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Zhao J, Ma H, Gao M, Qian D, Wang Q, Shiung Lam S. Advancements in medium chain fatty acids production through chain elongation: Key mechanisms and innovative solutions for overcoming rate-limiting steps. BIORESOURCE TECHNOLOGY 2024; 408:131133. [PMID: 39033828 DOI: 10.1016/j.biortech.2024.131133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2024] [Revised: 07/08/2024] [Accepted: 07/18/2024] [Indexed: 07/23/2024]
Abstract
The depletion of fossil fuels has prompted an urgent search for alternative chemicals from renewable sources. Current technology in medium chain fatty acids (MCFAs) production though chain elongation (CE) is becoming increasingly sustainable, hence the motivation for this review, which provides the detailed description, insights and analysis of the metabolic pathways, substrates type, inoculum and fermentation process. The main rate-limiting steps of microbial MCFAs production were comprehensively revealed and the corresponding innovative solutions were also critically evaluated. Innovative strategies such as substrate pretreatment, electrochemical regulation, product separation, fermentation parameter optimization, and electroactive additives have shown significant advantages in overcoming the rate-limiting steps. Furthermore, novel regulatory strategies such as quorum sensing and electronic bifurcation are expected to further increase the MCFAs yield. Finally, the techno-economic analysis was carried out, and the future research focuses were also put forward.
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Affiliation(s)
- Jihua Zhao
- Department of Environmental Science and Engineering, University of Science and Technology Beijing, Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China
| | - Hongzhi Ma
- Department of Environmental Science and Engineering, University of Science and Technology Beijing, Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China; Xinjiang Key Laboratory of Clean Conversion and High Value Utilization of Biomass Resources, School of Resource and Environmental Science, Yili Normal University, Yining 835000, China.
| | - Ming Gao
- Department of Environmental Science and Engineering, University of Science and Technology Beijing, Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China
| | - Dayi Qian
- Department of Environmental Science and Engineering, University of Science and Technology Beijing, Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China; Xinjiang Key Laboratory of Clean Conversion and High Value Utilization of Biomass Resources, School of Resource and Environmental Science, Yili Normal University, Yining 835000, China
| | - Qunhui Wang
- Department of Environmental Science and Engineering, University of Science and Technology Beijing, Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China
| | - Su Shiung Lam
- Higher Institution Centre of Excellence (HICoE), Institute of Tropical Aquaculture and Fisheries (AKUATROP), Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia; Center for Global Health Research (CGHR), Saveetha Medical College, Saveetha Institute of Medical and Technical Sciences (SIMATS), Saveetha University, Chennai, India
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2
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Spirito CM, Lucas TN, Patz S, Jeon BS, Werner JJ, Trondsen LH, Guzman JJ, Huson DH, Angenent LT. Variability in n-caprylate and n-caproate producing microbiomes in reactors with in-line product extraction. mSystems 2024; 9:e0041624. [PMID: 38990071 PMCID: PMC11334527 DOI: 10.1128/msystems.00416-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Accepted: 06/18/2024] [Indexed: 07/12/2024] Open
Abstract
Medium-chain carboxylates (MCCs) are used in various industrial applications. These chemicals are typically extracted from palm oil, which is deemed not sustainable. Recent research has focused on microbial chain elongation using reactors to produce MCCs, such as n-caproate (C6) and n-caprylate (C8), from organic substrates such as wastes. Even though the production of n-caproate is relatively well-characterized, bacteria and metabolic pathways that are responsible for n-caprylate production are not. Here, three 5 L reactors with continuous membrane-based liquid-liquid extraction (i.e., pertraction) were fed ethanol and acetate and operated for an operating period of 234 days with different operating conditions. Metagenomic and metaproteomic analyses were employed. n-Caprylate production rates and reactor microbiomes differed between reactors even when operated similarly due to differences in H2 and O2 between the reactors. The complete reverse β-oxidation (RBOX) pathway was present and expressed by several bacterial species in the Clostridia class. Several Oscillibacter spp., including Oscillibacter valericigenes, were positively correlated with n-caprylate production rates, while Clostridium kluyveri was positively correlated with n-caproate production. Pseudoclavibacter caeni, which is a strictly aerobic bacterium, was abundant across all the operating periods, regardless of n-caprylate production rates. This study provides insight into microbiota that are associated with n-caprylate production in open-culture reactors and provides ideas for further work.IMPORTANCEMicrobial chain elongation pathways in open-culture biotechnology systems can be utilized to convert organic waste and industrial side streams into valuable industrial chemicals. Here, we investigated the microbiota and metabolic pathways that produce medium-chain carboxylates (MCCs), including n-caproate (C6) and n-caprylate (C8), in reactors with in-line product extraction. Although the reactors in this study were operated similarly, different microbial communities dominated and were responsible for chain elongation. We found that different microbiota were responsible for n-caproate or n-caprylate production, and this can inform engineers on how to operate the systems better. We also observed which changes in operating conditions steered the production toward and away from n-caprylate, but more work is necessary to ascertain a mechanistic understanding that could be predictive. This study provides pertinent research questions for future work.
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Affiliation(s)
- Catherine M. Spirito
- Department of Biological and Environmental Engineering, Cornell University, Riley-Robb Hall, Ithaca, New York, USA
- Office of Undergraduate Research, University of Maryland, College Park, Maryland, USA
| | - Timo N. Lucas
- Institute for Bioinformatics and Medical Informatics, University of Tübingen, Tübingen, Germany
| | - Sascha Patz
- Institute for Bioinformatics and Medical Informatics, University of Tübingen, Tübingen, Germany
| | - Byoung Seung Jeon
- Department of Geosciences, University of Tübingen, Tübingen, Germany
| | - Jeffrey J. Werner
- Chemistry Department, SUNY-Cortland, Bowers Hall, Cortland, New York, USA
| | - Lauren H. Trondsen
- Department of Biological and Environmental Engineering, Cornell University, Riley-Robb Hall, Ithaca, New York, USA
| | - Juan J. Guzman
- Department of Biological and Environmental Engineering, Cornell University, Riley-Robb Hall, Ithaca, New York, USA
| | - Daniel H. Huson
- Institute for Bioinformatics and Medical Informatics, University of Tübingen, Tübingen, Germany
| | - Largus T. Angenent
- Department of Biological and Environmental Engineering, Cornell University, Riley-Robb Hall, Ithaca, New York, USA
- Department of Geosciences, University of Tübingen, Tübingen, Germany
- AG Angenent, Max Planck Institute for Biology Tübingen, Tübingen, Germany
- Department of Biological and Chemical Engineering, Aarhus University, Aarhus, Denmark
- The Novo Nordisk Foundation CO2 Research Center (CORC), Aarhus University, Aarhus, Denmark
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3
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Liu Y, Chen L, Duan Y, Li R, Yang Z, Liu S, Li G. Recent progress and prospects for chain elongation of transforming biomass waste into medium-chain fatty acids. CHEMOSPHERE 2024; 355:141823. [PMID: 38552798 DOI: 10.1016/j.chemosphere.2024.141823] [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: 02/04/2024] [Revised: 03/18/2024] [Accepted: 03/26/2024] [Indexed: 04/06/2024]
Abstract
Chain elongation technology utilises microorganisms in anaerobic digestion to transform waste biomass into medium-chain fatty acids that have greater economic value. This innovative technology expands upon traditional anaerobic digestion methods, requiring abundant substrates that serve as electron donors and acceptors, and inoculating microorganisms with chain elongation functions. While this process may result in the production of by-products and elicit competitive responses, toxicity suppression of microorganisms by substrates and products remains a significant obstacle to the industrialisation of chain elongation technology. This study provides a comprehensive overview of existing research on widely employed electron donors and their synthetic reactions, competitive reactions, inoculum selection, toxicity inhibition of substrates and products, and increased chain elongation approaches. Additionally, it presents actionable recommendations for future research and development endeavours in this domain, intending to inspire and guide researchers in advancing the frontiers of chain elongation technology.
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Affiliation(s)
- Yuhao Liu
- School of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou, 450046, Henan Province, China.
| | - Long Chen
- School of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou, 450046, Henan Province, China
| | - Yacong Duan
- School of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou, 450046, Henan Province, China
| | - Ruihua Li
- School of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou, 450046, Henan Province, China
| | - Ziyan Yang
- School of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou, 450046, Henan Province, China
| | - Shuli Liu
- School of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou, 450046, Henan Province, China
| | - Guoting Li
- School of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou, 450046, Henan Province, China
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Villegas-Rodríguez SB, Arreola-Vargas J, Buitrón G. Influence of pH and temperature on the performance and microbial community during the production of medium-chain carboxylic acids using winery effluents as substrate. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024:10.1007/s11356-024-33103-5. [PMID: 38558339 DOI: 10.1007/s11356-024-33103-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 03/22/2024] [Indexed: 04/04/2024]
Abstract
Winery effluents containing high ethanol concentrations and diverse organic matter are ideal substrates for producing medium-chain carboxylic acids via fermentation and chain elongation. However, the process needs to be better understood. This study presents novel insights into the bioconversion mechanisms of medium-chain carboxylic acids by correlating fermentation and chain elongation kinetic profiles with the study of microbial communities at different pH (5 to 7) conditions and temperatures (30 to 40 °C). It was found that high productivities of MCCA were obtained using a native culture and winery effluents as a natural substrate. Minor pH variations significantly affected the metabolic pathway of the microorganisms for MCCA production. The maximal productivities of hexanoic (715 mg/L/d) and octanoic (350 mg/L/d) acids were found at pH 6 and 35 °C. Results evidence that the presence of Clostridium, Bacteroides, and Negativicutes promotes the high productions of MCCA. The formation of heptanoic acid was favor when Mogibacterium and Burkholderia were present.
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Affiliation(s)
- Sharon B Villegas-Rodríguez
- Laboratory for Research On Advanced Processes for Water Treatment, Unidad Académica Juriquilla, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Blvd. Juriquilla 3001, 76230, Queretaro, Mexico
| | - Jorge Arreola-Vargas
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, 77843, USA
| | - Germán Buitrón
- Laboratory for Research On Advanced Processes for Water Treatment, Unidad Académica Juriquilla, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Blvd. Juriquilla 3001, 76230, Queretaro, Mexico.
