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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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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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3
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Zhang P, Shen D, Shao J, He X, Zeng J, Wu SL, Long Y, Wei W, Ni BJ. Green synthesis of Fe 3O 4@ceramsite from sludge improving anaerobic digestion performance of waste activated sludge. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 359:121085. [PMID: 38728986 DOI: 10.1016/j.jenvman.2024.121085] [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: 03/24/2024] [Revised: 04/30/2024] [Accepted: 05/03/2024] [Indexed: 05/12/2024]
Abstract
Anaerobic digestion (AD) is a promising technique for waste management, which can achieve sludge stabilization and energy recovery. This study successfully prepared Fe3O4@ceramsite from WAS and applied it as an additive in sludge digestion, aiming to improve the conversion of organics to biomethane efficiency. Results showed that after adding the Fe3O4@ceramsite, the methane production was enhanced by 34.7% compared with the control group (88.0 ± 0.1 mL/g VS). Further mechanisms investigation revealed that Fe3O4@ceramsite enhanced digesta stability by strong buffering capacity, improved sludge conductivity, and promoted Fe (III) reduction. Moreover, Fe3O4@ceramsite has a larger surface area and better porous structure, which also facilitated AD performance. Microbial community analysis showed that some functional anaerobes related to AD such as Spirochaeta and Smithella were enriched with Fe3O4@ceramsite treatment. Potential syntrophic metabolisms between syntrophic bacteria (Syntrophomonas, associated with DIET) and methanogens were also detected in the Fe3O4@ceramsite treatment AD system.
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Affiliation(s)
- Pengqu Zhang
- School of Environmental Science and Engineering, Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Zhejiang Engineering Research Center of Non-ferrous Metal Waste Recycling, Zhejiang Gongshang University, Hangzhou, 310018, Zhejiang Province, China
| | - Dongsheng Shen
- School of Environmental Science and Engineering, Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Zhejiang Engineering Research Center of Non-ferrous Metal Waste Recycling, Zhejiang Gongshang University, Hangzhou, 310018, Zhejiang Province, China
| | - Jinyang Shao
- School of Environmental Science and Engineering, Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Zhejiang Engineering Research Center of Non-ferrous Metal Waste Recycling, Zhejiang Gongshang University, Hangzhou, 310018, Zhejiang Province, China
| | - Xiaoyu He
- Hangzhou Guotai Environmental Protection Technology Co., Ltd, China
| | - Jianjun Zeng
- School of Environmental Science and Engineering, Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Zhejiang Engineering Research Center of Non-ferrous Metal Waste Recycling, Zhejiang Gongshang University, Hangzhou, 310018, Zhejiang Province, China
| | - Shu-Lin Wu
- School of Environmental Science and Engineering, Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Zhejiang Engineering Research Center of Non-ferrous Metal Waste Recycling, Zhejiang Gongshang University, Hangzhou, 310018, Zhejiang Province, China.
| | - Yuyang Long
- School of Environmental Science and Engineering, Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Zhejiang Engineering Research Center of Non-ferrous Metal Waste Recycling, Zhejiang Gongshang University, Hangzhou, 310018, Zhejiang Province, China
| | - Wei Wei
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Bing-Jie Ni
- School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW, 2052, Australia
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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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Liu H, Zhen F, Wu D, Wang Z, Kong X, Li Y, Xing T, Sun Y. Co-production of lactate and volatile fatty acids through repeated-batch fermentation of fruit and vegetable waste: Effect of cycle time and replacement ratio. BIORESOURCE TECHNOLOGY 2023; 387:129678. [PMID: 37579859 DOI: 10.1016/j.biortech.2023.129678] [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: 07/02/2023] [Revised: 08/10/2023] [Accepted: 08/11/2023] [Indexed: 08/16/2023]
Abstract
In this study, repeated-batch fermentation was used to convert fruit and vegetable waste to lactate and volatile fatty acids (VFAs), which are essential carbon sources for medium-chain fatty acids (MCFAs) production. The effect of cycle time and replacement ratio on acidification in long-term fermentation was investigated. The results showed that they had a significant impact on product yield, productivity, and type of products. Considering the yield, productivity, and lactate/VFAs ratio, a replacement ratio of 30% and a cycle time of 2 d may be more suitable for further production of MCFAs. Its productivity and lactate/VFAs ratio were 4.07 ± 0.24 g/(L·d) and 5 ± 0.6, respectively. The lactic acid bacteria, such as Enterococcus (63%) and Lactobacillus (33%), stabilized in the reactor, resulting in the generation of both lactate and VFAs by heterolactic fermentation. The present study demonstrated a new strategy with the potential to recover high-value products from organic waste streams.
