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Li Z, Gu J, Ding J, Ren N, Xing D. Molecular mechanism of ethanol-H 2 co-production fermentation in anaerobic acidogenesis: Challenges and perspectives. Biotechnol Adv 2020; 46:107679. [PMID: 33316366 DOI: 10.1016/j.biotechadv.2020.107679] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 12/04/2020] [Accepted: 12/07/2020] [Indexed: 12/29/2022]
Abstract
Ethanol-type fermentation (ETF) is one of three fermentation types during the acidogenesis of the anaerobic biological treatment. Ethanoligenens, a representative genus of ETF, displays acidophilic, autoaggregative, and ethanol-H2 co-producing characteristics and facilitates subsequent methanogenesis. Here, the latest advances in the molecular mechanisms of the metabolic regulation of ethanol-H2 co-producing bacteria based on multi-omics studies were comprehensively reviewed. Comparative genomics demonstrated a low genetic similarity between Ethanoligenens and other hydrogen-producing genera. FeFe‑hydrogenases (FeFe-H2ases) and pyruvate ferredoxin oxidoreductase (PFOR) played critical roles in the ethanol-H2 co-metabolic pathway of Ethanoligenens. Global transcriptome analysis revealed that highly expressed [FeFe]-H2ases and ferredoxins drove hydrogen production by Ethanoligenens at low pH conditions (4.0-4.5). Quantitative proteomic analysis also proved that this genus resists acetic acid-induced intracellular acidification through the up-regulated expression of pyrimidine metabolism related proteins. The autoaggregation of Ethanoligenen facilitated its granulation with acetate-oxidizing bacteria in co-culture systems and mitigated a fast pH drop, providing a new approach for solving a pH imbalance and improving hydrogen production. In-depth studies of the regulatory mechanism underlying ethanol-H2 co-production metabolism and the syntrophic interactions of ethanol-H2 co-producing Ethanoligenens with other microorganisms will provide insights into the improvement of bioenergy recovery in anaerobic biotechnology. The coupling of ETF with other biotechnologies, which based on the regulation of electron flow direction, syntrophic interaction, and metabolic flux, can be potential strategies to enhance the cascade recovery of energy and resources.
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Affiliation(s)
- Zhen Li
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Jiayu Gu
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Jie Ding
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Nanqi Ren
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Defeng Xing
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
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52
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Fu X, Ye R, Jin X, Lu W. Effect of nano zero-valent iron addition on caproate fermentation in carboxylate chain elongation system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 743:140664. [PMID: 32679493 DOI: 10.1016/j.scitotenv.2020.140664] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 06/15/2020] [Accepted: 06/29/2020] [Indexed: 06/11/2023]
Abstract
Carboxylate chain elongation is a burgeoning research area for producing added value bio-products from organic fraction of municipal solid waste. Effect of nano zero-valent iron (NZVI) on chain elongation and its possible mechanism was investigated. Highest caproate concentration, 28.0 mmol·L-1 was achieved with 2 g·L-1 NZVI amendment, which is about 16.7% higher than the control. Promoted ethanol utilization was considered as the main reason for the increment of caproate production and hydrogen generation. Electron balance analysis shows that NZVI did not improve the total electron recovery efficiency but favoured the electron flow toward longer carboxylate chain product, i.e. caproate. Finally, full-length 16s rRNA sequencing of bacterial community showed NZVI reshaped the bacterial community by exerting reduction selectivity. And Oscillibacter and Clostridium could be the potential functional species for carboxylate chain elongation.
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Affiliation(s)
- Xindi Fu
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Rong Ye
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Xi Jin
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Wenjing Lu
- School of Environment, Tsinghua University, Beijing 100084, China.
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53
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Wu SL, Wei W, Sun J, Xu Q, Dai X, Ni BJ. Medium-Chain fatty acids and long-chain alcohols production from waste activated sludge via two-stage anaerobic fermentation. WATER RESEARCH 2020; 186:116381. [PMID: 32916621 DOI: 10.1016/j.watres.2020.116381] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 08/17/2020] [Accepted: 09/01/2020] [Indexed: 06/11/2023]
Abstract
Traditional bioenergy recovery in the form of short chain fatty acids (SCFAs) from waste activated sludge (WAS) is generally limited by economic unattractiveness and complexity of products separation. Herein, a novel biotechnology process of two-stage anaerobic fermentation for converting the WAS into high energy density, easy-separated medium chain fatty acids (MCFAs) and long-chain alcohols (LCAs) was evaluated. In this process, the WAS was first converted to WAS alkaline fermentation liquid (WASAFL), serving as electron acceptors (EAs) and inoculum, then adding ethanol as electron donor (ED) for chain elongation (CE). The co-production of MCFAs and LCAs during CE were studied under three different ED to EA ratios, i.e., 3:1, 4:1 and 5:1. Experimental results demonstrated that when the ratio of ED to EA increased from 3:1 to 5:1, the production of MCFA and LCAs respectively increased from 5.57 ± 0.17 and 2.58 ± 0.18 to7.67 ± 0.48 and 4.21 ± 0.19 g COD/L. A similar observation was made in the total product electron efficiency, increasing from 59.9% to 72.1%. However, the highest total product selectivity (i.e., 68.0%) and highest products production yield (i.e., 59.77%) were not achieved at the ED to EA ratio of 5:1 due to toxicity caused by higher accumulation of n-caproate. The kinetic analysis further confirmed that high ratio of ED to EA induced improvement in product maximum yield, production rate for both MCFAs and LCAs. Microbial community analysis indicated that Clostridium, Caproiciproducens, Acinetobacter, Exilispira, and Oscillibacter were clearly enriched in the CE reactor and had positive correlation with MCFAs and LCAs production.
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Affiliation(s)
- Shu-Lin Wu
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China
| | - Wei Wei
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China
| | - Jing Sun
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China
| | - Qiuxiang Xu
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China.
| | - Xiaohu Dai
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China
| | - Bing-Jie Ni
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China.
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54
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Wang G, Li Y, Sheng L, Xing Y, Liu G, Yao G, Ngo HH, Li Q, Wang XC, Li YY, Chen R. A review on facilitating bio-wastes degradation and energy recovery efficiencies in anaerobic digestion systems with biochar amendment. BIORESOURCE TECHNOLOGY 2020; 314:123777. [PMID: 32665106 DOI: 10.1016/j.biortech.2020.123777] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 06/28/2020] [Accepted: 06/30/2020] [Indexed: 06/11/2023]
Abstract
In this review, progress in the potential mechanisms of biochar amendment for AD performance promotion was summarized. As adsorbents, biochar was beneficial for alleviating microbial toxicity, accelerating refractory substances degradation, and upgrading biogas quality. The buffering capacity of biochar balanced pH decreasing caused by volatile fatty acids accumulation. Moreover, biochar regulated microbial metabolism by boosting activities, mediating electron transfer between syntrophic partners, and enriching functional microbes. Recent studies also suggested biochar as potential useful additives for membrane fouling alleviation in anaerobic membrane bioreactors (AnMBR). By analyzing the reported performances based on different operation models or substrate types, debatable issues and associated research gaps of understanding the real role of biochar in AD were critically discussed. Accordingly, Future perspectives of developing biochar-amended AD technology for real-world applications were elucidated. Lastly, with biochar-amended AD as a core process, a novel integrated scheme was proposed towards high-efficient energy-resource recovery from various bio-wastes.
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Affiliation(s)
- Gaojun Wang
- Key Lab of Environmental Engineering, Shaanxi Province, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China; International S&T Cooperation Center for Urban Alternative Water Resources Development, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China
| | - Yu Li
- Key Lab of Environmental Engineering, Shaanxi Province, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China
| | - Li Sheng
- Key Lab of Environmental Engineering, Shaanxi Province, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China
| | - Yao Xing
- Key Lab of Environmental Engineering, Shaanxi Province, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China
| | - Guohao Liu
- Key Lab of Environmental Engineering, Shaanxi Province, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China
| | - Gaofei Yao
- Key Lab of Environmental Engineering, Shaanxi Province, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China
| | - Huu Hao Ngo
- International S&T Cooperation Center for Urban Alternative Water Resources Development, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China; Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Qian Li
- Key Lab of Environmental Engineering, Shaanxi Province, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China; International S&T Cooperation Center for Urban Alternative Water Resources Development, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China
| | - Xiaochang C Wang
- Key Lab of Environmental Engineering, Shaanxi Province, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China; International S&T Cooperation Center for Urban Alternative Water Resources Development, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China
| | - Yu-You Li
- Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, 6-6-06 Aoba, Aramaki-Aza, Sendai, Miyagi 980-8579, Japan
| | - Rong Chen
- Key Lab of Environmental Engineering, Shaanxi Province, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China; International S&T Cooperation Center for Urban Alternative Water Resources Development, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China.
