater Studiorum University of Bologna, Via Terracini 28, 40131 Bologna, Italy
| | - Rosaria Capuozzo
- Dept. of Civil, Chemical, Environmental and Material Engineering (DICAM), Alma Mater Studiorum University of Bologna, Via Terracini 28, 40131 Bologna, Italy
| | - Fabio Fava
- Dept. of Civil, Chemical, Environmental and Material Engineering (DICAM), Alma Mater Studiorum University of Bologna, Via Terracini 28, 40131 Bologna, Italy
| | - Elena Biagi
- Dept. of Civil, Chemical, Environmental and Material Engineering (DICAM), Alma Mater Studiorum University of Bologna, Via Terracini 28, 40131 Bologna, Italy.
| | - Giulio Zanaroli
- Dept. of Civil, Chemical, Environmental and Material Engineering (DICAM), Alma Mater Studiorum University of Bologna, Via Terracini 28, 40131 Bologna, Italy
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Li T, Li W, Chai X, Dai X, Wu B. PHA stimulated denitrification through regulation of preferential cofactor provision and intracellular carbon metabolism at different dissolved oxygen levels by Pseudomonas stutzeri. CHEMOSPHERE 2022; 309:136641. [PMID: 36183891 DOI: 10.1016/j.chemosphere.2022.136641] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 09/08/2022] [Accepted: 09/26/2022] [Indexed: 06/16/2023]
Abstract
Denitrification, a typical biological process mediated by complex environmental factors, i.e., carbon sources and dissolved oxygen (DO), has attracted great attention due to its contribution to the control of eutrophication and the biochemical cycling of nitrogen. However, the effects of carbon source on electron distribution and enzyme expression for enhanced denitrification under competition of electron acceptors (DO and nitrate) remain unclear. Here, we profile the carbon metabolic pathway of polyhydroxybutyrate (PHB) and glucose (Glu) at high and low DO levels (50% and 10% saturated DO, respectively). It was found that PHB enhanced the growth of Pseudomonas stutzeri (model denitrifying bacterium) and improved the specific nitrogen removal rate (SNRR) at all DO levels. The functional proteins had a better affinity for the cofactor nicotinamide-adenine dinucleotide (NADH) than for nicotinamide adenine dinucleotide phosphate (NADPH); thus, more electrons were involved in nitrogen reduction and intracellular PHB production in the PHB groups than in the Glu groups. Furthermore, the expression difference of enzymes in glucose and PHB metabolism was demonstrated by metaproteomic and target protein analysis, implying that PHB-driven intracellular carbon accumulation could optimize the intracellular electron allocation and correspondingly promote nitrogen metabolism. Our work integrated the mechanisms of intracellular carbon metabolism with preferences for electron transfer pathways in denitrification, providing a new perspective on how the selective parameters regulated microbial functions involved in denitrification.
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Affiliation(s)
- Tingting Li
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Wenxuan Li
- NUS Environmental Research Institute, National University of Singapore, 5A Engineering Drive 1, #02-01 T-Lab Building, 117411, Singapore
| | - Xiaoli Chai
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Xiaohu Dai
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Boran Wu
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China.
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Novel Production Methods of Polyhydroxyalkanoates and Their Innovative Uses in Biomedicine and Industry. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27238351. [PMID: 36500442 PMCID: PMC9740486 DOI: 10.3390/molecules27238351] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/25/2022] [Accepted: 11/27/2022] [Indexed: 12/03/2022]
Abstract
Polyhydroxyalkanoate (PHA), a biodegradable polymer obtained from microorganisms and plants, have been widely used in biomedical applications and devices, such as sutures, cardiac valves, bone scaffold, and drug delivery of compounds with pharmaceutical interests, as well as in food packaging. This review focuses on the use of polyhydroxyalkanoates beyond the most common uses, aiming to inform about the potential uses of the biopolymer as a biosensor, cosmetics, drug delivery, flame retardancy, and electrospinning, among other interesting uses. The novel applications are based on the production and composition of the polymer, which can be modified by genetic engineering, a semi-synthetic approach, by changing feeding carbon sources and/or supplement addition, among others. The future of PHA is promising, and despite its production costs being higher than petroleum-based plastics, tools given by synthetic biology, bioinformatics, and machine learning, among others, have allowed for great production yields, monomer and polymer functionalization, stability, and versatility, a key feature to increase the uses of this interesting family of polymers.
