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Wu H, Li A, Zhang H, Gao S, Li S, Cai J, Yan R, Xing Z. The potential and sustainable strategy for swine wastewater treatment: Resource recovery. CHEMOSPHERE 2023; 336:139235. [PMID: 37343397 DOI: 10.1016/j.chemosphere.2023.139235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 05/30/2023] [Accepted: 06/14/2023] [Indexed: 06/23/2023]
Abstract
Swine wastewater is highly polluted with complex and harmful substances that require effective treatment to minimize environmental damage. There are three commonly used biological technologies for treating swine wastewater: conventional biological technology (CBT), microbial electrochemical technology (MET), and microalgae technology (MT). However, there is a lack of comparison among these technologies and a lack of understanding of their unique advantages and efficient operation strategies. This review aims to compare and contrast the characteristics, influencing factors, improvement methods, and microbial mechanisms of each technology. CBT is cost-effective but has low resource recovery efficiency, while MET and MT have the highest potential for resource recovery. However, all three technologies are affected by various factors and toxic substances such as heavy metals and antibiotics. Improved methods include exogenous/endogenous enhancement, series reactor operation, algal-bacterial symbiosis system construction, etc. Though MET is limited by construction costs, CBT and MT have practical applications. While swine wastewater treatment processes have developed automatic control systems, the application need further promotion. Furthermore, key functional microorganisms involved in CBT's pollutant removal or transformation have been detected, as have related genes. The unique electroactive microbial cooperation mode and symbiotic mode of MET and MT were also revealed, respectively. Importantly, the future research should focus on broadening the scope and scale of engineering applications, preventing and controlling emerging pollutants, improving automated management level, focusing on microbial synergistic metabolism, enhancing resource recovery performance, and building a circular economy based on low-cost and resource utilization.
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Affiliation(s)
- Heng Wu
- College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling, Shaanxi, 712100, PR China.
| | - Anjie Li
- College of Grassland Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, PR China
| | - Huaiwen Zhang
- College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling, Shaanxi, 712100, PR China
| | - Sicong Gao
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, 712100, PR China
| | - Suqi Li
- College of Life and Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, PR China
| | - Jindou Cai
- School of Culture and Tourism, Chongqing City Management College, Chongqing, 402160, PR China
| | - Ruixiao Yan
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, 712100, PR China
| | - Zhilin Xing
- School of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing, 400054, PR China.
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Paganin ACL, Monzani PS, Carazzolle MF, Araujo RB, Gonzalez-Esquerra R, Haese D, Kill JL, Rezende GS, de Lima CG, Malavazi I, de Melo Freire CC, da Cunha AF. Assessment of cecal microbiota modulation from piglet dietary supplementation with copper. BMC Microbiol 2023; 23:92. [PMID: 37003969 PMCID: PMC10064724 DOI: 10.1186/s12866-023-02826-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 03/15/2023] [Indexed: 04/03/2023] Open
Abstract
BACKGROUND Swine production expanded in the last decades. Efforts have been made to improve meat production and to understand its relationship to pig gut microbiota. Copper (Cu) is a usual supplement to growth performance in animal production. Here, two performance studies were conducted to investigate the effects of three different sources of Cu on the microbiota of piglets. A total of 256 weaned piglets were randomly allocated into 4 treatments (10 replicates per treatment of 4 piglets per pen in Trial 1 and 8 replicates of 3 piglets per pen in Trial 2). Treatments included a control group (fed 10 mg/kg of Cu from CuSO4), a group fed at 160 mg/kg of Copper (II) sulfate (CuSO4) or tri-basic copper chloride (TBCC), and a group fed with Cu methionine hydroxy analogue chelated (Cu-MHAC) at 150, 80, and 50 mg/kg in Phases 1 (24-35 d), 2 (36-49 d), and 3 (50-70 d), respectively. At 70 d, the cecum luminal contents from one pig per pen were collected and polled for 16 S rRNA sequencing (V3/V4 regions). Parameters were analyzed in a completely randomized block design, in which each experiment was considered as a block. RESULTS A total of 1337 Operational Taxonomic Units (OTUs) were identified. Dominance and Simpson ecological metrics were statistically different between control and treated groups (P < 0.10) showing that different Cu sources altered the gut microbiota composition with the proliferation of some bacteria that improve gut health. A high abundance of Prevotella was observed in all treatments while other genera were enriched and differentially modulated, according to the Cu source and dosage. The supplementation with Cu-MHAC can modify a group of bacteria involved in feed efficiency (FE) and short chain fatty acids (SCFA) production (Clostridium XIVa, Desulfovibrio, and Megasphera). These bacteria are also important players in the activation of ghrelin and growth hormones that were previously reported to correlate with Cu-MHAC supplementation. CONCLUSIONS These results indicated that some genera seem to be directly affected by the Cu source offered to the animals. TBCC and Cu-MHAC (even in low doses) can promote healthy modifications in the gut bacterial composition, being a promising source of supplementation for piglets.
