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Bian B, Zhang W, Yu N, Yang W, Xu J, Logan BE, Saikaly PE. Lactate-mediated medium-chain fatty acid production from expired dairy and beverage waste. ENVIRONMENTAL SCIENCE AND ECOTECHNOLOGY 2024; 21:100424. [PMID: 38774191 PMCID: PMC11106833 DOI: 10.1016/j.ese.2024.100424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 04/18/2024] [Accepted: 04/18/2024] [Indexed: 05/24/2024]
Abstract
Fruits, vegetables, and dairy products are typically the primary sources of household food waste. Currently, anaerobic digestion is the most used bioprocess for the treatment of food waste with concomitant generation of biogas. However, to achieve a circular carbon economy, the organics in food waste should be converted to new chemicals with higher value than energy. Here we demonstrate the feasibility of medium-chain carboxylic acid (MCCA) production from expired dairy and beverage waste via a chain elongation platform mediated by lactate. In a two-stage fermentation process, the first stage with optimized operational conditions, including varying temperatures and organic loading rates, transformed expired dairy and beverage waste into lactate at a concentration higher than 900 mM C at 43 °C. This lactate was then used to produce >500 mM C caproate and >300 mM C butyrate via microbial chain elongation. Predominantly, lactate-producing microbes such as Lactobacillus and Lacticaseibacillus were regulated by temperature and could be highly enriched under mesophilic conditions in the first-stage reactor. In the second-stage chain elongation reactor, the dominating microbes were primarily from the genera Megasphaera and Caproiciproducens, shaped by varying feed and inoculum sources. Co-occurrence network analysis revealed positive correlations among species from the genera Caproiciproducens, Ruminococcus, and CAG-352, as well as Megasphaera, Bacteroides, and Solobacterium, indicating strong microbial interactions that enhance caproate production. These findings suggest that producing MCCAs from expired dairy and beverage waste via lactate-mediated chain elongation is a viable method for sustainable waste management and could serve as a chemical production platform in the context of building a circular bioeconomy.
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Affiliation(s)
- Bin Bian
- Water Desalination and Reuse Center (WDRC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
- Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Wenxiang Zhang
- Water Desalination and Reuse Center (WDRC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
- Research Centre of Ecology & Environment for Coastal Area and Deep Sea, Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 511458, China
| | - Najiaowa Yu
- Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Wei Yang
- Water Desalination and Reuse Center (WDRC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Jiajie Xu
- Water Desalination and Reuse Center (WDRC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
- School of Marine Science, Ningbo University, Ningbo, 315211, China
| | - Bruce E. Logan
- Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Pascal E. Saikaly
- Water Desalination and Reuse Center (WDRC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
- Environmental Science and Engineering Program, Biological and Environmental Science and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
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2
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Wu L, Ngo HH, Wang C, Hou Y, Chen X, Guo W, Duan H, Ni BJ, Wei W. Lactobacillus inoculation mediated carboxylates and alcohols production from waste activated sludge fermentation system: Insight into process outcomes and metabolic network. BIORESOURCE TECHNOLOGY 2024:131191. [PMID: 39094964 DOI: 10.1016/j.biortech.2024.131191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2024] [Revised: 07/28/2024] [Accepted: 07/30/2024] [Indexed: 08/04/2024]
Abstract
Producing medium chain fatty acids (MCFAs) from waste activated sludge (WAS) is crucial for sustainable chemical industries. This study addressed the electron donor requirement for MCFAs production by inoculating Lactobacillus at varying concentrations (7.94 × 1010, 3.18 × 1011, and 6.35 × 1011 cell/L) to supply lactate internally. Interestingly, the highest MCFAs yield (∼2000 mg COD/L) occurred at the lowest Lactobacillus inoculation. Higher inoculation concentrations redirected more carbon from WAS towards alcohols production rather than MCFAs generation, with up to 2852 mg COD/L alcohols obtained under 6.35 × 1011 cell/L inoculation. Clostridium dominance and increased genes abundance for substrate hydrolysis, lactate conversion, and MCFAs/alcohol production collectively enhanced WAS-derived MCFAs and alcohols synthesis after Lactobacillus inoculation. Overall, the strategy of Lactobacillus inoculation regulated fermentation outcomes and subsequent carbon recovery in WAS, presenting a sustainable technology to achieve liquid bio-energy production from underutilized wet wastes.
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Affiliation(s)
- Lan Wu
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Huu Hao Ngo
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Chen Wang
- School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Yanan Hou
- School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Xueming Chen
- College of Environment and Safety Engineering, Fuzhou University, Fuzhou 350116, China
| | - Wenshan Guo
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Haoran Duan
- School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Bing-Jie Ni
- School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Wei Wei
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia.