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Affiliation(s)
- Huiliang Liu
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Feng Zhen
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, China
| | - Di Wu
- Chongqing Institute of Green and Intelligent Technology Chinese Academy of Sciences, Chongqing 400714, China
| | - Zhi Wang
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, China; University of Science and Technology of China, Hefei 230026, China
| | - Xiaoying Kong
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, China
| | - Ying Li
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, China
| | - Tao Xing
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, China.
| | - Yongming Sun
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, China
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6
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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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Zhang L, Wang X, Chen Y, Zhang B, Xu H, Li C, Zhou Y. Medium-chain fatty acid production from thermal hydrolysed sludge without external electron donor supplementation. BIORESOURCE TECHNOLOGY 2023; 374:128805. [PMID: 36849100 DOI: 10.1016/j.biortech.2023.128805] [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: 01/08/2023] [Revised: 02/11/2023] [Accepted: 02/24/2023] [Indexed: 06/18/2023]
Abstract
In this study, medium-chain fatty acid (MCFA) generation from mixed sludge (including primary sludge and waste activated sludge) was investigated without additional electron donors (EDs). 0.5 g COD/L of MCFAs was produced and the in situ generated ethanol could serve as the EDs during the anaerobic fermentation of mixed sludge without thermal hydrolysis process (THP) pretreatment. THP increased the MCFA production by approximately 128% in the anaerobic fermentation. During 102 days of operation, the fermentation of THP pre-treated mixed sludge stably generated 2.9 g COD/L MCFAs. The self-generated EDs could not maximize MCFA production, and external addition of ethanol improved MCFA yield. Caproiciproducens was the dominant chain-elongating bacteria. PICRUST2 revealed that both fatty acid biosynthesis and reverse β-oxidation pathways could participate in MCFA synthesis, and ethanol addition could enhance the contribution of the reverse β-oxidation pathway. Future studies should focus on the improvement of MCFA production from THP-assisted sludge fermentation.
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Affiliation(s)
- Liang Zhang
- Guangdong Provincial Key Lab of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, China
| | - Xiuping Wang
- Guangdong Provincial Key Lab of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, China
| | - Yun Chen
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore 637141, Singapore
| | - Baorui Zhang
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore 637141, Singapore
| | - Hui Xu
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore 637141, Singapore
| | - Chenchen Li
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore 637141, Singapore
| | - Yan Zhou
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore 637141, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, Singapore 639798, Singapore.
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Wu KK, Zhao L, Sun ZF, Wang ZH, Chen C, Ren HY, Yang SS, Ren NQ. Synergistic effect of hydrogen and nanoscale zero-valent iron on ex-situ biogas upgrading and acetate recovery. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 856:159100. [PMID: 36174700 DOI: 10.1016/j.scitotenv.2022.159100] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 09/16/2022] [Accepted: 09/24/2022] [Indexed: 06/16/2023]
Abstract
Hydrogen (H2) assisted ex-situ biogas upgrading and liquid chemicals production can augment the fossil fuel-dominated energy market, and alleviate CO2-induced global warming. Recent investigations confirmed that nanoscale zero-valent iron (nZVI) enabled the enhancement of anaerobic digestion for biogas production. However, little is known about the effect of nZVI on the downstream ex-situ biogas upgrading. Herein, different levels (0 mg L-1, 100 mg L-1, 200 mg L-1, 500 mg L-1, 1000 mg L-1, 2000 mg L-1) of nZVI were added for H2-assisted ex-situ biogas upgrading, to study whether nZVI could impact the biomethane purity and acetate yield for the first time. Results showed that all tested nZVI levels were favorable for biogas upgrading in the presence of H2, the highest biomethane content (94.1 %, v/v), the CO2 utilization ratio (95.9 %), and acetate yield (19.4 mmol L-1) were achieved at 500 mg L-1 nZVI, respectively. Further analysis indicated that increased biogas upgrading efficiency was related to an increase in extracellular polymeric substances, which ensures the microbial activity and stability of the ex-situ biogas upgrading. Microbial community characterization showed that the Petrimonas, Romboutsia, Acidaminococcus, and Clostridium predominated the microbiome during biogas upgrading at 500 mg L-1 nZVI with H2 supply. These results suggested that nZVI and H2 contributed jointly to promoting the bioconversion of CO2 in biogas to acetate. The findings could be helpful for paving a new way for efficient simultaneous ex-situ biogas upgrading and liquid chemicals 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
| | - Lei Zhao
- 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
| | - Zi-Han Wang
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Chuan Chen
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Hong-Yu Ren
- 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
| | - Nan-Qi Ren
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
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10