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Affiliation(s)
| | - Paulo Sérgio Monzani
- Faculdade de Zootecnia e Engenharia de Alimentos, Departamento de Medicina Veterinária, Universidade de São Paulo, Pirassununga, SP, Brasil
| | | | | | | | - Douglas Haese
- Centro de Tecnologia Animal Ltda, Espirito Santo - ES, Domingos Martins, Brasil
| | - João L Kill
- Centro de Tecnologia Animal Ltda, Espirito Santo - ES, Domingos Martins, Brasil
| | - Graziela Silva Rezende
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, SP, Brasil
| | - César Gonçalves de Lima
- Faculdade de Zootecnia e Engenharia de Alimentos, Departamento de Medicina Veterinária, Universidade de São Paulo, Pirassununga, SP, Brasil
| | - Iran Malavazi
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, SP, Brasil
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Dalantai T, Rhee C, Kim DW, Yu SI, Shin J, Triolo JM, Shin SG. Complex network analysis of slaughterhouse waste anaerobic digestion: From failure to success of long-term operation. BIORESOURCE TECHNOLOGY 2022; 361:127673. [PMID: 35878765 DOI: 10.1016/j.biortech.2022.127673] [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: 05/31/2022] [Revised: 07/17/2022] [Accepted: 07/19/2022] [Indexed: 06/15/2023]
Abstract
The study explored slaughterhouse waste (SHW) as prime feedstock associated with and without supplement of an external slowly degradable lignocellulosic carbon source to overcome the synergistic co-inhibitions of ammonia and fatty acids. Long-term solid-state digestion (SSD) and liquid-state digestion (LSD) were investigated using a mixture of pork liver and fat. At 2.0 g volatile solids (VS) L-1 d-1 of organic loading rate (OLR), the two reactors of SSD experienced operational instability due to ammonia inhibition and volatile fatty acid (VFA) accumulation while LSD successfully produced 0.725 CH4 L CH4 g-1VS during 197 d of working days under unfavorable condition with high total ammonia nitrogen (>4.7 g/L) and VFAs concentration (>1.9 g/L). The network analysis between complex microflora and operational parameters provided an insight for sustainable biogas production using SHW. Among all, hydrogenotrophic methanogens have shown better resistance than acetoclastic methanogens.
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Affiliation(s)
- Tergel Dalantai
- Department of Energy Engineering, Future Convergence Technology Research Institute, Gyeongsang National University, 33 Dongjin-ro, Jinju, Gyeongnam 52828, Republic of Korea
| | - Chaeyoung Rhee
- Department of Energy Engineering, Future Convergence Technology Research Institute, Gyeongsang National University, 33 Dongjin-ro, Jinju, Gyeongnam 52828, Republic of Korea
| | - Dae Wook Kim
- Department of Energy Engineering, Future Convergence Technology Research Institute, Gyeongsang National University, 33 Dongjin-ro, Jinju, Gyeongnam 52828, Republic of Korea
| | - Sung Il Yu
- Department of Energy Engineering, Future Convergence Technology Research Institute, Gyeongsang National University, 33 Dongjin-ro, Jinju, Gyeongnam 52828, Republic of Korea; School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology, 50 UNIST-gil, Ulju-gun, Ulsan 44919, Republic of Korea
| | - Juhee Shin
- Department of Energy Engineering, Future Convergence Technology Research Institute, Gyeongsang National University, 33 Dongjin-ro, Jinju, Gyeongnam 52828, Republic of Korea
| | - Jin Mi Triolo
- Department of Energy Engineering, Future Convergence Technology Research Institute, Gyeongsang National University, 33 Dongjin-ro, Jinju, Gyeongnam 52828, Republic of Korea.
| | - Seung Gu Shin
- Department of Energy Engineering, Future Convergence Technology Research Institute, Gyeongsang National University, 33 Dongjin-ro, Jinju, Gyeongnam 52828, Republic of Korea; Department of Energy System Engineering, Gyeongsang National University, 33 Dongjin-ro, Jinju, Gyeongnam 52828, Republic of Korea
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4
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Zhou H, Jiang J, Zhao Q, Li L, Wang K, Wei L. Effects of organic loading rates on high-solids anaerobic digestion of food waste in horizontal flow reactor: Methane production, stability and mechanism. CHEMOSPHERE 2022; 293:133650. [PMID: 35063566 DOI: 10.1016/j.chemosphere.2022.133650] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 01/11/2022] [Accepted: 01/14/2022] [Indexed: 06/14/2023]
Abstract
To maximize the methane production efficiency of high-solids anaerobic digestion (HSAD) of food waste (FW), a horizontal flow reactor was operated under mesophilic, semi-continuous condition at organic loading rates (OLRs) ranging from 1.00 to 13.80 kg-VS/(m3 d). The gas production, substrate transformation, and microbial community characteristics of the horizontal flow HSAD reactor were evaluated. The results indicated that the methane yield (0.173-0.516 L/(g d)) fluctuated with the increasing OLR, volumetric methane production rate (0.25-5.69 L/(L d)) increased with increasing OLR, and the volatile solids (VS) reduction rate ranged between 83.30% and 93.05%. The relationship of biogas or methane production with OLR and HRT in the horizontal flow HSAD reactor were characterized with an empirical equation. The concentrations of soluble COD and volatile fatty acid exhibited significant fluctuations, and free ammonia-nitrogen peaked at the OLR of 13.80 kg-VS/(m3 d). Microbial community analysis revealed that the methanogenic metabolic pathway changes along the propelling direction of the horizontal flow HSAD reactor from CH3COOH and H2/CO2 pathways to CH3COOH, H2/CO2, and H2/methyl co-dominant pathways. These results provide theoretical support for stable methane production from FW and deeper insight into horizontal flow HSAD for FW treatment.