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Fernández-Blanco C, Pereira A, Veiga MC, Kennes C, Ganigué R. Comprehensive comparative study on n-caproate production by Clostridium kluyveri: batch vs. continuous operation modes. BIORESOURCE TECHNOLOGY 2024; 408:131138. [PMID: 39043275 DOI: 10.1016/j.biortech.2024.131138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Revised: 07/06/2024] [Accepted: 07/19/2024] [Indexed: 07/25/2024]
Abstract
Recently, there has been notable interest in researching and industrially producing medium-chain carboxylic acids (MCCAs) like n-caproate and n-caprylate via chain elongation process. This study presents a comprehensive assessment of the behavior and MCCA production profiles of Clostridium kluyveri in batch and continuous modes, at different ethanol:acetate molar ratios (1.5:1, 3.5:1 and 5.5:1). The highest n-caproate concentration, 12.9 ± 0.67 g/L (92.9 ± 1.39 % MCCA selectivity), was achieved in batch mode at a 3.5:1 ratio. Interestingly, higher ratios favored batch mode selectivity over continuous mode when this was equal or higher to 3.5:1. Steady state operation yielded the highest n-caproate (9.5 ± 0.13 g/L) and n-caprylate (0.35 ± 0.020 g/L) concentrations at the 3.5:1 ratio. Increased ethanol:acetate ratios led to a higher excessive ethanol oxidation (EEO) in both operational modes, potentially limiting n-caproate production and selectivity, especially at the 5.5:1 ratio. Overall, this study reports the efficient MCCA production of both batch and continuous modes by C. kluyveri.
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Affiliation(s)
- Carla Fernández-Blanco
- Chemical Engineering Laboratory, Faculty of Sciences and Interdisciplinary Centre of Chemistry and Biology - Centro Interdisciplinar de Química e Bioloxía (CICA), BIOENGIN Group, University of A Coruña, E-15008-A Coruña, Spain
| | - Alexandra Pereira
- Center for Microbial Ecology and Technology (CMET), Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, Ghent 9000, Belgium; Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Frieda Saeysstraat, Ghent 9052, Belgium
| | - María C Veiga
- Chemical Engineering Laboratory, Faculty of Sciences and Interdisciplinary Centre of Chemistry and Biology - Centro Interdisciplinar de Química e Bioloxía (CICA), BIOENGIN Group, University of A Coruña, E-15008-A Coruña, Spain
| | - Christian Kennes
- Chemical Engineering Laboratory, Faculty of Sciences and Interdisciplinary Centre of Chemistry and Biology - Centro Interdisciplinar de Química e Bioloxía (CICA), BIOENGIN Group, University of A Coruña, E-15008-A Coruña, Spain
| | - Ramon Ganigué
- Center for Microbial Ecology and Technology (CMET), Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, Ghent 9000, Belgium; Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Frieda Saeysstraat, Ghent 9052, Belgium.
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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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Lanfranchi A, Desmond-Le Quéméner E, Magdalena JA, Cavinato C, Trably E. Conversion of wine lees and waste activated sludge into caproate and heptanoate: Thermodynamic and microbiological insights. BIORESOURCE TECHNOLOGY 2024; 408:131126. [PMID: 39029767 DOI: 10.1016/j.biortech.2024.131126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Revised: 06/27/2024] [Accepted: 07/16/2024] [Indexed: 07/21/2024]
Abstract
In this study, wine lees and waste activated sludge (WAS) were co-fermented for the first time in a 4:1 ratio (COD basis) at 20, 40, 70 and 100 gCOD/L, in batch at 37 °C and pH 7.0. The substrates were successfully converted to caproate (C6) and heptanoate (C7) with a high selectivity (40.2 % at 40 gCOD/L). The rapidly-growing chain-elongating microbiome was enriched inClostridiaceaeandOscillospiraceae, representing together 3.4-8.8 % of the community. Substrate concentrations higher than 40 gCOD/L negatively affected C6 and C7 selectivities and yields, probably due to microbial inhibition by high ethanol concentrations (15.82-22.93 g/L). At 70 and 100 gCOD/L, chain elongation shifted from ethanol-based to lactate-based, with a microbiome enriched in the lactic acid bacteriaRoseburia intestinalis(27.3 %) andEnterococcus hirae(13.8 %). The partial pressure of H2(pH2) was identified by thermodynamic analysis as a fundamental parameter for controlling ethanol oxidation and improving C6 and C7 selectivities.
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Affiliation(s)
- A Lanfranchi
- INRAE, Univ Montpellier, LBE, 102 Avenue Des Etangs, 11100 Narbonne, France; Dipartimento di Scienze Ambientali, Informatica e Statistica, Università Ca' Foscari Venezia, Mestre 30174, Italy.