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5
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Gao S, Chen Z, Zhu S, Yu J, Wen X. Enhancement of medium-chain fatty acids production from sludge anaerobic fermentation liquid under moderate sulfate reduction. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 354:120459. [PMID: 38402788 DOI: 10.1016/j.jenvman.2024.120459] [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: 09/21/2023] [Revised: 01/10/2024] [Accepted: 02/20/2024] [Indexed: 02/27/2024]
Abstract
In recent years, there has been a marked increase in the production of excess sludge. Chain-elongation (CE) fermentation presents a promising approach for carbon resource recovery from sludge, enabling the transformation of carbon into medium-chain fatty acids (MCFAs). However, the impact of sulfate, commonly presents in sludge, on the CE process remains largely unexplored. In this study, batch tests for CE process of sludge anaerobic fermentation liquid (SAFL) under different SCOD/SO42- ratios were performed. The moderate sulfate reduction under the optimum SCOD/SO42- of 20:1 enhanced the n-caproate production, giving the maximum n-caproate concentration, selectivity and production rate of 5.49 g COD/L, 21.4% and 4.87 g COD/L/d, respectively. The excessive sulfate reduction under SCOD/SO42- ≤ 5 completely inhibited the CE process, resulting in almost no n-caproate generation. The variations in n-caproate production under different conditions of SCOD/SO42- were all well fitted with the modified Gompertz kinetic model. Alcaligenes and Ruminococcaceae_UCG-014 were the dominant genus-level biomarkers under moderate sulfate reduction (SCOD/SO42- = 20), which enhanced the n-caproate production by increasing the generation of acetyl-CoA and the hydrolysis of difficult biodegradable substances in SAFL. The findings presented in this work elucidate a strategy and provide a theoretical framework for the further enhancement of MCFAs production from excess sludge.
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Affiliation(s)
- Shan Gao
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China
| | - Zhan Chen
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China.
| | - Shihui Zhu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China
| | - Jinlan Yu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China
| | - Xianghua Wen
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China.
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Allaart MT, Fox BB, Nettersheim IHMS, Pabst M, Sousa DZ, Kleerebezem R. Physiological and stoichiometric characterization of ethanol-based chain elongation in the absence of short-chain carboxylic acids. Sci Rep 2023; 13:17370. [PMID: 37833311 PMCID: PMC10576071 DOI: 10.1038/s41598-023-43682-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 09/27/2023] [Indexed: 10/15/2023] Open
Abstract
Hexanoate is a valuable chemical that can be produced by microorganisms that convert short-chain- to medium-chain carboxylic acids through a process called chain elongation. These microorganisms usually produce mixtures of butyrate and hexanoate from ethanol and acetate, but direct conversion of ethanol to hexanoate is theoretically possible. Steering microbial communities to ethanol-only elongation to hexanoate circumvents the need for acetate addition and simplifies product separation. The biological feasibility of ethanol elongation to hexanoate was validated in batch bioreactor experiments with a Clostridium kluyveri-dominated enrichment culture incubated with ethanol, acetate and butyrate in different ratios. Frequent liquid sampling combined with high-resolution off-gas measurements allowed to monitor metabolic behavior. In experiments with an initial ethanol-to-acetate ratio of 6:1, acetate depletion occurred after ± 35 h of fermentation, which triggered a metabolic shift to direct conversion of ethanol to hexanoate despite the availability of butyrate (± 40 mCmol L-1). When only ethanol and no external electron acceptor was supplied, stable ethanol to hexanoate conversion could be maintained until 60-90 mCmol L-1 of hexanoate was produced. After this, transient production of either acetate and butyrate or butyrate and hexanoate was observed, requiring a putative reversal of the Rnf complex. This was not observed before acetate depletion or in presence of low concentrations (40-60 mCmol L-1) of butyrate, suggesting a stabilizing or regulatory role of butyrate or butyrate-related catabolic intermediates. This study sheds light on previously unknown versatility of chain elongating microbes and provides new avenues for optimizing (waste) bioconversion for hexanoate production.
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Affiliation(s)
| | - Bartholomeus B Fox
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | | | - Martin Pabst
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Diana Z Sousa
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
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7
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Parera Olm I, Sousa DZ. Upgrading dilute ethanol to odd-chain carboxylic acids by a synthetic co-culture of Anaerotignum neopropionicum and Clostridium kluyveri. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:83. [PMID: 37194097 DOI: 10.1186/s13068-023-02336-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 05/03/2023] [Indexed: 05/18/2023]
Abstract
BACKGROUND Dilute ethanol streams generated during fermentation of biomass or syngas can be used as feedstocks for the production of higher value products. In this study, we describe a novel synthetic microbial co-culture that can effectively upgrade dilute ethanol streams to odd-chain carboxylic acids (OCCAs), specifically valerate and heptanoate. The co-culture consists of two strict anaerobic microorganisms: Anaerotignum neopropionicum, a propionigenic bacterium that ferments ethanol, and Clostridium kluyveri, well-known for its chain-elongating metabolism. In this co-culture, A. neopropionicum grows on ethanol and CO2 producing propionate and acetate, which are then utilised by C. kluyveri for chain elongation with ethanol as the electron donor. RESULTS A co-culture of A. neopropionicum and C. kluyveri was established in serum bottles with 50 mM ethanol, leading to the production of valerate (5.4 ± 0.1 mM) as main product of ethanol-driven chain elongation. In a continuous bioreactor supplied with 3.1 g ethanol L-1 d-1, the co-culture exhibited high ethanol conversion (96.6%) and produced 25% (mol/mol) valerate, with a steady-state concentration of 8.5 mM and a rate of 5.7 mmol L-1 d-1. In addition, up to 6.5 mM heptanoate was produced at a rate of 2.9 mmol L-1 d-1. Batch experiments were also conducted to study the individual growth of the two strains on ethanol. A. neopropionicum showed the highest growth rate when cultured with 50 mM ethanol (μmax = 0.103 ± 0.003 h-1) and tolerated ethanol concentrations of up to 300 mM. Cultivation experiments with C. kluyveri showed that propionate and acetate were used simultaneously for chain elongation. However, growth on propionate alone (50 mM and 100 mM) led to a 1.8-fold reduction in growth rate compared to growth on acetate. Our results also revealed sub-optimal substrate use by C. kluyveri during odd-chain elongation, where excessive ethanol was oxidised to acetate. CONCLUSIONS This study highlights the potential of synthetic co-cultivation in chain elongation processes to target the production of OCCAs. Furthermore, our findings shed light on to the metabolism of odd-chain elongation by C. kluyveri.
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Affiliation(s)
- Ivette Parera Olm
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands.
- Centre for Living Technologies, Eindhoven-Wageningen-Utrecht Alliance, Utrecht, The Netherlands.
| | - Diana Z Sousa
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands
- Centre for Living Technologies, Eindhoven-Wageningen-Utrecht Alliance, Utrecht, The Netherlands
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8
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Electrochemical synthesis of propionic acid from reduction of ethanol and carbon dioxide at various applied potentials. Biochem Eng J 2023. [DOI: 10.1016/j.bej.2023.108896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
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9
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Li L, Liu C, Xu L, Zhuang H, He J, He Q, Zhang J. Acclimation of anaerobic fermentation microbiome with acetate and ethanol for chain elongation and the biochemical response. CHEMOSPHERE 2023; 320:138083. [PMID: 36754309 DOI: 10.1016/j.chemosphere.2023.138083] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 01/10/2023] [Accepted: 02/05/2023] [Indexed: 06/18/2023]
Abstract
Medium chain fatty acids (MCFAs) production is a promising method for resource recovery from organic wastes. In this study, the microbial community structure shift along the long-term acclimation experiment and the concomitant effect of H2 level on chain elongation performance was investigated. Chain elongation microbiome could be rapidly acclimated from traditional anaerobic fermentation consortia. Genera Caproiciproducens, Clostridium sensu stricto 12, Rummeliibacillus and Oscillibacter was found to be dominant during the operation. The H2 was accumulated in the headspace by increasing the ethanol input, which inhibited oxidation of caproate and butyrate immediately, while its inhibition effect on chain elongation was delayed. H2 level in the headspace was positively correlated to the MCFAs production related bacteria. However, too much H2 accumulated might be suppressive for MCFAs production in the long term. It might result from the thermodynamic barrier for discarding excess reducing equivalents under high H2 level, which further gave rise to ethanol accumulation in this system.
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Affiliation(s)
- Lin Li
- College of Environment and Ecology, Chongqing University, Chongqing 400044, China; State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Chang Liu
- College of Environment and Ecology, Chongqing University, Chongqing 400044, China
| | - Linji Xu
- College of Environment and Ecology, Chongqing University, Chongqing 400044, China.
| | - Huichuan Zhuang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Junguo He
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China; School of Civil Engineering, Guangzhou University, Guangzhou 510006, China.
| | - Qiang He
- College of Environment and Ecology, Chongqing University, Chongqing 400044, China
| | - Jie Zhang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
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Zhang Y, Bai J, Zuo J. Performance and mechanisms of medium-chain fatty acid production by anaerobic fermentation of food waste without external electron donors. BIORESOURCE TECHNOLOGY 2023; 374:128735. [PMID: 36781145 DOI: 10.1016/j.biortech.2023.128735] [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: 01/10/2023] [Revised: 02/08/2023] [Accepted: 02/09/2023] [Indexed: 06/18/2023]
Abstract
This study performed a long-term operation to achieve efficient medium-chain fatty acids (MCFAs) production by anaerobic fermentation of food waste without external electron donors. The results show that total MCFAs reached the highest concentration of 29,886.10 mg COD/L, and n-caproate was the primary product, reaching the current maximum concentration of 28,191.66 mg COD/L. Microbial composition analysis demonstrated Lactobacillus, Bifidobacterium, Sporanaerobacter, and Caproiciproducens constituted the core community throughout the process. Metagenomic analysis suggested that two pathways, reverse β-oxidization (RBO) and fatty acid biosynthesis (FAB), were observed, and the FAB pathway was the main CE pathway. Unclassified_f_Ruminococcaceae and Limosilactobacillus were the main participants in the FAB pathway. This study is expected to provide new insights into MCFAs production from organic waste.
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Affiliation(s)
- Yanyan Zhang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Jiazhe Bai
- Tsinghua Shenzhen International Graduate School, Shenzhen 518055, China
| | - Jiane Zuo
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; Tsinghua Shenzhen International Graduate School, Shenzhen 518055, China.