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Affiliation(s)
- Huimin Zhou
- School of Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Junqiu Jiang
- School of Environment, Harbin Institute of Technology, Harbin, 150090, China.
| | - Qingliang Zhao
- School of Environment, Harbin Institute of Technology, Harbin, 150090, China; State Key Laboratory of Urban Water Resources and Environments (SKLUWRE), Harbin Institute of Technology, Harbin, 150090, China.
| | - Lili Li
- School of Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Kun Wang
- School of Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Liangliang Wei
- School of Environment, Harbin Institute of Technology, Harbin, 150090, China; State Key Laboratory of Urban Water Resources and Environments (SKLUWRE), Harbin Institute of Technology, Harbin, 150090, China
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Guimarães de Oliveira M, Marques Mourão JM, Souza Silva FS, Bezerra Dos Santos A, Lopes Pereira E. Effect of microaerophilic treatment on swine wastewater (SWW) treatment: Engineering and microbiological aspects. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 299:113598. [PMID: 34481377 DOI: 10.1016/j.jenvman.2021.113598] [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: 04/27/2021] [Revised: 07/22/2021] [Accepted: 08/21/2021] [Indexed: 06/13/2023]
Abstract
The microaerobic process on swine wastewater (SWW) treatment was investigated, evaluating its effect on organic matter hydrolysis and removal, biogas production, operational stability, and microbial community structure. UASB reactors operating under higher organic loading rates (OLRs) and lower hydraulic retention times (HRTs) than those found in the SWW treatment literature were also assessed. The microaerophilic reactor R2 presented a higher total and particulate organic matter removals and operational stability than the anaerobic reactor R1, reaching CODP removals of 79.4 ± 4.6%. In the specific methanogenic activity (SMA) tests, the microaerobic sludge (R2) showed hydrolytic and acetogenic/methanogenic activity superior to inoculum and anaerobic sludge (R1). The microbiological evaluation of R2 revealed the high presence of hydrolytic microorganisms, therefore justifying the higher hydrolytic activity found in the SMA tests and higher particulate organic matter removal found in the microaerobic reactor.
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Affiliation(s)
| | - José Marcos Marques Mourão
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | | | - André Bezerra Dos Santos
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - Erlon Lopes Pereira
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil
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Vendruscolo ECG, Mesa D, Rissi DV, Meyer BH, de Oliveira Pedrosa F, de Souza EM, Cruz LM. Microbial communities network analysis of anaerobic reactors fed with bovine and swine slurry. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 742:140314. [PMID: 33167293 DOI: 10.1016/j.scitotenv.2020.140314] [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: 03/01/2020] [Revised: 05/18/2020] [Accepted: 06/15/2020] [Indexed: 05/28/2023]
Abstract
Anaerobic digestion can produce biogas as an eco-friendly energy source, driven by a microbial community-dependent process and, as such, suffer influences from many biotic and abiotic factors. Understanding the players and how they interact, the mechanisms involved, what the factors are, and how they influence the biogas process and production is an important way to better control it and make it more efficient. Metagenomic approach is a powerful tool to assess microbial diversity and further, allow correlating changes in microbial communities with multiple factors in virtually all environments. In the present study, we used metagenomic approach to assess microbial community structure changes in two biodigesters, differing in their biogas production capacity, architecture, and feed. A total of 1,440,096 reads of the 16S rRNA gene V4 region were obtained and analyzed. The main bacterial phyla were Firmicutes and Bacteroidetes in both biodigesters, but the biodiversity was greater in the Upflow Anaerobic Sludge Blanket (UASB) reactor fed with bovine manure than in the Continuous Stirred Tank Reactor (CSTR) fed with swine manure, which also correlated with an increase in biogas or methane production. Microbial community structure associated with biodigesters changed seasonally and depended on animal growth stage. Random forest algorithm analysis revealed key microbial taxa for each biodigester. Candidatus Cloacomonas, Methanospirillum, and Methanosphaera were the marker taxa for UASB and the archaea groups Methanobrevibacter and Candidatus Methanoplasma were the marker taxa for CSTR. A high abundance of Candidatus Methanoplasma and Marinimicrobia SAR406 clade suggested lower increments in methane production. Network analysis pointed to negative and positive associations and specific key groups, essential in maintaining the anaerobic digestion (AD) process, as being uncultured Parcubacteria bacteria, Candidatus Cloacomonas, and Candidatus Methanoplasma groups, whose functions in AD require investigation.
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Affiliation(s)
| | - Dany Mesa
- Department of Biochemistry and Molecular Biology, Federal University of Paraná, Av. Coronel Francisco H. dos Santos,100, CP 19031, Centro Politécnico, Curitiba, PR, 81531-980, Brazil
| | - Daniel Vasconcelos Rissi
- Sector of Professional and Technological Education, Federal University of Paraná, R. Dr. Alcides Vieira Arcoverde, 1225 - Jardim das Américas, Curitiba, PR, 81520-260, Brazil
| | - Bruno Henrique Meyer
- Department of Informatics, Federal University of Paraná, R. Evaristo F. Ferreira da Costa, 383-391 - Jardim das Américas, Curitiba, PR, 82590-300, Brazil
| | - Fábio de Oliveira Pedrosa
- Department of Biochemistry and Molecular Biology, Federal University of Paraná, Av. Coronel Francisco H. dos Santos,100, CP 19031, Centro Politécnico, Curitiba, PR, 81531-980, Brazil
| | - Emanuel Maltempi de Souza
- Department of Biochemistry and Molecular Biology, Federal University of Paraná, Av. Coronel Francisco H. dos Santos,100, CP 19031, Centro Politécnico, Curitiba, PR, 81531-980, Brazil
| | - Leonardo Magalhães Cruz
- Department of Biochemistry and Molecular Biology, Federal University of Paraná, Av. Coronel Francisco H. dos Santos,100, CP 19031, Centro Politécnico, Curitiba, PR, 81531-980, Brazil; Department of Informatics, Federal University of Paraná, R. Evaristo F. Ferreira da Costa, 383-391 - Jardim das Américas, Curitiba, PR, 82590-300, Brazil
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7
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Fonseca RF, de Oliveira GHD, Zaiat M. Modeling anaerobic digestion metabolic pathways for antibiotic-contaminated wastewater treatment. Biodegradation 2020; 31:341-368. [PMID: 33040265 DOI: 10.1007/s10532-020-09914-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 09/18/2020] [Indexed: 11/26/2022]
Abstract
Anaerobic digestion has been used to treat antibiotic-contaminated wastewaters. However, it is not always effective, since biodegradation is the main removal mechanism and depends on the compound chemical characteristics and on how microbial metabolic pathways are affected by the reactor operational conditions and hydrodynamic characteristics. The aim of this study was to develop a mathematical model to describe 16 metabolic pathways of an anaerobic process treating sulfamethazine-contaminated wastewater. Contois kinetics and a useful reaction volume term were used to represent the biomass concentration impact on bed porosity in a N continuously stirred tank modeling approach. Two sulfamethazine removal hypotheses were evaluated: an apparent enzymatic reaction and a cometabolic degradation. Additionally, long-term modeling was developed to describe how the operational conditions affected the performance of the process. The best degradation correlations were associated with the consumption of carbohydrates, proteins and it was inversely related to acetic acid production during acidogenesis.