| | | | - J A Magdalena
- INRAE, Univ Montpellier, LBE, 102 Avenue Des Etangs, 11100 Narbonne, France; Vicerrectorado de Investigación Y Transferencia de La Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - C Cavinato
- Dipartimento di Scienze Ambientali, Informatica e Statistica, Università Ca' Foscari Venezia, Mestre 30174, Italy
| | - E Trably
- INRAE, Univ Montpellier, LBE, 102 Avenue Des Etangs, 11100 Narbonne, France
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Niu C, Zhao X, Shi D, Ying Y, Wu M, Lai CY, Guo J, Hu S, Liu T. Bioreduction of chromate in a syngas-based membrane biofilm reactor. JOURNAL OF HAZARDOUS MATERIALS 2024; 470:134195. [PMID: 38581872 DOI: 10.1016/j.jhazmat.2024.134195] [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: 01/02/2024] [Revised: 03/07/2024] [Accepted: 03/31/2024] [Indexed: 04/08/2024]
Abstract
This study leveraged synthesis gas (syngas), a renewable resource attainable through the gasification of biowaste, to achieve efficient chromate removal from water. To enhance syngas transfer efficiency, a membrane biofilm reactor (MBfR) was employed. Long-term reactor operation showed a stable and high-level chromate removal efficiency > 95%, yielding harmless Cr(III) precipitates, as visualised by scanning electron microscopy and energy dispersive X-ray analysis. Corresponding to the short hydraulic retention time of 0.25 days, a high chromate removal rate of 80 µmol/L/d was attained. In addition to chromate reduction, in situ production of volatile fatty acids (VFAs) by gas fermentation was observed. Three sets of in situ batch tests and two groups of ex situ batch tests jointly unravelled the mechanisms, showing that biological chromate reduction was primarily driven by VFAs produced from in situ syngas fermentation, whereas hydrogen originally present in the syngas played a minor role. 16 S rRNA gene amplicon sequencing has confirmed the enrichment of syngas-fermenting bacteria (such as Sporomusa), who performed in situ gas fermentation leading to the synthesis of VFAs, and organics-utilising bacteria (such as Aquitalea), who utilised VFAs to drive chromate reduction. These findings, combined with batch assays, elucidate the pathways orchestrating synergistic interactions between fermentative microbial cohorts and chromate-reducing microorganisms. The findings facilitate the development of cost-effective strategies for groundwater and drinking water remediation and present an alternative application scenario for syngas.
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Affiliation(s)
- Chenkai Niu
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Xinyu Zhao
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Danting Shi
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, 999077, Hong Kong Special Administrative Region of China
| | - Yifeng Ying
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Mengxiong Wu
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Chun-Yu Lai
- College of Environmental and Resource Science, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Jianhua Guo
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Shihu Hu
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Tao Liu
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, St. Lucia, Queensland 4072, Australia; Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, 999077, Hong Kong Special Administrative Region of China.
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7
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Zhao W, Jiang H, Dong W, Liang Q, Yan B, Zhang Y. Elevated caproic acid production from one-stage anaerobic fermentation of organic waste and its selective recovery by electro-membrane process. BIORESOURCE TECHNOLOGY 2024; 399:130647. [PMID: 38561152 DOI: 10.1016/j.biortech.2024.130647] [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: 01/15/2024] [Revised: 03/27/2024] [Accepted: 03/29/2024] [Indexed: 04/04/2024]
Abstract
A constructed microbial consortia-based strategy to enhance caproic acid production from one-stage mixed-fermentation of glucose was developed, which incubated with acidogens (Clostridium sensu stricto 1, 11 dominated) and chain elongators (including Clostridium sensu stricto 12, Sporanaerobacter, and Caproiciproducens) acclimated from anaerobic sludge. Significant product upgrading toward caproic acid (8.31 g‧L-1) and improved substrate degradation was achieved, which can be greatly attributed to the lactic acid platform. Whereas, a small amount of caproic acid was observed in the control incubating with acidogens, with an average concentration of 2.09 g‧L-1. The strategy accelerated the shape and cooperation of the specific microbial community dominated by Clostridium sensu stricto and Caproiciproducens, which thereby contributed to caproic acid production via the fatty acid biosynthesis pathway. Moreover, the tailored electrodialysis with bipolar membrane enabled progressive up-concentration and acidification, allowing selective separation of caproic acid as an immiscible product with a purity of 82.58 % from the mixture.
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Affiliation(s)
- Wenyan Zhao
- College of Environment and Ecology, Hunan Agricultural University, No. 1 Nongda Road, Changsha 410128, China; Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189 Songling Road, Laoshan District, Qingdao 266101, China; University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China
| | - Heqing Jiang
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189 Songling Road, Laoshan District, Qingdao 266101, China; University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China
| | - Wenjian Dong
- College of Environment and Ecology, Hunan Agricultural University, No. 1 Nongda Road, Changsha 410128, China
| | - Qiaochu Liang
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, 53 Zhengzhou Road, Qingdao 266042, China
| | - Binghua Yan
- College of Environment and Ecology, Hunan Agricultural University, No. 1 Nongda Road, Changsha 410128, China.
| | - Yang Zhang
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, 53 Zhengzhou Road, Qingdao 266042, China
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de Leeuw KD, van Willigen MJW, Vrauwdeunt T, Strik DPPTB. CO 2 supply is a powerful tool to control homoacetogenesis, chain elongation and solventogenesis in ethanol and carboxylate fed reactor microbiomes. Front Bioeng Biotechnol 2024; 12:1329288. [PMID: 38720876 PMCID: PMC11076876 DOI: 10.3389/fbioe.2024.1329288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Accepted: 03/25/2024] [Indexed: 05/12/2024] Open
Abstract
Anaerobic fermentation technology enables the production of medium chain carboxylates and alcohols through microbial chain elongation. This involves steering reactor microbiomes to yield desired products, with CO2 supply playing a crucial role in controlling ethanol-based chain elongation and facilitating various bioprocesses simultaneously. In the absence of CO2 supply (Phase I), chain elongation predominantly led to n-caproate with a high selectivity of 96 Cmol%, albeit leaving approximately 80% of ethanol unconverted. During this phase, C. kluyveri and Proteiniphilum-related species dominated the reactors. In Phase II, with low CO2 input (2.0 NmL L-1 min-1), formation of n-butyrate, butanol, and hexanol was stimulated. Increasing CO2 doses in Phase III (6 NmL L-1 min-1) led to CO2 utilization via homoacetogenesis, coinciding with the enrichment of Clostridium luticellarii, a bacterium that can use CO2 as an electron acceptor. Lowering CO2 dose to 0.5 NmL L-1 min-1 led to a shift in microbiome composition, diminishing the dominance of C. luticellarii while increasing C. kluyveri abundance. Additionally, other Clostridia, Proteiniphilum, and Lactobacillus sakei-related species became prevalent. This decrease in CO2 load from 6 to 0.5 NmL L-1 min-1 minimized excessive ethanol oxidation from 30%-50% to 0%-3%, restoring a microbiome favoring net n-butyrate consumption and n-caproate production. The decreased ethanol oxidation coincided with the resurgence of hydrogen formation at partial pressures above 1%. High concentrations of butyrate, caproate, and ethanol in the reactor, along with low acetate concentration, promoted the formation of butanol and hexanol. It is evident that CO2 supply is indispensable for controlling chain elongation in an open culture and it can be harnessed to stimulate higher alcohol formation or induce CO2 utilization as an electron acceptor.