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55
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Wang Y, Wei W, Wu SL, Ni BJ. Zerovalent Iron Effectively Enhances Medium-Chain Fatty Acids Production from Waste Activated Sludge through Improving Sludge Biodegradability and Electron Transfer Efficiency. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:10904-10915. [PMID: 32867479 DOI: 10.1021/acs.est.0c03029] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A novel zerovalent iron (ZVI) technique to simultaneously improve the production of medium-chain fatty acids (MCFAs) from waste activated sludge (WAS) and enhance WAS degradation during anaerobic WAS fermentation was proposed in this study. Experimental results showed that the production and selectivity of MCFAs were effectively promoted when ZVI was added at 1-20 g/L. The maximum MCFAs production of 15.4 g COD (Chemical Oxygen Demand)/L and MCFAs selectivity of 71.7% were both achieved at 20 g/L ZVI, being 5.3 and 4.8 times that without ZVI (2.9 g COD/L and 14.9%). Additionally, ZVI also promoted WAS degradation, which increased from 0.61 to 0.96 g COD/g VS when ZVI increased from 0 to 20 g/L. The microbial community analysis revealed that the ZVI increased the populations of key anaerobes related to hydrolysis, acidification, and chain elongation. Correspondingly, the solubilization, hydrolysis, and acidification processes of WAS were revealed to be improved by ZVI, thereby providing more substrates (short-chain fatty acids (SCFAs)) for producing MCFAs. The mechanism studies showed that ZVI declined the oxidation-reduction potential (ORP), creating a more favorable environment for the anaerobic biological processes. More importantly, ZVI with strong conductivity could act as an electron shuttle, contributing to increasing electron transfer efficiency from electron donor to acceptor. This strategy provides a new paradigm of transforming waste sludge into assets by a low-cost waste to bring significant economic benefits to sludge disposal and wastewater treatment.
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Affiliation(s)
- Yun Wang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China
| | - Wei Wei
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China
| | - Shu-Lin Wu
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China
| | - Bing-Jie Ni
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, P.R. China
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56
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Venkateswar Reddy M, Kumar G, Mohanakrishna G, Shobana S, Al-Raoush RI. Review on the production of medium and small chain fatty acids through waste valorization and CO 2 fixation. BIORESOURCE TECHNOLOGY 2020; 309:123400. [PMID: 32371319 DOI: 10.1016/j.biortech.2020.123400] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/15/2020] [Accepted: 04/16/2020] [Indexed: 06/11/2023]
Abstract
The developing approaches in the recovery of resources from biowastes for the production of renewable value-added products and fuels, using microbial cultures as bio-catalyst have now became promising aspect. In the path of anaerobic digestion, the microorganisms are assisting transformation of a complex organic feedstock/waste to biomass and biogas. This potentiality consequently leads to the production of intermediate precursors of renewable value-added products. Particularly, a set of anaerobic pathways in the fermentation process, yields small-chain fatty acids (SCFA), and medium-chain fatty acids (MCFA) via chain elongation pathways from waste valorization and CO2 fixation. This review focuses on the production of SCFA and MCFA from CO2, synthetic substrates and waste materials. Moreover, the review introduces the metabolic engineering of Escherichia coli and Saccharomyces cerevisiae for SCFAs/MCFAs production. Furtherly, it concludes that future critical research might target progress of this promising approach as a valorization of complex organic wastes.
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Affiliation(s)
- M Venkateswar Reddy
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms Universität, Corrensstr. 3, 48149 Münster, Germany
| | - Gopalakrishnan Kumar
- School of Civil and Environmental Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Gunda Mohanakrishna
- Department of Civil and Architectural Engineering, College of Engineering, Qatar University, P O Box 2713, Doha, Qatar.
| | - Sutha Shobana
- Department of Chemistry & Research Centre, Mohamed Sathak Engineering College, Kilakarai, 623 806 Ramanathapuram, Tamil Nadu, India
| | - Riyadh I Al-Raoush
- Department of Civil and Architectural Engineering, College of Engineering, Qatar University, P O Box 2713, Doha, Qatar
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57
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Zhang F, Qian DK, Wang XB, Dai K, Wang T, Zhang W, Zeng RJ. Stimulation of methane production from benzoate with addition of carbon materials. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 723:138080. [PMID: 32220738 DOI: 10.1016/j.scitotenv.2020.138080] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 03/18/2020] [Accepted: 03/18/2020] [Indexed: 06/10/2023]
Abstract
Huge amounts of wastewater that contain aromatic compounds such as benzene and phenols are discharged worldwide. Benzoate is a typical intermediate in the anaerobic transformation of those aromatic compounds. In this study, electrically conductive carbon-based materials of granulated activated carbon (GAC), multiwalled carbon nanotubes (MwCNTs), and graphite were evaluated for the ability to promote the benzoate degradation. The results showed that 82-93% of the electrons were recovered in CH4 production from benzoate. The carbon materials stimulated benzoate degradation in the sequence of GAC (5 g/L) > MwCNTs (1 g/L) ~ Graphite (0.1 g/L) > Control. Acetate was the only detected intermediate in the process of benzoate degradation. Taxonomic analyses revealed that benzoate was degraded by Syntrophus to acetate and H2, which were subsequently converted to methane by Methanosarcina (both acetoclastic methanogens and hydrogenotrophic methanogens) and Methanoculleus (hydrogenotrophic methanogens), and direct interspecies electron transfer (DIET) of Desulfovibrio and Methanosarcina. Thus, these results suggest a method to effectively enhance the removal of aromatic compounds and methane recovery.
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Affiliation(s)
- Fang Zhang
- Center of Wastewater Resource Recovery, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Ding-Kang Qian
- Center of Wastewater Resource Recovery, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Xian-Bin Wang
- 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
| | - Kun Dai
- Center of Wastewater Resource Recovery, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Ting Wang
- 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
| | - Wei Zhang
- 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
| | - Raymond Jianxiong Zeng
- Center of Wastewater Resource Recovery, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China; 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.
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58
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Zagrodnik R, Duber A, Łężyk M, Oleskowicz-Popiel P. Enrichment Versus Bioaugmentation-Microbiological Production of Caproate from Mixed Carbon Sources by Mixed Bacterial Culture and Clostridium kluyveri. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:5864-5873. [PMID: 32267683 PMCID: PMC7588035 DOI: 10.1021/acs.est.9b07651] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Chain elongation is a process that produces medium chain fatty acids such as caproic acid, which is one of the promising products of the carboxylate platform. This study analyzed the impact of bioaugmentation of heat-treated anaerobic digester sludge with Clostridium kluyveri (AS + Ck) on caproic acid production from a mixed substrate (lactose, lactate, acetate, and ethanol). It was compared with processes initiated with non-augmented heat-treated anaerobic digester sludge (AS) and mono-culture of C. kluyveri (Ck). Moreover, stability of the chain elongation process was evaluated by performing repeated batch experiments. All bacterial cultures demonstrated efficient caproate production in the first batch cycle. After 18 days, caproate concentration reached 9.06 ± 0.43, 7.86 ± 0.38, and 7.67 ± 0.37 g/L for AS, Ck, and AS + Ck cultures, respectively. In the second cycle, AS microbiome was enriched toward caproate production and showed the highest caproate concentration of 11.44 ± 0.47 g/L. On the other hand, bioaugmented culture showed the lowest caproate production in the second cycle (4.10 ± 0.30 g/L). Microbiome analysis in both AS and AS + Ck culture samples indicated strong enrichment toward the anaerobic order of Clostridia. Strains belonging to genera Sporanaerobacter, Paraclostridium, Haloimpatiens, Clostridium, and Bacillus were dominating in the bioreactors.