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Polyhydroxyalkanoate (PHA) Biopolyesters - Emerging and Major Products of Industrial Biotechnology. THE EUROBIOTECH JOURNAL 2022. [DOI: 10.2478/ebtj-2022-0007] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Abstract
Background: Industrial Biotechnology (“White Biotechnology”) is the large-scale production of materials and chemicals using renewable raw materials along with biocatalysts like enzymes derived from microorganisms or by using microorganisms themselves (“whole cell biocatalysis”). While the production of ethanol has existed for several millennia and can be considered a product of Industrial Biotechnology, the application of complex and engineered biocatalysts to produce industrial scale products with acceptable economics is only a few decades old. Bioethanol as fuel, lactic acid as food and PolyHydroxyAlkanoates (PHA) as a processible material are some examples of products derived from Industrial Biotechnology.
Purpose and Scope: Industrial Biotechnology is the sector of biotechnology that holds the most promise in reducing our dependence on fossil fuels and mitigating environmental degradation caused by pollution, since all products that are made today from fossil carbon feedstocks could be manufactured using Industrial Biotechnology – renewable carbon feedstocks and biocatalysts. To match the economics of fossil-based bulk products, Industrial Biotechnology-based processes must be sufficiently robust. This aspect continues to evolve with increased technological capabilities to engineer biocatalysts (including microorganisms) and the decreasing relative price difference between renewable and fossil carbon feedstocks. While there have been major successes in manufacturing products from Industrial Biotechnology, challenges exist, although its promise is real. Here, PHA biopolymers are a class of product that is fulfilling this promise.
Summary and Conclusion: The authors illustrate the benefits and challenges of Industrial Biotechnology, the circularity and sustainability of such processes, its role in reducing supply chain issues, and alleviating societal problems like poverty and hunger. With increasing awareness among the general public and policy makers of the dangers posed by climate change, pollution and persistent societal issues, Industrial Biotechnology holds the promise of solving these major problems and is poised for a transformative upswing in the manufacture of bulk chemicals and materials from renewable feedstocks and biocatalysts.
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Zhang M, Wang X, Yang J, Wang D, Liang J, Zhou L. Nitrogen removal performance of high ammonium and high salt wastewater by adding carbon source from food waste fermentation with different acidogenic metabolic pathways. CHEMOSPHERE 2022; 292:133512. [PMID: 34990718 DOI: 10.1016/j.chemosphere.2022.133512] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 12/27/2021] [Accepted: 12/31/2021] [Indexed: 06/14/2023]
Abstract
Food waste fermentation liquid components, mainly lactate and volatile fatty acids (VFAs), can be used as alternative carbon sources to improve the nitrogen removal efficiency. To investigate the effects of carbon sources generated from food waste (FW) fermentation liquid on nitrogen removal for the treatment of high ammonium and high salt wastewater (HAHS), the lactate, acetate, propionate, butyrate, and their mixtures were added in activated sludge systems operating over 130-days. Lactate and butyrate inhibited nitrifiers by enriching polyphosphate accumulating organisms (PAOs), thus deteriorated nitrogen removal after a long-term period. When fed with acetate or propionate, the dominant glycogen accumulating organisms (GAOs) groups simultaneously realized nitrification and denitrification. The mixed carbon source enhanced microbial community robustness and the transformation of Polyhydroxyalkanoate (PHA), advancing nitrogen removal efficiency. Mixed carbon source of acetate-propionate was preferred, in which the coexisting groups of GAOs and PAOs enhanced the denitrification rate of denitrifiers and kept balancing with nitrifiers, where the highest denitrification rate (DNR) was 1.05 mg N/(h·g VSS) and the average TN removal efficiency was above 98% under the maximum nitrogen load of 0.48 kg N/(kg VSS·d). In addition, the primary pathways of nitrogen removal were heterotrophic nitrification and denitrification, since the autotrophic nitrifiers were inhibited by the free ammonium and salinity. This study illustrated the differences of nitrogen removal performance and mechanisms with fermentation liquid components as carbon sources processing of HAHS wastewater.