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Affiliation(s)
- Kasper D. de Leeuw
- Environmental Technology, Wageningen University and Research, Wageningen, Netherlands
- ChainCraft B.V., Amsterdam, Netherlands
| | | | - Ton Vrauwdeunt
- Environmental Technology, Wageningen University and Research, Wageningen, Netherlands
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Wang Y, Chen F, Guo H, Sun P, Zhu T, Horn H, Liu Y. Permanganate (PM) pretreatment improves medium-chain fatty acids production from sewage sludge: The role of PM oxidation and in-situ formed manganese dioxide. WATER RESEARCH 2024; 249:120869. [PMID: 38007897 DOI: 10.1016/j.watres.2023.120869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Revised: 11/03/2023] [Accepted: 11/12/2023] [Indexed: 11/28/2023]
Abstract
Medium-chain fatty acids (MCFAs) production from sewage sludge is mainly restricted by the complex substrate structure, competitive metabolism and low electron transfer rate. This study proposes a novel permanganate (PM)-based strategy to promote sludge degradation and MCFAs production. Results show that PM pretreatment significantly increases MCFAs production, i.e., attaining 12,036 mg COD/L, and decreases the carbon fluxes of electron acceptor (EA)/electron donor (ED) to byproducts. Further analysis reveals that PM oxidation enhances the release and biochemical conversion of organic components via disrupting extracellular polymers (EPS) structure and reducing viable cells ratio, providing directly available EA for chain elongation (CE). The microbial activity positively correlated with MCFAs generation are apparently heightened, while the competitive metabolism of CE (i.e., methanogensis) can be completely inhibited. Accordingly, the functional bacteria related to critical bio-steps and dissimilatory manganese reduction are largely enriched. Further mechanism exploration indicates that the main contributors for sludge solubilization are 1O2 (61.6 %) and reactive manganese species (RMnS), i.e., Mn(V)/Mn(VI) (22.3 %) and Mn(III) (∼16.1 %). As the main reducing product of PM reaction, manganese dioxide (MnO2) can enable the formation of microbial aggregates, and serve as electron shuttles to facilitate the carbon fluxes to MCFAs during CE process. Overall, this strategy can achieve simultaneous hydrogen recovery, weaken competitive metabolisms and provide electron transfer accelerator for CE reactions.
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Affiliation(s)
- Yufen Wang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Feng Chen
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Haixiao Guo
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Peizhe Sun
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Tingting Zhu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Harald Horn
- Engler-Bunte-Institut, Water Chemistry and Water Technology, Karlsruhe Institute of Technology, Engler-Bunte-Ring 9, Karlsruhe 76131, Germany
| | - Yiwen Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China.
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Ulčar B, Regueira A, Podojsteršek M, Boon N, Ganigué R. Why do lactic acid bacteria thrive in chain elongation microbiomes? Front Bioeng Biotechnol 2024; 11:1291007. [PMID: 38274012 PMCID: PMC10809155 DOI: 10.3389/fbioe.2023.1291007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 12/11/2023] [Indexed: 01/27/2024] Open
Abstract
Efficient waste management is necessary to transition towards a more sustainable society. An emerging trend is to use mixed culture biotechnology to produce chemicals from organic waste. Insights into the metabolic interactions between community members and their growth characterization are needed to mediate knowledge-driven bioprocess development and optimization. Here, a granular sludge bioprocess for the production of caproic acid through sugar-based chain elongation metabolism was established. Lactic acid and chain-elongating bacteria were identified as the two main functional guilds in the granular community. The growth features of the main community representatives (isolate Limosilactobacillus musocae G03 for lactic acid bacteria and type strain Caproiciproducens lactatifermentans for chain-elongating bacteria) were characterized. The measured growth rates of lactic acid bacteria (0.051 ± 0.005 h-1) were two times higher than those of chain-elongating bacteria (0.026 ± 0.004 h-1), while the biomass yields of lactic acid bacteria (0.120 ± 0.005 g biomass/g glucose) were two times lower than that of chain-elongating bacteria (0.239 ± 0.007 g biomass/g glucose). This points towards differential growth strategies, with lactic acid bacteria resembling that of a r-strategist and chain-elongating bacteria resembling that of a K-strategist. Furthermore, the half-saturation constant of glucose for L. mucosae was determined to be 0.35 ± 0.05 g/L of glucose. A linear trend of caproic acid inhibition on the growth of L. mucosae was observed, and the growth inhibitory caproic acid concentration was predicted to be 13.6 ± 0.5 g/L, which is the highest reported so far. The pre-adjustment of L. mucosae to 4 g/L of caproic acid did not improve the overall resistance to it, but did restore the growth rates at low caproic acid concentrations (1-4 g/L) to the baseline values (i.e., growth rate at 0 g/L of caproic acid). High resistance to caproic acid enables lactic acid bacteria to persist and thrive in the systems intended for caproic acid production. Here, insights into the growth of two main functional guilds of sugar-based chain elongation systems are provided which allows for a better understanding of their interactions and promotes future bioprocess design and optimization.