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11
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Konstantinidi S, Skiadas IV, Gavala HN. Microbial Enrichment Techniques on Syngas and CO2 Targeting Production of Higher Acids and Alcohols. Molecules 2023; 28:molecules28062562. [PMID: 36985533 PMCID: PMC10056454 DOI: 10.3390/molecules28062562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/07/2023] [Accepted: 03/08/2023] [Indexed: 03/15/2023] Open
Abstract
(1) Background: Microbial conversion of gaseous molecules, such as CO2, CO and H2, to valuable compounds, has come to the forefront since the beginning of the 21st century due to increasing environmental concerns and the necessity to develop alternative technologies that contribute to a fast transition to a more sustainable era. Research efforts so far have focused on C1–C2 molecules, i.e., ethanol and methane, while interest in molecules with higher carbon atoms has also started to emerge. Research efforts have already started to pay off, and industrial installments on ethanol production from steel-mill off-gases as well as methane production from the CO2 generated in biogas plants are a reality. (2) Methodology: The present study addresses C4–C6 acids and butanol as target molecules and responds to how the inherent metabolic potential of mixed microbial consortia could be revealed and exploited based on the application of different enrichment methods (3) Results and Conclusions: In most of the enrichment series, the yield of C4–C6 acids was enhanced with supplementation of acetic acid and ethanol together with the gas substrates, resulting in a maximum of 43 and 68% (e-mol basis) for butyric and caproic acid, respectively. Butanol formation was also enhanced, to a lesser degree though and up to 9% (e-mol basis). Furthermore, the microbial community exhibited significant shifts depending on the enrichment conditions applied, implying that a more profound microbial analysis on the species level taxonomy combined with the development of minimal co-cultures could set the basis for discovering new microbial co-cultures and/or co-culturing schemes.
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12
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Fu B, Lu Y, Liu H, Zhang X, Ozgun H, Ersahin ME, Liu H. One-stage anaerobic fermentation of excess sludge for caproate production by supplementing chain elongation enrichments with ethanol as electron donor. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 326:116723. [PMID: 36403461 DOI: 10.1016/j.jenvman.2022.116723] [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: 09/07/2022] [Revised: 10/26/2022] [Accepted: 11/04/2022] [Indexed: 06/16/2023]
Abstract
Medium chain fatty acids (MCFAs) production from excess sludge have recently received great research interest due to higher energy densities, easy-separation capability and high economic benefits. Here, the addition of chain elongation (CE) enrichments with ethanol as electron donor was used to enhance caproate production from one-stage sludge fermentation. Compared with 0.20 g/L of controls, caproate production reached 9.00 g/L by supplementing CE enrichments with ethanol/acetate ratio of 3:1 after 7 days of acidification of organic matter in pretreated sludge fermentation. Clostridium_sensu_stricto_12, that refers to CE, was enriched in the first and second transfer of the sludge microbial consortium. Maintaining the stability of the microbial consortium would be the key that enables stable and efficient caproate production from sludge fermentation by supplementing CE enrichments.
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Affiliation(s)
- Bo Fu
- School of Environmental and Civil Engineering, Jiangsu Key Laboratory of Anaerobic Biotechnology, Jiangsu Engineering Laboratory for Biomass Energy and Carbon Reduction Technology, Jiangnan University, Wuxi, China; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, Suzhou, China
| | - Yujie Lu
- School of Environmental and Civil Engineering, Jiangsu Key Laboratory of Anaerobic Biotechnology, Jiangsu Engineering Laboratory for Biomass Energy and Carbon Reduction Technology, Jiangnan University, Wuxi, China
| | - Hongbo Liu
- School of Environmental and Civil Engineering, Jiangsu Key Laboratory of Anaerobic Biotechnology, Jiangsu Engineering Laboratory for Biomass Energy and Carbon Reduction Technology, Jiangnan University, Wuxi, China; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, Suzhou, China
| | - Xuedong Zhang
- School of Environmental and Civil Engineering, Jiangsu Key Laboratory of Anaerobic Biotechnology, Jiangsu Engineering Laboratory for Biomass Energy and Carbon Reduction Technology, Jiangnan University, Wuxi, China
| | - Hale Ozgun
- Istanbul Technical University, Civil Engineering Faculty, Environmental Engineering Department, Ayazaga Campus, Maslak, 34469, Istanbul, Turkey; National Research Center on Membrane Technologies, Istanbul Technical University, 34469, Maslak, Istanbul, Turkey
| | - Mustafa Evren Ersahin
- Istanbul Technical University, Civil Engineering Faculty, Environmental Engineering Department, Ayazaga Campus, Maslak, 34469, Istanbul, Turkey; National Research Center on Membrane Technologies, Istanbul Technical University, 34469, Maslak, Istanbul, Turkey
| | - He Liu
- School of Environmental and Civil Engineering, Jiangsu Key Laboratory of Anaerobic Biotechnology, Jiangsu Engineering Laboratory for Biomass Energy and Carbon Reduction Technology, Jiangnan University, Wuxi, China; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, Suzhou, China.
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13
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Gazzola G, Maria Braguglia C, Crognale S, Gallipoli A, Mininni G, Piemonte V, Rossetti S, Tonanzi B, Gianico A. Biorefining food waste through the anaerobic conversion of endogenous lactate into caproate: A fragile balance between microbial substrate utilization and product inhibition. WASTE MANAGEMENT (NEW YORK, N.Y.) 2022; 150:328-338. [PMID: 35907330 DOI: 10.1016/j.wasman.2022.07.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 06/27/2022] [Accepted: 07/21/2022] [Indexed: 06/15/2023]
Abstract
New technologies development and renewable source exploitation are key tools to realize the European Green Deal and to boost the bio-based economy. In this context, fermentation of organic residues as food waste is an efficient method to obtain marketable products such as carboxylic acids widely applied in industrial production. Under favourable thermodynamic conditions, short chain fatty acids deriving from primary fermentation could be biologically converted into medium-chain fatty acids as caproate via chain elongation (CE) process, by using ethanol or lactate as electron donors. This study evaluates the effectivity of producing caproate from Food Waste extract rich in organics with in situ electron donor production. The test carried out at OLR 15 gCOD L-1d-1 showed high Volatile Fatty Acids (from acetic to caproic acid) yields (0.37 g g-1CODfed), with a maximum caproate concentration of 8 g L-1. The associated microbiome was composed by lactate-producing bacteria (Corynebacterium, Lactobacillus, and Olsenella) and by chain elongators (Clostridiaceae and Caproiciproducens). By stressing the system with OLR increase up to 20 gCOD L-1d-1, the CE process was inhibited by the high concentration of caproate (low occurrence of Clostridiaceae and Caproiciproducens). Nevertheless, after few days of stop-feeding regime imposed to the system, the microbiome restored its capability to proceed with lactate-based CE pathways. Different batch tests carried out with the inhibited biomass at increasing initial caproate concentration confirmed its impact on lactate utilization kinetics.
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Affiliation(s)
- Giulio Gazzola
- Water Research Institute, National Research Council of Italy, CNR-IRSA, Area della Ricerca RM1, Via Salaria km 29.300, 00015 Monterotondo, Roma, Italy
| | - Camilla Maria Braguglia
- Water Research Institute, National Research Council of Italy, CNR-IRSA, Area della Ricerca RM1, Via Salaria km 29.300, 00015 Monterotondo, Roma, Italy
| | - Simona Crognale
- Water Research Institute, National Research Council of Italy, CNR-IRSA, Area della Ricerca RM1, Via Salaria km 29.300, 00015 Monterotondo, Roma, Italy
| | - Agata Gallipoli
- Water Research Institute, National Research Council of Italy, CNR-IRSA, Area della Ricerca RM1, Via Salaria km 29.300, 00015 Monterotondo, Roma, Italy
| | - Giuseppe Mininni
- Water Research Institute, National Research Council of Italy, CNR-IRSA, Area della Ricerca RM1, Via Salaria km 29.300, 00015 Monterotondo, Roma, Italy
| | - Vincenzo Piemonte
- Faculty of Engineering, University Campus Bio-Medico, Via Alvaro del Portillo, 21, 00128 Roma, Italy
| | - Simona Rossetti
- Water Research Institute, National Research Council of Italy, CNR-IRSA, Area della Ricerca RM1, Via Salaria km 29.300, 00015 Monterotondo, Roma, Italy
| | - Barbara Tonanzi
- Water Research Institute, National Research Council of Italy, CNR-IRSA, Area della Ricerca RM1, Via Salaria km 29.300, 00015 Monterotondo, Roma, Italy
| | - Andrea Gianico
- Water Research Institute, National Research Council of Italy, CNR-IRSA, Area della Ricerca RM1, Via Salaria km 29.300, 00015 Monterotondo, Roma, Italy.
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14
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Xiang S, Wu Q, Ren W, Guo W, Ren N. Mechanism of powdered activated carbon enhancing caproate production. CHINESE CHEM LETT 2022. [DOI: 10.1016/j.cclet.2022.07.057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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15
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Zhang Z, Ni BJ, Zhang L, Liu Z, Fu W, Dai X, Sun J. Medium-chain fatty acids production from carbohydrates-rich wastewater through two-stage yeast biofilm processes without external electron donor addition: Biofilm development and pH impact. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 828:154428. [PMID: 35276160 DOI: 10.1016/j.scitotenv.2022.154428] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 03/04/2022] [Accepted: 03/05/2022] [Indexed: 05/12/2023]
Abstract
The production of medium-chain fatty acids (MCFAs) is considered promising for carbon resource recovery from waste streams. However, a large quantity of external electron donors are often required, causing great cost and environmental impact. Therefore, in this study, a two-stage technology was developed to produce MCFAs from carbohydrate-rich wastewater without external electron donor addition, with the biofilm development and pH impact being explored. Stage I aimed at converting organics into ethanol and a yeast biofilm reactor is innovatively applied. The results showed that the yeast biofilm could quickly form on carriers with steady-state thickness reaching 50-200 μm. However, the attachment of yeast biofilm was weak at the initial stage so that the violent turbulence should be avoided during operation. The polyurethane foam was the most suitable for yeast biofilm development among the tested carriers, as evidenced by the highest ethanol production, accounting for 74.2% of soluble organics. The Nakaseomyces was the main fungal genus in the steady-state biofilm, while lactic acid bacteria were also developed, resulting in lactate and acetate production. In Stage II, the yeast biofilm reactor effluent was applied for MCFA production at different pH (5-8). However, the MCFA production selectivity was significantly affected by pH, with 65.2% at pH of 5 but decreasing substantially to 3.0% at pH of 8. Both the microbial and electron transfer efficiency analysis suggested that mildly acidic pH can promote the electron transfer from ethanol toward the chain elongation process instead of its excessive oxidation. Thus, if conditions of online extraction or microbial tolerance permit, a lower pH should be recommended for Stage II in the developed technology as well as other ethanol-based MCFA production process. This is a conceptual study that eliminated external electron donor addition in MCFAs production and provide a sustainable and reliable way in carbon resources recovery.