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Affiliation(s)
- Rafael Frederico Fonseca
- Biological Processes Laboratory, Center for Research, Development and Innovation in Environmental Engineering, São Carlos School of Engineering (EESC), University of São Paulo (USP), Engenharia Ambiental - Bloco 4-F, Av. João Dagnone, 1100 - Santa Angelina, São Carlos, SP, 13.563-120, Brazil.
| | - Guilherme Henrique Duarte de Oliveira
- Biological Processes Laboratory, Center for Research, Development and Innovation in Environmental Engineering, São Carlos School of Engineering (EESC), University of São Paulo (USP), Engenharia Ambiental - Bloco 4-F, Av. João Dagnone, 1100 - Santa Angelina, São Carlos, SP, 13.563-120, Brazil
| | - Marcelo Zaiat
- Biological Processes Laboratory, Center for Research, Development and Innovation in Environmental Engineering, São Carlos School of Engineering (EESC), University of São Paulo (USP), Engenharia Ambiental - Bloco 4-F, Av. João Dagnone, 1100 - Santa Angelina, São Carlos, SP, 13.563-120, Brazil
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de Sousa e Silva A, Sales Morais NW, Maciel Holanda Coelho M, Lopes Pereira E, Bezerra dos Santos A. Potentialities of biotechnological recovery of methane, hydrogen and carboxylic acids from agro-industrial wastewaters. ACTA ACUST UNITED AC 2020. [DOI: 10.1016/j.biteb.2020.100406] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Cheng HH, Narindri B, Chu H, Whang LM. Recent advancement on biological technologies and strategies for resource recovery from swine wastewater. BIORESOURCE TECHNOLOGY 2020; 303:122861. [PMID: 32046939 DOI: 10.1016/j.biortech.2020.122861] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 01/18/2020] [Accepted: 01/20/2020] [Indexed: 06/10/2023]
Abstract
Swine wastewater is categorized as one of the agricultural wastewater with high contents of organics and nutrients including nitrogen and phosphorus, which may lead to eutrophication in the environment. Insufficient technologies to remove those nutrients could lead to environmental problems after discharge. Several physical and chemical methods have been applied to treat the swine wastewater, but biological treatments are considered as the promising methods due to the cost effectiveness and performance efficiency along with the production of valuable products and bioenergies. This review summarizes the characteristics of swine wastewaters in the beginning, and briefly describes the current issues on the treatments of swine wastewaters. Several biological techniques, such as anaerobic digestion, A/O process, microbial fuel cells, and microalgae cultivations, and their future aspects will be addressed. Finally, the potentials to reutilize biomass produced during the treatment processes are also presented under the consideration of circular economy.
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Affiliation(s)
- Hai-Hsuan Cheng
- Department of Environmental Engineering, National Cheng Kung University, No. 1, University Road, Tainan 701, Taiwan
| | - Birgitta Narindri
- Department of Environmental Engineering, National Cheng Kung University, No. 1, University Road, Tainan 701, Taiwan
| | - Hsin Chu
- Department of Environmental Engineering, National Cheng Kung University, No. 1, University Road, Tainan 701, Taiwan
| | - Liang-Ming Whang
- Department of Environmental Engineering, National Cheng Kung University, No. 1, University Road, Tainan 701, Taiwan; Sustainable Environment Research Laboratory (SERL), National Cheng Kung University, No. 1, University Road, Tainan 701, Taiwan; Research Center for Energy Technology and Strategy (RCETS), National Cheng Kung University, No. 1, University Road, Tainan 701, Taiwan.
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Nzila A, Razzak SA, Sankara S, Nazal MK, Al-Momani M, Kang GU, Ibal JC, Shin JH. Characterisation and microbial community analysis of lipid utilising microorganisms for biogas formation. PLoS One 2019; 14:e0224989. [PMID: 31703100 PMCID: PMC6839884 DOI: 10.1371/journal.pone.0224989] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 10/25/2019] [Indexed: 12/12/2022] Open
Abstract
In the anaerobic process, fat-oil-grease (FOG) is hydrolysed to long-chain fatty acids (LCFAs) and glycerol (GLYC), which are then used as substrates to produce biogas. The increase in FOG and LCFAs inhibits methanogenesis, and so far, most work investigating this inhibition has been carried out when FOG or LCFAs were used as co-substrates. In the current work, the inhibition of methanogenesis by FOG, LCFAs and GLYC was investigated when used as sole substrates. To gain more insight on the dynamics of this process, the change of microbial community was analysed using 16S rRNA gene amplicon sequencing. The results indicate that, as the concentrations of cooking olive oil (CO, which represents FOG) and LCFAs increase, methanogenesis is inhibited. For instance, at 0.01 g. L-1 of FOG, the rate of biogas formation was around 8 ml.L-1.day-1, and this decreased to <4 ml.L-1.day-1 at 40 g.L-1. Similar results were observed with the use of LCFAs. However, GLYC concentrations up to 100g.L-1 did not affect the rate of biogas formation. Acidic pH, temperature > = 45°C and NaCl > 3% led to a significant decrease in the rate of biogas formation. Microbial community analyses were carried out from samples from 3 different bioreactors (CO, OLEI and GLYC), on day 1, 5 and 15. In each bioreactor, microbial communities were dominated by Proteobacteria, Firmicutes and Bacteroidetes phyla. The most important families were Enterobacteriaceae, Pseudomonadaceae and Shewanellaceae (Proteobacteria phylum), Clostridiacea and Ruminococcaceae (Firmicutes) and Porphyromonadaceae and Bacteroidaceae (Bacteroidetes). In CO bioreactor, Proteobacteria bacteria decreased over time, while those of OLEI and GLYC bioreactors increased. A more pronounced increase in Bacteroidetes and Firmicutes were observed in CO bioreactor. The methanogenic archaea Methanobacteriaceae and Methanocorpusculaceae were identified. This analysis has shown that a set of microbial population is selected as a function of the substrate.
