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Ortiz Vanegas GO, Kim HW. Improved hydrolysis of sewage sludge by air-assisted non-thermal plasma for enhanced biomethane recovery. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:28814-28826. [PMID: 38561541 DOI: 10.1007/s11356-024-33006-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 03/16/2024] [Indexed: 04/04/2024]
Abstract
Conventional pretreatment technologies have been assessed to resolve the slow hydrolysis of sewage sludge, but high operating costs have prevented their wide use. This study investigated non-thermal plasma (NTP) technologies as an alternative to promote anaerobic digestion (AD). Various contact time (CT) and temperature (T) conditions were used to assess how NTP pretreatment improves the methane conversion of organics in sewage sludge. A multi-response surface model (RSM) using a central composite design (CCD) identified the optimal CT (4.6 h) and T (45 °C). This statistical optimization of NTP pretreatment led to an enhanced biochemical methane potential of 297 ± 46 mL CH4 g-1 COD by reducing operating cost as power consumption as low as 0.08 USD L-1. The result was comparable to those of other advanced oxidation processes (0.14 - 0.60 USD L-1) demonstrating that accelerated hydrolysis of sewage sludge using NTP pretreatment show potential for improving renewable energy recovery from sewage sludge.
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Affiliation(s)
- Gerardo Oswaldo Ortiz Vanegas
- Department of Environment and Energy, Jeonbuk National University, 567 Baekje-Daero, Deokjin-Gu, Jeonju, 54896, Republic of Korea
| | - Hyun-Woo Kim
- Department of Environment and Energy, Jeonbuk National University, 567 Baekje-Daero, Deokjin-Gu, Jeonju, 54896, Republic of Korea.
- Department of Environmental Engineering, Division of Civil, Environmental, Mineral Resources and Energy Engineering, Soil Environment Research Center, Jeonbuk National University, 567 Baekje-Daero, Deokjin-Gu, Jeonju, 54896, Republic of Korea.
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2
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Fu J, Yan B, Gui S, Fu Y, Xia S. Anaerobic co-digestion of thermo-alkaline pretreated microalgae and sewage sludge: Methane potential and microbial community. J Environ Sci (China) 2023; 127:133-142. [PMID: 36522047 DOI: 10.1016/j.jes.2022.04.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 04/14/2022] [Accepted: 04/18/2022] [Indexed: 06/17/2023]
Abstract
To improve methane production from sewage sludge (SS), co-digestion of SS and microalgae (MA) was studied and the application of thermo-alkaline pretreatment to MA was evaluated. The results showed that thermo-alkaline pretreatment at 90°C for 120 min on MA was the optimum pretreatment condition. Furthermore, when the volatile solids (VS) ratio of SS and MA was 1:2, the methane yield reached maximum (368.94 mL/g VS). Fourier transform infrared (FT-IR) and thermogravimetric analysis confirmed the synergetic effects of thermo-alkaline pretreated MA on its co-digestion with SS. The analyses of microbial community indicated that Methanobacterium and Methanosarcina were the dominant methanogens during the co-digestion process. However, the relative abundance of Methanosarcina in thermo-alkaline pretreated groups was higher compared to unpretreated groups. The microbial community structure might be affected by thermo-alkaline pretreatment rather than by the MA dosage in the co-digestion.
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Affiliation(s)
- Jiaqi Fu
- Institute of Energy Research, Jiangxi Academy of Sciences, Nanchang 330096, China
| | - Bing Yan
- Institute of Energy Research, Jiangxi Academy of Sciences, Nanchang 330096, China
| | - Shuanglin Gui
- Institute of Energy Research, Jiangxi Academy of Sciences, Nanchang 330096, China
| | - Yinxuan Fu
- Institute of Energy Research, Jiangxi Academy of Sciences, Nanchang 330096, China
| | - Song Xia
- Institute of Energy Research, Jiangxi Academy of Sciences, Nanchang 330096, China.
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Chakraborty A, Rattray JE, Drake SS, Matthews S, Li C, Jørgensen BB, Hubert CRJ. Metabolic responses of thermophilic endospores to sudden heat-induced perturbation in marine sediment samples. Front Microbiol 2022; 13:958417. [PMID: 36033870 PMCID: PMC9411986 DOI: 10.3389/fmicb.2022.958417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 07/19/2022] [Indexed: 11/13/2022] Open
Abstract
Microbially mediated processes in a given habitat tend to be catalyzed by abundant populations that are ecologically adapted to exploit specific environmental characteristics. Typically, metabolic activities of rare populations are limited but may be stimulated in response to acute environmental stressors. Community responses to sudden changes in temperature and pressure can include suppression and activation of different populations, but these dynamics remain poorly understood. The permanently cold ocean floor hosts countless low-abundance microbes including endospores of thermophilic bacteria. Incubating sediments at high temperature resuscitates viable spores, causing the proliferation of bacterial populations. This presents a tractable system for investigating changes in a microbiome's community structure in response to dramatic environmental perturbations. Incubating permanently cold Arctic fjord sediments at 50°C for 216 h with and without volatile fatty acid amendment provoked major changes in community structure. Germination of thermophilic spores from the sediment rare biosphere was tracked using mass spectrometry-based metabolomics, radiotracer-based sulfate reduction rate measurements, and high-throughput 16S rRNA gene sequencing. Comparing community similarity at different intervals of the incubations showed distinct temporal shifts in microbial populations, depending on organic substrate amendment. Metabolite patterns indicated that amino acids and other sediment-derived organics were decomposed by fermentative Clostridia within the first 12–48 h. This fueled early and late phases of exponential increases in sulfate reduction, highlighting the cross-feeding of volatile fatty acids as electron donors for different sulfate-reducing Desulfotomaculia populations. The succession of germinated endospores triggered by sudden exposure to high temperature and controlled by nutrient availability offers a model for understanding the ecological response of dormant microbial communities following major environmental perturbations.
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Affiliation(s)
- Anirban Chakraborty
- Department of Biological Sciences, Idaho State University, Pocatello, ID, United States
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
- *Correspondence: Anirban Chakraborty
| | - Jayne E. Rattray
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Sienna S. Drake
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Stuart Matthews
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Carmen Li
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Bo Barker Jørgensen
- Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Casey R. J. Hubert
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
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4
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Individual Phenolic Acids in Distillery Stillage Inhibit Its Biomethanization. ENERGIES 2022. [DOI: 10.3390/en15155377] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Polyphenols that are abundant in various organic wastes can inhibit anaerobic degradation of these wastes. This study investigated the effect of the concentration of individual phenolic acids (p-OH benzoic, vanillic, ferulic, sinapic, syringic, and p-coumaric acids) and their mixture on the methane potential of distillery stillage. An increase in phenolic acid concentration adversely affected biogas production and composition, as well as the methane-production rate. The inhibition constants for methane production were 0.5–1.0 g/L of individual phenolic acids and 1.5 g/L of the mixture of these acids. At lower concentrations, the phenolic acids were utilized as a carbon source, but the process was impeded when their concentrations exceeded the threshold value, due to their negative effect on microbial growth. When distillery stillage was spiked with vanillic acid, two-phase methane production was observed. Spiking distillery stillage with vanillic, p-coumaric, syringic, or ferulic acids affected anaerobic digestion the most; 2 g/L of these acids completely inhibited methane production. With 4.0 g/L of all individual phenolic acids, no methane production was observed. As the concentration of these phenolic acids increased from 0.5 to 4.0 g/L, the abundance of methanogenic Archaea, in which acetoclastic methanogens predominated, decreased by about 30 times.
