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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] [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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Duber A, Zagrodnik R, Juzwa W, Gutowska N, Oleskowicz-Popiel P. Simultaneous medium chain carboxylic acids and 1,3-propanediol production in a bioaugmented lactate-based chain elongation induced with glycerol. BIORESOURCE TECHNOLOGY 2024; 393:130123. [PMID: 38042435 DOI: 10.1016/j.biortech.2023.130123] [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: 10/31/2023] [Revised: 11/26/2023] [Accepted: 11/27/2023] [Indexed: 12/04/2023]
Abstract
The objective was to investigate the impact of the bioaugmentation on chain elongation process using glycerol, lactate and lactose as substrates in an open culture fermentation. In the batch trials the highest selectivity for chain elongation product, i.e. caproate, was observed in trials inoculated with co-culture of Megasphaera elsdenii and Eubacterium limosum grown on glycerol (28.6%), and in non-bioaugmented open culture run on lactose + lactate (14.8%). The results showed that E. limosum, out of two bioaugmented strains, was able to survive in the open culture. A continuous open culture fermentation of glycerol led to caproate and 1,3-propanediol (1,3-PDO) formation, while lactate addition led to 1,3-PDO and short chain carboxylates production. Moving the process into batch mode triggered even-carbon chain elongation. Presence of E. limosum promoted odd-carbon chain elongation and valerate production. Imaging flow cytometry combined with machine learning enabled the discrimination of Eubacterium cells from other microbial strains during the process.
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Affiliation(s)
- Anna Duber
- Water Supply and Bioeconomy Division, Faculty of Environmental Engineering and Energy, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland.
| | - Roman Zagrodnik
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznanskiego 8, 61-614 Poznan, Poland.
| | - Wojciech Juzwa
- Department of Biotechnology and Food Microbiology, Poznan University of Life Sciences, Wojska Polskiego 48, 60-627 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.
| | - 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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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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Lagoa-Costa B, Kennes C, Veiga MC. Influence of feedstock mix ratio on microbial dynamics during acidogenic fermentation for polyhydroxyalkanoates production. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 303:114132. [PMID: 34863075 DOI: 10.1016/j.jenvman.2021.114132] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 10/26/2021] [Accepted: 11/16/2021] [Indexed: 06/13/2023]
Abstract
The nature of microbial populations plays an essential role in the production of volatile fatty acids (VFA) during acidogenesis, the first stage in polyhydroxyalkanoates (PHA) production using mixed cultures. However, the composition of microbial communities is generally affected by substrate alterations. This work aimed to unravel the microbial dynamics in response to a gradual change in the feedstock composition in an acidogenic reactor, with subsequent PHA production. To achieve this, co-digestion of cheese whey and brewery wastewater (BW) was carried out for the production of VFA, in which the ratio of these feedstocks was varied by gradually increasing the proportion of BW from 0 up to 50% of the organic content. Bacteria such as Megasphaera, Bifidobacterium or Caproiciproducens were the most abundant in the first stages of the co-digestion. However, when BW reached 25% of the organic load, new taxa emerged and displaced the former ones; like Selenomonas, Ethanoligenens or an undefined member of the Bacteroidales order. Accordingly, the production of butyric acid dropped from 52 down to 27%, while the production of acetic acid increased from 36 up to 52%. Furthermore, the gradual increase of the BW ratio led to a progressive drop in the degree of acidification, from 72 down to 57%. In a subsequent approach, the VFA-rich streams, obtained from the co-digestion, were used as substrates in PHA accumulation tests. All the tests yielded similar PHA contents, but with slightly different monomeric composition. The overall results confirmed that the microbiome was altered by a gradual change in the feedstock composition and, consequently, the VFA profile and the monomeric composition of the biopolymer also did.
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Affiliation(s)
- Borja Lagoa-Costa
- Chemical Engineering Laboratory, Faculty of Sciences and Centre for Advanced Scientific Research (CICA), University of A Coruña, Rúa da Fraga 10, 15008, A Coruña, Spain
| | - Christian Kennes
- Chemical Engineering Laboratory, Faculty of Sciences and Centre for Advanced Scientific Research (CICA), University of A Coruña, Rúa da Fraga 10, 15008, A Coruña, Spain
| | - María C Veiga
- Chemical Engineering Laboratory, Faculty of Sciences and Centre for Advanced Scientific Research (CICA), University of A Coruña, Rúa da Fraga 10, 15008, A Coruña, Spain.
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Brodowski F, Łężyk M, Gutowska N, Oleskowicz-Popiel P. Effect of external acetate on lactate-based carboxylate platform: Shifted lactate overloading limit and hydrogen co-production. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 802:149885. [PMID: 34474295 DOI: 10.1016/j.scitotenv.2021.149885] [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: 06/25/2021] [Revised: 08/05/2021] [Accepted: 08/20/2021] [Indexed: 06/13/2023]
Abstract
Chain elongation is an anaerobic biotechnological process that converts short chain carboxylates and an electron donor (e.g. ethanol, lactate) into more valuable medium chain carboxylates. Caproate production in lactate-based chain elongation is gaining popularity, however, the relation between lactate (electron donor) and acetate (electron acceptor) has not yet been fully elucidated. Herein, for the first time, the effect of an external acetate on the lactate-based chain elongation in a continuously-fed bioreactor was tested to verify how the external acetate would affect the product spectrum, gas production, as well as stability and efficiency of carboxylates production. Periodic fluctuations in caproate production were observed in bioreactor continuously fed with lactate as a sole carbon source due to the lack of an electron acceptor (acetate) and low chain elongation performance. The recovery of stable caproate production (68.9 ± 2.2 mmol C/L/d), total lactate consumption, and high hydrogen co-production (748 ± 76 mLH2/d) was observed as an effect of the addition of an external acetate. The lactate conversion with the external acetate in the second bioreactor ensured stable and dominant caproate production from the beginning of the process. Moreover, despite the continuous lactate overloading in the process with external acetate, stable caproate production was achieved (71.7 ± 2.4 mmol C/L/d) and previously unobserved hydrogen production occurred (213 ± 30 mLH2/d). Thus, external electron acceptor addition (i.e. acetate) was proposed as an effective method for stable lactate-based caproate production. Microbiological analysis showed the dominance of microbes closely related to Ruminococcaceae bacterium CPB6 and Acinetobacter throughout the process. Co-occurrence networks based on taxon abundances and process parameters revealed microbial sub-networks responding to lactate concentrations.