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Affiliation(s)
- Mingjiang Zhang
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Xiaomeng Wang
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jiawei Yang
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Dianzhan Wang
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jianru Liang
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Lixiang Zhou
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China; Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing, 210095, China.
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Hossain MI, Cheng L, Cord-Ruwisch R. Sustained and enhanced anaerobic removal of COD and nitrogen in a zeolite amended glycogen accumulating organism dominated biofilm process. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 807:150602. [PMID: 34592273 DOI: 10.1016/j.scitotenv.2021.150602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 08/27/2021] [Accepted: 09/22/2021] [Indexed: 06/13/2023]
Abstract
Activated sludge, the most widely used biological wastewater treatment process is known to be expensive to operate, largely due to energy expense for oxygen transfer into the bulk wastewater solution. The alternative of using passive aeration facilitates oxygen supply directly from the air resulting in aeration energy savings. The current study demonstrated sustained and improved removal of chemical oxygen demand (COD) and nitrogen in a zeolite modified glycogen accumulating organisms (GAOs) dominated biofilm reactor, which achieved anaerobic removal of COD and ammonium by the activity of GAOs and zeolite, respectively. Draining of the batch-operated reactor enabled the biofilm to directly uptake oxygen from air (passive aeration) to carry out simultaneous nitrification and denitrification due to the activity of GAO (Candidatus competibacter) and nitrifying bacteria (Nitrosomonas and Nitrospira). Under stable long-term (4-months) operation, the process achieved COD and nitrogen removal at rates of 1354 and 79.1 g m-3 d-1, respectively. The biofilm process demonstrated >90% nitrogen removal efficiency in multi-cycle (4/8 cycles) strategy with a short treatment time of 8 h. Due to the passive aeration scheme, the energy consumption of the proposed wastewater treatment process is calculated to be about 13-times less than that of traditional activated sludge process. Therefore, the Passive Aeration Simultaneous Nitrification and Denitrification (PASND) biofilm process is a promising low-energy treatment step for efficient removal of COD and nitrogen from wastewater.
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Affiliation(s)
- Md Iqbal Hossain
- School of Engineering and Information Technology, Murdoch University, 90 South Street, Murdoch 6150, Western Australia, Australia.
| | - Liang Cheng
- School of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China.
| | - Ralf Cord-Ruwisch
- School of Engineering and Information Technology, Murdoch University, 90 South Street, Murdoch 6150, Western Australia, Australia.
