1
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Lv Y, Ren WT, Huang Y, Wang HZ, Wu QL, Guo WQ. Upgrading soybean dreg to caproate via intermediate of lactate and mediator of biochar. BIORESOURCE TECHNOLOGY 2024; 406:130958. [PMID: 38876284 DOI: 10.1016/j.biortech.2024.130958] [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: 03/13/2024] [Revised: 05/07/2024] [Accepted: 06/11/2024] [Indexed: 06/16/2024]
Abstract
To address the environmental hazards posed by high-yield soybean dreg (SD), a high-value strategy is firstly proposed by synthesizing caproate through chain elongation (CE). Optimized conditions for lactate-rich broth as intermediate, utilizing 50 % inoculum ratio, 40 g/L substrate concentration, and pH 5, resulting in 2.05 g/L caproate from direct fermentation. Leveraging lactate-rich broth supplemented with ethanol, caproate was optimized to 2.76 g/L under a refined electron donor to acceptor of 2:1. Furthermore, incorporating 20 g/L biochar elevated caproate production to 3.05 g/L and significantly shortened the lag phase. Mechanistic insights revealed that biochar's surface-existed quinone and hydroquinone groups exhibit potent redox characteristics, thereby facilitating electron transfer. Moreover, biochar up-regulated the abundance of key genes involved in CE process (especially fatty acids biosynthesis pathway), also enriching Lysinibacillus and Pseudomonas as an unrecognized cooperation to CE. This study paves a way for sustainable development of SD by upgrading to caproate.
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Affiliation(s)
- Yang Lv
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Wei-Tong Ren
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Yu Huang
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Hua-Zhe Wang
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Qing-Lian Wu
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
| | - Wan-Qian Guo
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
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2
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Nwanebu E, Jezernik M, Lawson C, Bruant G, Tartakovsky B. Impact of cathodic pH and bioaugmentation on acetate and CH 4 production in a microbial electrosynthesis cell. RSC Adv 2024; 14:22962-22973. [PMID: 39086992 PMCID: PMC11290334 DOI: 10.1039/d4ra03906h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2024] [Accepted: 06/20/2024] [Indexed: 08/02/2024] Open
Abstract
This study compares carbon dioxide conversion in carbonate-fed microbial electrosynthesis (MES) cells operated at low (5.3), neutral (7) and high (8) pH levels and inoculated either with wild-type or bioaugmented mixed microbial populations. Two 100 mL (cathode volume) MES cells inoculated with anaerobic digester sludge were operated with a continuous supply of carbonate solution (5 g L-1 as CO3 2-). Acetate production was highest at low pH, however CH4 production still persisted, possibly due to pH gradients within the cathodic biofilm, resulting in acetate and CH4 volumetric (per cathode compartment volume) production rates of 1.0 ± 0.1 g (Lc d)-1 and 0.84 ± 0.05 L (Lc d)-1, respectively. To enhance production of carboxylic acids, four strains of acetogenic bacteria (Clostridium carboxidivorans, Clostridium ljungdahlii, Clostridium autoethanogenum, and Eubacterium limosum) were added to both MES cells. In the bioaugmented MES cells, acetate production increased to 2.0 g (Lc d)-1. However, production of other carboxylic acids such as butyrate and caproate was insignificant. Furthermore, 16S rRNA gene sequencing of cathodic biofilm and suspended biomass suggested a low density of introduced acetogenic bacteria implying that selective pressure rather than bioaugmentation led to improved acetate production.
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Affiliation(s)
- Emmanuel Nwanebu
- Energy, Mining and Environment Research Centre, National Research Council Canada 6100 Royalmount Avenue Montreal Quebec H4P 2R2 Canada
| | - Mara Jezernik
- Department of Chemical Engineering & Applied Chemistry, University of Toronto Toronto Canada
| | - Christopher Lawson
- Department of Chemical Engineering & Applied Chemistry, University of Toronto Toronto Canada
| | - Guillaume Bruant
- Energy, Mining and Environment Research Centre, National Research Council Canada 6100 Royalmount Avenue Montreal Quebec H4P 2R2 Canada
| | - Boris Tartakovsky
- Energy, Mining and Environment Research Centre, National Research Council Canada 6100 Royalmount Avenue Montreal Quebec H4P 2R2 Canada
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3
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Gu X, Sun J, Wang T, Li J, Wang H, Wang J, Wang Y. Comprehensive review of microbial production of medium-chain fatty acids from waste activated sludge and enhancement strategy. BIORESOURCE TECHNOLOGY 2024; 402:130782. [PMID: 38701982 DOI: 10.1016/j.biortech.2024.130782] [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: 03/02/2024] [Revised: 04/30/2024] [Accepted: 04/30/2024] [Indexed: 05/06/2024]
Abstract
Microbial production of versatile applicability medium-chain fatty acids (MCFAs) (C6-C10) from waste activated sludge (WAS) provides a pioneering approach for wastewater treatment plants (WWTPs) to achieve carbon recovery. Mounting studies emerged endeavored to promote the MCFAs production from WAS while struggling with limited MCFAs production and selectivity. Herein, this review covers comprehensive introduction of the transformation process from WAS to MCFAs and elaborates the mechanisms for unsatisfactory MCFAs production. The enhancement strategies for biotransformation of WAS to MCFAs was presented. Especially, the robust performance of iron-based materials is highlighted. Furthermore, knowledge gaps are identified to outline future research directions. Recycling MCFAs from WAS presents a promising option for future WAS treatment, with iron-based materials emerging as a key regulatory strategy in advancing the application of WAS-to-MCFAs biotechnology. This review will advance the understanding of MCFAs recovery from WAS and promote sustainable resource management in WWTPs.
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Affiliation(s)
- Xin Gu
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Jing Sun
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Tong Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Jia Li
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Han Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Jialin Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Yayi Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
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4
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Wang Z, Fernández-Blanco C, Chen J, Veiga MC, Kennes C. Effect of electron acceptors on product selectivity and carbon flux in carbon chain elongation with Megasphaera hexanoica. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169509. [PMID: 38141983 DOI: 10.1016/j.scitotenv.2023.169509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/14/2023] [Accepted: 12/17/2023] [Indexed: 12/25/2023]
Abstract
Megasphaera hexanoica is a bacterial strain following the reverse β-oxidation pathway to synthesize caproate (CA) using lactate (LA) as an electron donor (ED) and acetate (AA) or butyrate (BA) as electron acceptors (EA). Differences in the type and concentration of EA lead to distinctions in product distribution and energy bifurcation of carbon fluxes in ED pathways, thereby affecting CA production. In this study, the effect of various ratios of AA, BA, and AA+BA as EA on carbon flux and CA specific titer during the carbon chain elongation in M. hexanoica was explored. The results indicated that the maximum levels of CA were 18.81 mM and 31.48 mM when the molar ratios of LA/AA and LA/BA were 10:1 and 3:1, respectively. Meanwhile, when AA and BA were used as combined EA (LA, AA, and BA molar amounts of 100, 23, and 77 mM), a maximum CA production of 39.45 mM was obtained. Further analysis revealed that the combined EA exhibited a CA production carbon flux of 49 % (4.3 % and 19.5 % higher compared to AA or BA, respectively) and a CA production specific titer of 45.24 mol (80.89 % and 58.51 % higher compared to AA or BA, respectively), indicating that the effective carbon utilization rate and CA production efficiency were greatly improved. Finally, a scaled-up experiment was conducted in a 1.2 L (working volume) automated bioreactor, implying high biomass (optical density at 600 nm or OD600 = 1.809) and a slight decrease in CA production (28.45 mM). A decrease in H2 production (4.11 g/m3) and an increase in CO2 production (0.632 g/m3) demonstrated the appropriate metabolic adaptation of M. hexanoica to environmental changes such as stirring shear.