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Affiliation(s)
- Zisha Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze River Water Environment, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Bing-Jie Ni
- Centre for Technology in Water and Wastewater (CTWW), School of Civil and Environmental Engineering, University of Technology Sydney (UTS), Sydney, NSW 2007, Australia
| | - Lu Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze River Water Environment, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Zhitong Liu
- State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze River Water Environment, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Weng Fu
- School of Chemical Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Xiaohu Dai
- State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze River Water Environment, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Jing Sun
- State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze River Water Environment, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China; Anhui Provincial Key Laboratory of Environmental Pollution Control and Resource Reuse, Hefei 230000, China.
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16
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Yuan S, Jin Z, Ali A, Wang C, Liu J. Caproic Acid-Producing Bacteria in Chinese Baijiu Brewing. Front Microbiol 2022; 13:883142. [PMID: 35602080 PMCID: PMC9114508 DOI: 10.3389/fmicb.2022.883142] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 04/19/2022] [Indexed: 11/25/2022] Open
Abstract
Caproic acid can be used as spices, preservatives, animal feed additives, and biofuels. At the same time, caproic acid plays an important role in Chinese Baijiu. It is the precursor substance for the synthesis of ethyl caproate, which directly affects the quality of Chinese Baijiu. Caproic acid-producing bacteria are the main microorganisms that synthesize caproic acid in Chinese Baijiu, and the most common strain is Clostridium kluyveri. Caproic acid-producing bacteria synthesize n-caproic acid through reverse β-oxidation to extend the carboxylic acid chain. This method mainly uses ethanol and lactic acid as substrates. Ethanol and lactic acid are converted into acetyl-CoA, and acetyl-CoA undergoes a series of condensation, dehydrogenation, dehydration, and reduction to extend the carboxylic acid chain. This review addresses the important issues of caproic acid-producing bacteria in the brewing process of Baijiu: the common caproic acid-producing bacteria that have been reported metabolic pathways, factors affecting acid production, biological competition pathways, and the effect of mixed bacteria fermentation on acid production. It is hoped that this will provide new ideas for the study of caproic acid-producing bacteria in Chinese Baijiu.
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Affiliation(s)
- Siqi Yuan
- School of Biological Engineering, Sichuan University of Science & Engineering, Zigong, China.,Luzhou Laojiao Group Co. Ltd., Luzhou, China.,Key Laboratory of Brewing Biotechnology and Application of Sichuan Province, Yibin, China
| | - Ziyang Jin
- School of Biological Engineering, Sichuan University of Science & Engineering, Zigong, China
| | - Ayaz Ali
- School of Biological Engineering, Sichuan University of Science & Engineering, Zigong, China
| | - Chengjun Wang
- School of Biological Engineering, Sichuan University of Science & Engineering, Zigong, China.,Wuliangye Group Co. Ltd., Yibin, China
| | - Jun Liu
- School of Biological Engineering, Sichuan University of Science & Engineering, Zigong, China.,Key Laboratory of Brewing Biotechnology and Application of Sichuan Province, Yibin, China
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17
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Calvo DC, Luna HJ, Arango JA, Torres CI, Rittmann BE. Determining global trends in syngas fermentation research through a bibliometric analysis. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 307:114522. [PMID: 35066199 DOI: 10.1016/j.jenvman.2022.114522] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 01/10/2022] [Accepted: 01/13/2022] [Indexed: 06/14/2023]
Abstract
Syngas fermentation, in which microorganisms convert H2, CO, and CO2 to acids and alcohols, is a promising alternative for carbon cycling and valorization. The intellectual landscape of the topic was characterized through a bibliometric analysis using a search query (SQ) that included all relevant documents on syngas fermentation available through the Web of Science database up to December 31st, 2021. The SQ was validated with a preliminary analysis in bibliometrix and a review of titles and abstracts of all sources. Although syngas fermentation began in the early 1980s, it grew rapidly beginning in 2008, with 92.5% of total publications and 87.3% of total citations from 2008 to 2021. The field has been steadily moving from fundamentals towards applications, suggesting that the field is maturing scientifically. The greatest number of publications and citations are from the USA, and researchers in China, Germany, and Spain also are highly active. Although collaborations have increased in the past few years, author-cluster analysis shows specialized research domains with little collaboration between groups. Based on topic trends, the main challenges to be address are related to mass-transfer limitations, and researchers are starting to explore mixed cultures, genetic engineering, microbial chain elongation, and biorefineries.
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Affiliation(s)
- Diana C Calvo
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ, PO Box 85287-3005, USA; Biodesign Center for Health Through Microbiomes, Arizona State University, Tempe, AZ, PO Box 85287-3005, USA.
| | - Hector J Luna
- Grupo GRESIA, Department of Environmental Engineering, Universidad Antonio Nariño, Bogotá, 110231, Colombia; Environmental and Chemical Technology Group, Department of Chemistry, Federal University of Ouro Preto, Campus University, Campus Universitario, Brazil
| | - Jineth A Arango
- Pontificia Universidad Católica de Valparaíso, Valparaíso, 2362803, Chile.
| | - Cesar I Torres
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ, PO Box 85287-3005, USA.
| | - Bruce E Rittmann
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ, PO Box 85287-3005, USA.
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18
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Wu SL, Wei W, Wang Y, Song L, Ni BJ. Transforming waste activated sludge into medium chain fatty acids in continuous two-stage anaerobic fermentation: Demonstration at different pH levels. CHEMOSPHERE 2022; 288:132474. [PMID: 34619255 DOI: 10.1016/j.chemosphere.2021.132474] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 09/11/2021] [Accepted: 10/03/2021] [Indexed: 05/20/2023]
Abstract
Bioenergy recovery in the form of medium-chain fatty acids (MCFAs) from waste activated sludge (WAS) is increasingly attractive, which are valuable building blocks for fuel production. This study experimentally demonstrated the long-term MCFAs (C6-C8) production from WAS in two-stage anaerobic sludge fermentation at different pH conditions, using continuously operated bench-scale anaerobic reactors. The WAS was continuously converted to short chain fatty acids (SCFAs, 3500-3800 mg chemical oxygen demand (COD)/L) at the first stage via alkaline anaerobic fermentation, which was directly fed into the second stage as both substrates and inoculum for MCFAs production through chain elongation (CE). The productions of MCFAs at the second stage were continuously studied under three different pH conditions (i.e., 10, 7 and 5.5). The results demonstrated that there was no significant MCFAs production at pH 10 during the steady state, whereas the MCFAs productions were clearly observed at both pH 7 and pH 5.5, with much higher MCFAs production from WAS at pH 7 (i.e., 10.32 g COD/L MCFAs) than that at pH 5.5 (i.e., 8.73 g COD/L MCFAs) during the steady state. A higher MCFAs selectivity of 62.3% was also achieved at pH 7. The relatively lower MCFAs production and selectivity at pH 5.5 was likely due to the higher undissociated MCFAs generated at pH 5.5, which would pose toxicity impact on CE microbes and thus inhibit the CE process. Microbial community analysis confirmed that the relative abundances of CE related microbes (e.g., Clostridium sensu stricto 12 sp. and Clostridium sensu stricto 1) increased at pH 7 compared to those at pH 5.5, which enabled more efficient MCFAs production from WAS.
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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
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW, 2007, Australia.
| | - Yun Wang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, PR China
| | - Lan Song
- School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, PR China
| | - Bing-Jie Ni
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW, 2007, Australia.
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19
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Guo H, Zhao S, Xia D, Zhao W, Li Q, Liu X, Lv J. The biochemical mechanism of enhancing the conversion of chicken manure to biogenic methane using coal slime as additive. BIORESOURCE TECHNOLOGY 2022; 344:126226. [PMID: 34798250 DOI: 10.1016/j.biortech.2021.126226] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 10/22/2021] [Accepted: 10/23/2021] [Indexed: 06/13/2023]
Abstract
To improve the efficiency of methane production from chicken manure (CM) anaerobic digestion, the mechanism of coal slime (CS) as an additive on methane production characteristics were investigated. The results showed that adding an appropriate amount of CS quickened the start of the fermentation and effectively increased the methane yield. In addition, the pH changed in a stable manner in the liquid phase, and the concentrations of total ammonia nitrogen (TAN) and free ammonia nitrogen (FAN) were reduced. Moreover, organic matter was decomposed and volatile fatty acids (VFAs) were consumed effectively. The abundance of Bacteroides in the bacterial community and Methanosarcina in the archaea was increased. In addition, the reduction of CO2 was the main methanogenic pathway, and adding CS raised the abundance of genes for key enzymes in metabolic pathways during methane metabolism. The results provide a novel method for the efficient methane production from CM.
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Affiliation(s)
- Hongyu Guo
- School of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, China; Collaborative Innovation Center of Coalbed Methane and Shale Gas for Central Plains Economic Region, Jiaozuo 454000, China
| | - Shufeng Zhao
- School of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, China
| | - Daping Xia
- School of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, China; Collaborative Innovation Center of Coalbed Methane and Shale Gas for Central Plains Economic Region, Jiaozuo 454000, China.
| | - Weizhong Zhao
- Institute of Resources and Environment Henan Polytechnic University, Jiaozuo 454000, China
| | - Qingchao Li
- School of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, China
| | - XiaoLei Liu
- College of safety Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, China
| | - Jinghui Lv
- College of Chemistry and Chemical Engineering, Henan Polytechnic University, Jiaozuo 454000, China
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20
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Kim H, Kang S, Sang BI. Metabolic cascade of complex organic wastes to medium-chain carboxylic acids: A review on the state-of-the-art multi-omics analysis for anaerobic chain elongation pathways. BIORESOURCE TECHNOLOGY 2022; 344:126211. [PMID: 34710599 DOI: 10.1016/j.biortech.2021.126211] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/18/2021] [Accepted: 10/20/2021] [Indexed: 06/13/2023]
Abstract
Medium-chain carboxylic acid (MCCA) production from organic wastes has attracted much attention because of their higher energy contents and diverse applications. Anaerobic reactor microbiomes are stable and resilient and have resulted in efficient performance during many years of operation for thousands of full-scale anaerobic digesters worldwide. The method underlying how the relevant microbial pathways contribute to elongate carbon chains in reactor microbiomes is important. In particular, the reverse β-oxidation pathway genes are critical to upgrading short-chain fermentation products to MCCAs via a chain elongation (CE) process. Diverse genomics and metagenomics studies have been conducted in various fields, ranging from intracellular metabolic pathways to metabolic cascades between different strains. This review covers taxonomic approach to culture processes depending on types of organic wastes and the deeper understanding of genome and metagenome-scale CE pathway construction, and the co-culture and multi-omics technology that should be addressed in future research.