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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
| | - 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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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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Lu S, Jin H, Wang Y, Tao Y. Genome-Wide Transcriptomic Analysis of n-Caproic Acid Production in Ruminococcaceae Bacterium CPB6 with Lactate Supplementation. J Microbiol Biotechnol 2021; 31:1533-1544. [PMID: 34489376 PMCID: PMC9705837 DOI: 10.4014/jmb.2107.07009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 08/25/2021] [Accepted: 08/25/2021] [Indexed: 12/15/2022]
Abstract
n-Caproic acid (CA) is gaining increased attention due to its high value as a chemical feedstock. Ruminococcaceae bacterium strain CPB6 is an anaerobic mesophilic bacterium that is highly prolific in its ability to perform chain elongation of lactate to CA. However, little is known about the genome-wide transcriptional analysis of strain CPB6 for CA production triggered by the supplementation of exogenous lactate. In this study, cultivation of strain CPB6 was carried out in the absence and presence of lactate. Transcriptional profiles were analyzed using RNA-seq, and differentially expressed genes (DEGs) between the lactate-supplemented cells and control cells without lactate were analyzed. The results showed that lactate supplementation led to earlier CA p,roduction, and higher final CA titer and productivity. 295 genes were substrate and/or growth dependent, and these genes cover crucial functional categories. Specifically, 5 genes responsible for the reverse β-oxidation pathway, 11 genes encoding ATP-binding cassette (ABC) transporters, 6 genes encoding substrate-binding protein (SBP), and 4 genes encoding phosphotransferase system (PTS) transporters were strikingly upregulated in response to the addition of lactate. These genes would be candidates for future studies aiming at understanding the regulatory mechanism of lactate conversion into CA, as well as for the improvement of CA production in strain CPB6. The findings presented herein reveal unique insights into the biomolecular effect of lactate on CA production at the transcriptional level.
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Affiliation(s)
- Shaowen Lu
- CAS Key Laboratory of Environmental and Applied Microbiology and Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, P.R. China
| | - Hong Jin
- School of Basic Medical Science, Chengdu Medical College, Chengdu 610083, P.R. China
| | - Yi Wang
- Department of Biosystems Engineering, Auburn University, Auburn, Alabama, Alabama 36849, USA
| | - Yong Tao
- CAS Key Laboratory of Environmental and Applied Microbiology and Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, P.R. China,Faculty of Bioengineering, Sichuan University of Science and Engineering, Xueyuan Street 180#, Huixing Rd. Zigong 643000, P.R. China,Corresponding author Phone: 86-028-82890211 Fax: 86-028-82890211 E-mail:
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Xie S, Ma J, Li L, He Q, Xu P, Ke S, Shi Z. Anaerobic caproate production on carbon chain elongation: Effect of lactate/butyrate ratio, concentration and operation mode. BIORESOURCE TECHNOLOGY 2021; 329:124893. [PMID: 33690059 DOI: 10.1016/j.biortech.2021.124893] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 02/17/2021] [Accepted: 02/19/2021] [Indexed: 06/12/2023]
Abstract
The objective of this study was to understand how lactate-to-butyrate ratio and substrates concentrations affect the caproate production and product structure. The results showed that a higher butyrate-to-lactate ratio is beneficial to caproate production at low initial lactate concentration. Low pH (5.0) and low substrate concentration (20 mM and 40 mM) effectively decreased propionate production via restrained acrylate pathway, resulting in higher electron efficiency of caproate. With the optimum mole ratio of lactate to butyrate (1:4) and 80 mM initial butyrate concentration, the electron efficiency of caproate reached the maximum (43.10%). Moreover, high butyrate concentration suppressed the production of odd-carbon-number carboxylates while promoting the production of caproate. Compared with the batch operation, the caproate production in semi-continuous operation was enhanced by 3.45 times to 30.91 ± 1.07 mM as the acrylate pathway was successfully inhibited in semi-continuous experiments due to low pH and low lactate concentration.
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Affiliation(s)
- Shanbiao Xie
- Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha, Hunan 410082, PR China
| | - Jingwei Ma
- Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha, Hunan 410082, PR China.
| | - Lu Li
- Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha, Hunan 410082, PR China
| | - Qiulai He
- Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha, Hunan 410082, PR China
| | - Peng Xu
- Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha, Hunan 410082, PR China
| | - Shuizhou Ke
- Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha, Hunan 410082, PR China
| | - Zhou Shi
- Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha, Hunan 410082, PR China
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