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Khuntia HK, Paliwal A, Kumar DR, Chanakya HN. Review on solid-state anaerobic digestion of lignocellulosic biomass and organic solid waste. ENVIRONMENTAL MONITORING AND ASSESSMENT 2022; 194:514. [PMID: 35726107 DOI: 10.1007/s10661-022-10160-2] [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: 11/14/2021] [Accepted: 05/28/2022] [Indexed: 06/15/2023]
Abstract
Sustainable management of organic solid wastes especially the municipal solid waste (MSW) is essential for the realization of various sustainable development goals (SDGs). Resource recovery centric waste processing technologies generate valorizable products to meet the operations and maintenance (O&M) costs while reducing the GHG emissions. Solid-state anaerobic digestion (SSAD) of organic solid wastes is a biomethanation process performed at a relatively higher total solids (TS) loading in the range of 10-45%. SSAD overcomes various limitations posed by conventional anaerobic slurry digesters such as higher degradable matter per unit volume of the bioreactor resulting in a smaller footprint, low freshwater consumption, low wastewater generation, simple upstream and downstream processes, relatively lower operation, and maintenance costs. This review elucidates the recent developments and critical assessment of different aspects of SSAD, such as bioreactor design, operational strategy, process performances, mass balance, microbial ecology, applications, and mathematical models. A critical assessment revealed that the operating scale of SSAD varies between 1000 and 100,000 ts/year at organic loading rate (OLR) of 2-15 g volatile solids (VS)/L·day. The SSAD experiences process failures due to the formation of volatile fatty acids (VFAs), biogas pockets and clogging of the digestate outlet. Acclimatization of microbes accelerates the startup phase, steady-state performances, and the enrichment of syntrophic microbes with 10-50 times greater population of cellulolytic and xylanolytic microbes in thermophilic SSAD over mesophilic SSAD. Experimental limitations in the accurate determination of rate constants and the oversimplification of biochemical reactions result in an inaccurate prediction by the models.
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Affiliation(s)
- Himanshu K Khuntia
- Centre for Sustainable Technologies, Indian Institute of Science, Bengaluru, India, 560012.
| | - Aastha Paliwal
- Centre for Sustainable Technologies, Indian Institute of Science, Bengaluru, India, 560012
| | - D Ravi Kumar
- Centre for Sustainable Technologies, Indian Institute of Science, Bengaluru, India, 560012
| | - H N Chanakya
- Centre for Sustainable Technologies, Indian Institute of Science, Bengaluru, India, 560012
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Hou T, Zhao J, Lei Z, Shimizu K, Zhang Z. Supplementation of KOH to improve salt tolerance of methanogenesis in the two-stage anaerobic digestion of food waste using pre-acclimated anaerobically digested sludge by air-nanobubble water. BIORESOURCE TECHNOLOGY 2022; 346:126360. [PMID: 34801723 DOI: 10.1016/j.biortech.2021.126360] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/12/2021] [Accepted: 11/12/2021] [Indexed: 06/13/2023]
Abstract
Air-nanobubble water (NBW) was applied to pre-acclimate anaerobically digested sludge that was then used as the inoculum in the two-stage anaerobic digestion (AD) of high saline (20 g NaCl/L) food waste (FW) to optimize NBW application in the AD of high saline FW. K+ was simultaneously supplemented during the methanogenic stage to resist the inhibition of salt on methanogens. Results showed that after the second pre-acclimation cycle, the inoculum activity was increased 27% in the Air-NBW supplemented reactor in comparison to the deionized water (DW) supplemented one. In the first-stage AD, H2 yield was enhanced by 46% in the Air-NBW pre-acclimated sludge reactor compared with the DW pre-acclimated sludge reactor. Besides, supplementation of KOH in the methanogenic stage could enhance methane production by 17-25% in the DW reactors at initial pH 7.5, 8.0, and 9.0 when compared to the control reactor (using NaOH adjusted initial pH to 7.5), respectively.
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Affiliation(s)
- Tingting Hou
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Jiamin Zhao
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Zhongfang Lei
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Kazuya Shimizu
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Zhenya Zhang
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
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Alarcón-Vivero M, Moena NRT, Gonzalez F, Jopia-Contreras P, Aspé E, Briones HU, Fernandez KS. Anaerobic biofilm enriched with an ammonia tolerant methanogenic consortium to improve wastewater treatment in the fishing industry. Biotechnol Lett 2022; 44:239-251. [PMID: 35037233 DOI: 10.1007/s10529-021-03213-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 11/29/2021] [Indexed: 11/29/2022]
Abstract
The digestion efficiency of liquid industrial wastes increases when using bioreactors colonized by microbial biofilms. High concentrations of proteins derived from the fish processing industry lead to the production of ammonia, which inhibits methane production. Two bioreactors were constructed to compare methanogenic activity: one enriched with mMPA (methylaminotrofic methane production archaea) consortia (control bioreactor), and the second with NH3 tolerant consortia (treatment bioreactor). Ammonia tolerant activity was assessed by applying an ammonia shock (755 mg NH3/L). Methane production, consumption of total organic carbon (TOC) and the taxonomic composition of bacteria and archaea was evaluated using 16S rDNA in the acclimatization, ammonia shock, and recovery phases.The ammonia shock significantly affected both methane production and the consumption of TOC in the control reactor (p < 0.05) and taxonomical composition of the microbial consortia (OTU). These values remained constant in the treatment reactor. The analysis of biofilm composition showed a predominance of Methanosarcinaceae (Methanomethylovorans sp., and probably two different species of Methanosarcina sp.) in bioreactors. These results demonstrate that using acclimated biofilms enriched with ammonia tolerant methanogens control the inhibitory effect of ammonia on methanogenesis.
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Affiliation(s)
- Manuel Alarcón-Vivero
- Instituto de Acuicultura, Universidad Austral de Chile (UACh), Sede Puerto Montt, Puerto Montt, Chile
| | - Nathaly Ruiz-Tagle Moena
- Lab. Biopelículas y Microbiología Ambiental, Centro de Biotecnología, Universidad de Concepción, Concepción, Chile
| | - Fidelina Gonzalez
- Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | | | - Estrella Aspé
- Departamento de Ingeniería Química, Facultad de Ingeniería, Universidad de Concepción, Concepción, Chile
| | - Homero Urrutia Briones
- Lab. Biopelículas y Microbiología Ambiental, Centro de Biotecnología, Universidad de Concepción, Concepción, Chile.,Departamento de Microbiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Katherine Sossa Fernandez
- Lab. Biopelículas y Microbiología Ambiental, Centro de Biotecnología, Universidad de Concepción, Concepción, Chile. .,Facultad de Ciencias Forestales, Universidad de Concepción, Concepción, Chile.
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8
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Wang J, Liu GH, Shao Y, Zhang Q, Wei Q, Luo F, Sun W, Liu S, Liu Y, Zhang J, Qi L, Wang H. Regulation of anaerobic fermentation for producing short-chain fatty acids from primary sludge in WWTPs by different alkalis. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 299:113623. [PMID: 34481372 DOI: 10.1016/j.jenvman.2021.113623] [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: 06/06/2021] [Revised: 08/12/2021] [Accepted: 08/23/2021] [Indexed: 06/13/2023]
Abstract
Carbon source production from primary sludge in wastewater treatment plants (WWTPs) via anaerobic fermentation process has been paid more attention. However, slow hydrolysis rate and low yield of short-chain fatty acids (SCFAs) limited its application. This study aimed at improving the anaerobic fermentation efficiency of primary sludge by alkali regulation (NaOH, Na2CO3 and Ca(OH)2), and revealing the mechanism. Results showed that three kinds of alkalis allowed enhancing hydrolysis and acidification, and reducing methane production in the anaerobic fermentation process of primary sludge. The Na2CO3 regulation contributed to highest yield and productivity of SCFAs, reaching 1626 mg COD/L and 0.189 g COD/g VSS at 4th day, respectively. Microbial community structure analysis indicated that the relative abundance of fermentative microbial community was improved in the alkali regulation system, where methanogenic archaea was effectively inhibited. The continuous flow experiment further verified that the Na2CO3 regulation could steadily increase yield of SCFAs in the anaerobic fermentation process of primary sludge, and the yield was also the highest among three kinds of alkali regulation.