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Affiliation(s)
- Alexis Nzila
- Department of Life Sciences, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia
| | - Shaikh Abdur Razzak
- Departments of Chemical Engineering, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia
| | - Saravanan Sankara
- Department of Life Sciences, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia
| | - Mazen K. Nazal
- Research Institute, Center for Environment and Water, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia
| | - Marwan Al-Momani
- Departments of Mathematics & Statistics, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia
| | - Gi-Ung Kang
- School of Applied Biosciences, College of Agriculture and Life Sciences, Kyungpook National University, Daegu, Republic of Korea
| | - Jerald Conrad Ibal
- School of Applied Biosciences, College of Agriculture and Life Sciences, Kyungpook National University, Daegu, Republic of Korea
| | - Jae-Ho Shin
- School of Applied Biosciences, College of Agriculture and Life Sciences, Kyungpook National University, Daegu, Republic of Korea
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Botello Suárez WA, da Silva Vantini J, Duda RM, Giachetto PF, Cintra LC, Tiraboschi Ferro MI, de Oliveira RA. Predominance of syntrophic bacteria, Methanosaeta and Methanoculleus in a two-stage up-flow anaerobic sludge blanket reactor treating coffee processing wastewater at high organic loading rate. BIORESOURCE TECHNOLOGY 2018; 268:158-168. [PMID: 30077172 DOI: 10.1016/j.biortech.2018.06.091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 06/26/2018] [Accepted: 06/27/2018] [Indexed: 06/08/2023]
Abstract
The effect of the organic loading rate (OLR) on the performance and microbial composition of a two-stage UASB system treating coffee processing wastewater was assessed. The system was operated with OLR up to 18.2 g COD (L d)-1 and effluent recirculation. Methane production and effluent characteristics were monitored. The microbial composition was examined through next-generation sequencing and qPCR from the anaerobic sludge of the first reactor (R1) operated at low and high OLR. The system showed operational stability, obtaining a maximum methane production of 2.2 L CH4 (L d)-1, with a removal efficiency of COD and phenolic compounds of 84 and 73%, respectively. The performance of R1 at high OLR in steady conditions was associated with an appropriate proportion of nutrients (particularly Fe) and a marked increase of the syntrophic bacteria Syntrophus and Candidatus Cloacimonas, and acetoclastic and hydrogenotrophic methanogens, mainly Methanosaeta, Methanoculleus, Methanobacterium and Methanomassiliicoccus.
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Affiliation(s)
- Wilmar Alirio Botello Suárez
- Post-Graduate Program in Agricultural and Livestock Microbiology, São Paulo State University (UNESP), School of Agricultural and Veterinarian Sciences, Jaboticabal, SP, Brazil; Laboratory of Environmental Sanitation, Department of Rural Engineering, São Paulo State University (UNESP), School of Agricultural and Veterinarian Sciences, Jaboticabal, SP, Brazil
| | - Juliana da Silva Vantini
- Post-Graduate Program in Agricultural and Livestock Microbiology, São Paulo State University (UNESP), School of Agricultural and Veterinarian Sciences, Jaboticabal, SP, Brazil; Laboratory of Biochemistry and Molecular Biology, Department of Technology, São Paulo State University (UNESP), School of Agricultural and Veterinarian Sciences, Jaboticabal, SP, Brazil
| | | | | | | | - Maria Inês Tiraboschi Ferro
- Post-Graduate Program in Agricultural and Livestock Microbiology, São Paulo State University (UNESP), School of Agricultural and Veterinarian Sciences, Jaboticabal, SP, Brazil; Laboratory of Biochemistry and Molecular Biology, Department of Technology, São Paulo State University (UNESP), School of Agricultural and Veterinarian Sciences, Jaboticabal, SP, Brazil
| | - Roberto Alves de Oliveira
- Post-Graduate Program in Agricultural and Livestock Microbiology, São Paulo State University (UNESP), School of Agricultural and Veterinarian Sciences, Jaboticabal, SP, Brazil; Laboratory of Environmental Sanitation, Department of Rural Engineering, São Paulo State University (UNESP), School of Agricultural and Veterinarian Sciences, Jaboticabal, SP, Brazil.