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Affiliation(s)
- Barbara Ulčar
- Center for Microbial Ecology and Technology (CMET), Department of Biotechnology, Ghent University, Gent, Belgium
- Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Gent, Belgium
| | - Alberte Regueira
- Center for Microbial Ecology and Technology (CMET), Department of Biotechnology, Ghent University, Gent, Belgium
- Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Gent, Belgium
- Department of Chemical Engineering, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Maja Podojsteršek
- Center for Microbial Ecology and Technology (CMET), Department of Biotechnology, Ghent University, Gent, Belgium
- Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Gent, Belgium
| | - Nico Boon
- Center for Microbial Ecology and Technology (CMET), Department of Biotechnology, Ghent University, Gent, Belgium
- Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Gent, Belgium
| | - Ramon Ganigué
- Center for Microbial Ecology and Technology (CMET), Department of Biotechnology, Ghent University, Gent, Belgium
- Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Gent, Belgium
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11
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Candry P, Flinkstrom Z, Henriikka Winkler MK. Wetlands harbor lactic acid-driven chain elongators. Microbiol Spectr 2024; 12:e0210523. [PMID: 38084977 PMCID: PMC10783096 DOI: 10.1128/spectrum.02105-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 11/02/2023] [Indexed: 01/13/2024] Open
Abstract
IMPORTANCE Wetlands are globally significant carbon cycling hotspots that both sequester large amounts of CO2 as soil carbon as well as emit a third of all CH4 globally. Their outsized role in the global carbon cycle makes it critical to understand microbial processes contributing to carbon breakdown and storage in these ecosystems. Here, we confirm the presence of chain-elongating organisms in freshwater wetland soils. These organisms take small carbon compounds formed during the breakdown of biomass and turn them into larger compounds (six to eight carbon organic acids) that may potentially contribute to the formation of soil organic matter and long-term carbon storage. Moreover, we find that these chain-elongating organisms may be widely distributed in wetlands globally. Future work should identify these organisms' contribution to carbon cycling in wetlands and the potential role of the products they form in carbon sequestration in wetlands.
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Affiliation(s)
- Pieter Candry
- Civil and Environmental Engineering, University of Washington, Seattle, Washington, USA
| | - Zachary Flinkstrom
- Civil and Environmental Engineering, University of Washington, Seattle, Washington, USA
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12
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Huo W, Ye R, Hu T, Lu W. CO 2 uptake in ethanol-driven chain elongation system: Microbial metabolic mechanisms. WATER RESEARCH 2023; 247:120810. [PMID: 37918202 DOI: 10.1016/j.watres.2023.120810] [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: 08/22/2023] [Revised: 10/06/2023] [Accepted: 10/28/2023] [Indexed: 11/04/2023]
Abstract
CO2 as a byproduct of organic waste/wastewater fermentation has an important impact on the carboxylate chain elongation. In this study, a semi-continuous flow reactor was used to investigate the effects of CO2 loading rates (Low = 0.5 LCO2·L-1·d-1, Medium = 1.0 LCO2·L-1·d-1, High = 2.0 LCO2·L-1·d-1) on chain elongation system Ethanol and acetate were utilized as the electron donor and electron acceptor, respectively. The results demonstrate that low loading rate of CO2 has a positive effect on chain elongation. The maximum production of caproate and CH4 were observed at a low CO2 loading rate. Caproate production reached 1.88 g COD·L-1·d-1 with a selectivity of 62.55 %, while CH4 production reached 129.7 ml/d, representing 47.4 % of the total. Metagenomic analysis showed that low loading rate of CO2 favored the enrichment of Clostridium kluyveri, with its abundance being 3.8 times higher than at of high CO2 loading rate. Metatranscriptomic analysis revealed that high CO2 loading rate induced oxidative stress in microorganisms, as evidenced by increased expression of heat shock proteins and superoxide dismutase genes. Further investigation suggested that genes associated with the reverse β-oxidation pathway, CO2 uptake pathway and hydrogenotrophic methanogenesis pathway were reduced at high CO2 loading rate. These findings provide insight into the underlying mechanisms of how CO2 affects chain elongation, and it could be a crucial reason for the poor performance of chain elongation systems with high endogenous CO2 production.
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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
| | - Tong Hu
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Wenjing Lu
- School of Environment, Tsinghua University, Beijing 100084, China.