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Affiliation(s)
- Hyunjin Kim
- Department of Chemical Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Seongcheol Kang
- Department of Chemical Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Byoung-In Sang
- Department of Chemical Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea.
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21
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Wang J, Yin Y. Biological production of medium-chain carboxylates through chain elongation: An overview. Biotechnol Adv 2021; 55:107882. [PMID: 34871718 DOI: 10.1016/j.biotechadv.2021.107882] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 11/01/2021] [Accepted: 11/28/2021] [Indexed: 12/15/2022]
Abstract
Medium chain carboxylates (MCCs) have wide applications in various industries, but the traditional MCCs production methods are costly and unsustainable. Anaerobic fermentation offers a more scalable, economical and eco-friendly platform for producing MCCs through chain elongation which converts short chain carboxylates and electron donor into more valuable MCCs. However, the underlying microbial pathways are not well understood. In this review, biological production of MCCs through chain elongation is introduced elaborately, including the metabolic pathways, electron donor and substrates, microorganisms and influencing factors. Then, the strategies for enhancing MCCs production are extensively analyzed and summarized, along with the technologies for MCCs separation from the fermentation broth. Finally, challenges and perspectives concerning the large-scale MCCs production are proposed, providing suggestions for the future research. Extensive review demonstrated that anaerobic fermentation has great potential in achieving economical and sustainable MCCs production from complex organic substrates, including organic waste streams, which would significantly broaden the application of MCCs, especially in the renewable energy field. An interdisciplinary approach with knowledge from microbiology and biochemistry to chemical separations and environmental engineering is required to use this promising technology as a valorization method for converting organic biomass or organic wastes into valuable MCCs.
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Affiliation(s)
- Jianlong Wang
- Laboratory of Environmental Technology, INET, Tsinghua University, Beijing 100084, PR China; Beijing Key Laboratory of Radioactive Waste Treatment, Tsinghua University, Beijing 100084, PR China.
| | - Yanan Yin
- Laboratory of Environmental Technology, INET, Tsinghua University, Beijing 100084, PR China
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22
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Zhang C, Liu Y, Zhang W, Sun L, Baeyens J. Modification of wheat straw to improve the caproate production in a cell immobilized system. BIORESOURCE TECHNOLOGY 2021; 342:125984. [PMID: 34563819 DOI: 10.1016/j.biortech.2021.125984] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 09/15/2021] [Accepted: 09/16/2021] [Indexed: 06/13/2023]
Abstract
Wheat straw is a favorable cell carrier in the caproate fermentation system, yet its smooth surface limits the biofilm formation. In this study, the modification of wheat straw was conducted using three different chemical methods and the influence of its modified surface on the caproate fermentation was investigated. Results showed that the sodium hydroxide was the optimum reagent for modification of wheat straw, where both the external and internal surfaces were effectively modified, resulting in 34.4% increased specific surface area. The highest caproate production of 21.1 g/L was obtained in fed-batch fermentation, which was ascribed to the formation of a thick biofilm on the modified carrier. Moreover, the crystallinity index of the carrier increased during the fed-batch fermentation, implying that the modified wheat straw was a stable matrix for cell immobilization. This study provides an effective way for efficient caproate production through modification of wheat straw.
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Affiliation(s)
- Cunsheng Zhang
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, Jiangsu Province 212013, PR China; Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou, Guangdong Province 510006, PR China; Jiangsu Key Laboratory for Biomass Energy and Material, Nanjing, Jiangsu Province 210042, PR China.
| | - Yan Liu
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, Jiangsu Province 212013, PR China
| | - Wenhui Zhang
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, Jiangsu Province 212013, PR China
| | - Ling Sun
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, Jiangsu Province 212013, PR China
| | - Jan Baeyens
- KU Leuven, Department of Chemical Engineering, Process and Environmental Technology Lab., 2860 Sint-Katelijne-Waver, Belgium
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23
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Dhakal N, Acharya B. Syngas Fermentation for the Production of Bio-Based Polymers: A Review. Polymers (Basel) 2021; 13:polym13223917. [PMID: 34833218 PMCID: PMC8618084 DOI: 10.3390/polym13223917] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 11/04/2021] [Accepted: 11/09/2021] [Indexed: 11/21/2022] Open
Abstract
Increasing environmental awareness among the general public and legislators has driven this modern era to seek alternatives to fossil-derived products such as fuel and plastics. Addressing environmental issues through bio-based products driven from microbial fermentation of synthetic gas (syngas) could be a future endeavor, as this could result in both fuel and plastic in the form of bioethanol and polyhydroxyalkanoates (PHA). Abundant availability in the form of cellulosic, lignocellulosic, and other organic and inorganic wastes presents syngas catalysis as an interesting topic for commercialization. Fascination with syngas fermentation is trending, as it addresses the limitations of conventional technologies like direct biochemical conversion and Fischer–Tropsch’s method for the utilization of lignocellulosic biomass. A plethora of microbial strains is available for syngas fermentation and PHA production, which could be exploited either in an axenic form or in a mixed culture. These microbes constitute diverse biochemical pathways supported by the activity of hydrogenase and carbon monoxide dehydrogenase (CODH), thus resulting in product diversity. There are always possibilities of enzymatic regulation and/or gene tailoring to enhance the process’s effectiveness. PHA productivity drags the techno-economical perspective of syngas fermentation, and this is further influenced by syngas impurities, gas–liquid mass transfer (GLMT), substrate or product inhibition, downstream processing, etc. Product variation and valorization could improve the economical perspective and positively impact commercial sustainability. Moreover, choices of single-stage or multi-stage fermentation processes upon product specification followed by microbial selection could be perceptively optimized.
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Fan YX, Zhang JZ, Zhang Q, Ma XQ, Liu ZY, Lu M, Qiao K, Li FL. Biofuel and chemical production from carbon one industry flux gas by acetogenic bacteria. ADVANCES IN APPLIED MICROBIOLOGY 2021; 117:1-34. [PMID: 34742365 DOI: 10.1016/bs.aambs.2021.07.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Carbon one industry flux gas generated from fossil fuels, various industrial and domestic waste, as well as lignocellulosic biomass provides an innovative raw material to lead the sustainable development. Through the chemical and biological processing, the gas mixture composed of CO, CO2, and H2, also termed as syngas, is converted to biofuels and high-value chemicals. Here, the syngas fermentation process is elaborated to provide an overview. Sources of syngas are summarized and the influences of impurities on biological fermentation are exhibited. Acetogens and carboxydotrophs are the two main clusters of syngas utilizing microorganisms, their essential characters are presented, especially the energy metabolic scheme with CO, CO2, and H2. Synthetic biology techniques and microcompartment regulation are further discussed and proposed to create a high-efficiency cell factory. Moreover, the influencing factors in fermentation and products in carboxylic acids, alcohols, and others such like polyhydroxyalkanoate and poly-3-hydroxybutyrate are addressed. Biological fermentation from carbon one industry flux gas is a promising alternative, the latest scientific advances are expatiated hoping to inspire more creative transformation.
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Affiliation(s)
- Yi-Xuan Fan
- Shandong Provincial Key Laboratory of Synthetic Biology, Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China; University of Chinese Academy of Sciences, Beijing, China
| | - Jun-Zhe Zhang
- Shandong Provincial Key Laboratory of Synthetic Biology, Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China; University of Chinese Academy of Sciences, Beijing, China
| | - Quan Zhang
- Sinopec Dalian (Fushun) Research Institute of Petroleum and Petrochemicals, Dalian, China
| | - Xiao-Qing Ma
- Shandong Provincial Key Laboratory of Synthetic Biology, Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China; Shandong Energy Institute, Qingdao, China
| | - Zi-Yong Liu
- Shandong Provincial Key Laboratory of Synthetic Biology, Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China; Shandong Energy Institute, Qingdao, China
| | - Ming Lu
- Shandong Provincial Key Laboratory of Synthetic Biology, Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China; Shandong Energy Institute, Qingdao, China
| | - Kai Qiao
- Sinopec Dalian (Fushun) Research Institute of Petroleum and Petrochemicals, Dalian, China.
| | - Fu-Li Li
- Shandong Provincial Key Laboratory of Synthetic Biology, Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China; Shandong Energy Institute, Qingdao, China; Dalian National Laboratory for Clean Energy, Dalian, China.
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Wu Q, Jiang Y, Chen Y, Liu M, Bao X, Guo W. Opportunities and challenges in microbial medium chain fatty acids production from waste biomass. BIORESOURCE TECHNOLOGY 2021; 340:125633. [PMID: 34315125 DOI: 10.1016/j.biortech.2021.125633] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/16/2021] [Accepted: 07/17/2021] [Indexed: 06/13/2023]
Abstract
Medium chain fatty acids (MCFAs) that produced from affordable waste biomass via chain elongation (CE) technology are recognized as the potential alternatives to part fossil-derived chemicals, contributing to the sustainable development of economy and environment. The purpose of this review is to provide comprehensive analyses on the opportunities and challenges of MCFAs production and application. First, both two microbial MCFAs synthesis pathways of reverse β-oxidation and fatty acid biosynthesis were introduced/compared in detail to give readers a thorough understanding of the CE process, with the expectation of further boosting MCFAs production by well distinguishing them. Furthermore, the six key MCFAs production bottlenecks, corresponding research progresses, and possible solutions were analyzed. Five major MCFAs production strategies with their production mechanism, performances, and characteristics were also critically assessed. Additionally, the commercial production status was introduced, and future alternative production mode and research priorities were also recommended.
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Affiliation(s)
- Qinglian Wu
- College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Yong Jiang
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Ying Chen
- College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Min Liu
- College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Xian Bao
- School of Civil and Environmental Engineering, Nanyang Technological University, Singapore 639798, Singapore.
| | - Wanqian Guo
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
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Zhou X, Lu Y, Huang L, Zhang Q, Wang X, Zhu J. Effect of pH on volatile fatty acid production and the microbial community during anaerobic digestion of Chinese cabbage waste. BIORESOURCE TECHNOLOGY 2021; 336:125338. [PMID: 34082333 DOI: 10.1016/j.biortech.2021.125338] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 05/22/2021] [Accepted: 05/25/2021] [Indexed: 06/12/2023]
Abstract
The effects of pH on the production of volatile fatty acids (VFAs) and the evolution of microbial community structure were studied via anaerobic fermentation of Chinese cabbage waste. The results showed that the concentration of total VFAs was highest at 20,241.4 mg COD/L at pH 6.0, followed by pH 7.0. Ethanol, acetate and butyrate were dominant under the acidic condition. The main products at pH 7.0 were acetate, propionate, and butyrate. Ethanol, acetate and butyrate were rapidly produced during the initial stage. The hexanoate concentration increased quickly from day 6 due to the chain extension between ethanol and butyrate, and was 4,885.1 mg COD/L on day 8, accounting for 30.4% of the total VFAs. As fermentation was extended, Bacteroidia and Clostridia were dominant at pH 6.0 and the uncontrolled pH, respectively. Clostridium IV, Ruminococcus, and Candida, were suspected to be related to hexanoate production.