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12
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Chiariotti A, Crisà A. Bio-Hydrogen Production From Buffalo Waste With Rumen Inoculum and Metagenomic Characterization of Bacterial and Archaeal Community. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2018. [DOI: 10.3389/fsufs.2018.00013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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13
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Campanaro S, Treu L, Kougias PG, Zhu X, Angelidaki I. Taxonomy of anaerobic digestion microbiome reveals biases associated with the applied high throughput sequencing strategies. Sci Rep 2018; 8:1926. [PMID: 29386622 PMCID: PMC5792648 DOI: 10.1038/s41598-018-20414-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 01/17/2018] [Indexed: 11/20/2022] Open
Abstract
In the past few years, many studies investigated the anaerobic digestion microbiome by means of 16S rRNA amplicon sequencing. Results obtained from these studies were compared to each other without taking into consideration the followed procedure for amplicons preparation and data analysis. This negligence was mainly due to the lack of knowledge regarding the biases influencing specific steps of the microbiome investigation process. In the present study, the main technical aspects of the 16S rRNA analysis were checked giving special attention to the approach used for high throughput sequencing. More specifically, the microbial compositions of three laboratory scale biogas reactors were analyzed before and after addition of sodium oleate by sequencing the microbiome with three different approaches: 16S rRNA amplicon sequencing, shotgun DNA and shotgun RNA. This comparative analysis revealed that, in amplicon sequencing, abundance of some taxa (Euryarchaeota and Spirochaetes) was biased by the inefficiency of universal primers to hybridize all the templates. Reliability of the results obtained was also influenced by the number of hypervariable regions under investigation. Finally, amplicon sequencing and shotgun DNA underestimated the Methanoculleus genus, probably due to the low 16S rRNA gene copy number encoded in this taxon.
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Affiliation(s)
- Stefano Campanaro
- Department of Biology, University of Padova, Via U. Bassi 58/b, 35121, Padova, Italy
| | - Laura Treu
- Department of Environmental Engineering, Technical University of Denmark, 2800, Kgs, Lyngby, Denmark.
| | - Panagiotis G Kougias
- Department of Environmental Engineering, Technical University of Denmark, 2800, Kgs, Lyngby, Denmark
| | - Xinyu Zhu
- Department of Environmental Engineering, Technical University of Denmark, 2800, Kgs, Lyngby, Denmark
| | - Irini Angelidaki
- Department of Environmental Engineering, Technical University of Denmark, 2800, Kgs, Lyngby, Denmark
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Oliveira GHD, Santos-Neto AJ, Zaiat M. Removal of the veterinary antimicrobial sulfamethazine in a horizontal-flow anaerobic immobilized biomass (HAIB) reactor subjected to step changes in the applied organic loading rate. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2017; 204:674-683. [PMID: 28957708 DOI: 10.1016/j.jenvman.2017.09.048] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 08/21/2017] [Accepted: 09/18/2017] [Indexed: 06/07/2023]
Abstract
A bench-scale horizontal-flow anaerobic immobilized biomass (HAIB) reactor treating synthetic swine wastewater was operated under different applied organic loading rates (OLR) through both variations in feed strength and in hydraulic retention time (HRT). The influence of step changes in OLR on the removal of the veterinary antimicrobial sulfamethazine (SMZ) was assessed. The highest observed SMZ removal efficiency, 75 ± 6%, was achieved with an OLR of 2.7 ± 0.4 kg O2 m-3 d-1 when a significant increase in COD removal rate was observed. The SMZ removal rate was positively correlated (r = 0.899) to the COD removal rate in all of the experimental conditions in which the HRT was kept at 24 h, indicating a cometabolic transformation of the antimicrobial. Decreasing the HRT caused a significant decrease in SMZ removal efficiency without affecting the HAIB reactor performance in terms of stability, COD removal or metabolic intermediates production. Functionally equivalent steady states were observed in four different operational phases with similar operating conditions but with widely different behavior in relation to SMZ removal. The experimental results showed the potential of anaerobic technology in removing environmentally relevant concentrations of SMZ, and the possibility of enhancing reactor performance by controlling operating conditions.
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Affiliation(s)
- G H D Oliveira
- Laboratory of Biological Processes, Center for Research, Development and Innovation in Environmental Engineering, São Carlos School of Engineering, University of São Paulo (USP), 1100, João Dagnone Ave., Santa Angelina, 13563-120, São Carlos, São Paulo, Brazil.
| | - A J Santos-Neto
- Institute of Chemistry of São Carlos, University of São Paulo (USP), 400, Trabalhador São-Carlense Ave., 13566-590, São Carlos, São Paulo, Brazil
| | - M Zaiat
- Laboratory of Biological Processes, Center for Research, Development and Innovation in Environmental Engineering, São Carlos School of Engineering, University of São Paulo (USP), 1100, João Dagnone Ave., Santa Angelina, 13563-120, São Carlos, São Paulo, Brazil
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15
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Barros VGD, Duda RM, Vantini JDS, Omori WP, Ferro MIT, Oliveira RAD. Improved methane production from sugarcane vinasse with filter cake in thermophilic UASB reactors, with predominance of Methanothermobacter and Methanosarcina archaea and Thermotogae bacteria. BIORESOURCE TECHNOLOGY 2017; 244:371-381. [PMID: 28783564 DOI: 10.1016/j.biortech.2017.07.106] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 07/19/2017] [Accepted: 07/20/2017] [Indexed: 06/07/2023]
Abstract
Biogas production from sugarcane vinasse has enormous economic, energy, and environmental management potential. However, methane production stability and biodigested vinasse quality remain key issues, requiring better nutrient and alkalinity availability, operational strategies, and knowledge of reactor microbiota. This study demonstrates increased methane production from vinasse through the use of sugarcane filter cake and improved effluent recirculation, with elevated organic loading rates (OLR) and good reactor stability. We used UASB reactors in a two-stage configuration, with OLRs up to 45gCODL-1d-1, and obtained methane production as high as 3LL-1d-1. Quantitative PCR indicated balanced amounts of bacteria and archaea in the sludge (109-1010copiesg-1VS), and of the predominant archaea orders, Methanobacteriales and Methanosarcinales (106-108copiesg-1VS). 16S rDNA sequencing also indicated the thermophilic Thermotogae as the most abundant class of bacteria in the sludge.