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13
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Candry P, Chadwick GL, Caravajal-Arroyo JM, Lacoere T, Winkler MKH, Ganigué R, Orphan VJ, Rabaey K. Trophic interactions shape the spatial organization of medium-chain carboxylic acid producing granular biofilm communities. THE ISME JOURNAL 2023; 17:2014-2022. [PMID: 37715042 PMCID: PMC10579388 DOI: 10.1038/s41396-023-01508-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 08/30/2023] [Accepted: 08/31/2023] [Indexed: 09/17/2023]
Abstract
Granular biofilms producing medium-chain carboxylic acids (MCCA) from carbohydrate-rich industrial feedstocks harbor highly streamlined communities converting sugars to MCCA either directly or via lactic acid as intermediate. We investigated the spatial organization and growth activity patterns of MCCA producing granular biofilms grown on an industrial side stream to test (i) whether key functional guilds (lactic acid producing Olsenella and MCCA producing Oscillospiraceae) stratified in the biofilm based on substrate usage, and (ii) whether spatial patterns of growth activity shaped the unique, lenticular morphology of these biofilms. First, three novel isolates (one Olsenella and two Oscillospiraceae species) representing over half of the granular biofilm community were obtained and used to develop FISH probes, revealing that key functional guilds were not stratified. Instead, the outer 150-500 µm of the granular biofilm consisted of a well-mixed community of Olsenella and Oscillospiraceae, while deeper layers were made up of other bacteria with lower activities. Second, nanoSIMS analysis of 15N incorporation in biofilms grown in normal and lactic acid amended conditions suggested Oscillospiraceae switched from sugars to lactic acid as substrate. This suggests competitive-cooperative interactions may govern the spatial organization of these biofilms, and suggests that optimizing biofilm size may be a suitable process engineering strategy. Third, growth activities were similar in the polar and equatorial biofilm peripheries, leaving the mechanism behind the lenticular biofilm morphology unexplained. Physical processes (e.g., shear hydrodynamics, biofilm life cycles) may have contributed to lenticular biofilm development. Together, this study develops an ecological framework of MCCA-producing granular biofilms that informs bioprocess development.
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Affiliation(s)
- Pieter Candry
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000, Ghent, Belgium
- Civil and Environmental Engineering, University of Washington, 201 More Hall, Box 352700, Seattle, WA, 98195-2700, USA
| | - Grayson L Chadwick
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, 91125, USA
| | - José Maria Caravajal-Arroyo
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Tim Lacoere
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | | | - Ramon Ganigué
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000, Ghent, Belgium
- Center for Advanced Processes and Technology for Urban Resource Recovery (CAPTURE), Frieda Saeysstraat 1, 9000, Ghent, Belgium
| | - Victoria J Orphan
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Korneel Rabaey
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000, Ghent, Belgium.
- Center for Advanced Processes and Technology for Urban Resource Recovery (CAPTURE), Frieda Saeysstraat 1, 9000, Ghent, Belgium.
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14
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Wu SL, Wei W, Ngo HH, Guo W, Wang C, Wang Y, Ni BJ. In-situ production of lactate driving the biotransformation of waste activated sludge to medium-chain fatty acid. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 345:118524. [PMID: 37423191 DOI: 10.1016/j.jenvman.2023.118524] [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: 05/16/2023] [Revised: 06/14/2023] [Accepted: 06/25/2023] [Indexed: 07/11/2023]
Abstract
Medium-chain fatty acids (MCFAs) have drawn great attention due to their high energy density and superior hydrophobicity. Waste activated sludge (WAS) has been documented as a renewable feedstock for MCFAs production via anaerobic fermentation. However, MCFAs production from WAS depends on exogenous addition of electron donor (ED, e.g., lactate) for chain elongation (CE) bioprocess, which results in increased economic cost and limited practical application. In this study, a novel biotechnology was proposed to produce MCFAs from WAS with in-situ self-formed lactate by inoculating Yoghurt starter powder containing with Lactobacillales cultures. The batch experimental results revealed that the lactate was in-situ generated from WAS and the maximum production of MCFAs increased from 1.17 to 3.99 g COD/L with the increased addition of Lactobacillales cultures from 6✕107 to 2.3✕108 CFU/mL WAS. In continuous long-term test over 97 days, average MCFA production reached up to 3.94 g COD/L with a caproate yield of 82.74% at sludge retention time (SRT) 12 days, and the average MCFA production increased to 5.87 g COD/L with 69.28% caproate and 25.18% caprylate at SRT 15 days. A comprehensive analysis of the metagenome and metatranscriptome demonstrated that the genus of Lactobacillus and Streptococcus were capable of producing lactate from WAS and upgrading to MCFAs. Moreover, another genus, i.e., Candidatus Promineofilum, was firstly revealed that it might be responsible for lactate and MCFAs production. Further investigation of related microbial pathways and enzyme expression suggested that D-lactate dehydrogenase and pyruvate ferredoxin oxidoreductase contributed to lactate and acetyl-CoA production, which were the crucial steps for MCFAs generation and were most actively expressed. This study provides a conceptual framework of MCFAs from WAS with endogenous ED, potentially enhancing the energy recovery from WAS treatment.