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Affiliation(s)
- Roman Zagrodnik
- Faculty
of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego
8, 61-614 Poznan, Poland
| | - Anna Duber
- Water
Supply and Bioeconomy Division, Faculty of Environmental Engineering
and Energy, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland
| | - Mateusz Łężyk
- Water
Supply and Bioeconomy Division, Faculty of Environmental Engineering
and Energy, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland
| | - Piotr Oleskowicz-Popiel
- Water
Supply and Bioeconomy Division, Faculty of Environmental Engineering
and Energy, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland
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59
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Pan XR, Huang L, Fu XZ, Yuan YR, Liu HQ, Li WW, Yu L, Zhao QB, Zuo J, Chen L, Lam PKS. Long-term, selective production of caproate in an anaerobic membrane bioreactor. BIORESOURCE TECHNOLOGY 2020; 302:122865. [PMID: 32004814 DOI: 10.1016/j.biortech.2020.122865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 01/16/2020] [Accepted: 01/21/2020] [Indexed: 06/10/2023]
Abstract
Fermentative caproate production from wastewater is attractive but is currently limited by the low product purity and concentration. In this work, continuous, selective production of caproate from acetate and ethanol, the common products of wastewater anaerobic fermentation, was achieved in an anaerobic membrane bioreactor (AnMBR). The reactor was continuously operated for over 522 days without need for chemical cleaning. With an ethanol-to-acetate ratio of 3.0, the effluent caproate concentration was 2.62 g/L on average and the caproate ratio in liquid products reached 74%. Further raising the influent ethanol content slightly increased the effluent caproate level but lowered the product selectivity and resulted in microbial inhibition. The Clostridia (the major caproate-producing bacteria) and Methanobacterium species (which consume hydrogen to alleviate microbial inhibition) was significantly enriched in the acclimated sludge. Our results imply a great potential of utilizing AnMBR to recover caproate from the effluent of wastewater acidogenic fermentation process.
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Affiliation(s)
- Xin-Rong Pan
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei 230026, China; Department of Chemistry, City University of Hong Kong, Hong Kong SAR 999077, China; State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Liang Huang
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei 230026, China
| | - Xian-Zhong Fu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei 230026, China
| | - Yan-Ru Yuan
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei 230026, China
| | - Hou-Qi Liu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei 230026, China
| | - Wen-Wei Li
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei 230026, China.
| | - Lei Yu
- Department of Environmental Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Quan-Bao Zhao
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei 230026, China
| | - Jiane Zuo
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Lei Chen
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Paul Kwan-Sing Lam
- Department of Chemistry, City University of Hong Kong, Hong Kong SAR 999077, China
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60
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San-Valero P, Abubackar HN, Veiga MC, Kennes C. Effect of pH, yeast extract and inorganic carbon on chain elongation for hexanoic acid production. BIORESOURCE TECHNOLOGY 2020; 300:122659. [PMID: 31893537 DOI: 10.1016/j.biortech.2019.122659] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 12/17/2019] [Accepted: 12/18/2019] [Indexed: 06/10/2023]
Abstract
Several anaerobic bioconversion technologies produce short chain volatile fatty acids and sometimes ethanol, which can together be elongated to hexanoic acid (C6 acid) by Clostridium kluyveri in a secondary fermentation process. Initiatives are needed to further optimize the process. Therefore, five strategies were tested aiming at elucidating their influence on hexanoic acid production from mixtures of acetic acid, butyric acid and ethanol. pH-regulated bioreactors, maintained at pH 7.5, 6.8 or 6.4 led to maximum C6 acid concentrations of, respectively, 19.4, 18.3 and 13.3 g L-1. At pH 6.8, yeast extract omission resulted in a decrease of the hexanoic acid concentration to 12.0 g L-1 while the addition of an inorganic carbon source, such as bicarbonate, for pH control, increased the C6 acid concentration up to 21.4 g L-1. This research provides guidelines for efficient improved production of hexanoic acid by pure cultures of C. kluyveri, contributing to the state of art.
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Affiliation(s)
- Pau San-Valero
- Chemical Engineering Laboratory, Faculty of Sciences and Center for Advanced Scientific Research (CICA), University of La Coruña, Rúa da Fraga 10, E - 15008 La Coruña, Spain
| | - Haris Nalakath Abubackar
- Chemical Engineering Laboratory, Faculty of Sciences and Center for Advanced Scientific Research (CICA), University of La Coruña, Rúa da Fraga 10, E - 15008 La Coruña, Spain
| | - María C Veiga
- Chemical Engineering Laboratory, Faculty of Sciences and Center for Advanced Scientific Research (CICA), University of La Coruña, Rúa da Fraga 10, E - 15008 La Coruña, Spain
| | - Christian Kennes
- Chemical Engineering Laboratory, Faculty of Sciences and Center for Advanced Scientific Research (CICA), University of La Coruña, Rúa da Fraga 10, E - 15008 La Coruña, Spain.
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61
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Indren M, Birzer CH, Kidd SP, Hall T, Medwell PR. Effects of biochar parent material and microbial pre-loading in biochar-amended high-solids anaerobic digestion. BIORESOURCE TECHNOLOGY 2020; 298:122457. [PMID: 31862677 DOI: 10.1016/j.biortech.2019.122457] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 11/17/2019] [Accepted: 11/18/2019] [Indexed: 06/10/2023]
Abstract
This study characterises the effect of biochar (pyrolysed biomass) produced from wood pellets, wheat straw and sheep manure on high-solids anaerobic digestion (HSAD) of poultry litter. Also, pre-loading biochar with microorganisms before addition to HSADs was investigated. The addition of wood pellet biochar provides a 32% increase to the methane yield compared with control digesters. The addition of biochar produced from either wheat straw or sheep manure has detrimental effects on digester performance compared with controls. The addition of wood pellet biochar pre-loaded by placing it in a high-solids digester for 90 days provides a 69% increase in the total methane yield, 44% increase in the peak daily methane yield and a 33% reduction in the lag time compared with controls. This study highlighted a need for careful selection of parent material for biochar production and, for the first time, the opportunities to re-use wood pellet biochar for further improvements.
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Affiliation(s)
- Mathu Indren
- School of Mechanical Engineering, The University of Adelaide, SA 5005, Australia; Humanitarian and Development Solutions Initiative, The University of Adelaide, SA 5005, Australia.
| | - Cristian H Birzer
- School of Mechanical Engineering, The University of Adelaide, SA 5005, Australia; Humanitarian and Development Solutions Initiative, The University of Adelaide, SA 5005, Australia
| | - Stephen P Kidd
- School of Biological Sciences, The University of Adelaide, SA 5005, Australia; Humanitarian and Development Solutions Initiative, The University of Adelaide, SA 5005, Australia
| | - Tony Hall
- Faculty of Sciences, The University of Adelaide, SA 5005, Australia
| | - Paul R Medwell
- School of Mechanical Engineering, The University of Adelaide, SA 5005, Australia; Humanitarian and Development Solutions Initiative, The University of Adelaide, SA 5005, Australia
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62
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Sun X, Atiyeh HK, Li M, Chen Y. Biochar facilitated bioprocessing and biorefinery for productions of biofuel and chemicals: A review. BIORESOURCE TECHNOLOGY 2020; 295:122252. [PMID: 31669180 DOI: 10.1016/j.biortech.2019.122252] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 10/04/2019] [Accepted: 10/05/2019] [Indexed: 05/22/2023]
Abstract
Biochar is traditionally used to improve soil properties in arable land and as adsorbent or precursor of activated carbon in wastewater treatment. Recent advances have shown biochar potentials in enhancing productions of biofuels and chemicals such as bio-ethanol, butanol, methane, hydrogen, bio-diesel, hydrocarbons and carboxylic acids. The properties of biochar such as high levels of porosity, functional groups, cation exchange capacity, pH buffering capacity, electron conductivity, and macro-/micro- nutrients (Na, K, Ca, Mg, P, S, Fe, etc.) provide appropriate conditions to relieve physicochemical stresses on microorganisms through pH buffering, detoxification, nutrients supply, serving as electron carrier and supportive microbial habitats. This paper critically reviewed biochar production and characteristics, biochar utilization in anaerobic digestion, composting, microbial fermentation, hydrolysate detoxification, catalysis in biomass refinery and biodiesel synthesis. This review provides novel vision of biochar application, which could guide future research towards cleaner and more economic production of renewable fuels and bio-based chemicals.