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Affiliation(s)
- Zeyu Wang
- Chemical Engineering Laboratory, Faculty of Sciences and Interdisciplinary Centre of Chemistry and Biology - Centro Interdisciplinar de Química y Biología (CICA), BIOENGIN group, University of La Coruña (UDC), E-15008 La Coruña, Spain; Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province, Interdisciplinary Research Academy, Zhejiang Shuren University, Hangzhou 310015, China
| | - Carla Fernández-Blanco
- Chemical Engineering Laboratory, Faculty of Sciences and Interdisciplinary Centre of Chemistry and Biology - Centro Interdisciplinar de Química y Biología (CICA), BIOENGIN group, University of La Coruña (UDC), E-15008 La Coruña, Spain
| | - Jun Chen
- Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province, Interdisciplinary Research Academy, Zhejiang Shuren University, Hangzhou 310015, China
| | - María C Veiga
- Chemical Engineering Laboratory, Faculty of Sciences and Interdisciplinary Centre of Chemistry and Biology - Centro Interdisciplinar de Química y Biología (CICA), BIOENGIN group, University of La Coruña (UDC), E-15008 La Coruña, Spain
| | - Christian Kennes
- Chemical Engineering Laboratory, Faculty of Sciences and Interdisciplinary Centre of Chemistry and Biology - Centro Interdisciplinar de Química y Biología (CICA), BIOENGIN group, University of La Coruña (UDC), E-15008 La Coruña, Spain.
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Wu KK, Zhao L, Wang ZH, Sun ZF, Wu JT, Chen C, Xing DF, Yang SS, Wang AJ, Zhang YF, Ren NQ. Simultaneous biogas upgrading and medium-chain fatty acids production using a dual membrane biofilm reactor. WATER RESEARCH 2024; 249:120915. [PMID: 38029487 DOI: 10.1016/j.watres.2023.120915] [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: 09/22/2023] [Revised: 11/21/2023] [Accepted: 11/22/2023] [Indexed: 12/01/2023]
Abstract
Utilizing H2-assisted ex-situ biogas upgrading and acetate recovery holds great promise for achieving high value utilization of biogas. However, it faces a significant challenge due to acetate's high solubility and limited economic value. To address this challenge, we propose an innovative strategy for simultaneous upgrading of biogas and the production of medium-chain fatty acids (MCFAs). A series of batch tests evaluated the strategy's efficiency under varying initial gas ratios (v/v) of H2, CH4, CO2, along with varying ethanol concentrations. The results identified the optimal conditions as initial gas ratios of 3H2:3CH4:2CO2 and an ethanol concentration of 241.2 mmol L-1, leading to maximum CH4 purity (97.2 %), MCFAs yield (54.2 ± 2.1 mmol L-1), and MCFAs carbon-flow distribution (62.3 %). Additionally, an analysis of the microbial community's response to varying conditions highlighted the crucial roles played by microorganisms such as Clostridium, Proteiniphilum, Sporanaerobacter, and Bacteroides in synergistically assimilating H2 and CO2 for MCFAs production. Furthermore, a 160-day continuous operation using a dual-membrane aerated biofilm reactor (dMBfR) was conducted. Remarkable achievements were made at a hydraulic retention time of 2 days, including an upgraded CH4 content of 96.4 ± 0.3 %, ethanol utilization ratio (URethanol) of 95.7 %, MCFAs production rate of 28.8 ± 0.3 mmol L-1 d-1, and MCFAs carbon-flow distribution of 70 ± 0.8 %. This enhancement is proved to be an efficient in biogas upgrading and MCFAs production. These results lay the foundation for maximizing the value of biogas, reducing CO2 emissions, and providing valuable insights into resource recovery.
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Affiliation(s)
- Kai-Kai Wu
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China; Department of Environmental & Resource Engineering, Technical University of Denmark, Lyngby DK-2800, Denmark
| | - Lei Zhao
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
| | - Zi-Han Wang
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Zhong-Fang Sun
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Jie-Ting Wu
- School of Environment, Liaoning University, Shenyang 110000, China
| | - Chuan Chen
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - De-Feng Xing
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Shan-Shan Yang
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Ai-Jie Wang
- Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; School of Civil and Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Yi-Feng Zhang
- Department of Environmental & Resource Engineering, Technical University of Denmark, Lyngby DK-2800, Denmark
| | - Nan-Qi Ren
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China; School of Civil and Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
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Chen G, Wang R, Sun M, Chen J, Iyobosa E, Zhao J. Carbon dioxide reduction to high-value chemicals in microbial electrosynthesis system: Biological conversion and regulation strategies. CHEMOSPHERE 2023; 344:140251. [PMID: 37769909 DOI: 10.1016/j.chemosphere.2023.140251] [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: 07/13/2023] [Revised: 09/19/2023] [Accepted: 09/21/2023] [Indexed: 10/03/2023]
Abstract
Large emissions of atmospheric carbon dioxide (CO2) are causing climatic and environmental problems. It is crucial to capture and utilize the excess CO2 through diverse methods, among which the microbial electrosynthesis (MES) system has become an attractive and promising technology to mitigate greenhouse effects while reducing CO2 to high-value chemicals. However, the biological conversion and metabolic pathways through microbial catalysis have not been clearly elucidated. This review first introduces the main acetogenic bacteria for CO2 reduction and extracellular electron transfer mechanisms in MES. It then intensively analyzes the CO2 bioconversion pathways and carbon chain elongation processes in MES, together with energy supply and utilization. The factors affecting MES performance, including physical, chemical, and biological aspects, are summarized, and the strategies to promote and regulate bioconversion in MES are explored. Finally, challenges and perspectives concerning microbial electrochemical carbon sequestration are proposed, and suggestions for future research are also provided. This review provides theoretical foundation and technical support for further development and industrial application of MES for CO2 reduction.