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Affiliation(s)
- Valciney Gomes de Barros
- Post-Graduate Program in Agricultural and Livestock Microbiology, São Paulo State University (UNESP), School of Agricultural and Veterinarian Sciences, Jaboticabal, SP, Brazil; Laboratory of Environmental Sanitation, Department of Rural Engineering, São Paulo State University (UNESP), School of Agricultural and Veterinarian Sciences, Jaboticabal, SP, Brazil
| | - Rose Maria Duda
- Laboratory of Environmental Sanitation, Department of Rural Engineering, São Paulo State University (UNESP), School of Agricultural and Veterinarian Sciences, Jaboticabal, SP, Brazil; Faculty of Technology "Nilo de Stéfani", Jaboticabal, SP, Brazil
| | - Juliana da Silva Vantini
- Post-Graduate Program in Agricultural and Livestock Microbiology, São Paulo State University (UNESP), School of Agricultural and Veterinarian Sciences, Jaboticabal, SP, Brazil; Laboratory of Biochemistry and Molecular Biology, Department of Technology, São Paulo State University (UNESP), School of Agricultural and Veterinarian Sciences, Jaboticabal, SP, Brazil
| | - Wellington Pine Omori
- Post-Graduate Program in Agricultural and Livestock Microbiology, São Paulo State University (UNESP), School of Agricultural and Veterinarian Sciences, Jaboticabal, SP, Brazil
| | - Maria Inês Tiraboschi Ferro
- Post-Graduate Program in Agricultural and Livestock Microbiology, São Paulo State University (UNESP), School of Agricultural and Veterinarian Sciences, Jaboticabal, SP, Brazil; Laboratory of Biochemistry and Molecular Biology, Department of Technology, São Paulo State University (UNESP), School of Agricultural and Veterinarian Sciences, Jaboticabal, SP, Brazil
| | - Roberto Alves de Oliveira
- Post-Graduate Program in Agricultural and Livestock Microbiology, São Paulo State University (UNESP), School of Agricultural and Veterinarian Sciences, Jaboticabal, SP, Brazil; Laboratory of Environmental Sanitation, Department of Rural Engineering, São Paulo State University (UNESP), School of Agricultural and Veterinarian Sciences, Jaboticabal, SP, Brazil.
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16
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Design of Indicators of Circular Economy as Instruments for the Evaluation of Sustainability and Efficiency in Wastewater from Pig Farming Industry. WATER 2017. [DOI: 10.3390/w9090653] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Wilkens C, Busk PK, Pilgaard B, Zhang WJ, Nielsen KL, Nielsen PH, Lange L. Diversity of microbial carbohydrate-active enzymes in Danish anaerobic digesters fed with wastewater treatment sludge. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:158. [PMID: 28649277 PMCID: PMC5480151 DOI: 10.1186/s13068-017-0840-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
BACKGROUND Improved carbohydrate-active enzymes (CAZymes) are needed to fulfill the goal of producing food, feed, fuel, chemicals, and materials from biomass. Little is known about how the diverse microbial communities in anaerobic digesters (ADs) metabolize carbohydrates or which CAZymes that are present, making the ADs a unique niche to look for CAZymes that can potentiate the enzyme blends currently used in industry. RESULTS Enzymatic assays showed that functional CAZymes were secreted into the AD environments in four full-scale mesophilic Danish ADs fed with primary and surplus sludge from municipal wastewater treatment plants. Metagenomes from the ADs were mined for CAZymes with Homology to Peptide Patterns (HotPep). 19,335 CAZymes were identified of which 30% showed 50% or lower identity to known proteins demonstrating that ADs make up a promising pool for discovery of novel CAZymes. A function was assigned to 54% of all CAZymes identified by HotPep. Many different α-glucan-acting CAZymes were identified in the four metagenomes, and the most abundant family was glycoside hydrolase family 13, which contains α-glucan-acting CAZymes. Cellulytic and xylanolytic CAZymes were also abundant in the four metagenomes. The cellulytic enzymes were limited almost to endoglucanases and β-glucosidases, which reflect the large amount of partly degraded cellulose in the sludge. No dockerin domains were identified suggesting that the cellulytic enzymes in the ADs studied operate independently. Of xylanolytic CAZymes, especially xylanases and β-xylosidase, but also a battery of accessory enzymes, were present in the four ADs. CONCLUSIONS Our findings suggest that the ADs are a good place to look for novel plant biomass degrading and modifying enzymes that can potentiate biological processes and provide basis for production of a range of added-value products from biorefineries.