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Affiliation(s)
- Xiaonan Zhou
- School of Agricultural Engineering and Food Science, Shandong University of Technology, Zibo 255000, China
| | - Yu Lu
- School of Agricultural Engineering and Food Science, Shandong University of Technology, Zibo 255000, China
| | - Liu Huang
- School of Agricultural Engineering and Food Science, Shandong University of Technology, Zibo 255000, China
| | - Qi Zhang
- School of Agricultural Engineering and Food Science, Shandong University of Technology, Zibo 255000, China
| | - Xiangyou Wang
- School of Agricultural Engineering and Food Science, Shandong University of Technology, Zibo 255000, China
| | - Jiying Zhu
- School of Agricultural Engineering and Food Science, Shandong University of Technology, Zibo 255000, China.
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27
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Allaart MT, Stouten GR, Sousa DZ, Kleerebezem R. Product Inhibition and pH Affect Stoichiometry and Kinetics of Chain Elongating Microbial Communities in Sequencing Batch Bioreactors. Front Bioeng Biotechnol 2021; 9:693030. [PMID: 34235138 PMCID: PMC8256265 DOI: 10.3389/fbioe.2021.693030] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 05/25/2021] [Indexed: 11/13/2022] Open
Abstract
Anaerobic microbial communities can produce carboxylic acids of medium chain length (e.g., caproate, caprylate) by elongating short chain fatty acids through reversed β-oxidation. Ethanol is a common electron donor for this process. The influence of environmental conditions on the stoichiometry and kinetics of ethanol-based chain elongation remains elusive. Here, a sequencing batch bioreactor setup with high-resolution off-gas measurements was used to identify the physiological characteristics of chain elongating microbial communities enriched on acetate and ethanol at pH 7.0 ± 0.2 and 5.5 ± 0.2. Operation at both pH-values led to the development of communities that were highly enriched (>50%, based on 16S rRNA gene amplicon sequencing) in Clostridium kluyveri related species. At both pH-values, stably performing cultures were characterized by incomplete substrate conversion and decreasing biomass-specific hydrogen production rates during an operational cycle. The process stoichiometries obtained at both pH-values were different: at pH 7.0, 71 ± 6% of the consumed electrons were converted to caproate, compared to only 30 ± 5% at pH 5.5. Operating at pH 5.5 led to a decrease in the biomass yield, but a significant increase in the biomass-specific substrate uptake rate, suggesting that the organisms employ catabolic overcapacity to deal with energy losses associated to product inhibition. These results highlight that chain elongating conversions rely on a delicate balance between substrate uptake- and product inhibition kinetics.
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Affiliation(s)
| | | | - Diana Z Sousa
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands
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28
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Fu X, Jin X, Ye R, Lu W. Nano zero-valent iron: A pH buffer, electron donor and activator for chain elongation. BIORESOURCE TECHNOLOGY 2021; 329:124899. [PMID: 33677422 DOI: 10.1016/j.biortech.2021.124899] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/19/2021] [Accepted: 02/20/2021] [Indexed: 06/12/2023]
Abstract
Chain elongation produce medium chain carboxylates, which are important precursors to many pharmaceuticals, antimicrobials and biofuels. Results in the presented investigations show that the supply of nano zero-valent iron (NZVI) can enhance caproate production. The highest caproate concentration achieved amounted to 27.2 mmol/L when 5 g/L NZVI were added, which was about 100% higher than the control. The study also showed increase of ethanol oxidation and decrease of butyrate and butanol with NZVI addition. Mechanism study showed NZVI can stimulate caproate production by preventing pH to fall below 5.4 through displacement reaction. Electron balance analysis displayed that NZVI provides extra electron by promoting ethanol oxidation and its dissolution. H2 was the potential electron shuttle between NZVI and chain elongators; High throughput sequencing showed function of NZVI on reshaping of microbial communities, especially enriching Oscillibacter Marseille-P3260, a kind of chain elongator and Corynebacterium which possesses fatty acid biosynthesis and iron utilization.
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Affiliation(s)
- Xindi Fu
- School of Environment, Tsinghua University, 100084 Beijing, China
| | - Xi Jin
- School of Environment, Tsinghua University, 100084 Beijing, China
| | - Rong Ye
- School of Environment, Tsinghua University, 100084 Beijing, China
| | - Wenjing Lu
- School of Environment, Tsinghua University, 100084 Beijing, China.
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29
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Baleeiro FCF, Kleinsteuber S, Sträuber H. Hydrogen as a Co-electron Donor for Chain Elongation With Complex Communities. Front Bioeng Biotechnol 2021; 9:650631. [PMID: 33898406 PMCID: PMC8059637 DOI: 10.3389/fbioe.2021.650631] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 03/12/2021] [Indexed: 01/04/2023] Open
Abstract
Electron donor scarcity is seen as one of the major issues limiting economic production of medium-chain carboxylates from waste streams. Previous studies suggest that co-fermentation of hydrogen in microbial communities that realize chain elongation relieves this limitation. To better understand how hydrogen co-feeding can support chain elongation, we enriched three different microbial communities from anaerobic reactors (A, B, and C with ascending levels of diversity) for their ability to produce medium-chain carboxylates from conventional electron donors (lactate or ethanol) or from hydrogen. In the presence of abundant acetate and CO2, the effects of different abiotic parameters (pH values in acidic to neutral range, initial acetate concentration, and presence of chemical methanogenesis inhibitors) were tested along with the enrichment. The presence of hydrogen facilitated production of butyrate by all communities and improved production of i-butyrate and caproate by the two most diverse communities (B and C), accompanied by consumption of acetate, hydrogen, and lactate/ethanol (when available). Under optimal conditions, hydrogen increased the selectivity of conventional electron donors to caproate from 0.23 ± 0.01 mol e-/mol e- to 0.67 ± 0.15 mol e-/mol e- with a peak caproate concentration of 4.0 g L-1. As a trade-off, the best-performing communities also showed hydrogenotrophic methanogenesis activity by Methanobacterium even at high concentrations of undissociated acetic acid of 2.9 g L-1 and at low pH of 4.8. According to 16S rRNA amplicon sequencing, the suspected caproate producers were assigned to the family Anaerovoracaceae (Peptostreptococcales) and the genera Megasphaera (99.8% similarity to M. elsdenii), Caproiciproducens, and Clostridium sensu stricto 12 (97-100% similarity to C. luticellarii). Non-methanogenic hydrogen consumption correlated to the abundance of Clostridium sensu stricto 12 taxa (p < 0.01). If a robust methanogenesis inhibition strategy can be found, hydrogen co-feeding along with conventional electron donors can greatly improve selectivity to caproate in complex communities. The lessons learned can help design continuous hydrogen-aided chain elongation bioprocesses.
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Affiliation(s)
- Flávio C F Baleeiro
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany.,Technical Biology, Institute of Process Engineering in Life Science II, Karlsruhe Institute of Technology - KIT, Karlsruhe, Germany
| | - Sabine Kleinsteuber
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
| | - Heike Sträuber
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
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Saadoun L, Campitelli A, Kannengiesser J, Stanojkovski D, El Alaoui El Fels A, Mandi L, Ouazzani N. Potential of medium chain fatty acids production from municipal solid waste leachate: Effect of age and external electron donors. WASTE MANAGEMENT (NEW YORK, N.Y.) 2021; 120:503-512. [PMID: 33129653 DOI: 10.1016/j.wasman.2020.10.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 10/06/2020] [Accepted: 10/08/2020] [Indexed: 06/11/2023]
Abstract
A large quantity of leachate is generated during municipal solid waste collection operation and in landfills due to the large amount of organic waste and high humidity. The content of medium chain fatty acids (MCFAs) in the leachate is a low cost feedstock for bio-based chemical and fuel production processes. The aim of this study is to investigate the MCFA production potential of three leachate ages through chain elongation process under uncontrolled pH batch test. Moreover, the effect of using different external electron donors (ethanol, methanol and a mixture of both) is studied. The experiment consists of characterizing the samples then adding external electron donors with a specific ratio to leachate samples under mesophilic temperature. For this investigation, also a statistical analysis is done, which shows the production of MCFAs is highly influenced by leachate age. The results indicate that the production of even-numbered acids increase from 600 to 1,000 mg/L by the end of the ethanol chain elongation experiment for young leachate. However, a higher MCFA production of more than 1,000 mg/L is achieved by using the mixture of methanol and ethanol as electron donor. Furthermore, all methanol chain elongation experiments lead to an odd-numbered production of MCFAs, such as pentanoic and heptanoic acids. These results confirm the potential improvement of MCFA production from leachate through choosing the optimal leachate age and electron donor. Overall, producing MCFAs from leachate is a good example of circular bio-economy because waste is used to produce biochemicals, which closes the material cycle.
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Affiliation(s)
- Lamia Saadoun
- Laboratory of Water, Biodiversity and Climate Change, Faculty of Sciences Semlalia, P.O. Box 2390, Cadi Ayyad University, Marrakech, Morocco; National Center for Studies and Research on Water and Energy (CNEREE), Cadi Ayyad University, P.O. Box 511, Marrakech, Morocco
| | - Alessio Campitelli
- Technical University of Darmstadt, Institute IWAR, Department of Material Flow Management and Resource Economy, Franziska-Braun-Straße 7, 64287 Darmstadt, Germany
| | - Jan Kannengiesser
- Technical University of Darmstadt, Institute IWAR, Department of Material Flow Management and Resource Economy, Franziska-Braun-Straße 7, 64287 Darmstadt, Germany
| | - Daniel Stanojkovski
- Technical University of Darmstadt, Institute IWAR, Department of Material Flow Management and Resource Economy, Franziska-Braun-Straße 7, 64287 Darmstadt, Germany
| | - Abdelhafid El Alaoui El Fels
- Laboratory of Water, Biodiversity and Climate Change, Faculty of Sciences Semlalia, P.O. Box 2390, Cadi Ayyad University, Marrakech, Morocco
| | - Laila Mandi
- Laboratory of Water, Biodiversity and Climate Change, Faculty of Sciences Semlalia, P.O. Box 2390, Cadi Ayyad University, Marrakech, Morocco; National Center for Studies and Research on Water and Energy (CNEREE), Cadi Ayyad University, P.O. Box 511, Marrakech, Morocco
| | - Naaila Ouazzani
- Laboratory of Water, Biodiversity and Climate Change, Faculty of Sciences Semlalia, P.O. Box 2390, Cadi Ayyad University, Marrakech, Morocco; National Center for Studies and Research on Water and Energy (CNEREE), Cadi Ayyad University, P.O. Box 511, Marrakech, Morocco.