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A Critical Review on the Economically Feasible and Sustainable Poly(3-Hydroxybutyrate- co-3-hydroxyvalerate) Production from Alkyl Alcohols. Polymers (Basel) 2022; 14:polym14040670. [PMID: 35215584 PMCID: PMC8876610 DOI: 10.3390/polym14040670] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 02/03/2022] [Accepted: 02/05/2022] [Indexed: 01/14/2023] Open
Abstract
Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(3HB-co-3HV)) is the most studied short-chain-length polyhydroxyalkanoates (PHA) with high application importance in various fields. The domination of high-cost propionate and valerate over other 3-hydroxyvalerate (3HV) precursors owing to their wide preference among PHA-producing bacteria has hindered the development of diverse production processes. As alkyl alcohols are mainly produced from inexpensive starting materials through oxo synthesis, they contribute a cost-effective advantage over propionate and valerate. Moreover, alkyl alcohols can be biosynthesized from natural substrates and organic wastes. Despite their great potential, their toxicity to most PHA-producing bacteria has been the major drawback for their wide implementation as 3HV precursors for decades. Although the standard PHA-producing bacteria Cupriavidus necator showed promising alcohol tolerance, the 3HV yield was discouraging. Continuous discovery of alkyl alcohols-utilizing PHA-producing bacteria has enabled broader choices in 3HV precursor selection for diverse P(3HB-co-3HV) production processes with higher economic feasibility. Besides continuous effort in searching for promising wild-type strains, genetic engineering to construct promising recombinant strains based on the understanding of the mechanisms involved in alkyl alcohols toxicity and tolerance is an alternative approach. However, more studies are required for techno-economic assessment to analyze the economic performance of alkyl alcohol-based production compared to that of organic acids.
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Liu W, Shen C, Liu C, Zhang S, Hao S, Peng Y, Li J. Achieving stable mainstream nitrogen and phosphorus removal assisted by hydroxylamine addition in a continuous partial nitritation/anammox process from real sewage. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 794:148478. [PMID: 34217093 DOI: 10.1016/j.scitotenv.2021.148478] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/31/2021] [Accepted: 06/11/2021] [Indexed: 06/13/2023]
Abstract
Hydroxylamine (NH2OH) as the putative intermediate for anammox ensures the robustness of partial nitritation/anammox (PN/A) process; however, the feasible for NH2OH addition to improve the stability of PN/A process under low-strength ammonia (NH4+-N) condition need to be further investigated. In this study, the restoration and steady operation of mainstream PN/A process were investigated to treat real sewage with in situ NH2OH added in a continuous alternating anoxic/aerobic with integrated fixed-film activated sludge (A3-IFAS) reactor. Results showed that the deteriorated PN/A process caused by nitrate (NO3--N) built-up was rapidly restored with a distinct decrease of the NO3--Nproduced/NH4+-Nconsumed ratio from 28.7% to <10.0% within 20 days, after 5 mg N/L of NH2OH was added daily into the aerobic zone of A3-IFAS reactor. After 230 days of operation, the average total nitrogen (TN) and phosphate (PO43--P) removal efficiencies of 80.8% and 91.5%, respectively were stably achieved, with average effluent sCOD, NH4+-N, TN and PO43--P concentrations reaching 23.1, 2.3, 7.7 and 0.4 mg/L, respectively. Microbial community characterization revealed Candidatus Brocadia (3.60% and 2.92%) and Ignavibacteriae (1.56% and 2.66%) as the dominant anammox bacteria and denitrifying bacteria, respectively, jointly attached in the biofilm_1 and biofilm_2, while Candidatus Microthrix (5.17%) dominant in floc sludge was main responsible for phosphorus removal. This study confirmed that NH2OH addition is an effective strategy for nitrite-oxidizing bacteria suppression, contributing to the in situ restoration of PN/A process and high stable mainstream nitrogen and phosphorus removal in a continuous PN/A process from real sewage.
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Affiliation(s)
- Wenlong Liu
- College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Chen Shen
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing 100124, China
| | - Chao Liu
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing 100124, China
| | - Shujun Zhang
- Beijing Drainage Group Co. Ltd (BDG), Beijing 100022, China
| | - Shufeng Hao
- Beijing Drainage Group Co. Ltd (BDG), Beijing 100022, China
| | - Yongzhen Peng
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing 100124, China
| | - Jun Li
- College of Environment, Zhejiang University of Technology, Hangzhou 310014, China.