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Affiliation(s)
- Gaoxiang Chen
- Key Laboratory of Yangtze Aquatic Environment (MOE), College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, Shanghai, PR China
| | - Rongchang Wang
- Key Laboratory of Yangtze Aquatic Environment (MOE), College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, Shanghai, PR China.
| | - Maoxin Sun
- Key Laboratory of Yangtze Aquatic Environment (MOE), College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, Shanghai, PR China
| | - Jie Chen
- Key Laboratory of Yangtze Aquatic Environment (MOE), College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, Shanghai, PR China
| | - Eheneden Iyobosa
- Key Laboratory of Yangtze Aquatic Environment (MOE), College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, Shanghai, PR China
| | - Jianfu Zhao
- Key Laboratory of Yangtze Aquatic Environment (MOE), College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, Shanghai, PR China
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7
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Du J, Xu PP, Ren HY, Cao GL, Xie GJ, Ren NQ, Liu BF. Improved sequential production of hydrogen and caproate by addition of biochar prepared from cornstalk residues. BIORESOURCE TECHNOLOGY 2023; 387:129702. [PMID: 37604256 DOI: 10.1016/j.biortech.2023.129702] [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: 06/29/2023] [Revised: 08/16/2023] [Accepted: 08/18/2023] [Indexed: 08/23/2023]
Abstract
This study proposes a new model in which ethanol and acetate produced by dark fermentation are processed by Clostridium kluyveri for chain elongation to produce caproate with an addition of biochar prepared from cornstalk residues after acid pretreatment and enzymatic hydrolysis (AERBC) in the dark fermentation and chain elongation processes. The results show a 6-25% increase in hydrogen production in dark fermentation with adding AERBC, and the maximum concentration of caproate in the new model reached 1740 mg/L, 61% higher than that in the control group. In addition, caproate was obtained by dark fermentation, using liquid metabolites as substrates with an initial pH range of 6.5-7.5. Finally, the electron balance and electron transfer efficiency in the new model were analyzed, and the role of AERBC in dark fermentation and chain elongation was investigated. This study provides a new reference for the use of dark-fermented liquid metabolites and cornstalk residue.
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Affiliation(s)
- Jian Du
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Pian-Pian Xu
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Hong-Yu Ren
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Guang-Li Cao
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Guo-Jun Xie
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Nan-Qi Ren
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Bing-Feng Liu
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
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8
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Tang J, Yang H, Pu Y, Hu Y, Huang J, Jin N, He X, Wang XC. Caproic acid production from food waste using indigenous microbiota: Performance and mechanisms. BIORESOURCE TECHNOLOGY 2023; 387:129687. [PMID: 37595807 DOI: 10.1016/j.biortech.2023.129687] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/12/2023] [Accepted: 08/14/2023] [Indexed: 08/20/2023]
Abstract
Caproic acid (CA) production from food waste (FW) is a promising way for waste recycling, while the fermentation processes need further exploration. In this study, FW acidogenic fermentation under different pH (uncontrolled, 4, 5, 6) using indigenous microbiota was investigated. Result showed that substrate hydrolysis, carbohydrate degradation and acidogenesis increased with the increase of pH. Although various microbial communities were observed in FW, lactic acid bacteria (Lactobacillus and Limosilactobacillus) were enriched at pH lower than 6, resulting in lactic acid accumulation. CA (88.24 mM) was produced at pH 6 accounting for 31.23% of the total product carbon. The enriched lactic acid bacteria were directionally replaced by chain elongators (Caproicibacter, Clostridium_sensu_stricto, unclassified_Ruminococcaceae) at pH 6, and carbohydrates in FW were firstly transformed into lactic acid, then to butyrate and CA through lactate-based chain elongation processes. This work provided a novel CA fermentation pathway and further enriched the FW valorization.
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Affiliation(s)
- Jialing Tang
- Department of Environmental Engineering, School of Architecture and Civil Engineering, Chengdu University, Chengdu 610106, China; Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China.
| | - Hao Yang
- Department of Environmental Engineering, School of Architecture and Civil Engineering, Chengdu University, Chengdu 610106, China
| | - Yunhui Pu
- Department of Environmental Engineering, School of Architecture and Civil Engineering, Chengdu University, Chengdu 610106, China; College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Yisong Hu
- Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an 710055, China
| | - Jin Huang
- Department of Environmental Engineering, School of Architecture and Civil Engineering, Chengdu University, Chengdu 610106, China
| | - Ni Jin
- Department of Environmental Engineering, School of Architecture and Civil Engineering, Chengdu University, Chengdu 610106, China
| | - Xinrui He
- Department of Environmental Engineering, School of Architecture and Civil Engineering, Chengdu University, Chengdu 610106, China
| | - Xiaochang C Wang
- Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an 710055, China
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Zhang L, Tsui TH, Wah Tong Y, Sharon S, Shoseyov O, Liu R. Biochar applications in microbial fermentation processes for producing non-methane products: Current status and future prospects. BIORESOURCE TECHNOLOGY 2023; 386:129478. [PMID: 37460021 DOI: 10.1016/j.biortech.2023.129478] [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: 06/06/2023] [Revised: 07/05/2023] [Accepted: 07/08/2023] [Indexed: 07/23/2023]
Abstract
The objective of this review is to encourage the technical development of biochar-assisted microbial fermentation. To this end, recent advances in biochar applications for microbial fermentation processes (i.e., non-methane products of hydrogen, acids, alcohols, and biofertilizer) have been critically reviewed, including process performance, enhanced mechanisms, and current research gaps. Key findings of enhanced mechanisms by biochar applications in biochemical conversion platforms are summarized, including supportive microbial habitats due to the immobilization effect, pH buffering due to alkalinity, nutrition supply due to being rich in nutrient elements, promoting electron transfer by acting as electron carriers, and detoxification of inhibitors due to high adsorption capacity. The current technical limitations and biochar's industrial applications in microbial fermentation processes are also discussed. Finally, suggestions like exploring functionalized biochar materials, biochar's automatic addition and pilot-scale demonstration are proposed. This review would further promote biochar applications in microbial fermentation processes for the production of non-methane products.
