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Harahap BM, Ahring BK. Acetate Production from Syngas Produced from Lignocellulosic Biomass Materials along with Gaseous Fermentation of the Syngas: A Review. Microorganisms 2023; 11:microorganisms11040995. [PMID: 37110418 PMCID: PMC10143712 DOI: 10.3390/microorganisms11040995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 04/05/2023] [Accepted: 04/10/2023] [Indexed: 04/29/2023] Open
Abstract
Biotransformation of lignocellulose-derived synthetic gas (syngas) into acetic acid is a promising way of creating biochemicals from lignocellulosic waste materials. Acetic acid has a growing market with applications within food, plastics and for upgrading into a wide range of biofuels and bio-products. In this paper, we will review the microbial conversion of syngas to acetic acid. This will include the presentation of acetate-producing bacterial strains and their optimal fermentation conditions, such as pH, temperature, media composition, and syngas composition, to enhance acetate production. The influence of syngas impurities generated from lignocellulose gasification will further be covered along with the means to alleviate impurity problems through gas purification. The problem with mass transfer limitation of gaseous fermentation will further be discussed as well as ways to improve gas uptake during the fermentation.
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Affiliation(s)
- Budi Mandra Harahap
- Bioproducts, Science, and Engineering Laboratory, Washington State University Tri-Cities, 2710, Crimson Way, Richland, WA 99354, USA
- Department of Biological System Engineering, Washington State University, L. J. Smith Hall, Pullman, WA 99164, USA
| | - Birgitte K Ahring
- Bioproducts, Science, and Engineering Laboratory, Washington State University Tri-Cities, 2710, Crimson Way, Richland, WA 99354, USA
- Department of Biological System Engineering, Washington State University, L. J. Smith Hall, Pullman, WA 99164, USA
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Wegner Hall, Pullman, WA 99164, USA
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He Y, Kennes C, Lens PNL. Enhanced solventogenesis in syngas bioconversion: Role of process parameters and thermodynamics. CHEMOSPHERE 2022; 299:134425. [PMID: 35351479 DOI: 10.1016/j.chemosphere.2022.134425] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 03/22/2022] [Accepted: 03/23/2022] [Indexed: 06/14/2023]
Abstract
Biofuels, such as ethanol and butanol, obtained from carbon monoxide-rich gas or syngas bioconversion (solventogenesis) are an attractive alternative to traditional fermentation processes with merits of no competition with food production and sustainability. However, there is a lack of comprehensive understanding of some key process parameters and mechanisms enhancing solventogenesis during the fermentation process. This review provides an overview of the current state of the art of the main influencing factors during the syngas fermentation process catalyzed by acetogenic species as well as undefined mixed cultures. The role of syngas pressure, syngas components, fermentation pH, temperature, trace metals, organic compounds and additional materials is overviewed. As a so far hardly considered approach, thermodynamic calculations of the Gibbs free energy of CO conversion to acetic acid, ethanol, butyric acid and butanol under different CO pressures and pH at 25, 33 and 55 °C are also addressed and reviewed. Strategies for enhancing mass transfer and longer carbon chain solvent production are considered as well.
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Affiliation(s)
- Yaxue He
- National University of Ireland Galway, H91 TK33, Galway, Ireland; Chemical Engineering Laboratory, Faculty of Sciences and Center for Advanced Scientific Research - Centro de Investigaciones Científicas Avanzadas (CICA), BIOENGIN Group, University of La Coruña (UDC), E-15008, La Coruña, Spain.
| | - Christian Kennes
- Chemical Engineering Laboratory, Faculty of Sciences and Center for Advanced Scientific Research - Centro de Investigaciones Científicas Avanzadas (CICA), BIOENGIN Group, University of La Coruña (UDC), E-15008, La Coruña, Spain
| | - Piet N L Lens
- National University of Ireland Galway, H91 TK33, Galway, Ireland
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Oh HJ, Ko JK, Gong G, Lee SM, Um Y. Production of Hexanol as the Main Product Through Syngas Fermentation by Clostridium carboxidivorans P7. Front Bioeng Biotechnol 2022; 10:850370. [PMID: 35547160 PMCID: PMC9081523 DOI: 10.3389/fbioe.2022.850370] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 04/04/2022] [Indexed: 11/24/2022] Open
Abstract
The production of hexanol from syngas by acetogens has gained attention as a replacement for petroleum-derived hexanol, which is widely used in the chemical synthesis and plastic industries. However, acetogenic bacteria generally produce C2 compounds (e.g., acetate and ethanol) as the main products. In this study, the gas fermentation conditions favorable for hexanol production were investigated at different temperatures (30-37°C) and CO gas contents (30-70%) in batch gas fermentation. Hexanol production increased from 0.02 to 0.09 g/L when the cultivation temperature was lowered from 37 to 30°C. As the CO content increased from 30 to 70%, the CO consumption rate and hexanol production (yield, titer, and ratio of C6 compound to total products) increased with the CO content. When 70% CO gas was repeatedly provided by flushing the headspace of the bottles at 30°C, the total alcohol production increased to 4.32 g/L at the expense of acids. Notably, hexanol production (1.90 g/L) was higher than that of ethanol (1.20 g/L) and butanol (1.20 g/L); this is the highest level of hexanol produced in gas fermentation to date and the first report of hexanol as the main product. Hexanol production was further enhanced to 2.34 g/L when 2 g/L ethanol was supplemented at the beginning of 70% CO gas refeeding fermentation. Particularly, hexanol productivity was significantly enhanced to 0.18 g/L/day while the supplemented ethanol was consumed, indicating that the conversion of ethanol to acetyl-CoA and reducing equivalents positively affected hexanol production. These optimized culture conditions (gas fermentation at 30°C and refeeding with 70% CO gas) and ethanol supplementation provide an effective and sustainable approach for bio-hexanol production.