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Affiliation(s)
- Xiao Sun
- Department of Bioproducts and Biosystems Engineering, University of Minnesota, Saint Paul 55108, MN, USA.
| | - Hasan K Atiyeh
- Department of Biosystems and Agricultural Engineering, Oklahoma State University, Stillwater 74078, OK, USA
| | - Mengxing Li
- Department of Biological Systems Engineering, University of Nebraska, Lincoln 68583, NE, USA
| | - Yan Chen
- School of Bioengineering, Dalian University of Technology, Dalian 116024, Liaoning, China
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63
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Zhang D, Shen J, Shi H, Su G, Jiang X, Li J, Liu X, Mu Y, Wang L. Substantially enhanced anaerobic reduction of nitrobenzene by biochar stabilized sulfide-modified nanoscale zero-valent iron: Process and mechanisms. ENVIRONMENT INTERNATIONAL 2019; 131:105020. [PMID: 31325713 DOI: 10.1016/j.envint.2019.105020] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 06/14/2019] [Accepted: 07/13/2019] [Indexed: 06/10/2023]
Abstract
Nanoscale zero-valent iron (nZVI), although being increasingly used in anaerobic systems for strengthening the removal of various refractory pollutants, is limited by various inherent drawbacks, such as easy precipitation, passivation, poor mass and electron transfer. To address the above issues, biochar stabilized sulfide-modified nZVI (S-nZVI@BC) was added into an up-flow anaerobic sludge blanket (UASB) to investigate the enhancement of anaerobic biodegradation of nitrobenzene (NB) and its impacts on microbial community structure. The results demonstrated that both NB reduction and aniline formation could be substantially facilitated in S-nZVI@BC coupled system compared to other anaerobic ones coupled with nZVI or S-nZVI. The dosage of S-nZVI@BC resulted in the formation of densely packed aggregates, evidently increased the extracellular polymeric substances content, promoted the volatile fatty acids transformation and stimulated the methane yield. Furthermore, species related to fermentation (Bacteroides and Longilinea), methanogenesis (Methanosarcina and Methanomethylovorans), electroactivity (Pelobacter, Thiobacillus and Phaselicystis) as well as reduction (Desulfovibrio) were considerably enriched in S-nZVI@BC coupled system. The activities of electron transport, total adenosine triphosphate, nitroreductase and NAD(P)H, which were closely related to microbial activity and NB transformation, were increased noticeably in S-nZVI@BC coupled anaerobic system. This study demonstrated the promising potential for long-term operation and full-scale application of S-nZVI@BC coupled system for the treatment of NB containing wastewater.
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Affiliation(s)
- Dejin Zhang
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Jinyou Shen
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
| | - Hefei Shi
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Guanyong Su
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Xinbai Jiang
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Jiansheng Li
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Xiaodong Liu
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Yang Mu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Applied Chemistry, University of Science and Technology of China, Hefei 230026, China.
| | - Lianjun Wang
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
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64
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Effect of Acid/Ethanol Ratio on Medium Chain Carboxylate Production with Different VFAs as the Electron Acceptor: Insight into Carbon Balance and Microbial Community. ENERGIES 2019. [DOI: 10.3390/en12193720] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Medium chain carboxylates (MCCs) are important precursors for biodiesel production. Using chain elongation to produce MCCs is an emerging bioenergy technology. In this study, batch tests were conducted to investigate fermentative MCC production through chain elongation from acetate, propionate, n-butyrate, and ethanol. The effect of the acid/ethanol ratio on MCC production by mixed culture was investigated. Better MCC production, especially n-caproate production, was achieved at optimal acid/ethanol ratios of 1:4, 1:3, and 1:2 with acetate, propionate, and n-butyrate as the electron acceptor, respectively. The n-caproate concentration was high, up to 41.54 mmol/L, and the highest n-caproate production efficiency was 57.96% with the n-butyrate/ethanol ratio of 1:2. The higher concentration of ethanol might stimulate the growth of chain elongation bacteria to promote chain elongation. The highest MCC production efficiency with different electron acceptors corresponded to less carbon loss and a higher chain elongation degree. In addition, with the optimal acid/ethanol ratio, the substrate was maximally utilized for chain elongation. The microbial community analysis confirmed the carbon balance analysis with the maximum relative abundance of 52.66–60.55% of the n-caproate producer Clostridium_sensu_stricto_12 enriched by the optimal acid/ethanol ratios with different volatile fatty acids (VFAs) as electron acceptors.
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San-Valero P, Fernández-Naveira Á, Veiga MC, Kennes C. Influence of electron acceptors on hexanoic acid production by Clostridium kluyveri. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2019; 242:515-521. [PMID: 31075646 DOI: 10.1016/j.jenvman.2019.04.093] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 04/12/2019] [Accepted: 04/22/2019] [Indexed: 05/12/2023]
Abstract
Clostridium kluyveri was used for chain elongation of C2C4 fatty acids in stirred tank bioreactors. The influence of different electron acceptors (acetic acid, butyric acid and the mixture of both) on C6 fatty acid production was evaluated in presence of ethanol using similar molar alcohol/acid ratios around 3.5. Bottle batch assays without pH regulation and with only acetic acid as electron acceptor yielded a final C6 fatty acid concentration of 6.8 ± 0.6 g L-1. Then, pH-regulated bioreactors were operated at constant pH of 6.8. Under such conditions, the maximum growth rate was 0.039 h-1 obtained using acetic acid and butyric acid as electron acceptors, whereas the lowest growth rate was 0.010 h-1 with only butyric acid as electron acceptor. The maximum growth rate with acetic acid only, was similar, though slightly lower, as with the mixture of C2C4 fatty acids. Besides, the maximum productions of hexanoic acid were 11.8 g L-1, 13.1 g L-1 and 21.2 g L-1 using, respectively, acetic acid, butyric acid and the mixture of both acids as electron acceptors. Thus, the use of a mixture of acetic acid and butyric acid in presence of ethanol for chain elongation, at constant pH, proved to be efficient for hexanoic acid production.
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Affiliation(s)
- P San-Valero
- Chemical Engineering Laboratory, Faculty of Sciences and Center for Advanced Scientific Research (CICA), University of La Coruña (UDC), Rúa da Fraga 10, E-15008, La Coruña, Spain
| | - Á Fernández-Naveira
- Chemical Engineering Laboratory, Faculty of Sciences and Center for Advanced Scientific Research (CICA), University of La Coruña (UDC), Rúa da Fraga 10, E-15008, La Coruña, Spain
| | - M C Veiga
- Chemical Engineering Laboratory, Faculty of Sciences and Center for Advanced Scientific Research (CICA), University of La Coruña (UDC), Rúa da Fraga 10, E-15008, La Coruña, Spain
| | - C Kennes
- Chemical Engineering Laboratory, Faculty of Sciences and Center for Advanced Scientific Research (CICA), University of La Coruña (UDC), Rúa da Fraga 10, E-15008, La Coruña, Spain.
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66
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Enhanced Anaerobic Mixed Culture Fermentation with Anion-Exchange Resin for Caproate Production. Processes (Basel) 2019. [DOI: 10.3390/pr7070404] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The bioproduction of caproate from organic waste by anaerobic mixed culture is a very attractive technology for upgrading low-grade biomass to a high-value resource. However, the caproate production process is markedly restricted by the feedback inhibition of caproate. In this study, four types of anion-exchange resin were investigated for their enhancing capability in caproate fermentation of anaerobic mixed culture. The strong base anion-exchange resin D201 showed the highest adsorption capacity (62 mg/g), selectivity (7.50), and desorption efficiency (88.2%) for caproate among the test resins. Subsequently, the optimal desorption temperature and NaOH concentration of eluent for D201 were determined. The adsorption and desorption efficiency of D201 remained stable during eight rounds of the adsorption–desorption cycle, indicating a satisfactory reusability of D201. Finally, performances of caproate fermentation with and without resin adsorption for carboxylate were evaluated. The results demonstrated that the final concentration of caproate was improved from 12.43 ± 0.29 g/L (without adsorption) to 17.30 ± 0.13 g/L (with adsorption) and the maximum caproate production rate was improved from 0.60 ± 0.01 g/L/d to 2.03 ± 0.02 g/L/d. In the group with adsorption, the cumulative caproate production was increased to 29.10 ± 0.33 g/L broth, which was 134% higher than that of the control group. Therefore, this study provides effective approaches to enhance caproate production.