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Wang C, Qiao S, Bi Z, Zhou J. Nitrate removal by anammox biomass with intracellular carbon source as electron donors via DNRA pathway. ENVIRONMENTAL RESEARCH 2021; 200:111390. [PMID: 34052243 DOI: 10.1016/j.envres.2021.111390] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 05/20/2021] [Accepted: 05/20/2021] [Indexed: 06/12/2023]
Abstract
In this work, a novel nitrate (NO3-) reduction pathway by anaerobic ammonium oxidation (anammox) biomass was firstly discovered with the intracellular carbon sources as the only electron donors. And the possible reaction mechanism was deduced to be intracellular dissimilatory nitrate reduction to ammonium (DNRA) pathway according to the experimental results. In batch experiments, without any external electron donors, NO3--N (about 50 mg/L) was reduced to N2 within 48 h, and a small amount of NO2--N was detected (the maximum of 2 mg/L) with the anammox biomass concentration of 4400 mg/L. Acetylene (4.46 mmol/L) addition resulted in obvious NH4+ accumulation during NO3- degradation by anammox biomass, since acetylene mainly interfered in hydrazine (N2H4) generation from NH4+ and NO. Without HCO3- addition, the NO3--N degradation rate was slower than that with HCO3- addition. Simultaneously, glycogen contents inside anammox biomass decreased to 133.22 ± 1.21 mg/g VSS and 129.79 ± 1.21 mg/g VSS with and without HCO3-, respectively, from 142.20 ± 0.61 mg/g VSS. In the long-term experiment, anammox biomass stably degraded NO3--N without external electron donors addition, and the maximum removal efficiency of NO3--N reached 55.4%. The above results indicated the anammox bacteria utilized the DNRA pathway to reduce NO3- to NO2- and further NH4+, then normal anammox metabolism would continue to convert the produced NO2- and NH4+ to N2. The intracellular stored carbon sources (e.g., glycogen) were supposed to be electron donors for NO3- degradation. This capability would enhance the viability and living space of anammox bacteria in different natural ecosystems, and make it plausible that complete nitrogen removal could be implemented only by the anammox process.
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Affiliation(s)
- Chao Wang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China.
| | - Sen Qiao
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China.
| | - Zhen Bi
- School of Environment Science and Engineering, Suzhou University of Science and Technology, Suzhou, 215002, China.
| | - Jiti Zhou
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China.
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Santorio S, Couto AT, Amorim CL, Val Del Rio A, Arregui L, Mosquera-Corral A, Castro PML. Sequencing versus continuous granular sludge reactor for the treatment of freshwater aquaculture effluents. WATER RESEARCH 2021; 201:117293. [PMID: 34146761 DOI: 10.1016/j.watres.2021.117293] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 04/28/2021] [Accepted: 05/21/2021] [Indexed: 06/12/2023]
Abstract
Ammonium and nitrite levels in water are crucial for fish health preservation and growth maintenance in freshwater aquaculture farms, limiting water recirculation. The aim of the present work was the evaluation and comparison of two granular sludge reactors which were operated to treat freshwater aquaculture streams at laboratory-scale: an Aerobic Granular Sludge - Sequencing Batch Reactor (AGS-SBR) and a Continuous Flow Granular Reactor (CFGR). Both units were fed with a synthetic medium mimicking an aquaculture recycling water (1.9-2.9 mg N/L), with low carbon content, and operational temperature varied between 17 and 25 °C. The AGS-SBR, inoculated with mature granules from a full-scale wastewater treatment plant, achieved high carbon and ammonium removal during the 157 operational days. Even at low hydraulic retention time (HRT), varying from 474 to 237 min, ammonium removal efficiencies of approximately 87-100% were observed, with an ammonium removal rate of approximately 14.5 mg NH4+-N/(L⋅d). Partial biomass washout occurred due to the extremely low carbon and nitrogen concentrations in the feeding, which could only support the growth of a small portion of bacteria, but no major changes on the reactor removal performance were observed. The CFGR was inoculated with activated sludge and operated for 98 days. Biomass granulation occurred in 7 days, improving the settling properties due to a high up-flow velocity of 11 m/h and an applied HRT of 5 min. The reactor presented mature granules after 32 days, achieving an average diameter of 1.9 mm at day 63. The CFGR ammonium removal efficiencies were of approximately 10-20%, with ammonium removal rates of 90.0 mg NH4+-N/(L⋅d). The main biological processes taking place in the AGS-SBR were nitrification and heterotrophic growth, while in the CFGR the ammonium removal occurred only by heterotrophic assimilation, with the reactor also presenting complete and partial denitrification, which caused nitrite production. Comparing both systems, the CFGR achieved 6 times higher ammonium removal rates than the AGS-SBR, being suitable for treating extremely high flows. On the other hand, the AGS-SBR removed almost 100% of ammonium content in the wastewater, discharging a better quality effluent, less toxic for the fish but treated lower flows.