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Affiliation(s)
- Jian Wang
- Low-carbon Water Environmental Technology Center, School of Environment & Natural Resource, Renmin University of China, 59 Zhongguancun Street, Beijing, 100872, PR China
| | - Guo-Hua Liu
- Low-carbon Water Environmental Technology Center, School of Environment & Natural Resource, Renmin University of China, 59 Zhongguancun Street, Beijing, 100872, PR China.
| | - Yuting Shao
- Low-carbon Water Environmental Technology Center, School of Environment & Natural Resource, Renmin University of China, 59 Zhongguancun Street, Beijing, 100872, PR China
| | - Qian Zhang
- Low-carbon Water Environmental Technology Center, School of Environment & Natural Resource, Renmin University of China, 59 Zhongguancun Street, Beijing, 100872, PR China
| | - Qi Wei
- Low-carbon Water Environmental Technology Center, School of Environment & Natural Resource, Renmin University of China, 59 Zhongguancun Street, Beijing, 100872, PR China
| | - Fangzhou Luo
- Low-carbon Water Environmental Technology Center, School of Environment & Natural Resource, Renmin University of China, 59 Zhongguancun Street, Beijing, 100872, PR China
| | - Wenzhuo Sun
- Low-carbon Water Environmental Technology Center, School of Environment & Natural Resource, Renmin University of China, 59 Zhongguancun Street, Beijing, 100872, PR China
| | - Shuai Liu
- Low-carbon Water Environmental Technology Center, School of Environment & Natural Resource, Renmin University of China, 59 Zhongguancun Street, Beijing, 100872, PR China
| | - Yuchen Liu
- Low-carbon Water Environmental Technology Center, School of Environment & Natural Resource, Renmin University of China, 59 Zhongguancun Street, Beijing, 100872, PR China
| | - Jingbing Zhang
- Low-carbon Water Environmental Technology Center, School of Environment & Natural Resource, Renmin University of China, 59 Zhongguancun Street, Beijing, 100872, PR China
| | - Lu Qi
- Low-carbon Water Environmental Technology Center, School of Environment & Natural Resource, Renmin University of China, 59 Zhongguancun Street, Beijing, 100872, PR China
| | - Hongchen Wang
- Low-carbon Water Environmental Technology Center, School of Environment & Natural Resource, Renmin University of China, 59 Zhongguancun Street, Beijing, 100872, PR China
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Hardy J, Bonin P, Lazuka A, Gonidec E, Guasco S, Valette C, Lacroix S, Cabrol L. Similar Methanogenic Shift but Divergent Syntrophic Partners in Anaerobic Digesters Exposed to Direct versus Successive Ammonium Additions. Microbiol Spectr 2021; 9:e0080521. [PMID: 34612672 PMCID: PMC8510171 DOI: 10.1128/spectrum.00805-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 08/02/2021] [Indexed: 01/04/2023] Open
Abstract
During anaerobic digestion (AD) of protein-rich wastewater, ammonium (NH4+) is released by amino acid degradation. High NH4+ concentrations disturb the AD microbiome balance, leading to process impairments. The sensitivity of the AD microbiome to NH4+ and the inhibition threshold depend on multiple parameters, especially the previous microbial acclimation to ammonium stress. However, little is known about the effect of different NH4+ acclimation strategies on the differential expression of key active microbial taxa. Here, we applied NH4+ inputs of increasing intensity (from 1.7 to 15.2 g N-NH4+ liters-1) in batch assays fed with synthetic wastewater, according to two different strategies: (i) direct independent inputs at a unique target concentration and (ii) successive inputs in a stepwise manner. In both strategies, along the NH4+ gradient, the active methanogens shifted from acetoclastic Methanosaeta to Methanosarcina and eventually hydrogenotrophic Methanoculleus. Despite shorter latency times, the successive input modality led to lower methane production rate, lower soluble chemical oxygen demand (sCOD) removal efficiency, and lower half maximal inhibitory concentration, together with higher volatile fatty acid (VFA) accumulation, compared to the independent input modality. These differential performances were associated with a drastically distinct succession pattern of the active bacterial partners in both experiments. In particular, the direct exposure modality was characterized by a progressive enrichment of VFA producers (mainly Tepidimicrobium) and syntrophic VFA oxidizers (mainly Syntrophaceticus) with increasing NH4+ concentration, while the successive exposure modality was characterized by a more dynamic succession of VFA producers (mainly Clostridium, Sporanaerobacter, Terrisporobacter) and syntrophic VFA oxidizers (mainly Tepidanaerobacter, Syntrophomonas). These results bring relevant insights for improved process management through inoculum adaptation, bioaugmentation, or community-driven optimization. IMPORTANCE Anaerobic digestion (AD) is an attractive biotechnological process for wastewater bioremediation and bioenergy production in the form of methane-rich biogas. However, AD can be inhibited by ammonium generated by protein-rich effluent, commonly found in agro-industrial activities. Insights in the microbial community composition and identification of AD key players are crucial for anticipating process impairments in response to ammonium stress. They can also help in defining an optimal microbiome adapted to high ammonium levels. Here, we compared two strategies for acclimation of AD microbiome to increasing ammonium concentration to better understand the effect of this stress on the methanogens and their bacterial partners. Our results suggest that long-term cumulative exposure to ammonia disrupted the AD microbiome more strongly than direct (independent) ammonium additions. We identified bioindicators with different NH4+ tolerance capacity among VFA producers and syntrophic VFA oxidizers.
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Affiliation(s)
- Julie Hardy
- MIO, Aix Marseille University, University of Toulon, CNRS, IRD, Marseille, France
- Scientific & Technological Expertise Department, Veolia, Maisons-Laffitte, France
| | - Patricia Bonin
- MIO, Aix Marseille University, University of Toulon, CNRS, IRD, Marseille, France
| | - Adele Lazuka
- Scientific & Technological Expertise Department, Veolia, Maisons-Laffitte, France
| | - Estelle Gonidec
- Scientific & Technological Expertise Department, Veolia, Maisons-Laffitte, France
| | - Sophie Guasco
- MIO, Aix Marseille University, University of Toulon, CNRS, IRD, Marseille, France
| | - Corinne Valette
- MIO, Aix Marseille University, University of Toulon, CNRS, IRD, Marseille, France
| | - Sébastien Lacroix
- Scientific & Technological Expertise Department, Veolia, Maisons-Laffitte, France
| | - Léa Cabrol
- MIO, Aix Marseille University, University of Toulon, CNRS, IRD, Marseille, France
- Instituto de Ecologia y Biodiversidad (IEB) Facultad de Ciencias, Universidad de Chile Las Palmeras, Nunoa, Santiago, Chile
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10
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Sanjaya EH, Cheng H, Qin Y, Kubota K, Li YY. The impact of calcium supplementation on methane fermentation and ammonia inhibition of fish processing wastewater. BIORESOURCE TECHNOLOGY 2021; 337:125471. [PMID: 34320751 DOI: 10.1016/j.biortech.2021.125471] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 06/20/2021] [Accepted: 06/24/2021] [Indexed: 06/13/2023]
Abstract
The effect of trace metal supplementation on the methane fermentation of fish processing wastewater (FPW) was studied in both batch and continuous experiments using a self-agitated anaerobic baffled reactor (SA-ABR). In the batch experiments, a single supplementation of Ca2+, Co2+ and Fe2+ was show to have a significant positive impact on the performance of methane fermentation. The continuous experiment results showed that supplementation with 1.5 g-Ca2+/L-substrate remarkably enhanced the performance of methane fermentation of the SA-ABR in treating FPW with the optimal organic loading rate achieved at 7.62 g-COD/L/d. During the steady states (stages 2 to 5), the average removal efficiencies of COD, protein, carbohydrate and lipid were 89, 85, 80 and 91%, respectively. The biogas conversion rates were in the range of 0.39 to 0.45 L-biogas/g-COD with a high methane content of 74%. Besides, Ca2+ supplementation also improved the resistance of the methane fermentation system to ammonia inhibition.