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67
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Yu J, Huang Z, Wu P, Zhao M, Miao H, Liu C, Ruan W. Performance and microbial characterization of two-stage caproate fermentation from fruit and vegetable waste via anaerobic microbial consortia. BIORESOURCE TECHNOLOGY 2019; 284:398-405. [PMID: 30959377 DOI: 10.1016/j.biortech.2019.03.124] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 03/24/2019] [Accepted: 03/25/2019] [Indexed: 05/24/2023]
Abstract
The regulation of two-stage caproate fermentation from fruit and vegetable waste (FVW) via anaerobic microbial consortia was investigated in this study. The results showed the highest caproate production achieved 14.9 g/L at the optimal inoculum to substrate ratio (ISR) of 2:1, ethanol to acid ratio (E/A) of 4:1, and pH of 7.5. The caproate yield and selectivity respectively reached 0.62 g/g and 80.8% (as COD). In acidification stage, an appropriate ISR provided a high conversion efficiency and more acetate formation, which was beneficial to caproate biosynthesis. In caproate production stage, chain elongation performance was sensitive to E/A and pH condition. Butyrate became the main by-product at low E/A or acidic conditions, while excessive ethanol or alkaline condition seriously suppressed substrate conversion. The caproate fermentation was dominated by Clostridium kluyveri. Furthermore, caproate formation was uncoupled with Clostridium kluyveri proliferation, which was mainly generated during the middle and late stages of growth.
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Affiliation(s)
- Jiangnan Yu
- Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Zhenxing Huang
- Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, Suzhou 215011, China
| | - Peng Wu
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Mingxing Zhao
- Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Hengfeng Miao
- Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China; Jiangsu Engineering Laboratory for Biomass Energy and Carbon Reduction Technology, Jiangnan University, Wuxi 214122, China
| | - Chunmei Liu
- Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Wenquan Ruan
- Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, Suzhou 215011, China.
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68
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Zhang C, Yang L, Tsapekos P, Zhang Y, Angelidaki I. Immobilization of Clostridium kluyveri on wheat straw to alleviate ammonia inhibition during chain elongation for n-caproate production. ENVIRONMENT INTERNATIONAL 2019; 127:134-141. [PMID: 30913458 DOI: 10.1016/j.envint.2019.03.032] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 02/18/2019] [Accepted: 03/14/2019] [Indexed: 06/09/2023]
Abstract
Biosynthesis of n-caproate from waste streams rich in acetate and ethanol through chain elongation has offered a potentially sustainable way for future production of liquid biofuels. However, most of the waste streams that fit with the purpose (e.g., digestate) are also rich in ammonium which at high concentration may cause toxic effects on the bioconversion process. This study aims to develop a robust, efficient, and cost-effective chain elongation process with high caproate productivity and tolerance to high ammonia concentration, through immobilization of Clostridium kluyveri on biomass particles as immobilization material. The threshold ammonia concentration for suspended cells cultivation was 2.1 g/L, while it was higher than 5.0 g/L for the wheat straw immobilized system. The caproate production process was dependent on the selected carriers and was performing in the order of: wheat straw > grass straw > saw dust. The biofilm immobilized on the wheat straw showed good reuse capability for caproate production under high ammonia concentration. Moreover, the lag phase for caproate production was shortened from 72 to 30 h after 8 times reuse. These results proved that caproate production and tolerance of chain elongation to ammonia toxicity could be enhanced via cell immobilization. This study offers insight into future development of efficient and cost-effective chain elongation system for production of caproate and other value-added products.
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Affiliation(s)
- Cunsheng Zhang
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, PR China
| | - Li Yang
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, PR China
| | - Panagiotis Tsapekos
- Department of Environmental Engineering, Technical University of Denmark, DK-2800 Lyngby, Denmark
| | - Yifeng Zhang
- Department of Environmental Engineering, Technical University of Denmark, DK-2800 Lyngby, Denmark.
| | - Irini Angelidaki
- Department of Environmental Engineering, Technical University of Denmark, DK-2800 Lyngby, Denmark
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69
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Wu Q, Bao X, Guo W, Wang B, Li Y, Luo H, Wang H, Ren N. Medium chain carboxylic acids production from waste biomass: Current advances and perspectives. Biotechnol Adv 2019; 37:599-615. [PMID: 30849433 DOI: 10.1016/j.biotechadv.2019.03.003] [Citation(s) in RCA: 100] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 03/01/2019] [Accepted: 03/03/2019] [Indexed: 11/29/2022]
Abstract
Alternative chemicals to diverse fossil-fuel-based products is urgently needed to mitigate the adverse impacts of fossil fuel depletion on human development. To this end, researchers have focused on the production of biochemical from readily available and affordable waste biomass. This is consistent with current guidelines for sustainable development and provides great advantages related to economy and environment. The search for suitable biochemical products is in progress worldwide. Therefore, this review recommends a biochemical (i.e., medium chain carboxylic acids (MCCAs)) utilizing an emerging biotechnological production platform called the chain elongation (CE) process. This work covers comprehensive introduction of the CE mechanism, functional microbes, available feedstock types and corresponding utilization strategies, major methods to enhance the performance of MCCAs production, and the challenges that need to be addressed for practical application. This work is expected to provide a thorough understanding of the CE technology, to guide and inspire researchers to solve existing problems in depth, and motivate large-scale MCCAs production.
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Affiliation(s)
- Qinglian Wu
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China
| | - Xian Bao
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China
| | - Wanqian Guo
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China.
| | - Bing Wang
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China
| | - Yunxi Li
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China
| | - Haichao Luo
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China
| | - Huazhe Wang
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China
| | - Nanqi Ren
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China
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70
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Jiang Y, May HD, Lu L, Liang P, Huang X, Ren ZJ. Carbon dioxide and organic waste valorization by microbial electrosynthesis and electro-fermentation. WATER RESEARCH 2019; 149:42-55. [PMID: 30419466 DOI: 10.1016/j.watres.2018.10.092] [Citation(s) in RCA: 100] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 10/29/2018] [Accepted: 10/30/2018] [Indexed: 06/09/2023]
Abstract
Carbon-rich waste materials (solid, liquid, or gaseous) are largely considered to be a burden on society due to the large capital and energy costs for their treatment and disposal. However, solid and liquid organic wastes have inherent energy and value, and similar as waste CO2 gas they can be reused to produce value-added chemicals and materials. There has been a paradigm shift towards developing a closed loop, biorefinery approach for the valorization of these wastes into value-added products, and such an approach enables a more carbon-efficient and circular economy. This review quantitatively analyzes the state-of-the-art of the emerging microbial electrochemical technology (MET) platform and provides critical perspectives on research advancement and technology development. The review offers side-by-side comparison between microbial electrosynthesis (MES) and electro-fermentation (EF) processes in terms of principles, key performance metrics, data analysis, and microorganisms. The study also summarizes all the processes and products that have been developed using MES and EF to date for organic waste and CO2 valorization. It finally identifies the technological and economic potentials and challenges on future system development.
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Affiliation(s)
- Yong Jiang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, PR China; Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, Boulder, CO, 80309, USA; Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Harold D May
- Hollings Marine Laboratory, Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, USA
| | - Lu Lu
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, Boulder, CO, 80309, USA; Department of Civil and Environmental Engineering and Andlinger Center for Energy and the Environment, Princeton University, Princeton, NJ, 08544, USA
| | - Peng Liang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, PR China.
| | - Xia Huang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, PR China
| | - Zhiyong Jason Ren
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, Boulder, CO, 80309, USA; Department of Civil and Environmental Engineering and Andlinger Center for Energy and the Environment, Princeton University, Princeton, NJ, 08544, USA.