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Affiliation(s)
- Le Zhang
- Biomass Energy Engineering Research Centre/Department of Resources and Environment, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, PR China; Shanghai Yangtze River Delta Eco-Environmental Change and Management Observation and Research Station, Ministry of Science and Technology, 800 Dongchuan Road, Shanghai 200240, PR China.
| | - To-Hung Tsui
- Department of Engineering Science, University of Oxford, OX1 3PJ, Oxford, UK
| | - Yen Wah Tong
- NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, Singapore 138602, Singapore; Energy and Environmental Sustainability for Megacities (E2S2) Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), 1 Create Way, Singapore 138602, Singapore; Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore
| | - Sigal Sharon
- Plant Molecular Biology and Nano Biotechnology, The Robert H Smith Institute of Plant Science and Genetics, The Robert H Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Herzl 229, Rehovot 7610001, Israel
| | - Oded Shoseyov
- Plant Molecular Biology and Nano Biotechnology, The Robert H Smith Institute of Plant Science and Genetics, The Robert H Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Herzl 229, Rehovot 7610001, Israel
| | - Ronghou Liu
- Biomass Energy Engineering Research Centre/Department of Resources and Environment, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, PR China; Shanghai Yangtze River Delta Eco-Environmental Change and Management Observation and Research Station, Ministry of Science and Technology, 800 Dongchuan Road, Shanghai 200240, PR China
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10
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Ma J, Tan L, Xie S, Feng Y, Shi Z, Ke S, He Q, Ke Q, Zhao Q. The role of hydrochloric acid pretreated activated carbon in chain elongation of D-lactate to caproate: Adsorption and facilitation. ENVIRONMENTAL RESEARCH 2023; 233:116387. [PMID: 37302743 DOI: 10.1016/j.envres.2023.116387] [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: 02/14/2023] [Revised: 06/03/2023] [Accepted: 06/09/2023] [Indexed: 06/13/2023]
Abstract
Medium chain fatty acids (MCFA) generation is attracting growing interest due to fossil fuel depletion. To promote the production of MCFA, especially caproate, hydrochloric acid pretreated activated carbon (AC) was introduced into chain elongation fermentation. In this study, the role of pretreated AC on caproate production was investigated using lactate and butyrate as electron donor and electron acceptor, respectively. The results showed that AC did not improve the chain elongation reaction at beginning but promoted the caproate production at later stage. The addition of 15 g/L AC facilitated reactor reaching the peak of caproate concentration (78.92 mM), caproate electron efficiency (63.13%), and butyrate utilization rate (51.88%). The adsorption experiment revealed a positive correlation between the adsorption capacity of pretreated AC and the concentration as well as the carbon chain length of carboxylic acids. Moreover, the adsorption of undissociated caproate by pretreated AC contributed to a mitigated toxicity towards microorganisms, thereby facilitating the production of MCFA. Microbial community analysis revealed an increasing enrichment of key functional chain elongation bacteria, including Eubacterium, Megasphaera, Caproiciproducens, and Pseudoramibacter, but a suppression on acrylate pathway microorganism Veillonella, as the dosage of pretreated AC increasing. The findings of this study demonstrated the substantial impact of the adsorption effect of acid-pretreated AC on promoting caproate production, which would aid to the development of more efficient caproate production process.
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Affiliation(s)
- Jingwei Ma
- Hunan Engineering Research Center of Water Security Technology and Application, College of Civil Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Hunan University, Changsha, 410082, PR China
| | - Liyi Tan
- Hunan Engineering Research Center of Water Security Technology and Application, College of Civil Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Hunan University, Changsha, 410082, PR China
| | - Shanbiao Xie
- Hunan Engineering Research Center of Water Security Technology and Application, College of Civil Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Hunan University, Changsha, 410082, PR China
| | - Yingxin Feng
- Hunan Engineering Research Center of Water Security Technology and Application, College of Civil Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Hunan University, Changsha, 410082, PR China
| | - Zhou Shi
- Hunan Engineering Research Center of Water Security Technology and Application, College of Civil Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Hunan University, Changsha, 410082, PR China
| | - Shuizhou Ke
- Hunan Engineering Research Center of Water Security Technology and Application, College of Civil Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Hunan University, Changsha, 410082, PR China
| | - Qiulai He
- Hunan Engineering Research Center of Water Security Technology and Application, College of Civil Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Hunan University, Changsha, 410082, PR China.
| | - Qiang Ke
- National and Local Joint Engineering Research Center of Ecological Treatment Technology for Urban Water Pollution, Wenzhou University, Wenzhou, 325035, PR China.
| | - Quanbao Zhao
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, PR China
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11
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Huo W, Ye R, Shao Y, Bao M, Stegmann R, Lu W. Enhanced ethanol-driven carboxylate chain elongation by Pt@C in simulated sequencing batch reactors: Process and mechanism. BIORESOURCE TECHNOLOGY 2023:129310. [PMID: 37315622 DOI: 10.1016/j.biortech.2023.129310] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 06/06/2023] [Accepted: 06/08/2023] [Indexed: 06/16/2023]
Abstract
Carboxylate chain elongation can create value-added bioproducts from the organic waste. The effects of Pt@C on chain elongation and associated mechanisms were investigated in simulated sequencing batch reactors. 5.0 g/L of Pt@C greatly increased the synthesis of caproate, with an average yield of 21.5 g COD/L, which was 207.4% higher than the trial without Pt@C. Integrated metagenomic and metaproteomic analyses were used to reveal the mechanism of Pt@C-enhanced chain elongation. Pt@C enriched chain elongators by increasing the relative abundance of dominant species by 115.5%. The expression of functional genes related to chain elongation was promoted in the Pt@C trial. This study also demonstrates that Pt@C may promote overall chain elongation metabolism by enhancing CO2 uptake of Clostridium kluyveri. The study provides insights into the fundamental mechanisms of how chain elongation can perform CO2 metabolism and how it can be enhanced by Pt@C to upgrade bioproducts from organic waste streams.
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Affiliation(s)
- Weizhong Huo
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Rong Ye
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Yuchao Shao
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Menggang Bao
- School of Environment, Tsinghua University, Beijing 100084, China
| | | | - Wenjing Lu
- School of Environment, Tsinghua University, Beijing 100084, China.
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12
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Ho Ahn J, Hwan Jung K, Seok Lim E, Min Kim S, Ok Han S, Um Y. Recent advances in microbial production of medium chain fatty acid from renewable carbon resources: a comprehensive review. BIORESOURCE TECHNOLOGY 2023; 381:129147. [PMID: 37169199 DOI: 10.1016/j.biortech.2023.129147] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 04/29/2023] [Accepted: 05/04/2023] [Indexed: 05/13/2023]
Abstract
Microbial production of medium chain length fatty acids (MCFAs) from renewable resources is becoming increasingly important in establishing a sustainable and clean chemical industry. This review comprehensively summarizes current advances in microbial MCFA production from renewable resources. Detailed information is provided on two major MCFA production pathways using various renewable resources and other auxiliary pathways supporting MCFA production to help understand the fundamentals of bio-based MCFA production. In addition, conventional and well-studied MCFA producers are classified into two categories, natural and synthetic producers, and their characteristics on MCFA production are outlined. Moreover, various engineering strategies employed to achieve the highest MCFAs production up to date are showcased together with key enzymes suggested for MCFA overproduction. Finally, future challenges and perspectives are discussed towards more efficient production of bio-based MCFA production.