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31
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Izadi P, Fontmorin JM, Lim SS, Head IM, Yu EH. Enhanced bio-production from CO 2 by microbial electrosynthesis (MES) with continuous operational mode. Faraday Discuss 2021; 230:344-359. [PMID: 34259692 DOI: 10.1039/d0fd00132e] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Technologies able to convert CO2 to various feedstocks for fuels and chemicals are emerging due to the urge of reducing greenhouse gas emissions and de-fossilizing chemical production. Microbial electrosynthesis (MES) has been shown a promising technique to synthesize organic products particularly acetate using microorganisms and electrons. However, the efficiency of the system is low. In this study, we demonstrated the simple yet efficient strategy in enhancing the efficiency of MES by applying continuous feeding regime. Compared to the fed-batch system, continuous operational mode provided better control of pH and constant medium refreshment, resulting in higher acetate production rate and more diverse bio-products, when the cathodic potential of -1.0 V Ag/AgCl and dissolved CO2 were provided. It was observed that hydraulic retention time (HRT) had a direct effect on the pattern of production, acetate production rate and coulombic efficiency. At HRT of 3 days, pH was around 5.2 and acetate was the dominant product with the highest production rate of 651.8 ± 214.2 ppm per day and a significant coulombic efficiency of 90%. However at the HRT of 7 days, pH was lower at around 4.5, and lower but stable acetate production rate of 280 ppm per day and a maximum coulombic efficiency of 80% was obtained. In addition, more diverse and longer chain products, such as butyrate, isovalerate and caproate, were detected with low concentrations only at the HRT of 7 days. Although microbial community analysis showed the change in the planktonic cells communities after switching the fed-batch mode to continuous feeding regime, Acetobacterium still remained as the responsible bacteria for CO2 reduction to acetate, dominating the cathodic biofilm.
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Affiliation(s)
- Paniz Izadi
- School of Engineering, Newcastle University, Newcastle upon Tyne, UK.
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32
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Rajesh Banu J, Ginni G, Kavitha S, Yukesh Kannah R, Adish Kumar S, Bhatia SK, Kumar G. Integrated biorefinery routes of biohydrogen: Possible utilization of acidogenic fermentative effluent. BIORESOURCE TECHNOLOGY 2021; 319:124241. [PMID: 33254464 DOI: 10.1016/j.biortech.2020.124241] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 10/03/2020] [Accepted: 10/05/2020] [Indexed: 06/12/2023]
Abstract
Biohydrogen production and integration possibilities are vital towards hydrogen economy and sustainability of the environment. Acidogenic fermentation is acquiring great interest and it is one of the prime pathways to produce biohydrogen and short chain carboxylic acids. In addition to hydrogen recovery, simultaneously nearly 60 percent of the organics may get converted to ethanol, 1,3propanediol and organic acids. Besides, these organics (fermentative effluents) can be used indirectly as a raw material for the generation of value- added products such as biolipid, polyhydroxyalkanoates, excess hydrogen, methane and electrical energy recovery. In this regard, this review has been assessed as a valuable biorefinery for biofuel and value- added products recovery. The biorefinery can be used to minimize entire cost of the approach by obtaining extra profits.
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Affiliation(s)
- J Rajesh Banu
- Department of Life Sciences, Central University of Tamil Nadu, Neelakudi, Thiruvarur, Tamil Nadu 610005, India
| | - G Ginni
- Department of Civil Engineering, Amrita College of Engineering and Technology, Amritagiri, Nagercoil, Tamil Nadu, 629901, India
| | - S Kavitha
- Department of Civil Engineering, Anna University Regional Campus, Tirunelveli, Tamil Nadu, 627007, India
| | - R Yukesh Kannah
- Department of Civil Engineering, Anna University Regional Campus, Tirunelveli, Tamil Nadu, 627007, India
| | - S Adish Kumar
- Department of Civil Engineering, University V.O.C College of Engineering, Anna University, Thoothukudi Campus, Tamil Nadu, 628008, India
| | - Shashi Kant Bhatia
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Gopalakrishnan Kumar
- School of Civil and Environmental Engineering, Yonsei University, Seoul 03722, Republic of Korea.
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Fermentation of organic wastes and CO2 + H2 off-gas by microbiotas provides short-chain fatty acids and ethanol for n-caproate production. J CO2 UTIL 2020. [DOI: 10.1016/j.jcou.2020.101314] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Syngas Derived from Lignocellulosic Biomass Gasification as an Alternative Resource for Innovative Bioprocesses. Processes (Basel) 2020. [DOI: 10.3390/pr8121567] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A hybrid system based on lignocellulosic biomass gasification and syngas fermentation represents a second-generation biorefinery approach that is currently in the development phase. Lignocellulosic biomass can be gasified to produce syngas, which is a gas mixture consisting mainly of H2, CO, and CO2. The major challenge of biomass gasification is the syngas’s final quality. Consequently, the development of effective syngas clean-up technologies has gained increased interest in recent years. Furthermore, the bioconversion of syngas components has been intensively studied using acetogenic bacteria and their Wood–Ljungdahl pathway to produce, among others, acetate, ethanol, butyrate, butanol, caproate, hexanol, 2,3-butanediol, and lactate. Nowadays, syngas fermentation appears to be a promising alternative for producing commodity chemicals in comparison to fossil-based processes. Research studies on syngas fermentation have been focused on process design and optimization, investigating the medium composition, operating parameters, and bioreactor design. Moreover, metabolic engineering efforts have been made to develop genetically modified strains with improved production. In 2018, for the first time, a syngas fermentation pilot plant from biomass gasification was built by LanzaTech Inc. in cooperation with Aemetis, Inc. Future research will focus on coupling syngas fermentation with additional bioprocesses and/or on identifying new non-acetogenic microorganisms to produce high-value chemicals beyond acetate and ethanol.
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35
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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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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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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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Wang Q, Zhang P, Bao S, Liang J, Wu Y, Chen N, Wang S, Cai Y. Chain elongation performances with anaerobic fermentation liquid from sewage sludge with high total solid as electron acceptor. BIORESOURCE TECHNOLOGY 2020; 306:123188. [PMID: 32199398 DOI: 10.1016/j.biortech.2020.123188] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 03/08/2020] [Accepted: 03/11/2020] [Indexed: 06/10/2023]
Abstract
This work studied the effect of total solid (TS) of sewage sludge on VFA production and composition in anaerobic fermentation. Results revealed that VFA concentration reached the highest of 10.16 g/L and the ratio of acetic acid, propionic acid and n-butyric acid was 5:2:2 with the 8% TS sewage sludge. In subsequent chain elongation with sludge fermentation liquid, n-caproic acid concentration reached 43.45 mmol/L. The microbial community analysis indicated that relative abundance of Clostridium_sensu_stricto_12 for n-caproic acid production was high (52.41%). The chain elongation with sludge fermentation liquid had more pathways to produce n-caproic acid, and the chain elongation reactions were thermodynamically possible. The mixed VFAs and high concentration of n-butyric acid benefitted n-caproic acid production. Carbon balance revealed that the VFA composition of sludge fermentation liquid was beneficial to the chain elongation. This study will contribute to wasted sludge minimization and high-value material production.
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Affiliation(s)
- Qingyan Wang
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Panyue Zhang
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China; School of Environmental and Chemical Engineering, Chongqing Three Gorges University, Chongqing 404632, China.
| | - Shuai Bao
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Jinsong Liang
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Yan Wu
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China; School of Environmental and Chemical Engineering, Chongqing Three Gorges University, Chongqing 404632, China
| | - Na Chen
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Siqi Wang
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Yajing Cai
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
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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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40
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Kim H, Choi O, Jeon BS, Choe WS, Sang BI. Impact of feedstocks and downstream processing technologies on the economics of caproic acid production in fermentation by Megasphaera elsdenii T81. BIORESOURCE TECHNOLOGY 2020; 301:122794. [PMID: 31981909 DOI: 10.1016/j.biortech.2020.122794] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 01/09/2020] [Accepted: 01/10/2020] [Indexed: 06/10/2023]
Abstract
Caproic acid (CA) was produced by Megasphaera elsdenii T81 with Jerusalem artichoke tubers (JA) as a feedstock. More CA was produced under the medium with the acid hydrolysate of JA than the comparative medium with a carbon composition similar to that of JA. CA was produced up to 13.0 g/L and 0.52 g/L/h with extractive fermentation using a mixed solvent of alamine 336 in oleyl alcohol at 37 °C. The JA cost to produce 1 ton of CA is only 505 USD, which is much lower than that required for purchasing sucrose (860 USD) in CA production. As a result of the analysis performed using SuperPro Designer, including the cost of distillation to obtain pure CA, the estimated production cost for CA from dry JA is 1869 USD/ton CA at the production scale of 2000 ton/year, which is lower than the current market price for petroleum-derived CA (~2500 USD/ton).
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Affiliation(s)
- Hyunjin Kim
- Department of Chemical Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Okkyoung Choi
- Department of Chemical Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Byoung Seung Jeon
- Centrum for Applied Geosciences, University of Tübingen, Hölderlinstraße 12, Tübingen 72074, Germany
| | - Woo-Seok Choe
- SKKU Advanced Institute of Nano-Technology (SAINT) and School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, Gyeonggi-do 16419, Republic of Korea
| | - Byoung-In Sang
- Department of Chemical Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea.