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Affiliation(s)
- Sergio Santorio
- CRETUS Institute, Department of Chemical Engineering, Universidade de Santiago de Compostela, Rúa Lope Gómez de Marzoa s/n, E-15705 Santiago de Compostela, Spain.
| | - Ana T Couto
- Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Rua Diogo Botelho 1327, 4169-005 Porto, Portugal
| | - Catarina L Amorim
- Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Rua Diogo Botelho 1327, 4169-005 Porto, Portugal
| | - Angeles Val Del Rio
- CRETUS Institute, Department of Chemical Engineering, Universidade de Santiago de Compostela, Rúa Lope Gómez de Marzoa s/n, E-15705 Santiago de Compostela, Spain
| | - Luz Arregui
- Grupo Tres Mares, S.L. Lires s/n, E-15270 Cee, A Coruña, Spain
| | - Anuska Mosquera-Corral
- CRETUS Institute, Department of Chemical Engineering, Universidade de Santiago de Compostela, Rúa Lope Gómez de Marzoa s/n, E-15705 Santiago de Compostela, Spain
| | - Paula M L Castro
- Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Rua Diogo Botelho 1327, 4169-005 Porto, Portugal
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Roibás-Rozas A, Val Del Rio A, Hospido A, Mosquera-Corral A. Strategies for the valorisation of a protein-rich saline waste stream into polyhydroxyalkanoates (PHA). BIORESOURCE TECHNOLOGY 2021; 334:124964. [PMID: 33958271 DOI: 10.1016/j.biortech.2021.124964] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 03/04/2021] [Accepted: 03/05/2021] [Indexed: 06/12/2023]
Abstract
Saline Mussels Cooking Wastewater was valorised to produce PHA with Mixed Microbial Cultures (MMC). Due to the high protein content (1.8-5.7 g CODPROT/L), PHA accumulating capacity was below 10%, so several strategies were tested. In the acidification unit, Na(HCO3) was added, increasing protein conversion into Volatile Fatty Acids (VFA) from 10.3% to 69.2% and subsequent PHA accumulation from 6.9 to 14.7%. In the enrichment unit, the incorporation of a settling stage after the feast phase provoked a shift in the proteins' oxidation from the feast to the famine phase, where the nitrogen released in the famine is used by the MMC for growth. This increased the biomass concentration and the tolerated COD (from 1.6 to 4.2 g VSS/L and from 2.2 to 4.38 g COD/L). Finally, varying the proteins/VFA ratio for MMC acclimation to proteins allowed increasing PHA accumulation from 8.8 to 41.5%.
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Affiliation(s)
- Alba Roibás-Rozas
- CRETUS Institute, Department of Chemical Engineering, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Galicia, Spain.
| | - Angeles Val Del Rio
- CRETUS Institute, Department of Chemical Engineering, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Galicia, Spain
| | - Almudena Hospido
- CRETUS Institute, Department of Chemical Engineering, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Galicia, Spain
| | - Anuska Mosquera-Corral
- CRETUS Institute, Department of Chemical Engineering, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Galicia, Spain
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