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Affiliation(s)
- Eli Hendrik Sanjaya
- Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan; Department of Chemistry, State University of Malang (Universitas Negeri Malang), Jl. Semarang No. 5, Malang, East Java 65145, Indonesia
| | - Hui Cheng
- Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan; School of Environmental and Chemical Engineering, Shanghai University, 333 Nanchen Road, Shanghai 200444, China
| | - Yu Qin
- Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Kengo Kubota
- Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan; Graduate School of Environmental Studies, Tohoku University, 6-6-06 Aramaki Aza Aoba, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Yu-You Li
- Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan; Graduate School of Environmental Studies, Tohoku University, 6-6-06 Aramaki Aza Aoba, Aoba-ku, Sendai, Miyagi 980-8579, Japan.
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11
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Quispe-Cardenas E, Rogers S. Microbial adaptation and response to high ammonia concentrations and precipitates during anaerobic digestion under psychrophilic and mesophilic conditions. WATER RESEARCH 2021; 204:117596. [PMID: 34530226 DOI: 10.1016/j.watres.2021.117596] [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: 04/20/2021] [Revised: 07/19/2021] [Accepted: 08/22/2021] [Indexed: 06/13/2023]
Abstract
This study explored microbial adaptation to high ammonia concentrations (<1000 mg/L to 4000 mg/L) during anaerobic digestion (AD) under psychrophilic and mesophilic conditions, the latter of which yielded precipitates facilitating investigation of microbial response. The experimental setup was performed at bench-scale using microbial consortia from four different operating anaerobic digesters treating different organic wastes (WW-wastewater sludge, MN-manure, FW- food waste and CO-co-digestion (FW & MN)). Adaptation experiments were conducted with semi-continuous flow mode to resemble large-scale operation. Metagenome and 16S RNA analysis were performed for the first time in a psychrophilic reactor during an ammonia acclimation process. These analyses were also performed in mesophilic reactor exposed to precipitates and high ammonia levels. Diversity reduced when adaptation occurred successfully from 1.1 to 4 g/L of total ammonia nitrogen (TAN) under psychrophilic conditions, while the microbial community became more diverse under mesophilic conditions with ammonia inhibition. We report for the first time Methanocorposculum as a robust hydrogenotrophic methanogen at high ammoniacal concentrations under psychrophilic conditions. Additionally, Methanosarcina was present in low and high ammoniacal concentrations in mesophilic conditions, but there was a shift in species dominance. Methanosarcina barkeri stands out as a more resilient methanogen compared to Methanosarcina mazei, which initially dominated at <1.1 g/L TAN. We also explored the effects of sudden precipitates on methanogenic communities and methane production when they occurred under mesophilic conditions in two reactors. Methane production declined by more than 50% when precipitates occurred and was accompanied by pH reduction and VFA accumulation. Diversity data corroborated that methanogens were severely reduced. These two reactors were not able to recover with 50 days of added operation, demonstrating potential for long-term negative impacts of precipitate formation on AD performance stemming from negative impact to methanogenic communities.
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Affiliation(s)
| | - Shane Rogers
- Institute for a Sustainable Environment, Clarkson University, Potsdam 13699, NY, USA; Civil and Environmental Engineering, Clarkson University, Potsdam 13699, NY, USA.
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Hao L, Fan L, Chapleur O, Guenne A, Bize A, Bureau C, Lü F, He P, Bouchez T, Mazéas L. Gradual development of ammonia-induced syntrophic acetate-oxidizing activities under mesophilic and thermophilic conditions quantitatively tracked using multiple isotopic approaches. WATER RESEARCH 2021; 204:117586. [PMID: 34474248 DOI: 10.1016/j.watres.2021.117586] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 08/13/2021] [Accepted: 08/17/2021] [Indexed: 06/13/2023]
Abstract
Insights into microbiota adaptation to increased ammonia stress, and identification of indicator microorganisms can help to optimize the operation of anaerobic digesters. To identify microbial indicators and investigate their metabolic contribution to acetoclastic methanogenesis (AM), syntrophic acetate oxidation (SAO) or hydrogenotrophic methanogenesis (HM), 40 anaerobic batch reactors fed with acetate of 110 mmol/L were set up at NH4+-N concentrations of 0.14 g/L, 5.00 g/L or 7.00 g/L, inoculated with thermophilic or mesophilic microbiota with or without pre-exposure to ammonia stress. Four stable carbon isotope probing approaches were applied in parallel, with [1,2-13C]-CH3COOH, [2-13C]-CH3COOH, [13C]NaHCO3 or non-labeled CH3COOH used individually. The last three approaches were used to quantify the methanogenic pathways by tracking labeled 13C or natural 13C signatures in the resulting CH4 and CO2, and consistently detected the dynamic transition of dominant pathways from AM to SAO-HM under ammonia stress. Results of quantitative PCR and fluorescence in-situ hybridization illustrated the procedure, acetotrophic methanogens being outcompeted by acetate-oxidizing syntrophs. The first and last isotope-labeling approaches were designed to probe the active acetate-mineralizing microbes with DNA-SIP. Known acetate-oxidizing bacteria like Syntrophaceticus and Tepidanaerobacter, as well as novel members of Pseudomonas, Bacillus and Symbiobacteraceae were detected, with Methanoculleus as the predominant H2/CO2-utilizing partner. Using NanoSIMS, some bacterial cells were observed to be fixing CO2 from [13C]NaHCO3. In this study, Methanosaeta was only active with ammonia < 200 mg-N/L; the syntrophs catalyzing SAO-HM started to compete with AM-conducting Methanosarcina at intermediate concentrations of ammonia, i.e. 200-500 mg-N/L, and outcompeted the acetotrophic methanogens with ammonia > 500 mg-N/L. Under ammonia stress, diverse known and novel microbial taxa were involved in acetate mineralization, comparable with those identified in previous studies.
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Affiliation(s)
- Liping Hao
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
| | - Lu Fan
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
| | - Olivier Chapleur
- Université Paris-Saclay, INRAE, PRocédés biOtechnologiques au Service de l'Environnement, Antony 92761, France
| | - Angéline Guenne
- Université Paris-Saclay, INRAE, PRocédés biOtechnologiques au Service de l'Environnement, Antony 92761, France
| | - Ariane Bize
- Université Paris-Saclay, INRAE, PRocédés biOtechnologiques au Service de l'Environnement, Antony 92761, France
| | - Chrystelle Bureau
- Université Paris-Saclay, INRAE, PRocédés biOtechnologiques au Service de l'Environnement, Antony 92761, France
| | - Fan Lü
- Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092, China
| | - Pinjing He
- Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092, China.
| | - Théodore Bouchez
- Université Paris-Saclay, INRAE, PRocédés biOtechnologiques au Service de l'Environnement, Antony 92761, France.
| | - Laurent Mazéas
- Université Paris-Saclay, INRAE, PRocédés biOtechnologiques au Service de l'Environnement, Antony 92761, France.