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71
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De Groof V, Coma M, Arnot T, Leak DJ, Lanham AB. Medium Chain Carboxylic Acids from Complex Organic Feedstocks by Mixed Culture Fermentation. Molecules 2019; 24:E398. [PMID: 30678297 PMCID: PMC6384945 DOI: 10.3390/molecules24030398] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 01/10/2019] [Accepted: 01/18/2019] [Indexed: 12/22/2022] Open
Abstract
Environmental pressures caused by population growth and consumerism require the development of resource recovery from waste, hence a circular economy approach. The production of chemicals and fuels from organic waste using mixed microbial cultures (MMC) has become promising. MMC use the synergy of bio-catalytic activities from different microorganisms to transform complex organic feedstock, such as by-products from food production and food waste. In the absence of oxygen, the feedstock can be converted into biogas through the established anaerobic digestion (AD) approach. The potential of MMC has shifted to production of intermediate AD compounds as precursors for renewable chemicals. A particular set of anaerobic pathways in MMC fermentation, known as chain elongation, can occur under specific conditions producing medium chain carboxylic acids (MCCAs) with higher value than biogas and broader applicability. This review introduces the chain elongation pathway and other bio-reactions occurring during MMC fermentation. We present an overview of the complex feedstocks used, and pinpoint the main operational parameters for MCCAs production such as temperature, pH, loading rates, inoculum, head space composition, and reactor design. The review evaluates the key findings of MCCA production using MMC, and concludes by identifying critical research targets to drive forward this promising technology as a valorisation method for complex organic waste.
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Affiliation(s)
- Vicky De Groof
- EPSRC Centre for Doctoral Training in Sustainable Chemical Technologies, University of Bath, Claverton Down, Bath BA2 7AY, UK.
- Department of Chemical Engineering, University of Bath, Claverton Down, Bath BA2 7AY, UK.
| | - Marta Coma
- Centre for Sustainable Chemical Technologies (CSCT), University of Bath, Claverton Down, Bath BA2 7AY, UK.
| | - Tom Arnot
- Department of Chemical Engineering, University of Bath, Claverton Down, Bath BA2 7AY, UK.
- Water Innovation & Research Centre (WIRC), University of Bath, Claverton Down, Bath BA2 7AY, UK.
| | - David J Leak
- Centre for Sustainable Chemical Technologies (CSCT), University of Bath, Claverton Down, Bath BA2 7AY, UK.
- Department of Biology & Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK.
| | - Ana B Lanham
- Department of Chemical Engineering, University of Bath, Claverton Down, Bath BA2 7AY, UK.
- Water Innovation & Research Centre (WIRC), University of Bath, Claverton Down, Bath BA2 7AY, UK.
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72
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He P, Liu Y, Shao L, Zhang H, Lü F. Particle size dependence of the physicochemical properties of biochar. CHEMOSPHERE 2018; 212:385-392. [PMID: 30149311 DOI: 10.1016/j.chemosphere.2018.08.106] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 08/18/2018] [Accepted: 08/20/2018] [Indexed: 05/27/2023]
Abstract
The inadequate definition of different particle sizes of biochar impedes the establishment of guidelines concerning the selection of suitable particle sizes. In this study, various properties of a series of ten biochar samples of varying particle size (5-5000 μm) from the same origin have been investigated and compared. Cluster analysis and principal component analysis based on all of the parameters were executed to evaluate the dissimilarity of different particle sizes of biochar, and to classify the size ranges determining the relevant properties. The results showed that the series of ten biochar samples with different particle sizes could be separated into four groups, indicating that there were significant characteristic differences between different particle sizes of biochar. The greater the difference in particle size, the more disparate the properties. Moreover, 75-150 μm has been identified as a turning point along the continuous particle size range. A deviation in the properties of biochar particles smaller than 5 μm confirmed that different preparation methods would lead to highly significant differences between different particle sizes of biochar, even if the pristine materials were the same. The need for definition of the characteristics of biochar required for a specific environmental application should be emphasized.
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Affiliation(s)
- Pinjing He
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, 1239 Siping Road, Shanghai, 200092, PR China; Institute of Waste Treatment and Reclamation, Tongji University, 1239 Siping Road, Shanghai, 200092, PR China; Centre for the Technology Research and Training on Household Waste in Small Towns & Rural Area, Ministry of Housing and Urban-Rural Development of PR China (MOHURD), 1239 Siping Road, Shanghai, 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, 1239 Siping Road, Shanghai, 200092, PR China.
| | - Yuhao Liu
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, 1239 Siping Road, Shanghai, 200092, PR China; Institute of Waste Treatment and Reclamation, Tongji University, 1239 Siping Road, Shanghai, 200092, PR China.
| | - Liming Shao
- Centre for the Technology Research and Training on Household Waste in Small Towns & Rural Area, Ministry of Housing and Urban-Rural Development of PR China (MOHURD), 1239 Siping Road, Shanghai, 200092, PR China.
| | - Hua Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, 1239 Siping Road, Shanghai, 200092, PR China; Institute of Waste Treatment and Reclamation, Tongji University, 1239 Siping Road, Shanghai, 200092, PR China.
| | - Fan Lü
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, 1239 Siping Road, Shanghai, 200092, PR China; Institute of Waste Treatment and Reclamation, Tongji University, 1239 Siping Road, Shanghai, 200092, PR China.
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Wu Q, Guo W, Bao X, Meng X, Yin R, Du J, Zheng H, Feng X, Luo H, Ren N. Upgrading liquor-making wastewater into medium chain fatty acid: Insights into co-electron donors, key microflora, and energy harvest. WATER RESEARCH 2018; 145:650-659. [PMID: 30205336 DOI: 10.1016/j.watres.2018.08.046] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Revised: 08/18/2018] [Accepted: 08/22/2018] [Indexed: 05/24/2023]
Abstract
Ethanol and lactate are considered suitable electron donors (EDs) for chain elongation (CE); however, their respective shortcomings still limit the substrate conversion ratio and medium chain fatty acid (MCFA) production. To address this limitation, different EDs and electron acceptors (EAs) were combined to compare their CE performances, and to investigate whether the combination of ethanol and lactate could further enhance the MCFA production based on the complementary characteristics of ethanol and lactate. The results verified, for the first time, ethanol and lactate as the co-EDs formed a cooperative relationship to largely promote the conversion of substrates into MCFA. The co-EDs of ethanol and lactate stimulated the transformation of dispersive lactate-carbon flux from the competing acrylate pathway into n-heptylate. Additionally, the coexisting by-products (H2 and CO2) from ethanol and lactate also contributed to the supererogatory MCFA generation. The key microbial taxa that distinguished the co-EDs from their single action were the preponderant species from class Negativicutes and family Ruminococcaceae. In addition, the co-EAs of acetate, n-butyrate, and n-caproate also promoted MCFA generation. Low concentration of n-caproate could be directly elongated into n-caprylate, while n-caproate concentration exceeding the toxic limit was unsuitable as an EA. This research provided a guide for substrate selection and collocation for CE technology. Chinese liquor-making wastewater (CLMW) was subsequently used as a substrate for MCFA production since it contains abundant lactate, ethanol, and short-chain fatty acids. In this study, a MCFA selectivity of 80.34 ± 5.26%, a slightly higher selectivity which is in the range of previously reported ones, was obtained. This study paves a way for the sustainable development of Chinese liquor industry by recycling the high-output CLMW into MCFA.