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Affiliation(s)
- Jung Ho Ahn
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Division of Energy and Environment Technology, KIST School, University of Science and Technology (UST), Daejeon 34113, Republic of Korea
| | - Kweon Hwan Jung
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Eui Seok Lim
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Sang Min Kim
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Sung Ok Han
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Youngsoon Um
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Division of Energy and Environment Technology, KIST School, University of Science and Technology (UST), Daejeon 34113, Republic of Korea.
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13
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Li L, Xu L, He J, He Q, Zhang J. Effect of granular activated carbon and chloroform on chain elongation with simple substrate ethanol and acetate. ENVIRONMENTAL RESEARCH 2023; 221:115324. [PMID: 36669585 DOI: 10.1016/j.envres.2023.115324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/31/2022] [Accepted: 01/16/2023] [Indexed: 06/17/2023]
Abstract
Chain elongation is a promising technology for production of medium-chain fatty acids (MCFAs). Granular activated carbon (GAC) is commonly used in anaerobic fermentation. Low level CHCl3 can inhibit methanogenesis and homoacetogenesis at the same time. However, the effect of them on chain elongation performance with highly enriched consortia and simple substrate (i.e., ethanol and acetate) was still unclear. Hence, the effects of CHCl3 and on MCFAs production and the microbial community was studied here. CHCl3 displayed fatal effect on chain elongation system when its concentration was higher than 0.1% v/v. 0.05% v/v CHCl3 was enough to inhibit homoacetogens and further decreased the caproate production efficiency without altering the core bacteria tremendously. GAC was found to be adverse for chain elongation with simple substrate (i.e., ethanol and acetate) and highly enriched microbial consortia dominated by Clostridium sensu stricto, less than 20% electrons were finally distributed in caproate. It might be attributed to other electron consuming activities induced by GAC.
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Affiliation(s)
- Lin Li
- Key Laboratory of the Three Gorges Reservoir Region's Eco-environment, Ministry of Education, College of Environment and Ecology, Chongqing University, Chongqing, 400045, China; State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, China.
| | - Linji Xu
- Key Laboratory of the Three Gorges Reservoir Region's Eco-environment, Ministry of Education, College of Environment and Ecology, Chongqing University, Chongqing, 400045, China.
| | - 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
- Key Laboratory of the Three Gorges Reservoir Region's Eco-environment, Ministry of Education, College of Environment and Ecology, Chongqing University, Chongqing, 400045, 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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14
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Romans-Casas M, Perona-Vico E, Dessì P, Bañeras L, Balaguer MD, Puig S. Boosting ethanol production rates from carbon dioxide in MES cells under optimal solventogenic conditions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 856:159124. [PMID: 36179842 DOI: 10.1016/j.scitotenv.2022.159124] [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: 07/18/2022] [Revised: 09/01/2022] [Accepted: 09/25/2022] [Indexed: 06/16/2023]
Abstract
Microbial Electrosynthesis (MES) has been widely applied for acetic acid (HA) production from CO2 and electricity. Ethanol (EtOH) has a higher market value than HA, and wide application in industry and as a biofuel. However, it has only been obtained sporadically and at low concentrations, probably due to sub-optimal operating conditions. This study aimed at enhancing EtOH productivity in MES cells by jointly optimising key operation parameters, including pH, H2 and CO2 partial pressure (pH2 and pCO2), and HA concentration, to promote solventogenesis. Two H-type cells were operated in fed-batch mode at -0.8 V vs. SHE with CO2 as the sole carbon source. A mixed culture, enriched with Clostridium ljungdahlii was used as the biocatalyst. The combination of low pH (<4.5) and pCO2 (<0.3 atm), along with high HA concentration (about 6 g L-1) and pH2 (>3 atm), were mandatory conditions for maintaining an efficient solventogenic culture, dominated by Clostridium sp., capable of high-rate EtOH production. The maximum EtOH production rate was 10.95 g m-2 d-1, and a concentration of 5.28 g L-1 was achieved. Up to 30 % of the electrons and 15.2 % of the carbon provided were directed towards EtOH production, and 28.1 kWh were required for the synthesis of 1 kg of EtOH from CO2. These results highlight that strict conditions are required for a continuous, reliable, EtOH production in MES cells. Future investigation should focus on improving cell configuration to achieve EtOH production at higher current densities while minimizing the electric energy input.
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Affiliation(s)
- M Romans-Casas
- LEQUiA, Institute of the Environment, University of Girona, Campus Montilivi, C/Maria Aurèlia Capmany, 69, E-17003 Girona, Spain
| | - E Perona-Vico
- gEMM. Group of Molecular Microbial Ecology, Institute of Aquatic Ecology, University of Girona, Campus Montilivi, C/Maria Aurèlia Capmany, 40, E-17003 Girona, Spain
| | - P Dessì
- LEQUiA, Institute of the Environment, University of Girona, Campus Montilivi, C/Maria Aurèlia Capmany, 69, E-17003 Girona, Spain
| | - L Bañeras
- gEMM. Group of Molecular Microbial Ecology, Institute of Aquatic Ecology, University of Girona, Campus Montilivi, C/Maria Aurèlia Capmany, 40, E-17003 Girona, Spain
| | - M D Balaguer
- LEQUiA, Institute of the Environment, University of Girona, Campus Montilivi, C/Maria Aurèlia Capmany, 69, E-17003 Girona, Spain
| | - S Puig
- LEQUiA, Institute of the Environment, University of Girona, Campus Montilivi, C/Maria Aurèlia Capmany, 69, E-17003 Girona, Spain.
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15
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Oh HJ, Gong G, Ahn JH, Ko JK, Lee SM, Um Y. Effective hexanol production from carbon monoxide using extractive fermentation with Clostridium carboxidivorans P7. BIORESOURCE TECHNOLOGY 2023; 367:128201. [PMID: 36374655 DOI: 10.1016/j.biortech.2022.128201] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/20/2022] [Accepted: 10/21/2022] [Indexed: 06/16/2023]
Abstract
This study achieved high production of hexanol via gas fermentation using Clostridium carboxidivorans P7 by extracting hexanol from the fermentation broth. The hexanol extraction efficiency and inhibitory effects on C. carboxidivorans P7 of 2-butyl-1-octanol, hexyl hexanoate and oleyl alcohol were examined, and oleyl alcohol was selected as the extraction solvent. Oleyl alcohol was added at the beginning of fermentation and during fermentation or a small volume of oleyl alcohol was repeatedly added during fermentation. The addition of a small volume of oleyl alcohol during fermentation was the most effective for CO consumption and hexanol production (5.06 g/L), yielding the highest known hexanol titer through any type of fermentation including gas fermentation. Hexanol production was further enhanced to 8.45 g/L with the repeated addition of oleyl alcohol and ethanol during gas fermentation. The results of this study will enable sustainable and carbon-neutral hexanol production via gas fermentation.