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Affiliation(s)
- Hyun Ju Oh
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul, South Korea
| | - Ja Kyong Ko
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul, South Korea
- Division of Energy and Environment Technology, KIST School, University of Science and Technology (UST), Daejeon, South Korea
| | - Gyeongtaek Gong
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul, South Korea
- Division of Energy and Environment Technology, KIST School, University of Science and Technology (UST), Daejeon, South Korea
| | - Sun-Mi Lee
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul, South Korea
- Division of Energy and Environment Technology, KIST School, University of Science and Technology (UST), Daejeon, South Korea
| | - Youngsoon Um
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul, South Korea
- Division of Energy and Environment Technology, KIST School, University of Science and Technology (UST), Daejeon, South Korea
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Jang YS, Seong HJ, Kwon SW, Lee YS, Im JA, Lee HL, Yoon YR, Lee SY. Clostridium acetobutylicum atpG-Knockdown Mutants Increase Extracellular pH in Batch Cultures. Front Bioeng Biotechnol 2021; 9:754250. [PMID: 34760879 PMCID: PMC8573202 DOI: 10.3389/fbioe.2021.754250] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/11/2021] [Indexed: 11/24/2022] Open
Abstract
ATPase, a key enzyme involved in energy metabolism, has not yet been well studied in Clostridium acetobutylicum. Here, we knocked down the atpG gene encoding the ATPase gamma subunit in C. acetobutylicum ATCC 824 using a mobile group II intron system and analyzed the physiological characteristics of the atpG gene knockdown mutant, 824-2866KD. Properties investigated included cell growth, glucose consumption, production of major metabolites, and extracellular pH. Interestingly, in 2-L batch fermentations, 824-2866KD showed no significant difference in metabolite biosynthesis or cell growth compared with the parent ATCC 824. However, the pH value in 824-2866KD cultures at the late stage of the solventogenic phase was abnormally high (pH 6.12), compared with that obtained routinely in the culture of ATCC 824 (pH 5.74). This phenomenon was also observed in batch cultures of another C. acetobutylicum, BEKW-2866KD, an atpG-knockdown and pta-buk double-knockout mutant. The findings reported in this study suggested that ATPase is relatively minor than acid-forming pathway in ATP metabolism in C. acetobutylicum.
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Affiliation(s)
- Yu-Sin Jang
- Division of Applied Life Science (BK21), Department of Applied Life Chemistry, Institute of Agriculture and Life Science (IALS), Gyeongsang National University, Jinju, South Korea
| | - Hyeon Jeong Seong
- Division of Applied Life Science (BK21), Department of Applied Life Chemistry, Institute of Agriculture and Life Science (IALS), Gyeongsang National University, Jinju, South Korea
| | - Seong Woo Kwon
- Division of Applied Life Science (BK21), Department of Applied Life Chemistry, Institute of Agriculture and Life Science (IALS), Gyeongsang National University, Jinju, South Korea
| | - Yong-Suk Lee
- Division of Applied Life Science (BK21), Department of Applied Life Chemistry, Institute of Agriculture and Life Science (IALS), Gyeongsang National University, Jinju, South Korea
| | - Jung Ae Im
- Department of Chemical and Biomolecular Engineering (BK21 Plus Program), BioProcess Engineering Research Center, Institute for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, South Korea
| | - Haeng Lim Lee
- Division of Applied Life Science (BK21), Department of Applied Life Chemistry, Institute of Agriculture and Life Science (IALS), Gyeongsang National University, Jinju, South Korea
| | - Ye Rin Yoon
- Division of Applied Life Science (BK21), Department of Applied Life Chemistry, Institute of Agriculture and Life Science (IALS), Gyeongsang National University, Jinju, South Korea
| | - Sang Yup Lee
- Department of Chemical and Biomolecular Engineering (BK21 Plus Program), BioProcess Engineering Research Center, Institute for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, South Korea
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