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Affiliation(s)
- Qinglian Wu
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Wanqian Guo
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, PR China.
| | - Xian Bao
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Xianbing Meng
- College of Resources and Environment, Northeast Agricultural University, Harbin, 150030, PR China
| | - Renli Yin
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Juanshan Du
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Heshan Zheng
- College of Chemistry and Chemical Engineering, Qiqihar University, Qiqihar, Heilongjiang, 161006, PR China
| | - Xiaochi Feng
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Haichao Luo
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Nanqi Ren
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, PR China
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74
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Metabolic Interactions of a Chain Elongation Microbiome. Appl Environ Microbiol 2018; 84:AEM.01614-18. [PMID: 30217839 DOI: 10.1128/aem.01614-18] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 08/22/2018] [Indexed: 12/19/2022] Open
Abstract
Carbon chain elongation (CCE), a reaction within the carboxylate platform that elongates short-chain to medium-chain carboxylates by mixed culture, has attracted worldwide interest. The present study provides insights into the microbial diversity and predictive microbial metabolic pathways of a mixed-culture CCE microbiome on the basis of a comparative analysis of the metagenome and metatranscriptome. We found that the microbial structure of an acclimated chain elongation microbiome was a highly similar to that of the original inoculating biogas reactor culture; however, the metabolic activities were completely different, demonstrating the high stability of the microbial structure and flexibility of its functions. Additionally, the fatty acid biosynthesis (FAB) pathway, rather than the well-known reverse β-oxidation (RBO) pathway for CCE, was more active and pivotal, though the FAB pathway had more steps and consumed more ATP, a phenomenon that has rarely been observed in previous CCE studies. A total of 91 draft genomes were reconstructed from the metagenomic reads, of which three were near completion (completeness, >97%) and were assigned to unknown strains of Methanolinea tarda, Bordetella avium, and Planctomycetaceae The last two strains are likely new-found active participators of CCE in the mixed culture. Finally, a conceptual framework of CCE, including both pathways and the potential participators, was proposed.IMPORTANCE Carbon chain elongation means the conversion of short-chain volatile fatty acids to medium-chain carboxylates, such as n-caproate and n-caprylate with electron donors under anaerobic condition. This bio-reaction can both expand the resource of valuable biochemicals and broaden the utilization of low-grade organic residues in a sustainable biorefinery context. Clostridium kluyveri is conventionally considered model microbe for carbon chain elongation which uses the reverse β-oxidation pathway. However, little is known about the detailed microbial structure and function of other abundant microorganism in a mixed culture (or open culture) of chain elongation. We conducted the comparative metagenomic and metatranscriptomic analysis of a chain elongation microbiome to throw light on the underlying functional microbes and alternative pathways.
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75
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Sun X, Atiyeh HK, Kumar A, Zhang H, Tanner RS. Biochar enhanced ethanol and butanol production by Clostridium carboxidivorans from syngas. BIORESOURCE TECHNOLOGY 2018; 265:128-138. [PMID: 29886351 DOI: 10.1016/j.biortech.2018.05.106] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Revised: 05/29/2018] [Accepted: 05/30/2018] [Indexed: 06/08/2023]
Abstract
Biochar has functional groups, pH buffering capacity and cation exchange capacity (CEC) that can be beneficial in syngas fermentation. This study examined the properties of biochar made from switchgrass (SGBC), forage sorghum (FSBC), red cedar (RCBC) and poultry litter (PLBC), and their effects on ethanol and butanol production from syngas using Clostridium carboxidivorans. Experiments were performed in 250 mL bottle reactors with a 50 mL working volume at 37 °C fed syngas containing CO:H2:CO2 (40:30:30 by volume). Results showed that PLBC and SGBC enhanced ethanol production by 90% and 73%, respectively, and butanol production by fourfold compared to standard yeast extract medium without biochar (control). CO and H2 utilization in PLBC and SGBC media increased compared to control. PLBC had the highest pH buffering capacity, CEC and total amount of cations compared with SGBC, FSBC and RCBC, which could have contributed to its highest enhancement of ethanol and butanol production.
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Affiliation(s)
- Xiao Sun
- Biosystems and Agricultural Engineering, Oklahoma State University, Stillwater, OK, USA
| | - Hasan K Atiyeh
- Biosystems and Agricultural Engineering, Oklahoma State University, Stillwater, OK, USA.
| | - Ajay Kumar
- Biosystems and Agricultural Engineering, Oklahoma State University, Stillwater, OK, USA
| | - Hailin Zhang
- Department of Plant and Soil Sciences, Oklahoma State University, Stillwater, OK, USA
| | - Ralph S Tanner
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA
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76
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He S, Ding L, Pan Y, Hu H, Ye L, Ren H. Nitrogen loading effects on nitrification and denitrification with functional gene quantity/transcription analysis in biochar packed reactors at 5 °C. Sci Rep 2018; 8:9844. [PMID: 29959416 PMCID: PMC6026168 DOI: 10.1038/s41598-018-28305-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 06/05/2018] [Indexed: 11/09/2022] Open
Abstract
This study investigated the nitrogen transformation rates of different nitrogen-loading (20, 30, and 50 mg TN/L) biochar packed reactors (C:N:P = 100:5:1) within 125 days at 5 °C. The results showed that high nitrogen loading resulted in an NH4+ (TN) removal efficiency decline from 98% (57%) to 83% (29%), with biochar yielding a higher NH4+, TN and DON removal rate than conventional activated sludge. Moreover, all biochar packed reactors realized a quick start-up by dropping in temperature stage by stage, and the effluent dissolved organic nitrogen (DON) concentrations of R20, R30, and R50 were 0.44 ± 0.18, 0.85 ± 0.35, and 0.66 ± 0.26 mg/L, respectively. The nirS/amoA, nxrA/amoA, and amoA/(narG + napA) were deemed to be the markers of ammonium oxidation rate (SAOR), specific nitrite oxidation rate (SNOR), and specific nitrate reduction rate (SNRR), respectively. Compared with functional gene quantity data, transcription data (mRNA) introduced into stepwise regression analyses agreed well with nitrogen transformation rates. High nitrogen loading also resulted in the cell viability decreased in R50. Nitrogen loadings and operation time both led to a significant variation in cell membrane composition, and unsaturated fatty acids (UFAs) significantly increased in R30 (46.49%) and R50 (36.34%). High-throughput sequencing revealed that nitrogen loadings increased the abundance of nitrifying bacteria (e.g., Nitrospira) and reduced the abundance of denitrifying bacteria (e.g., Nakamurella, Thermomonas, and Zoogloea) through linear discriminant analysis (LDA).
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Affiliation(s)
- Su He
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China
| | - Lili Ding
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China
| | - Yao Pan
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China
| | - Haidong Hu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China
| | - Lin Ye
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China
| | - Hongqiang Ren
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China.
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Wang H, Li X, Wang Y, Tao Y, Lu S, Zhu X, Li D. Improvement of n-caproic acid production with Ruminococcaceae bacterium CPB6: selection of electron acceptors and carbon sources and optimization of the culture medium. Microb Cell Fact 2018; 17:99. [PMID: 29940966 PMCID: PMC6019802 DOI: 10.1186/s12934-018-0946-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 06/16/2018] [Indexed: 12/02/2022] Open
Abstract
Background Global energy and resource shortages make it necessary to quest for renewable resources. n-Caproic acid (CA) production based on carboxylate platform by anaerobic fermentation is booming. Recently, a novel Ruminococcaceae bacterium CPB6 is shown to be a potential biotransformation factory for CA production from lactate-containing wastewater. However, little is known about the effects of different electron acceptors (EAs) on the fermentative products of strain CPB6, as well as the optimum medium for CA production. Results In this study, batch experiments were performed to investigate the fermentative products of strain CPB6 in a lactate medium supplemented with different EAs and sugars. Supplementation of acetate, butyrate and sucrose dramatically increased cell growth and CA production. The addition of propionate or pentanoate resulted in the production of C5 or C7 carboxylic acid, respectively. Further, a Box–Behnken experiment was conducted to optimize the culture medium for CA production. The result indicated that a medium containing 13.30 g/L sucrose, 22.35 g/L lactate and 16.48 g/L butyrate supported high-titer CA production (16.73 g/L) with a maximum productivity of 6.50 g/L/day. Conclusions This study demonstrated that strain CPB6 could produce C6–C7 carboxylic acids from lactate (as electron donor) with C2–C5 short-chain carboxylic acids (as EAs), but CA (C6 carboxylic acid) was the most major and potential product. Butyrate and sucrose were the most significant EA and carbon source respectively for CA production from lactate by strain CPB6. High titer of CA can be produced from a synthetic substrate containing sucrose, lactate and butyrate. The work provided significant implications for improving CA production in industry-scale.![]() Electronic supplementary material The online version of this article (10.1186/s12934-018-0946-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Han Wang
- Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China.,University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Xiangzhen Li
- Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China.,Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China
| | - Yi Wang
- Department of Biosystems Engineering, Auburn University, Auburn, AL, 36849, USA
| | - Yong Tao
- Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China. .,Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China.