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Brodowski F, Łężyk M, Gutowska N, Kabasakal T, Oleskowicz-Popiel P. Influence of lactate to acetate ratio on biological production of medium chain carboxylates via open culture fermentation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 851:158171. [PMID: 35988608 DOI: 10.1016/j.scitotenv.2022.158171] [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: 07/01/2022] [Revised: 08/08/2022] [Accepted: 08/16/2022] [Indexed: 06/15/2023]
Abstract
Waste valorisation via biological production of widely used in the industry medium chain carboxylates (MCCs) via open culture fermentation (OCF) could be a promising alternative to the commonly used anaerobic digestion. Lactate-rich waste streams are considered as valuable substrates for carboxylate chain elongation (CE), however, there are certain limitations related to the production efficiency. Acetate produced and accumulated in the acetogenesis plays an important role in CE, i.e. acetate is elongated to butyrate and then to caproate which is most popular MCC. Henceforth, it was investigated whether the ratio of lactate to acetate (L:A) affected carboxylates yields and product distribution in the lactate-based CE in OCF. The tested L:A ratios influenced carboxylates selectivity in batch trials. In the ones with lactate as the sole carbon source, propionate production was predominant but when a higher relative acetate concentration was used, the production of butyrate and CE to caproate was favored. The co-utilization of lactate and acetate in a continuous process increased the production of butyrate and caproate compared to the phase with lactate as the sole carbon source, however, controlling the relative concentration of lactate and acetate during co-utilization was not an effective strategy for increasing caproate production. 16S rRNA gene amplicon reads mapping to Caproiciproducens were the most abundant in samples collected throughout the continuous processes regardless of the L:A ratios.
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Affiliation(s)
- Filip Brodowski
- 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
| | - Natalia Gutowska
- Water Supply and Bioeconomy Division, Faculty of Environmental Engineering and Energy, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland
| | - Tugba Kabasakal
- 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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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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Revealing the Characteristics of Glucose- and Lactate-Based Chain Elongation for Caproate Production by Caproicibacterium lactatifermentans through Transcriptomic, Bioenergetic, and Regulatory Analyses. mSystems 2022; 7:e0053422. [PMID: 36073803 PMCID: PMC9600882 DOI: 10.1128/msystems.00534-22] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Caproate, an important medium-chain fatty acid, can only be synthesized by limited bacterial species by using ethanol, lactate, or certain saccharides. Caproicibacterium lactatifermentans is a promising caproate producer due to its glucose and lactate utilization capabilities. However, the global cellular responses of this bacterium to different carbon sources were not well understood. Here, C. lactatifermentans showed robust growth on glucose but more active caproate synthesis on lactate. Comparative transcriptome revealed that the genes involved in reverse β-oxidation for caproate synthesis and V-type ATPase-dependent ATP generation were upregulated under lactate condition, while several genes responsible for biomass synthesis were upregulated under glucose condition. Based on metabolic pathway reconstructions and bioenergetics analysis, the biomass accumulation on glucose condition may be supported by sufficient supplies of ATP and metabolite intermediates via glycolysis. In contrast, the ATP yield per glucose equivalent from lactate conversion into caproate was only 20% of that from glucose. Thus, the upregulation of the reverse β-oxidation genes may be essential for cell survival under lactate conditions. Furthermore, the remarkably decreased lactate utilization was observed after glucose acclimatization, indicating the negative modulation of lactate utilization by glucose metabolism. Based on the cotranscription of the lactate utilization repressor gene lldR with sugar-specific PTS genes and the opposite expression patterns of lldR and lactate utilization genes, a novel regulatory mechanism of glucose-repressed lactate utilization mediated via lldR was proposed. The results of this study suggested the molecular mechanism underlying differential physiologic and metabolic characteristics of C. lactatifermentans grown on glucose and lactate. IMPORTANCE Caproicibacterium lactatifermentans is a unique and robust caproate-producing bacterium in the family Oscillospiraceae due to its lactate utilization capability, whereas its close relatives such as Caproicibacterium amylolyticum, Caproiciproducens galactitolivorans, and Caproicibacter fermentans cannot utilize lactate but produce lactate as the main fermentation end product. Moreover, C. lactatifermentans can also utilize several saccharides such as glucose and maltose. Although the metabolic versatility of the bacterium makes it to be a promising industrial caproate producer, the cellular responses of C. lactatifermentans to different carbon sources were unknown. Here, the molecular mechanisms of biomass synthesis supported by glucose utilization and the cell survival supported by lactate utilization were revealed. A novel insight into the regulatory machinery in which glucose negatively regulates lactate utilization was proposed. This study provides a valuable basis to control and optimize caproate production, which will contribute to achieving a circular economy and environmental sustainability.