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Affiliation(s)
- Shu-Lin Wu
- Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Zhejiang Engineering Research Center of Non-ferrous Metal Waste Recycling, Zhejiang Gongshang University, PR China
| | - Wei Wei
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW, 2007, Australia.
| | - Huu Hao Ngo
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Wenshan Guo
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Chen Wang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, PR China
| | - Yun Wang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, PR China
| | - Bing-Jie Ni
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW, 2007, Australia.
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15
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Allaart MT, Fox BB, Nettersheim IHMS, Pabst M, Sousa DZ, Kleerebezem R. Physiological and stoichiometric characterization of ethanol-based chain elongation in the absence of short-chain carboxylic acids. Sci Rep 2023; 13:17370. [PMID: 37833311 PMCID: PMC10576071 DOI: 10.1038/s41598-023-43682-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 09/27/2023] [Indexed: 10/15/2023] Open
Abstract
Hexanoate is a valuable chemical that can be produced by microorganisms that convert short-chain- to medium-chain carboxylic acids through a process called chain elongation. These microorganisms usually produce mixtures of butyrate and hexanoate from ethanol and acetate, but direct conversion of ethanol to hexanoate is theoretically possible. Steering microbial communities to ethanol-only elongation to hexanoate circumvents the need for acetate addition and simplifies product separation. The biological feasibility of ethanol elongation to hexanoate was validated in batch bioreactor experiments with a Clostridium kluyveri-dominated enrichment culture incubated with ethanol, acetate and butyrate in different ratios. Frequent liquid sampling combined with high-resolution off-gas measurements allowed to monitor metabolic behavior. In experiments with an initial ethanol-to-acetate ratio of 6:1, acetate depletion occurred after ± 35 h of fermentation, which triggered a metabolic shift to direct conversion of ethanol to hexanoate despite the availability of butyrate (± 40 mCmol L-1). When only ethanol and no external electron acceptor was supplied, stable ethanol to hexanoate conversion could be maintained until 60-90 mCmol L-1 of hexanoate was produced. After this, transient production of either acetate and butyrate or butyrate and hexanoate was observed, requiring a putative reversal of the Rnf complex. This was not observed before acetate depletion or in presence of low concentrations (40-60 mCmol L-1) of butyrate, suggesting a stabilizing or regulatory role of butyrate or butyrate-related catabolic intermediates. This study sheds light on previously unknown versatility of chain elongating microbes and provides new avenues for optimizing (waste) bioconversion for hexanoate production.
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Affiliation(s)
| | - Bartholomeus B Fox
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | | | - Martin Pabst
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Diana Z Sousa
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
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16
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Robles A, Sundar SV, Mohana Rangan S, Delgado AG. Butanol as a major product during ethanol and acetate chain elongation. Front Bioeng Biotechnol 2023; 11:1181983. [PMID: 37274171 PMCID: PMC10233103 DOI: 10.3389/fbioe.2023.1181983] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 05/08/2023] [Indexed: 06/06/2023] Open
Abstract
Chain elongation is a relevant bioprocess in support of a circular economy as it can use a variety of organic feedstocks for production of valuable short and medium chain carboxylates, such as butyrate (C4), caproate (C6), and caprylate (C8). Alcohols, including the biofuel, butanol (C4), can also be generated in chain elongation but the bioreactor conditions that favor butanol production are mainly unknown. In this study we investigated production of butanol (and its precursor butyrate) during ethanol and acetate chain elongation. We used semi-batch bioreactors (0.16 L serum bottles) fed with a range of ethanol concentrations (100-800 mM C), a constant concentration of acetate (50 mM C), and an initial total gas pressure of ∼112 kPa. We showed that the butanol concentration was positively correlated with the ethanol concentration provided (up to 400 mM C ethanol) and to chain elongation activity, which produced H2 and further increased the total gas pressure. In bioreactors fed with 400 mM C ethanol and 50 mM C acetate, a concentration of 114.96 ± 9.26 mM C butanol (∼2.13 g L-1) was achieved after five semi-batch cycles at a total pressure of ∼170 kPa and H2 partial pressure of ∼67 kPa. Bioreactors with 400 mM C ethanol and 50 mM C acetate also yielded a butanol to butyrate molar ratio of 1:1. At the beginning of cycle 8, the total gas pressure was intentionally decreased to ∼112 kPa to test the dependency of butanol production on total pressure and H2 partial pressure. The reduction in total pressure decreased the molar ratio of butanol to butyrate to 1:2 and jolted H2 production out of an apparent stall. Clostridium kluyveri (previously shown to produce butyrate and butanol) and Alistipes (previously linked with butyrate production) were abundant amplicon sequence variants in the bioreactors during the experimental phases, suggesting the microbiome was resilient against changes in bioreactor conditions. The results from this study clearly demonstrate the potential of ethanol and acetate-based chain elongation to yield butanol as a major product. This study also supports the dependency of butanol production on limiting acetate and on high total gas and H2 partial pressures.