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Su L, Chen M, Wang S, Ji R, Liu C, Lu X, Zhen G, Zhang L. Fluorescence characteristics of dissolved organic matter during anaerobic digestion of oil crop straw inoculated with rumen liquid. RSC Adv 2021; 11:14347-14356. [PMID: 35423965 PMCID: PMC8697682 DOI: 10.1039/d1ra01176f] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 04/06/2021] [Indexed: 11/21/2022] Open
Abstract
Fluorescence excitation-emission matrix (EEM) spectroscopy is a powerful tool for characterizing dissolved organic matter (DOM), a key component of anaerobic digestion. In this study, the fluorescence characteristics of DOM during 55 days of anaerobic digestion of oil crop straw inoculated with rumen liquid were investigated. EEM spectroscopy coupled with parallel factor analysis (PARAFAC) showed that three major fluorescence components, tyrosine- (C1), humic- (C2) and tryptophan-like substances (C3), were identified in all DOM samples. The F max values of C1 and C3 increased rapidly during the first 5 d, decreased dramatically from day 5 to day 35, and then remained stable, while C2 was not biodegraded. The changes in the F max values of the fluorescence components reflected the biodegradation of lignin and/or embedded cellulose by rumen microorganisms. The changes in the Stokes shift of the fluorescence peak were readily explained by the variation in the hydrophobic/hydrophilic fraction distribution. The humidification index (HIX) and A : T ratio of the DOM decreased after 5 d and then increased gradually. Compared with the McKnight fluorescence index (MFI), the Y fluorescence index (YFI) was better able to track the evolution of the DOM. Correlation analysis of the different fluorescence indices (intensities) and absorbance indices was also carried out. The EEM-PARAFAC individual components, HIX and A : T ratio were conveniently used to characterize the degree of anaerobic conversion of the organic matter, and the peak at the Stokes shift of ∼1.0 μm-1 was used as one of the indicators showing the stabilization of anaerobic digestion. These findings may assist in developing fluorescence technology for monitoring the anaerobic digestion of crop straw.
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Affiliation(s)
- Lianghu Su
- Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment 8 Jiangwangmiao Street Nanjing 210042 P. R. China
| | - Mei Chen
- Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment 8 Jiangwangmiao Street Nanjing 210042 P. R. China
| | - Saier Wang
- Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment 8 Jiangwangmiao Street Nanjing 210042 P. R. China
| | - Rongting Ji
- Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment 8 Jiangwangmiao Street Nanjing 210042 P. R. China
| | - Chenwei Liu
- Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment 8 Jiangwangmiao Street Nanjing 210042 P. R. China
| | - Xueqin Lu
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University Dongchuan Rd 500 Shanghai 200241 P. R. China .,Institute of Eco-Chongming (IEC) 3663 N. Zhongshan Rd Shanghai 200062 P. R. China
| | - Guangyin Zhen
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University Dongchuan Rd 500 Shanghai 200241 P. R. China .,Shanghai Institute of Pollution Control and Ecological Security 1515 North Zhongshan Rd (no. 2) Shanghai 200092 P. R. China.,Technology Innovation Center for Land Spatial Eco-restoration in Metropolitan Area, Ministry of Natural Resources 3663 N. Zhongshan Road Shanghai 200062 P. R. China
| | - Longjiang Zhang
- Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment 8 Jiangwangmiao Street Nanjing 210042 P. R. China
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Dusad V, Thiel D, Barahona M, Keun HC, Oyarzún DA. Opportunities at the Interface of Network Science and Metabolic Modeling. Front Bioeng Biotechnol 2021; 8:591049. [PMID: 33569373 PMCID: PMC7868444 DOI: 10.3389/fbioe.2020.591049] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 12/22/2020] [Indexed: 12/17/2022] Open
Abstract
Metabolism plays a central role in cell physiology because it provides the molecular machinery for growth. At the genome-scale, metabolism is made up of thousands of reactions interacting with one another. Untangling this complexity is key to understand how cells respond to genetic, environmental, or therapeutic perturbations. Here we discuss the roles of two complementary strategies for the analysis of genome-scale metabolic models: Flux Balance Analysis (FBA) and network science. While FBA estimates metabolic flux on the basis of an optimization principle, network approaches reveal emergent properties of the global metabolic connectivity. We highlight how the integration of both approaches promises to deliver insights on the structure and function of metabolic systems with wide-ranging implications in discovery science, precision medicine and industrial biotechnology.
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Affiliation(s)
- Varshit Dusad
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Denise Thiel
- Department of Mathematics, Imperial College London, London, United Kingdom
| | - Mauricio Barahona
- Department of Mathematics, Imperial College London, London, United Kingdom
| | - Hector C. Keun
- Department of Surgery and Cancer, Imperial College London, London, United Kingdom
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
| | - Diego A. Oyarzún
- School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
- School of Informatics, University of Edinburgh, Edinburgh, United Kingdom
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Mutschlechner M, Praeg N, Illmer P. Soil-Derived Inocula Enhance Methane Production and Counteract Common Process Failures During Anaerobic Digestion. Front Microbiol 2020; 11:572759. [PMID: 33193175 PMCID: PMC7606279 DOI: 10.3389/fmicb.2020.572759] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 09/14/2020] [Indexed: 02/01/2023] Open
Abstract
Although soil-borne methanogens are known to be highly diverse and adapted to extreme environments, their application as potential (anaerobic) inocula to improve anaerobic digestion has not been investigated until now. The present study aimed at evaluating if soil-derived communities can be beneficial for biogas (methane, CH4) production and endure unfavorable conditions commonly associated with digestion failure. Nine study sites were chosen and tested for suitability as inoculation sources to improve biogas production via in situ measurements (CH4 fluxes, physical and chemical soil properties, and abundance of methanogens) and during a series of anaerobic digestions with (a) combinations of both sterile or unsterile soil and diluted fermenter sludge, and (b) pH-, acetate-, propionate-, and ammonium-induced disturbance. Amplicon sequencing was performed to assess key microbial communities pivotal for successful biogas production. Four out of nine tested soil inocula exerted sufficient methanogenic activity and repeatedly allowed satisfactory CH4/biogas production even under deteriorated conditions. Remarkably, the significantly highest CH4 production was observed using unsterile soil combined with sterile sludge, which coincided with both a higher relative abundance of methanogens and predicted genes involved in CH4 metabolism in these variants. Different bacterial and archaeal community patterns depending on the soil/sludge combinations and disturbance variations were established and these patterns significantly impacted CH4 production. Methanosarcina spp. seemed to play a key role in CH4 formation and prevailed even under stressed conditions. Overall, the results provided evidence that soil-borne methanogens can be effective in enhancing digestion performance and stability and, thus, harbor vast potential for further exploitation.
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Affiliation(s)
| | - Nadine Praeg
- Department of Microbiology, Universität Innsbruck, Innsbruck, Austria
| | - Paul Illmer
- Department of Microbiology, Universität Innsbruck, Innsbruck, Austria
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Sanjaya EH, Cheng H, Li YY. Mesophilic methane fermentation performance and ammonia inhibition of fish processing wastewater treatment using a self-agitated anaerobic baffled reactor. BIORESOURCE TECHNOLOGY 2020; 313:123644. [PMID: 32544803 DOI: 10.1016/j.biortech.2020.123644] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 06/02/2020] [Accepted: 06/05/2020] [Indexed: 06/11/2023]
Abstract
The performance of the self-agitated anaerobic baffled reactor (SA-ABR) was investigated by increasing the organic loading rates (OLRs) from 0.46 to 9.50 g-COD/L/d. A good performance was achieved by the SA-ABR for the treatment of fish processing wastewater (FPW). The maximum OLR was 6.77 g-COD/L/d and the biogas production rate reached 2.16 L/L-reactor/d with a methane content of 69% at this OLR. The COD, carbohydrate, protein, lipid and VS removal efficiencies were as high as 64, 65, 68, 78 and 79%, respectively. Ammonia inhibition was assumed with inhibition concentrations of 10% (IC10) and 20% (IC20) at 4140 and 5780 mg/L. However, it was found that the reactor could tolerate ammonia at a high concentration range of 4500-6373 mg/L after a long-term continuous experiment. Ammonia inhibition was addressed by diluting the substrate and the sludge in the reactor with tap water.
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Affiliation(s)
- Eli Hendrik Sanjaya
- Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan; Department of Chemistry, State University of Malang (Universitas Negeri Malang), Jl. Semarang No. 5, Malang, East Java 65145, Indonesia
| | - Hui Cheng
- Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Yu-You Li
- Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan.