| | - Shaowen Lu
- Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China.,Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China
| | - Xiaoyu Zhu
- Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China.,Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China
| | - Daping Li
- Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China.,Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China
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Roghair M, Liu Y, Adiatma JC, Weusthuis RA, Bruins ME, Buisman CJN, Strik DPBTB. Effect of n-Caproate Concentration on Chain Elongation and Competing Processes. ACS SUSTAINABLE CHEMISTRY & ENGINEERING 2018; 6:7499-7506. [PMID: 29910994 PMCID: PMC5997465 DOI: 10.1021/acssuschemeng.8b00200] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Revised: 04/13/2018] [Indexed: 05/26/2023]
Abstract
Chain elongation is an open-culture fermentation process that facilitates conversion of organic residues with an additional electron donor, such as ethanol, into valuable n-caproate. Open-culture processes are catalyzed by an undefined consortium of microorganisms which typically also bring undesired (competing) processes. Inhibition of competing processes, such as syntrophic ethanol oxidation, will lead to a more selective n-caproate production process. In this study, we investigated the effect of n-caproate concentration on the specific activity of chain elongation and competing processes using batch inhibition assays. With "synthetic medium sludge" (originally operating at 3.4 g/L n-caproate), syntrophic ethanol oxidation was proportionally inhibited by n-caproate until 45% inhibition at 20 g/L n-caproate. Hydrogenotrophic methanogenesis was for 58% inhibited at 20 g/L n-caproate. Chain elongation of volatile fatty acids (volatile fatty acid upgrading; the desired process), was completely inhibited at 20 g/L n-caproate with all tested sludge types. "Adapted sludge" (operating at 23.2 g/L n-caproate) showed a 10 times higher volatile fatty acid upgrading activity at 15 g/L n-caproate compared to "nonadapted sludge" (operating at 7.1 g/L n-caproate). This shows that open cultures do adapt to perform chain elongation at high n-caproate concentrations which likely inhibits syntrophic ethanol oxidation through hydrogenotrophic methanogenesis. As such, we provide supporting evidence that the formation of n-caproate inhibits syntrophic ethanol oxidation which leads to a more selective medium chain fatty acid production process.
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Affiliation(s)
- Mark Roghair
- Sub-department
of Environmental Technology, Wageningen
University & Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
| | - Yuchen Liu
- Sub-department
of Environmental Technology, Wageningen
University & Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
| | - Julius C. Adiatma
- Sub-department
of Environmental Technology, Wageningen
University & Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
| | - Ruud A. Weusthuis
- Bioprocess
Engineering, Wageningen University &
Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Marieke E. Bruins
- Wageningen
Food & Biobased Research, Wageningen
University & Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
| | - Cees J. N. Buisman
- Sub-department
of Environmental Technology, Wageningen
University & Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
| | - David P. B. T. B. Strik
- Sub-department
of Environmental Technology, Wageningen
University & Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
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80
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Roghair M, Liu Y, Strik DPBTB, Weusthuis RA, Bruins ME, Buisman CJN. Development of an Effective Chain Elongation Process From Acidified Food Waste and Ethanol Into n-Caproate. Front Bioeng Biotechnol 2018; 6:50. [PMID: 29755978 PMCID: PMC5934429 DOI: 10.3389/fbioe.2018.00050] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Accepted: 04/13/2018] [Indexed: 01/10/2023] Open
Abstract
Introduction: Medium chain fatty acids (MCFAs), such as n-caproate, are potential valuable platform chemicals. MCFAs can be produced from low-grade organic residues by anaerobic reactor microbiomes through two subsequent biological processes: hydrolysis combined with acidogenesis and chain elongation. Continuous chain elongation with organic residues becomes effective when the targeted MCFA(s) are produced at high concentrations and rates, while excessive ethanol oxidation and base consumption are limited. The objective of this study was to develop an effective continuous chain elongation process with hydrolyzed and acidified food waste and additional ethanol. Results: We fed acidified food waste (AFW) and ethanol to an anaerobic reactor while operating the reactor at long (4 d) and at short (1 d) hydraulic retention time (HRT). At long HRT, n-caproate was continuously produced (5.5 g/L/d) at an average concentration of 23.4 g/L. The highest n-caproate concentration was 25.7 g/L which is the highest reported n-caproate concentration in a chain elongation process to date. Compared to short HRT (7.1 g/L n-caproate at 5.6 g/L/d), long HRT resulted in 6.2 times less excessive ethanol oxidation. This led to a two times lower ethanol consumption and a two times lower base consumption per produced MCFA at long HRT compared to short HRT. Conclusions: Chain elongation from AFW and ethanol is more effective at long HRT than at short HRT not only because it results in a higher concentration of MCFAs but also because it leads to a more efficient use of ethanol and base. The HRT did not influence the n-caproate production rate. The obtained n-caproate concentration is more than twice as high as the maximum solubility of n-caproic acid in water which is beneficial for its separation from the fermentation broth. This study does not only set the record on the highest n-caproate concentration observed in a chain elongation process to date, it notably demonstrates that such high concentrations can be obtained from AFW under practical circumstances in a continuous process.
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Affiliation(s)
- Mark Roghair
- Sub-department of Environmental Technology, Wageningen University and Research, Wageningen, Netherlands
| | - Yuchen Liu
- Sub-department of Environmental Technology, Wageningen University and Research, Wageningen, Netherlands
| | - David P B T B Strik
- Sub-department of Environmental Technology, Wageningen University and Research, Wageningen, Netherlands
| | - Ruud A Weusthuis
- Bioprocess Engineering, Wageningen University and Research, Wageningen, Netherlands
| | - Marieke E Bruins
- Wageningen Food and Biobased Research, Wageningen University and Research, Wageningen, Netherlands
| | - Cees J N Buisman
- Sub-department of Environmental Technology, Wageningen University and Research, Wageningen, Netherlands
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81
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He P, Han W, Shao L, Lü F. One-step production of C6-C8 carboxylates by mixed culture solely grown on CO. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:4. [PMID: 29339973 PMCID: PMC5761104 DOI: 10.1186/s13068-017-1005-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Accepted: 12/23/2017] [Indexed: 05/29/2023]
Abstract
BACKGROUND This study aimed at producing C6-C8 medium-chain carboxylates (MCCAs) directly from gaseous CO using mixed culture. The yield and C2-C8 product composition were investigated when CO was continuously fed with gradually increasing partial pressure. RESULTS The maximal concentrations of n-caproate, n-heptylate, and n-caprylate were 1.892, 1.635, and 1.033 mmol L-1, which were achieved at the maximal production rates of 0.276, 0.442, and 0.112 mmol L-1 day-1, respectively. Microbial analysis revealed that long-term acclimation and high CO partial pressure were important to establish a CO-tolerant and CO-utilizing chain-elongating microbiome, rich in Acinetobacter, Alcaligenes, and Rhodobacteraceae and capable of forming MCCAs solely from CO. CONCLUSIONS These results demonstrated that carboxylate and syngas platform could be integrated in a shared growth vessel, and could be a promising one-step technique to convert gaseous syngas to preferable liquid biochemicals, thereby avoiding the necessity to coordinate syngas fermentation to short-chain carboxylates and short-to-medium-chain elongation. Thus, this method could provide an alternative solution for the utilization of waste-derived syngas and expand the resource of promising biofuels.
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Affiliation(s)
- Pinjing He
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai, 200092 People’s Republic of China
- Institute of Waste Treatment and Reclamation, Tongji University, Shanghai, 200092 People’s Republic of China
- Centre for the Technology Research and Training on Household Waste in Small Towns & Rural Area, Ministry of Housing and Urban–Rural Development of P. R. China (MOHURD), Shanghai, 200092 People’s Republic of China
| | - Wenhao Han
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai, 200092 People’s Republic of China
| | - Liming Shao
- Institute of Waste Treatment and Reclamation, Tongji University, Shanghai, 200092 People’s Republic of China
- Centre for the Technology Research and Training on Household Waste in Small Towns & Rural Area, Ministry of Housing and Urban–Rural Development of P. R. China (MOHURD), Shanghai, 200092 People’s Republic of China
| | - Fan Lü
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai, 200092 People’s Republic of China
- Institute of Waste Treatment and Reclamation, Tongji University, Shanghai, 200092 People’s Republic of China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092 People’s Republic of China
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