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Affiliation(s)
- Hyun Ju Oh
- Clean Energy Research Center, Korea Institute of Science and Technology, 5 Hwarang-ro 14-gil, Seongbuk-gu, Seoul, Republic of Korea
| | - Gyeongtaek Gong
- Clean Energy Research Center, Korea Institute of Science and Technology, 5 Hwarang-ro 14-gil, Seongbuk-gu, Seoul, Republic of Korea; Division of Energy and Environment Technology, KIST School, University of Science and Technology (UST), 217 Gajeong-ro, Yuseong-gu, Daejeon, Republic of Korea
| | - Jung Ho Ahn
- Clean Energy Research Center, Korea Institute of Science and Technology, 5 Hwarang-ro 14-gil, Seongbuk-gu, Seoul, Republic of Korea; Division of Energy and Environment Technology, KIST School, University of Science and Technology (UST), 217 Gajeong-ro, Yuseong-gu, Daejeon, Republic of Korea
| | - Ja Kyong Ko
- Clean Energy Research Center, Korea Institute of Science and Technology, 5 Hwarang-ro 14-gil, Seongbuk-gu, Seoul, Republic of Korea; Division of Energy and Environment Technology, KIST School, University of Science and Technology (UST), 217 Gajeong-ro, Yuseong-gu, Daejeon, Republic of Korea
| | - Sun-Mi Lee
- Clean Energy Research Center, Korea Institute of Science and Technology, 5 Hwarang-ro 14-gil, Seongbuk-gu, Seoul, Republic of Korea; Division of Energy and Environment Technology, KIST School, University of Science and Technology (UST), 217 Gajeong-ro, Yuseong-gu, Daejeon, Republic of Korea
| | - Youngsoon Um
- Clean Energy Research Center, Korea Institute of Science and Technology, 5 Hwarang-ro 14-gil, Seongbuk-gu, Seoul, Republic of Korea; Division of Energy and Environment Technology, KIST School, University of Science and Technology (UST), 217 Gajeong-ro, Yuseong-gu, Daejeon, Republic of Korea.
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16
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Huo W, Fu X, Bao M, Ye R, Shao Y, Liu Y, Bi J, Shi X, Lu W. Strategy of electron acceptors for ethanol-driven chain elongation from kitchen waste. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 846:157492. [PMID: 35870578 DOI: 10.1016/j.scitotenv.2022.157492] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 07/08/2022] [Accepted: 07/15/2022] [Indexed: 06/15/2023]
Abstract
A two-phase kitchen waste (KW) fermentation was proposed in the current study to enhance medium-chain fatty acids (MCFAs) production from kitchen waste. In particular, effect of acetate to butyrate ratio (ABR) on MCFAs production was investigated which can be regulated by different pH and organic loading during the acidification phase. Medium ABR (1.00) was obtained when pH is 5.5 and organic loading is 20 g VS/L in FW acidification fermentation. Subsequent chain elongation fermentation demonstrated that the highest yield of caproate 9.67 g/L with selectivity of 79 %, and highest ethanol conversion efficiency of 1.11 was achieved in medium ABR system. Microbial community study showed that medium ABR significantly enrich the functional bacteria especially Clostridium kluyveri. The study provides a new method for chain elongation enhancement without addition of other additives in kitchen waste fermentation system and gives a guide for the regulation of the short-chain fatty acids distribution in its acidification phase.
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Affiliation(s)
- Weizhong Huo
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Xindi Fu
- School of Environment, Tsinghua University, Beijing 100084, China; Everbright Environtech (China) Ltd., Nanjing 211102, China
| | - Menggang Bao
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Rong Ye
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Yuchao Shao
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Yanqing Liu
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Jiangtao Bi
- School of Ecology and Environment, Ningxia University, Ningxia 750021, China
| | - Xiong Shi
- Yangtze Eco-Environment Engineering Research Center, China Three Gorges Corporation, Beijing 100038, China; National Engineering Research Center of Eco-Environment Protection for Yangtze River Economic Belt, China
| | - Wenjing Lu
- School of Environment, Tsinghua University, Beijing 100084, China.
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17
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Sun X, Thunuguntla R, Zhang H, Atiyeh H. Biochar amended microbial conversion of C1 gases to ethanol and butanol: Effects of biochar feedstock type and processing temperature. BIORESOURCE TECHNOLOGY 2022; 360:127573. [PMID: 35792327 DOI: 10.1016/j.biortech.2022.127573] [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: 06/01/2022] [Revised: 06/29/2022] [Accepted: 06/30/2022] [Indexed: 06/15/2023]
Abstract
Biochar feedstock and production method affects its physicochemical properties and subsequent application. This study investigated the effects of biochar from switchgrass (SGB) and poultry litter (PLB) produced at 350 and 700 °C on alcohol formation using CO:CO2:H2 (40:30:30) by Clostridium carboxidivorans (P7) and C. ragsdalei (P11). Fermentations were performed in 250 mL bottles with a 50 mL working volume at 37 °C. Strains P7 and P11 produced 1.2- to 2.2-fold more alcohol and consumed 1.2- to 1.9-fold more syngas using biochars made at 700 °C compared to 350 °C. Both strains also produced 1.4- to1.9-fold more alcohol with both biochars made at 700 °C compared to control without biochar. Strain P11 produced 1.1- and 1.6-fold more alcohol and fatty acids, respectively, in medium with PLB made at 700 °C compared to strain P7. These results provide guidance towards the selection of biochar type and production temperature to improve syngas fermentation.
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Affiliation(s)
- Xiao Sun
- Biosystems and Agricultural Engineering, Oklahoma State University, Stillwater, OK, USA
| | - Rahul Thunuguntla
- Biosystems and Agricultural Engineering, Oklahoma State University, Stillwater, OK, USA
| | - Hailin Zhang
- Plant and Soil Sciences, Oklahoma State University, Stillwater, OK, USA
| | - Hasan Atiyeh
- Biosystems and Agricultural Engineering, Oklahoma State University, Stillwater, OK, USA.