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Ren W, Wu Q, Deng L, Hu Y, Guo W, Ren N. Simultaneous medium chain fatty acids production and process carbon emissions reduction in a continuous-flow reactor: Re-understanding of carbon flow distribution. ENVIRONMENTAL RESEARCH 2022; 212:113294. [PMID: 35460635 DOI: 10.1016/j.envres.2022.113294] [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: 12/31/2021] [Revised: 04/03/2022] [Accepted: 04/09/2022] [Indexed: 06/14/2023]
Abstract
Due to its wide application and high value, the production of medium chain fatty acids (MCFAs) from waste biomass has become one of the worldwide research hotspots. Increasing the carbon element participation from short-chain fatty acids to the form of MCFAs is also conductive to reduce the release of biogas from biological treatment process, because carbon is in the form of MCFAs instead of biogas which directly contribute to process carbon emissions reduction. However, many barriers limiting MCFAs production and application remain to be resolved. Aiming continuous MCFAs production from lactate-rich waste biomass, this study optimized the operation conditions and clarified the main limiting factors and possible mechanisms. The maximum caproic acid concentration of 2.757 g/L were obtained at the Upflow Velocity (ULV) of 1.15 m/h and pH 4.9-5.1. Caproiciproducens, Pseudoramibacter, norank_f_Eubacteriaceae, and Oscillibacter were identified to be the dominant microbial genus responsible for MCFAs production from lactate. The reduction of carbon emissions calculation was also studied in the present processes.
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Affiliation(s)
- Weitong Ren
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, China
| | - Qinglian Wu
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, China; College of Architecture and Environment, Sichuan University, Chengdu, 610065, China
| | - Lin Deng
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, China
| | - Yanbiao Hu
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, China
| | - Wanqian Guo
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, China.
| | - Nanqi Ren
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, China
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14
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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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Yin Y, Wang J. Medium-chain carboxylates production by co-fermentation of sewage sludge and macroalgae. BIORESOURCE TECHNOLOGY 2022; 347:126718. [PMID: 35032558 DOI: 10.1016/j.biortech.2022.126718] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/08/2022] [Accepted: 01/10/2022] [Indexed: 06/14/2023]
Abstract
The co-fermentation of sewage sludge and macroalgae at different mixing ratios was performed for medium-chain carboxylates (MCCs) production. The results showed that MCCs production was enhanced in co-fermentation groups due to the abundant readily available organics supplied by macroalgae and the alkaline buffer capacity provided by sewage sludge. Highest MCCs concentration of 112.7 mmol C/L (25.5 mmol C/g VSadded) was obtained in the co-fermentation group with sludge/macroalgae ratio of 4:6, which was higher than MCCs produced from the mono-fermentation of sewage sludge (41.7 mmol C/L, 9.4 mmol C/g VSadded) or macroalgae (79.9 mmol C/L, 18.1 mmol C/g VSadded). Microbial analysis showed that species from genus Romboutsia, Terrisporobacter, Clostridium_sensu_stricto_12, Paraclostridium, unclassified_f_Peptostreptococcaceae and Caproiciproducens were significantly positively correlated with MCCs production. Metabolic pathways analysis demonstrated that the co-fermentation promoted the chain elongation process by stimulating the rate-limiting steps involved in the conversion of ethanol to Acetyl-CoA and circular fatty acid biosynthesis pathway.
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Affiliation(s)
- Yanan Yin
- Laboratory of Environmental Technology, INET, Tsinghua University, Beijing 100084, PR China
| | - Jianlong Wang
- Laboratory of Environmental Technology, INET, Tsinghua University, Beijing 100084, PR China; Beijing Key Laboratory of Radioactive Waste Treatment, INET, Tsinghua University, Beijing 100084, PR China.
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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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