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17
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Yu L, Liu S, Jiang L, Wang X, Xiao L. Insight into the nitrogen accumulation in urban center river from functional genes and bacterial community. PLoS One 2020; 15:e0238531. [PMID: 32877444 PMCID: PMC7467313 DOI: 10.1371/journal.pone.0238531] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Accepted: 08/18/2020] [Indexed: 01/26/2023] Open
Abstract
Along with urbanization, the intensified nitrogen pollution in urban rivers and the form of black-odor rivers has become one of the biggest concerns. Better understanding of the nitrogen transformations and microbial mechanisms occurring within urban rivers could help to manage their water quality. In this study, pollution characteristics, potential nitrogen removal rate, composition and function of bacterial community, and abundance of functional genes associated with nitrogen transformation were comparatively investigated in a typical urban river (FC) and a suburban river (LH). Compared with LH, FC was characterized by higher content of nutrients, lower potential nitrogen removal rate and lower abundance of functional genes associated with nitrogen transformation in both overlying water and sediment, especially in summer. Sediment dissolved organic matter characterized by excitation−emission matrix (EEM) showed that FC was more severely polluted by high nitrogen organic matter. Our results revealed that anammox was the main nitrogen removal pathway in both rivers and potential nitrogen removal rates decreased significantly in summer. Bacterial community analysis showed that the benthic communities were more severely influenced by the pollutant than aquatic ones in both rivers. Furthermore, the FC benthic community was dominated by anaerobic respiring, fermentative, sulfate reduction bacteria. Quantitatively, the denitrification rate showed a significant positive correlation with the abundance of denitrification genes, whilst the anammox rate was significantly negatively correlated with bacterial diversity. Meanwhile, NH4+-N had a significant negative correlation to both denitrification and anammox in sediment. Taken together, the results indicated that the increased nitrogen pollutants in an urban river altered nitrogen removal pathways and bacterial communities, which could in turn exacerbate the nitrogen pollution to this river.
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Affiliation(s)
- Lei Yu
- School of the Environment, State Key Laboratory for Pollution Control and Resource Reuse (SKL-PCRR), Nanjing University, Nanjing, China
| | - ShuLei Liu
- School of the Environment, State Key Laboratory for Pollution Control and Resource Reuse (SKL-PCRR), Nanjing University, Nanjing, China
| | - LiJuan Jiang
- School of the Environment, State Key Laboratory for Pollution Control and Resource Reuse (SKL-PCRR), Nanjing University, Nanjing, China
| | - XiaoLin Wang
- School of the Environment, State Key Laboratory for Pollution Control and Resource Reuse (SKL-PCRR), Nanjing University, Nanjing, China
| | - Lin Xiao
- School of the Environment, State Key Laboratory for Pollution Control and Resource Reuse (SKL-PCRR), Nanjing University, Nanjing, China
- * E-mail:
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18
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Chen S, Dong B, Yang D, Li N, Dai X. Micron-sized silica particles in wastewater influenced the distribution of organic matters in sludge and their anaerobic degradation. JOURNAL OF HAZARDOUS MATERIALS 2020; 393:122340. [PMID: 32213426 DOI: 10.1016/j.jhazmat.2020.122340] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 02/12/2020] [Accepted: 02/15/2020] [Indexed: 06/10/2023]
Abstract
The influence of micron-sized silica particles on the distribution of organic matters in sludge and anaerobic degradation of macromolecular organic components (MOCs) in sludge was investigated. With the addition of micron-sized particles in the influent (VS/TS decreased gradually from 90.46 ± 0.21 % to 33.36 ± 0.17 %), the protein degradation percentage was significantly promoted while the polysaccharides degradation percentage was largely inhibited, resulting in the total MOCs degradation and methane production increasing firstly (with the promotion extent within 10 %) and then declining slightly, with the peak value at VS/TS of 56.03 ± 0.21 %. The shifted degradation percentage of protein and polysaccharides were caused by the significant changed distribution of organic matters in sludge. With the addition of micron-sized silica particles, the MW of EPS and secondary structure of protein in EPS changed little, which brought about little influence. While, the promoted extracellular protein content (so that the total protein content) and declined extracellular carbohydrates content (so that the total polysaccharides content), were found to be strongly correlated to the enhanced protein degradation and inhibited polysaccharides degradation. The results suggested that large amounts of grit in sludge might not be the main reason for lower degradability of sewage sludge in China.
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Affiliation(s)
- Sisi Chen
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, PR China
| | - Bin Dong
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, PR China.
| | - Dianhai Yang
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, PR China.
| | - Ning Li
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, PR 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, PR China
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19
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Schwan B, Abendroth C, Latorre-Pérez A, Porcar M, Vilanova C, Dornack C. Chemically Stressed Bacterial Communities in Anaerobic Digesters Exhibit Resilience and Ecological Flexibility. Front Microbiol 2020; 11:867. [PMID: 32477297 PMCID: PMC7235767 DOI: 10.3389/fmicb.2020.00867] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 04/14/2020] [Indexed: 12/02/2022] Open
Abstract
Anaerobic digestion is a technology known for its potential in terms of methane production. During the digestion process, multiple metabolites of high value are synthesized. However, recent works have demonstrated the high robustness and resilience of the involved microbiomes; these attributes make it difficult to manipulate them in such a way that a specific metabolite is predominantly produced. Therefore, an exact understanding of the manipulability of anaerobic microbiomes may open up a treasure box for bio-based industries. In the present work, the effect of nalidixic acid, γ-aminobutyric acid (GABA), and sodium phosphate on the microbiome of digested sewage sludge from a water treatment plant fed with glucose was investigated. Despite of the induced process perturbations, high stability was observed at the phylum level. However, strong variations were observed at the genus level, especially for the genera Trichococcus, Candidatus Caldatribacterium, and Phascolarctobacterium. Ecological interactions were analyzed based on the Lotka–Volterra model for Trichococcus, Rikenellaceae DMER64, Sedimentibacter, Candidatus Cloacimonas, Smithella, Cloacimonadaceae W5 and Longilinea. These genera dynamically shifted among positive, negative or no correlation, depending on the applied stressor, which indicates a surprisingly dynamic behavior. Globally, the presented work suggests a massive resilience and stability of the methanogenic communities coupled with a surprising flexibility of the particular microbial key players involved in the process.
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Affiliation(s)
- Benjamin Schwan
- Institute of Waste Management and Circular Economy, Technische Universität Dresden, Pirna, Germany
| | - Christian Abendroth
- Institute of Waste Management and Circular Economy, Technische Universität Dresden, Pirna, Germany.,Robert Boyle Institut e.V., Jena, Germany
| | - Adriel Latorre-Pérez
- Darwin Bioprospecting Excellence, S.L. Parc Cientific Universitat de València, Paterna, Spain
| | - Manuel Porcar
- Darwin Bioprospecting Excellence, S.L. Parc Cientific Universitat de València, Paterna, Spain.,Institute for Integrative Systems Biology, University of Valencia-CSIC, Paterna, Spain
| | - Cristina Vilanova
- Darwin Bioprospecting Excellence, S.L. Parc Cientific Universitat de València, Paterna, Spain
| | - Christina Dornack
- Institute of Waste Management and Circular Economy, Technische Universität Dresden, Pirna, Germany
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Xu Q, Liao Y, Cho E, Ko JH. Effects of biochar addition on the anaerobic digestion of carbohydrate-rich, protein-rich, and lipid-rich substrates. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION (1995) 2020; 70:455-467. [PMID: 32091971 DOI: 10.1080/10962247.2020.1733133] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 02/12/2020] [Accepted: 02/17/2020] [Indexed: 06/10/2023]
Abstract
Although biochar addition into the anaerobic digestion of food waste (FW) is an efficient means to enhance methane production, the effects of biochar on various FW components remain unclear. Laboratory batch experiments were conducted to investigate the impact of sewage sludge-derived biochar (SSB) supplementation on the anaerobic digestion (AD) of major FW components, including carbohydrate-rich, protein-rich, and lipid-rich substrates. The lag phase of AD with the carbohydrate-rich substrate was 48.6% shorter when SSB was added, and the cumulative methane yield was 4.74 times higher compared to AD without biochar. SSB supplementation also increased the rate of methane production from the lipid-rich substrate. However, the effect of SSB addition on AD of the protein-rich substrate was minor. Analysis of the microbial communities revealed that methanogen growth was enhanced during AD of the carbohydrate-rich and lipid-rich substrates, but not the protein-rich substrate, following SSB supplementation. Also, the most dominant methanogenic genus varied with the substrates. SSB addition promoted the growth of hydrolytic and fermentative bacteria, particularly phylum Bacteroidetes.Implications: Biochar supplementation has been studied to overcome the shortcomings of anaerobic digestion (AD). However, the effects of biochar on different substrates remain unclear. This study compared carbohydrate-rich, protein-rich, and lipid-rich substrates in anaerobic digestion with sewage sludge-derived biochar (SSB). SSB supplementation improved methane generation from all but the protein-rich substrate. The study results imply that the effect of SSB addition on AD varied with the substrate due to the substrates underwent different degradation processes with different microbial communities.