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18
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Otten JK, Zou Y, Papoutsakis ET. The potential of caproate (hexanoate) production using Clostridium kluyveri syntrophic cocultures with Clostridium acetobutylicum or Clostridium saccharolyticum. Front Bioeng Biotechnol 2022; 10:965614. [PMID: 36072287 PMCID: PMC9441933 DOI: 10.3389/fbioe.2022.965614] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 07/15/2022] [Indexed: 11/18/2022] Open
Abstract
Caproate (hexanoate) and other medium-chain fatty acids are valuable platform chemicals produced by processes utilizing petroleum or plant oil. Clostridium kluyveri, growing on short chain alcohols (notably ethanol) and carboxylic acids (such as acetate) is noted for its ability to perform chain elongation to produce 4- to 8-carbon carboxylates. C. kluyveri has been studied in monoculture and coculture conditions, which lead to relatively modest carboxylate titers after long fermentation times. To assess the biosynthetic potential of C. kluyveri for caproate production from sugars through coculture fermentations, in the absence of monoculture data in the literature suitable for our coculture experiments, we first explored C. kluyveri monocultures. Some monocultures achieved caproate titers of 150 to over 200 mM in 40–50 h with a production rate of 7.9 mM/h. Based on that data, we then explored two novel, syntrophic coculture partners for producing caproate from sugars: Clostridium acetobutylicum and Clostridium saccharolyticum. Neither species has been cocultured with C. kluyveri before, and both demonstrate promising results. Our experiments of C. kluyveri monocultures and C. kluyveri—C. saccharolyticum cocultures demonstrate exceptionally high caproate titers (145–200 mM), fast production rates (3.25–8.1 mM/h), and short fermentation times (18–45 h). These results represent the most caproate produced by a C. kluyveri coculture in the shortest known fermentation time. We also explored the possibility of heterologous cell fusion between the coculture pairs similar to the results seen previously in our group with C. acetobutylicum and Clostridium ljungdahlii. Fusion events were observed only in the C. acetobutylicum—C. kluyveri coculture pair, and we offer an explanation for the lack of fusion between C. saccharolyticum and C. kluyveri. This work supports the promise of coculture biotechnology for sustainable production of caproate and other platform chemicals.
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Affiliation(s)
- Jonathan K. Otten
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, United States
- Delaware Biotechnology Institute, University of Delaware, Newark, DE, United States
| | - Yin Zou
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, United States
| | - Eleftherios T. Papoutsakis
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, United States
- Delaware Biotechnology Institute, University of Delaware, Newark, DE, United States
- Department of Biological Sciences, University of Delaware, Newark, DE, United States
- *Correspondence: Eleftherios T. Papoutsakis,
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19
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Wu B, Lin R, Ning X, Kang X, Deng C, Dobson ADW, Murphy JD. An assessment of how the properties of pyrochar and process thermodynamics impact pyrochar mediated microbial chain elongation in steering the production of medium-chain fatty acids towards n-caproate. BIORESOURCE TECHNOLOGY 2022; 358:127294. [PMID: 35550922 DOI: 10.1016/j.biortech.2022.127294] [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: 03/07/2022] [Revised: 05/05/2022] [Accepted: 05/06/2022] [Indexed: 06/15/2023]
Abstract
Microbial chain elongation fermentation is an alternative technology for medium-chain fatty acid (MCFA) production. This paper proposed the addition of pyrochar and graphene in chain elongation to improve MCFA production using ethanol and acetate as substrates. Results showed that the yield of, and selectivity towards, C6 n-caproate were significantly enhanced with pyrochar addition. At the optimal mass ratio of pyrochar to substrate of 2 g/g, the maximum n-caproate yield of 13.67 g chemical oxygen demand/L and the corresponding selectivity of 56.8% were obtained; this represents an increase of 115% and 128% respectively as compared with no pyrochar addition. Such improvements were postulated as due to the high electrical conductivity and surface redox groups of pyrochar. The optimal ethanol to acetate molar ratio of 2 mol/mol achieved the highest MCFA yield under pyrochar mediated chain elongation conditions. Thermodynamic calculations modelled an energy benefit of 93.50 kJ/mol reaction for pyrochar mediated n-caproate production.
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Affiliation(s)
- Benteng Wu
- MaREI Centre, Environmental Research Institute, University College Cork, Cork T23 XE10, Ireland; Civil, Structural and Environmental Engineering, School of Engineering and Architecture, University College Cork, Cork T12 YN60, Ireland
| | - Richen Lin
- MaREI Centre, Environmental Research Institute, University College Cork, Cork T23 XE10, Ireland; Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing 211189, PR China.
| | - Xue Ning
- MaREI Centre, Environmental Research Institute, University College Cork, Cork T23 XE10, Ireland; Civil, Structural and Environmental Engineering, School of Engineering and Architecture, University College Cork, Cork T12 YN60, Ireland
| | - Xihui Kang
- MaREI Centre, Environmental Research Institute, University College Cork, Cork T23 XE10, Ireland; Civil, Structural and Environmental Engineering, School of Engineering and Architecture, University College Cork, Cork T12 YN60, Ireland
| | - Chen Deng
- MaREI Centre, Environmental Research Institute, University College Cork, Cork T23 XE10, Ireland; Civil, Structural and Environmental Engineering, School of Engineering and Architecture, University College Cork, Cork T12 YN60, Ireland
| | - Alan D W Dobson
- MaREI Centre, Environmental Research Institute, University College Cork, Cork T23 XE10, Ireland; School of Microbiology, University College Cork, Cork T12 K8AF, Ireland
| | - Jerry D Murphy
- MaREI Centre, Environmental Research Institute, University College Cork, Cork T23 XE10, Ireland; Civil, Structural and Environmental Engineering, School of Engineering and Architecture, University College Cork, Cork T12 YN60, Ireland
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20
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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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21
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Rovira-Alsina L, Romans-Casas M, Balaguer MD, Puig S. Thermodynamic approach to foresee experimental CO 2 reduction to organic compounds. BIORESOURCE TECHNOLOGY 2022; 354:127181. [PMID: 35447329 DOI: 10.1016/j.biortech.2022.127181] [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: 03/23/2022] [Revised: 04/12/2022] [Accepted: 04/14/2022] [Indexed: 06/14/2023]
Abstract
Anaerobic gas fermentation is a promising approach to transform carbon dioxide (CO2) into chemical building blocks. However, the main operational conditions to enhance the process and its selectivity are still unknown. The main objective of this study was to trigger chain elongation from a joint perspective of thermodynamic and experimental assessment. Thermodynamics revealed that acetic acid formation was the most spontaneous reaction, followed by n-caproic and n-butyric acids, while the doorway for alcohols production was bounded by the selected conditions. Best parameters combinations were applied in three 0.12 L fermenters. Experimentally, n-caproic acid formation was boosted at pH 7, 37 °C, Acetate:Ethanol mass ratio of 1:3 and low H2 partial pressure. Though these conditions did not match with those required to produce their main substrates, the unification of both perspectives yielded the highest n-caproic acid concentration (>11 g L-1) so far from simple substrates, accounting for 77 % of the total products.
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Affiliation(s)
- Laura Rovira-Alsina
- LEQUiA, Institute of the Environment, University of Girona, Campus Montilivi, C/Maria Aurèlia Capmany, 69, E-17003 Girona, Catalonia, Spain
| | - Meritxell Romans-Casas
- LEQUiA, Institute of the Environment, University of Girona, Campus Montilivi, C/Maria Aurèlia Capmany, 69, E-17003 Girona, Catalonia, Spain
| | - M Dolors Balaguer
- LEQUiA, Institute of the Environment, University of Girona, Campus Montilivi, C/Maria Aurèlia Capmany, 69, E-17003 Girona, Catalonia, Spain
| | - Sebastià Puig
- LEQUiA, Institute of the Environment, University of Girona, Campus Montilivi, C/Maria Aurèlia Capmany, 69, E-17003 Girona, Catalonia, Spain.