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41
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Morais NWS, Coelho MMH, Silva ADSE, Pereira EL, Leitão RC, Dos Santos AB. Kinetic modeling of anaerobic carboxylic acid production from swine wastewater. BIORESOURCE TECHNOLOGY 2020; 297:122520. [PMID: 31812597 DOI: 10.1016/j.biortech.2019.122520] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/25/2019] [Accepted: 11/27/2019] [Indexed: 06/10/2023]
Abstract
This work aimed to evaluate the potential of anaerobic carboxylic acids (CA) production from swine wastewater (SW), perform modeling studies of the acidogenic process and estimate the kinetic parameters. Tests were carried out in four batch reactors with 250 mL reaction volume, with brewery sludge as inoculum and using chloroform (0.05%, v/v) for methanogenesis inhibition. Hydrolysis was the main limiting step of CA production from SW, once that it took more than twenty days for the particulate COD consumption to stabilize and fourteen days to produce 60% of the acids formed. A yield of 0.33 mg mgCODA-1, corresponding to 0.40 mgCOD mgCODA-1, was obtained. Kinetic models describing logistic growth functions were best suited to simulate CA production.
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Affiliation(s)
- Naassom Wagner Sales Morais
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | | | - Amanda de Sousa E Silva
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - Erlon Lopes Pereira
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - Renato Carrhá Leitão
- Embrapa Agroindústria Tropical. Rua Dra. Sara Mesquita, 2270, Zip: 60511-110, Fortaleza, CE, Brazil
| | - André Bezerra Dos Santos
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil.
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42
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Stoll IK, Boukis N, Sauer J. Syngas Fermentation to Alcohols: Reactor Technology and Application Perspective. CHEM-ING-TECH 2020. [DOI: 10.1002/cite.201900118] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- I. Katharina Stoll
- Karlsruhe Institute of Technology (KIT)Institute of Catalysis Research and Technology (IKFT) Hermann-von-Helmholtz-Platz 1 76344 Eggenstein-Leopoldshafen Germany
| | - Nikolaos Boukis
- Karlsruhe Institute of Technology (KIT)Institute of Catalysis Research and Technology (IKFT) Hermann-von-Helmholtz-Platz 1 76344 Eggenstein-Leopoldshafen Germany
| | - Jörg Sauer
- Karlsruhe Institute of Technology (KIT)Institute of Catalysis Research and Technology (IKFT) Hermann-von-Helmholtz-Platz 1 76344 Eggenstein-Leopoldshafen Germany
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43
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Han W, He P, Shao L, Lü F. Road to full bioconversion of biowaste to biochemicals centering on chain elongation: A mini review. J Environ Sci (China) 2019; 86:50-64. [PMID: 31787190 DOI: 10.1016/j.jes.2019.05.018] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Revised: 05/16/2019] [Accepted: 05/16/2019] [Indexed: 06/10/2023]
Abstract
Production of biochemicals from waste streams has been attracting increasing worldwide interest to achieve climate protection goals. Chain elongation (CE) for production of medium-chain carboxylic acids (MCCAs, especially caproate, enanthate and caprylate) from diverse biowaste has emerged as a potential economic and environmental technology for a sustainable society. The present mini review summarizes the research utilizing various synthetic or real waste-derived substrates available for MCCA production. Additionally, the microbial characteristics of the CE process are surveyed and discussed. Considering that a large proportion of recalcitrantly biodegradable biowaste and residues cannot be further utilized by CE systems and remain to be treated and disposed, we propose here a loop concept of bioconversion of biowaste to MCCAs making full use of the biowaste with zero emission. This could make possible an alternative technology for synthesis of value-added products from a wide range of biowaste, or even non-biodegradable waste (such as, plastics and rubbers). Meanwhile, the remaining scientific questions, unsolved problems, application potential and possible developments for this technology are discussed.
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Affiliation(s)
- Wenhao Han
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Pinjing He
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China; Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092, China; Centre for the Technology Research and Training on Household Waste in Small Towns & Rural Area, Ministry of Housing and Urban-Rural Development of China (MOHURD), China
| | - Liming Shao
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China; Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092, China; Centre for the Technology Research and Training on Household Waste in Small Towns & Rural Area, Ministry of Housing and Urban-Rural Development of China (MOHURD), China
| | - Fan Lü
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China; Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092, China.
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44
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Syngas-aided anaerobic fermentation for medium-chain carboxylate and alcohol production: the case for microbial communities. Appl Microbiol Biotechnol 2019; 103:8689-8709. [PMID: 31612269 DOI: 10.1007/s00253-019-10086-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/06/2019] [Accepted: 08/07/2019] [Indexed: 01/01/2023]
Abstract
Syngas fermentation has been successfully implemented in commercial-scale plants and can enable the biochemical conversion of the driest fractions of biomass through synthesis gas (H2, CO2, and CO). The process relies on optimized acetogenic strains able to reach and maintain high productivity of ethanol and acetate. In parallel, microbial communities have shown to be the best choice for the production of valuable medium-chain carboxylates through anaerobic fermentation of biomass, demanding low technical complexity and being able to realize simultaneous hydrolysis of the substrate. Each of the two technologies benefits from different strong points and has different challenges to overcome. This review discusses the rationales for merging these two seemingly disparate technologies by analyzing previous studies and drawing opinions based on the lessons learned from such studies. For keeping the technical demands of the resulting process low, a case is built for using microbial communities instead of pure strains. For that to occur, a shift from conventional syngas-based to "syngas-aided" anaerobic fermentation is suggested. Strategies for tackling the intricacies of working simultaneously with communities and syngas, such as competing pathways, and thermodynamic aspects are discussed as well as the stoichiometry and economic feasibility of the concept. Overall, syngas-aided anaerobic fermentation seems to be a promising concept for the biorefinery of the future. However, the effects of process parameters on microbial interactions have to be understood in greater detail, in order to achieve and sustain feasible medium-chain carboxylate and alcohol productivity.
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45
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Rosales-Calderon O, Arantes V. A review on commercial-scale high-value products that can be produced alongside cellulosic ethanol. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:240. [PMID: 31624502 PMCID: PMC6781352 DOI: 10.1186/s13068-019-1529-1] [Citation(s) in RCA: 138] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 07/17/2019] [Indexed: 05/03/2023]
Abstract
The demand for fossil derivate fuels and chemicals has increased, augmenting concerns on climate change, global economic stability, and sustainability on fossil resources. Therefore, the production of fuels and chemicals from alternative and renewable resources has attracted considerable and growing attention. Ethanol is a promising biofuel that can reduce the consumption of gasoline in the transportation sector and related greenhouse gas (GHG) emissions. Lignocellulosic biomass is a promising feedstock to produce bioethanol (cellulosic ethanol) because of its abundance and low cost. Since the conversion of lignocellulose to ethanol is complex and expensive, the cellulosic ethanol price cannot compete with those of the fossil derivate fuels. A promising strategy to lower the production cost of cellulosic ethanol is developing a biorefinery which produces ethanol and other high-value chemicals from lignocellulose. The selection of such chemicals is difficult because there are hundreds of products that can be produced from lignocellulose. Multiple reviews and reports have described a small group of lignocellulose derivate compounds that have the potential to be commercialized. Some of these products are in the bench scale and require extensive research and time before they can be industrially produced. This review examines chemicals and materials with a Technology Readiness Level (TRL) of at least 8, which have reached a commercial scale and could be shortly or immediately integrated into a cellulosic ethanol process.
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Affiliation(s)
- Oscar Rosales-Calderon
- Department of Biotechnology, Lorena School of Engineering, University of Sao Paulo, Estrada Municipal do Campinho, Lorena, SP CEP 12602-810 Brazil
| | - Valdeir Arantes
- Department of Biotechnology, Lorena School of Engineering, University of Sao Paulo, Estrada Municipal do Campinho, Lorena, SP CEP 12602-810 Brazil
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An Efficient New Process for the Selective Production of Odd-Chain Carboxylic Acids by Simple Carbon Elongation Using Megasphaera hexanoica. Sci Rep 2019; 9:11999. [PMID: 31427713 PMCID: PMC6700076 DOI: 10.1038/s41598-019-48591-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 07/25/2019] [Indexed: 12/01/2022] Open
Abstract
The caproate-producing bacterium, Megasphaera hexanoica, metabolizes fructose to produce C2~C8 carbon-chain carboxylic acids using various electron acceptors. In particular, odd-chain carboxylic acids (OCCAs) such as valerate (C5) and heptanoate (C7), were produced at relatively high concentrations upon propionate supplementation. Using a statistical experimental design method, the optimal culture medium was established for the selective production of OCCAs among the total produced acids. In a medium containing 2.42 g L−1 sodium acetate and 18.91 g L−1 sodium propionate, M. hexanoica produced 9.48 g L−1 valerate, 2.48 g L−1 heptanoate, and 0.12 g L−1 caproate. To clarify the metabolism of the exogenous added propionate for OCCAs production, 13C tracer experiments were performed by supplementing the culture broth with [1,2,3-13C3] propionate. The metabolites analysis based on mass spectrometry showed that the propionate was only used to produce valerate and heptanoate without being participated in other metabolic pathways. Furthermore, the carbon elongation pathway in M. hexanoica was explained by the finding that the incorporation of propionate and acetate in the produced valerate occurred in only one orientation.
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47
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Lin M, Dai X, Weimer PJ. Shifts in fermentation end products and bacterial community composition in long-term, sequentially transferred in vitro ruminal enrichment cultures fed switchgrass with and without ethanol as a co-substrate. BIORESOURCE TECHNOLOGY 2019; 285:121324. [PMID: 30981010 DOI: 10.1016/j.biortech.2019.121324] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 04/03/2019] [Accepted: 04/05/2019] [Indexed: 06/09/2023]
Abstract
In vitro ruminal fermentations resemble in vivo fermentations with respect to substrate consumption and distribution of fermentation products in short term (1-5 d) incubations. However, little is known regarding changes in in vitro fermentations over prolonged incubation or multiple transfers. Gas production, pH, fermentation products, and bacterial community composition were examined in duplicate in vitro fermentations of switchgrass plus distillers grains that were transferred at 3-4 d intervals over 900 d. Additionally, duplicate fermentations inoculated from 160 d-old enrichments into the same medium but supplemented with ethanol, and transferred at 3-4 d over a 730 d period were characterized. SWG and SWG + E fermentation showed marked differences in community composition, pH, total product concentrations and ratios, relative to each other and to the original inoculum. The results have implications for the use of ruminal inocula for industrial production of short- and medium-chain fatty acids via the carboxylate platform.
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Affiliation(s)
- Miao Lin
- Department of Animal Sciences and Technology, Yangzhou University, Yangzhou, Jiangsu 225009, China.
| | - Xiaoxia Dai
- Department of Animal Sciences, University of Florida, Gainesville, FL 32611, USA.
| | - Paul J Weimer
- United States Department of Agriculture, Agricultural Research Service, US Dairy Forage Research Center, Madison, WI 53706, USA; Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA.
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48
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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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49
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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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50
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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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