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Affiliation(s)
- Casper Wilkens
- Center for Bioprocess Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads, Building 229, 2800 Kongens Lyngby, Denmark
| | - Peter Kamp Busk
- Center for Bioprocess Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads, Building 229, 2800 Kongens Lyngby, Denmark
| | - Bo Pilgaard
- Center for Bioprocess Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads, Building 229, 2800 Kongens Lyngby, Denmark
| | - Wen-Jing Zhang
- Section for Sustainable Biotechnology, Department of Chemistry and Bioscience, Aalborg University, A. C. Meyers Vænge 15, 2450 Copenhagen, Denmark
- Department of Animal Sciences, University of Wisconsin-Madison, Madison, WI 53706 USA
| | - Kåre L. Nielsen
- Center for Microbial Communities, Section for Biotechnology, Department of Chemistry and Bioscience, Aalborg University, Frederiks Bajer Vej 7, 9220 Aalborg, Denmark
| | - Per Halkjær Nielsen
- Center for Microbial Communities, Section for Biotechnology, Department of Chemistry and Bioscience, Aalborg University, Frederiks Bajer Vej 7, 9220 Aalborg, Denmark
| | - Lene Lange
- Center for Bioprocess Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads, Building 229, 2800 Kongens Lyngby, Denmark
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Mazareli RCDS, Duda RM, Leite VD, Oliveira RAD. Anaerobic co-digestion of vegetable waste and swine wastewater in high-rate horizontal reactors with fixed bed. WASTE MANAGEMENT (NEW YORK, N.Y.) 2016; 52:112-121. [PMID: 27055364 DOI: 10.1016/j.wasman.2016.03.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 03/11/2016] [Accepted: 03/14/2016] [Indexed: 06/05/2023]
Abstract
Considering the high waste generation that comes from agriculture and livestock farming, as well as the demand for natural gas, it is necessary to develop sustainable technologies which can reduce environmental impact. There is no available literature on the use of high-rate horizontal anaerobic reactors with fixed bed (HARFB) and continuous feed for the co-digestion of vegetable wastes (VW) and swine wastewater (SW). The aim of this work was to evaluate the reactor performance in terms of methane production, organic matter consumption, and removal of total and thermotolerant coliforms under different proportions of SW and VW, and organic loading rates (OLR) of 4.0, 5.2 and 11.0g COD (Ld)(-)(1). The mixture of SW and VW in the proportions of 90:10, 80:20 and 70:30 (SW:VW) with those OLRs provided great buffering capacity, with partial alkalinity reaching 3552mgL(-1), thereby avoiding the inhibition of methane production by volatile fatty acids produced during the fermentation process. Higher proportions of VW and higher OLR improved volumetric methane production with a maximum value of 1.08LCH4 (Ld)(-)(1), organic matter removal rates up to 98% and total and thermotolerant coliform removal rates of 99% were also observed.
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Affiliation(s)
- Raissa Cristina da Silva Mazareli
- Post-Graduate Program in Agricultural and Livestock Microbiology, Faculty of Agricultural and Veterinary Sciences, Univ Estadual Paulista, Campus of Jaboticabal, Department of Rural Engineering, Laboratory of Environmental Sanitation, 14884-900 Jaboticabal, SP, Brazil
| | - Rose Maria Duda
- Post-Graduate Program in Agricultural and Livestock Microbiology, Faculty of Agricultural and Veterinary Sciences, Univ Estadual Paulista, Campus of Jaboticabal, Department of Rural Engineering, Laboratory of Environmental Sanitation, 14884-900 Jaboticabal, SP, Brazil
| | - Valderi Duarte Leite
- Chemistry Department, Paraíba State University, Science and Technology Center, Floriano Peixoto - Bodocongo, 58100-000 Campina Grande, PB, Brazil
| | - Roberto Alves de Oliveira
- Faculty of Agricultural and Veterinary Sciences, Univ Estadual Paulista, Campus of Jaboticabal, Department of Rural Engineering, Laboratory of Environmental Sanitation, 14884-900 Jaboticabal, SP, Brazil.
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Campanaro S, Treu L, Kougias PG, De Francisci D, Valle G, Angelidaki I. Metagenomic analysis and functional characterization of the biogas microbiome using high throughput shotgun sequencing and a novel binning strategy. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:26. [PMID: 26839589 PMCID: PMC4736482 DOI: 10.1186/s13068-016-0441-1] [Citation(s) in RCA: 149] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 01/15/2016] [Indexed: 05/18/2023]
Abstract
BACKGROUND Biogas production is an economically attractive technology that has gained momentum worldwide over the past years. Biogas is produced by a biologically mediated process, widely known as "anaerobic digestion." This process is performed by a specialized and complex microbial community, in which different members have distinct roles in the establishment of a collective organization. Deciphering the complex microbial community engaged in this process is interesting both for unraveling the network of bacterial interactions and for applicability potential to the derived knowledge. RESULTS In this study, we dissect the bioma involved in anaerobic digestion by means of high throughput Illumina sequencing (~51 gigabases of sequence data), disclosing nearly one million genes and extracting 106 microbial genomes by a novel strategy combining two binning processes. Microbial phylogeny and putative taxonomy performed using >400 proteins revealed that the biogas community is a trove of new species. A new approach based on functional properties as per network representation was developed to assign roles to the microbial species. The organization of the anaerobic digestion microbiome is resembled by a funnel concept, in which the microbial consortium presents a progressive functional specialization while reaching the final step of the process (i.e., methanogenesis). Key microbial genomes encoding enzymes involved in specific metabolic pathways, such as carbohydrates utilization, fatty acids degradation, amino acids fermentation, and syntrophic acetate oxidation, were identified. Additionally, the analysis identified a new uncultured archaeon that was putatively related to Methanomassiliicoccales but surprisingly having a methylotrophic methanogenic pathway. CONCLUSION This study is a pioneer research on the phylogenetic and functional characterization of the microbial community populating biogas reactors. By applying for the first time high-throughput sequencing and a novel binning strategy, the identified genes were anchored to single genomes providing a clear understanding of their metabolic pathways and highlighting their involvement in anaerobic digestion. The overall research established a reference catalog of biogas microbial genomes that will greatly simplify future genomic studies.
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Affiliation(s)
- Stefano Campanaro
- />Department of Biology, University of Padua, Via U. Bassi 58/b, 35131 Padua, Italy
| | - Laura Treu
- />Department of Environmental Engineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Panagiotis G. Kougias
- />Department of Environmental Engineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Davide De Francisci
- />Department of Environmental Engineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Giorgio Valle
- />Department of Biology, University of Padua, Via U. Bassi 58/b, 35131 Padua, Italy
| | - Irini Angelidaki
- />Department of Environmental Engineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
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