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Affiliation(s)
- Qiyong Xu
- Shenzhen Engineering Laboratory for Eco-efficient Recycled Materials, School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, PR China
| | - Yuqing Liao
- Shenzhen Engineering Laboratory for Eco-efficient Recycled Materials, School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, PR China
| | - Eunil Cho
- Department of Environmental Engineering, College of Ocean Sciences, Jeju National University, Jeju-si, Republic of Korea
| | - Jae Hac Ko
- Department of Environmental Engineering, College of Ocean Sciences, Jeju National University, Jeju-si, Republic of Korea
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21
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Effects of Increasing Nitrogen Content on Process Stability and Reactor Performance in Anaerobic Digestion. ENERGIES 2020. [DOI: 10.3390/en13051139] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The aim of this study was to analyse the effect of different nitrogen increase rates in feedstock on the process stability and conversion efficiency in anaerobic digestion (AD). The research was conducted in continuously stirred tank reactors (CSTR), initially filled with two different inocula: inocula #1 with low and #2 with high nitrogen (N) concentrations. Three N feeding regimes were investigated: the “0-increase” feeding regime with a constant N amount in feeding and the regimes “0.25-increase” and “0.5-increase” where the N concentrations in feedstock were raised by 0.25 and 0.5 g·kg−1, respectively, related to fresh matter (FM) every second week. The N concentration inside the reactors increased according to the feeding regimes. The levels of inhibition (Inhibition) in specific methane yields (SMY), related to the conversion efficiency of the substrates, were quantified. At the N concentration in digestate of 10.82 ± 0.52 g·kg−1 FM measured in the reactors with inoculum #2 and “0.5-increase” feeding regime, the level of inhibition was equal to 38.99% ± 14.99%. The results show that high nitrogen increase rates in feeding regime are negatively related to the efficiency of the AD process, even if low volatile fatty acid (VFA) concentrations indicate a stable process.
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Fischer MA, Ulbricht A, Neulinger SC, Refai S, Waßmann K, Künzel S, Schmitz RA. Immediate Effects of Ammonia Shock on Transcription and Composition of a Biogas Reactor Microbiome. Front Microbiol 2019; 10:2064. [PMID: 31555248 PMCID: PMC6742706 DOI: 10.3389/fmicb.2019.02064] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 08/21/2019] [Indexed: 12/22/2022] Open
Abstract
The biotechnological process of biogas production from organic material is carried out by a diverse microbial community under anaerobic conditions. However, the complex and sensitive microbial network present in anaerobic degradation of organic material can be disturbed by increased ammonia concentration introduced into the system by protein-rich substrates and imbalanced feeding. Here, we report on a simulated increase of ammonia concentration in a fed batch lab-scale biogas reactor experiment. Two treatment conditions were used simulating total ammonia nitrogen concentrations of 4.9 and 8.0 g/L with four replicate reactors. Each reactor was monitored concerning methane generation and microbial composition using 16S rRNA gene amplicon sequencing, while the transcriptional activity of the overall process was investigated by metatranscriptomic analysis. This allowed investigating the response of the microbial community in terms of species composition and transcriptional activity to a rapid upshift to high ammonia conditions. Clostridia and Methanomicrobiales dominated the microbial community throughout the entire experiment under both experimental conditions, while Methanosarcinales were only present in minor abundance. Transcription analysis demonstrated clostridial dominance with respect to genes encoding for enzymes of the hydrolysis step (cellulase, EC 3.2.1.4) as well as dominance of key genes for enzymes of the methanogenic pathway (methyl-CoM reductase, EC 2.8.4.1; heterodisulfide reductase, EC 1.8.98.1). Upon ammonia shock, the selected marker genes showed significant changes in transcriptional activity. Cellulose hydrolysis as well as methanogenesis were significantly reduced at high ammonia concentrations as indicated by reduced transcription levels of the corresponding genes. Based on these experiments we concluded that, apart from the methanogenic archaea, hydrolytic cellulose-degrading microorganisms are negatively affected by high ammonia concentrations. Further, Acholeplasma and Erysipelotrichia showed lower abundance under increased ammonia concentrations and thus might serve as indicator species for an earlier detection in order to counteract against ammonia crises.
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Affiliation(s)
- Martin A. Fischer
- Department of Biology, Institute of General Microbiology, Christian-Albrechts-University Kiel, Kiel, Germany
| | - Andrea Ulbricht
- Department of Biology, Institute of General Microbiology, Christian-Albrechts-University Kiel, Kiel, Germany
| | - Sven C. Neulinger
- Department of Biology, Institute of General Microbiology, Christian-Albrechts-University Kiel, Kiel, Germany
| | - Sarah Refai
- Department of Biology, Institut für Mikrobiologie und Biotechnologie, University Bonn, Bonn, Germany
| | - Kati Waßmann
- Department of Biology, Institut für Mikrobiologie und Biotechnologie, University Bonn, Bonn, Germany
| | - Sven Künzel
- Department for Evolutionary Genetics, Max-Planck-Institute for Evolutionary Biology, Plön, Germany
| | - Ruth A. Schmitz
- Department of Biology, Institute of General Microbiology, Christian-Albrechts-University Kiel, Kiel, Germany
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23
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Wang X, Li Y, Zhang Y, Pan YR, Li L, Liu J, Butler D. Stepwise pH control to promote synergy of chemical and biological processes for augmenting short-chain fatty acid production from anaerobic sludge fermentation. WATER RESEARCH 2019; 155:193-203. [PMID: 30849733 DOI: 10.1016/j.watres.2019.02.032] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 02/18/2019] [Accepted: 02/19/2019] [Indexed: 05/27/2023]
Abstract
Although sludge-converted short-chain fatty acids (SCFAs) are promising feedstocks for biorefineries, it remains challenging to maximise SCFA production by enhancing synergies between chemical/biological hydrolysis and acidogenesis processes while employing a balanced composition of microbial communities to counteract methanogenesis. Herein, stepwise control of fermentation pH and chemical/microbiological composition analysis of fermented sludge were used to probe the underlying mechanisms of SCFA production. Fermentation at pH 11 during the first three days promoted both chemical and microbial hydrolysis of sludge proteins and provided a niche for Anaerobrancaceae sp. to transform soluble protein into SCFAs. When pH was decreased from 11 to 9, Acinetobacter, Proteiniborus, Proteiniclasticum, and other acetogens became predominant and stayed significantly more active than during first-stage fermentation at pH 11, which benefited the acidification of hydrolysed substrates. Further assays indicated that early-stage sludge fermentation at pH 11 decreased the total amount of methanogenic archaea and hence reduced the amount of SCFAs consumed for methane production. Thus, the use of stepwise pH control for sludge fermentation allowed one to establish process synergies, facilitate chemical and biological hydrolysis, inhibit methanogens, and promote the growth of acidifying bacterial communities, which resulted in efficient SCFA production from sludge.