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22
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Bu J, Hu BB, Wu HZ, Zhu MJ. Improved methane production with redox-active/conductive biochar amendment by establishing spatial ecological niche and mediating electron transfer. BIORESOURCE TECHNOLOGY 2022; 351:127072. [PMID: 35351565 DOI: 10.1016/j.biortech.2022.127072] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 03/21/2022] [Accepted: 03/23/2022] [Indexed: 06/14/2023]
Abstract
The multifunctional roles of biochar as an additive in improving the performance of anaerobic digestion (AD) has not been perfectly understood. In this study, the effects of different biochars on AD and the enhanced mechanisms were explored. The CH4 productions were significantly improved with an increase of 45.9%, 28.3% and 16.5% by amendment with biochar pyrolyzed at 300℃ (BC300), 450℃ (BC450) and 600℃ (BC600), respectively. The tightly-bound communities were established on biochar at the initial stage of fermentation and functional microbes were selectively enriched/colonized in biochar-amended systems. Distinctive loosely-bound microbial communities were observed in BC300 and BC600 amended systems, among which electroactive Desulforhabdus and Clostridiales were the dominant bacteria. Biochar amendments also led to the formation of distinctive spatial ecological niches and the selection preference of microbes for specific spatial locations. These results provided new insights in revealing the potential mechanisms of enhanced AD performance by biochar amendment.
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Affiliation(s)
- Jie Bu
- School of Biology and Biological Engineering, Guangdong Key Laboratory of Fermentation and Enzyme Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Panyu, Guangzhou 510006, China
| | - Bin-Bin Hu
- Yunnan Academy of Tobacco Agricultural Sciences, Kunming 650021, China
| | - Hai-Zhen Wu
- School of Biology and Biological Engineering, Guangdong Key Laboratory of Fermentation and Enzyme Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Panyu, Guangzhou 510006, China
| | - Ming-Jun Zhu
- School of Biology and Biological Engineering, Guangdong Key Laboratory of Fermentation and Enzyme Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Panyu, Guangzhou 510006, China; Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei University of Technology, Wuhan 430068, Hubei, China; The Key Laboratory of Biological Resources and Ecology of Pamirs Plateau in Xinjiang Uygur Autonomous Region, The Key Laboratory of Ecology and Biological Resources in Yarkand Oasis at Colleges & Universities under the Department of Education of Xinjiang Uygur Autonomous Region, College of Life and Geographic Sciences, Kashi University, Kashi 844006, China.
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23
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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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24
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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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25
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Ayol A, Peixoto L, Keskin T, Abubackar HN. Reactor Designs and Configurations for Biological and Bioelectrochemical C1 Gas Conversion: A Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph182111683. [PMID: 34770196 PMCID: PMC8583215 DOI: 10.3390/ijerph182111683] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/22/2021] [Accepted: 11/03/2021] [Indexed: 11/16/2022]
Abstract
Microbial C1 gas conversion technologies have developed into a potentially promising technology for converting waste gases (CO2, CO) into chemicals, fuels, and other materials. However, the mass transfer constraint of these poorly soluble substrates to microorganisms is an important challenge to maximize the efficiencies of the processes. These technologies have attracted significant scientific interest in recent years, and many reactor designs have been explored. Syngas fermentation and hydrogenotrophic methanation use molecular hydrogen as an electron donor. Furthermore, the sequestration of CO2 and the generation of valuable chemicals through the application of a biocathode in bioelectrochemical cells have been evaluated for their great potential to contribute to sustainability. Through a process termed microbial chain elongation, the product portfolio from C1 gas conversion may be expanded further by carefully driving microorganisms to perform acetogenesis, solventogenesis, and reverse β-oxidation. The purpose of this review is to provide an overview of the various kinds of bioreactors that are employed in these microbial C1 conversion processes.
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Affiliation(s)
- Azize Ayol
- Department of Environmental Engineering, Dokuz Eylul University, Izmir 35390, Turkey;
| | - Luciana Peixoto
- Centre of Biological Engineering (CEB), University of Minho, 4710-057 Braga, Portugal;
| | - Tugba Keskin
- Department of Environmental Protection Technologies, Izmir Democracy University, Izmir 35140, Turkey;
| | - Haris Nalakath Abubackar
- Chemical Engineering Laboratory, BIOENGIN Group, Faculty of Sciences and Centre for Advanced Scientific Research (CICA), University of A Coruña, 15008 A Coruña, Spain
- Correspondence:
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26
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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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27
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Li W, Cheng C, He L, Liu M, Cao G, Yang S, Ren N. Effects of feedstock and pyrolysis temperature of biochar on promoting hydrogen production of ethanol-type fermentation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 790:148206. [PMID: 34111796 DOI: 10.1016/j.scitotenv.2021.148206] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 04/29/2021] [Accepted: 05/30/2021] [Indexed: 06/12/2023]
Abstract
Biochar has been shown to benefit fermentative hydrogen production. However, the influencing factors and key characteristics of its promoting function remained to be elucidated. This study investigated the effects of two crucial factors, feedstock and pyrolysis temperature, on the hydrogen production-promoting function of biochar in ethanol-type fermentation. The physicochemical characteristics and promoting effects of biochars prepared with five biomass wastes (coffee ground, corn stalk, Ginkgo biloba leaf, mealworm frass, and sugarcane bagasse) were determined. Sugarcane bagasse-derived biochar (SBBC) showed the best hydrogen production-promoting effect in ethanol-type fermentation. The physicochemical properties of biochar, such as pH, element composition and surface features, were significantly affected by pyrolysis temperature, but the promoting effects were not significantly changed. The hydrogen production-promoting effect of biochar in ethanol-type fermentation was mainly affected by feedstock instead of pyrolysis temperature. A potential promoting mechanism was proposed that biochar prepared at low temperature boosted the hydrogen production with redox activity, while that at high temperature achieved the promotion via cell growth enhancement. This study revealed the key promoting factor of biochar in ethanol-type fermentative hydrogen production, and provided novel insights for the promoting mechanism of biochar.
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Affiliation(s)
- Weiming Li
- School of Environmental Science and Technology, Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education, Dalian University of Technology, Dalian 116024, China; State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Chi Cheng
- School of Bioengineering, Dalian University of Technology, Dalian 116024, China
| | - Lei He
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Meng Liu
- School of Environmental Science and Technology, Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education, Dalian University of Technology, Dalian 116024, China
| | - Guangli Cao
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Shanshan Yang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Nanqi Ren
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
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