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Affiliation(s)
- Xu Wang
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; Centre for Water Systems, Department of Engineering, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, EX4 4QF, United Kingdom; State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
| | - Yanbo Li
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ya Zhang
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, 73019, United States
| | - Yi-Rong Pan
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lin Li
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Junxin Liu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - David Butler
- Centre for Water Systems, Department of Engineering, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, EX4 4QF, United Kingdom
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24
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Dikicioglu D, Dereli Eke E, Eraslan S, Oliver SG, Kirdar B. Saccharomyces cerevisiae adapted to grow in the presence of low-dose rapamycin exhibit altered amino acid metabolism. Cell Commun Signal 2018; 16:85. [PMID: 30458881 PMCID: PMC6245637 DOI: 10.1186/s12964-018-0298-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 11/08/2018] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Rapamycin is a potent inhibitor of the highly conserved TOR kinase, the nutrient-sensitive controller of growth and aging. It has been utilised as a chemotherapeutic agent due to its anti-proliferative properties and as an immunosuppressive drug, and is also known to extend lifespan in a range of eukaryotes from yeast to mammals. However, the mechanisms through which eukaryotic cells adapt to sustained exposure to rapamycin have not yet been thoroughly investigated. METHODS Here, S. cerevisiae response to long-term rapamycin exposure was investigated by identifying the physiological, transcriptomic and metabolic differences observed for yeast populations inoculated into low-dose rapamycin-containing environment. The effect of oxygen availability and acidity of extracellular environment on this response was further deliberated by controlling or monitoring the dissolved oxygen level and pH of the culture. RESULTS Yeast populations grown in the presence of rapamycin reached higher cell densities complemented by an increase in their chronological lifespan, and these physiological adaptations were associated with a rewiring of the amino acid metabolism, particularly that of arginine. The ability to synthesise amino acids emerges as the key factor leading to the major mechanistic differences between mammalian and microbial TOR signalling pathways in relation to nutrient recognition. CONCLUSION Oxygen levels and extracellular acidity of the culture were observed to conjointly affect yeast populations, virtually acting as coupled physiological effectors; cells were best adapted when maximal oxygenation of the culture was maintained in slightly acidic pH, any deviation necessitated more extensive readjustment to additional stress factors.
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Affiliation(s)
- Duygu Dikicioglu
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK. .,Cambridge Systems Biology Centre, University of Cambridge, Cambridge, UK. .,Department of Chemical Engineering, Bogazici University, Istanbul, Turkey.
| | - Elif Dereli Eke
- Department of Chemical Engineering, Bogazici University, Istanbul, Turkey.,Present address: Unit of Blood Diseases and Stem Cells Transplantation, Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy
| | - Serpil Eraslan
- Department of Chemical Engineering, Bogazici University, Istanbul, Turkey.,Present address: Diagnostic Centre for Genetic Diseases, Koc University Hospital, Istanbul, Turkey
| | - Stephen G Oliver
- Cambridge Systems Biology Centre, University of Cambridge, Cambridge, UK.,Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Betul Kirdar
- Department of Chemical Engineering, Bogazici University, Istanbul, Turkey
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25
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Greses S, Gaby JC, Aguado D, Ferrer J, Seco A, Horn SJ. Microbial community characterization during anaerobic digestion of Scenedesmus spp. under mesophilic and thermophilic conditions. ALGAL RES 2017. [DOI: 10.1016/j.algal.2017.09.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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26
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He Q, Li L, Zhao X, Qu L, Wu D, Peng X. Investigation of foaming causes in three mesophilic food waste digesters: reactor performance and microbial analysis. Sci Rep 2017; 7:13701. [PMID: 29057910 PMCID: PMC5651842 DOI: 10.1038/s41598-017-14258-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 10/09/2017] [Indexed: 12/21/2022] Open
Abstract
Foaming negatively affects anaerobic digestion of food waste (FW). To identify the causes of foaming, reactor performance and microbial community dynamics were investigated in three mesophilic digesters treating FW. The digesters were operated under different modes, and foaming was induced with several methods. Proliferation of specific bacteria and accumulation of surface active materials may be the main causes of foaming. Volatile fatty acids (VFAs) and total ammonia nitrogen (TAN) accumulated in these reactors before foaming, which may have contributed to foam formation by decreasing the surface tension of sludge and increasing foam stability. The relative abundance of acid-producing bacteria (Petrimonas, Fastidiosipila, etc.) and ammonia producers (Proteiniphilum, Gelria, Aminobacterium, etc.) significantly increased after foaming, which explained the rapid accumulation of VFAs and NH4+ after foaming. In addition, the proportions of microbial genera known to contribute to foam formation and stabilization significantly increased in foaming samples, including bacteria containing mycolic acid in cell walls (Actinomyces, Corynebacterium, etc.) and those capable of producing biosurfactants (Corynebacterium, Lactobacillus, 060F05-B-SD-P93, etc.). These findings improve the understanding of foaming mechanisms in FW digesters and provide a theoretical basis for further research on effective suppression and early warning of foaming.
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Affiliation(s)
- Qin He
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, PR China
| | - Lei Li
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, PR China
| | - Xiaofei Zhao
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, PR China
| | - Li Qu
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, PR China
| | - Di Wu
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, PR China
| | - Xuya Peng
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, PR China.
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27
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Wang D, Liu B, Ding X, Sun X, Liang Z, Sheng S, Du L. Performance evaluation and microbial community analysis of the function and fate of ammonia in a sulfate-reducing EGSB reactor. Appl Microbiol Biotechnol 2017; 101:7729-7739. [DOI: 10.1007/s00253-017-8514-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 08/16/2017] [Accepted: 09/11/2017] [Indexed: 10/18/2022]
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28
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Chen Y, Jiang X, Xiao K, Shen N, Zeng RJ, Zhou Y. Enhanced volatile fatty acids (VFAs) production in a thermophilic fermenter with stepwise pH increase - Investigation on dissolved organic matter transformation and microbial community shift. WATER RESEARCH 2017; 112:261-268. [PMID: 28178608 DOI: 10.1016/j.watres.2017.01.067] [Citation(s) in RCA: 147] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 01/05/2017] [Accepted: 01/31/2017] [Indexed: 06/06/2023]
Abstract
In this study, a mixture of primary and wasted activated sludge was fermented in a semi-continuous reactor aiming for enhanced volatile fatty acids (VFAs) production. The reactor was subjected to a stepwise pH increase from 7 to 10 during approximately 130 days of operation. The result revealed that the maximum acidification was obtained at pH 8.9 (21%) resulting in the maximum production of VFAs (423.22 ± 25.49 mg COD/g VSS), while the maximum hydrolysis efficiency was observed at pH 9.9 (42%). The high pH was effective in releasing dissolved organic matter (DOM) including protein, carbohydrate, building blocks and low molecular weight (LMW) neutrals. More LMW DOMs were released than high molecular weight (HMW) DOMs fractions at higher pH. pH 9.9 favored hydrolysis of HMW DOMs while it did not enhance the acidogenesis of LMW DOMs. The microbial community analysis showed that the relative abundance of phyla Actinobacteria and Proteobacteria increased with the increased pH, which may lead to the maximum hydrolysis at pH 9.9. At pH 8.9, class Clostridia (59.16%) was the most dominant population where the maximum acidification (21%) was obtained. This suggested that the dominance of Clostridia was highly related to acidification extent. The relative abundance of Euryarchaeota decreased significantly from 58% to 2% with increased pH.
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Affiliation(s)
- Yun Chen
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore, 637141, Singapore; CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, People's Republic of China
| | - Xie Jiang
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore, 637141, Singapore
| | - Keke Xiao
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore, 637141, Singapore
| | - Nan Shen
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore, 637141, Singapore
| | - Raymond J Zeng
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, People's Republic of China
| | - Yan Zhou
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore, 637141, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore.
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