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Affiliation(s)
- Aide Robles
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ, United States
- School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ, United States
- Engineering Research Center for Bio-Mediated and Bio-Inspired Geotechnics, Arizona State University, Tempe, AZ, United States
| | - Skanda Vishnu Sundar
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ, United States
- School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ, United States
| | - Srivatsan Mohana Rangan
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ, United States
- School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ, United States
- Engineering Research Center for Bio-Mediated and Bio-Inspired Geotechnics, Arizona State University, Tempe, AZ, United States
| | - Anca G. Delgado
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ, United States
- School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ, United States
- Engineering Research Center for Bio-Mediated and Bio-Inspired Geotechnics, Arizona State University, Tempe, AZ, United States
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17
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Walters KA, Mohan G, Myers KS, Ingle AT, Donohue TJ, Noguera DR. A metagenome-level analysis of a microbial community fermenting ultra-filtered milk permeate. Front Bioeng Biotechnol 2023; 11:1173656. [PMID: 37324413 PMCID: PMC10263058 DOI: 10.3389/fbioe.2023.1173656] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 05/03/2023] [Indexed: 06/17/2023] Open
Abstract
Fermentative microbial communities have the potential to serve as biocatalysts for the conversion of low-value dairy coproducts into renewable chemicals, contributing to a more sustainable global economy. To develop predictive tools for the design and operation of industrially relevant strategies that utilize fermentative microbial communities, there is a need to determine the genomic features of community members that are characteristic to the accumulation of different products. To address this knowledge gap, we performed a 282-day bioreactor experiment with a microbial community that was fed ultra-filtered milk permeate, a low-value coproduct from the dairy industry. The bioreactor was inoculated with a microbial community from an acid-phase digester. A metagenomic analysis was used to assess microbial community dynamics, construct metagenome-assembled genomes (MAGs), and evaluate the potential for lactose utilization and fermentation product synthesis of community members represented by the assembled MAGs. This analysis led us to propose that, in this reactor, members of the Actinobacteriota phylum are important in the degradation of lactose, via the Leloir pathway and the bifid shunt, and the production of acetic, lactic, and succinic acids. In addition, members of the Firmicutes phylum contribute to the chain-elongation-mediated production of butyric, hexanoic, and octanoic acids, with different microbes using either lactose, ethanol, or lactic acid as the growth substrate. We conclude that genes encoding carbohydrate utilization pathways, and genes encoding lactic acid transport into the cell, electron confurcating lactate dehydrogenase, and its associated electron transfer flavoproteins, are genomic features whose presence in Firmicutes needs to be established to infer the growth substrate used for chain elongation.
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Affiliation(s)
- Kevin A. Walters
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, United States
- Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, WI, United States
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States
| | - Geethaanjali Mohan
- Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, WI, United States
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States
| | - Kevin S. Myers
- Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, WI, United States
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States
| | - Abel T. Ingle
- Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, WI, United States
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States
- Department of Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, WI, United States
| | - Timothy J. Donohue
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, United States
- Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, WI, United States
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States
| | - Daniel R. Noguera
- Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, WI, United States
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States
- Department of Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, WI, United States
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18
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Zhang C, Liu H, Wu P, Li J, Zhang J. Clostridium kluyveri enhances caproate production by synergistically cooperating with acetogens in mixed microbial community of electro-fermentation system. BIORESOURCE TECHNOLOGY 2023; 369:128436. [PMID: 36470493 DOI: 10.1016/j.biortech.2022.128436] [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: 10/24/2022] [Revised: 11/30/2022] [Accepted: 12/01/2022] [Indexed: 06/17/2023]
Abstract
As a chain elongation (CE) model strain, Clostridium kluyveri has been used in the studies of bioaugmentation of caproate production. However, its application in the novel electro-fermentation CE system for bioaugmentation is still unclear. In this study, the CE performances, with or without bioaugmentation and in conventional or electro-fermentation systems were compared. And the mechanism of electrochemical-bioaugmentation by constructing a co-culture of Acetobacterium woodii and Clostridium kluyveri were further verified. Results demonstrated that the bioaugmentation treatments have better CE performance, especially in electro-fermentation system, with a highest caproate concentration of 4.68 g·L-1. Mechanism analysis revealed that C. kluyveri responded to the electric field and emerged synergy with the acetogens, which was proved by the increases of C. kluyveri colonization and the acetogens abundance in biofilm and supported by the co-culture experiment. This study provides a novel insight of microbial synergy mechanism of C. kluyveri during CE bioaugmentation in electro-fermentation system.
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Affiliation(s)
- Chao Zhang
- School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - He Liu
- School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China; Jiangsu Key Laboratory of Anaerobic Biotechnology, Wuxi 214122, China; Jiangsu Collaborative Innovation Center of Water Treatment Technology and Material, Suzhou University of Science and Technology, 215011, China.
| | - Ping Wu
- School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Jing Li
- School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Jie Zhang
- School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China
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19
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Crognale S, Massimi A, Sbicego M, Braguglia CM, Gallipoli A, Gazzola G, Gianico A, Tonanzi B, Di Pippo F, Rossetti S. Ecology of food waste chain-elongating microbiome. Front Bioeng Biotechnol 2023; 11:1157243. [PMID: 37113665 PMCID: PMC10126515 DOI: 10.3389/fbioe.2023.1157243] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 03/31/2023] [Indexed: 04/29/2023] Open
Abstract
Microbial chain elongation has emerged as a valuable bioprocess for obtaining marketable products, such as medium chain fatty acids usable in several industrial applications, from organic waste. The understanding of the microbiology and microbial ecology in these systems is crucial to apply these microbiomes in reliable production processes controlling microbial pathways to promote favourable metabolic processes, which will in turn increase product specificity and yields. In this research, the dynamics, cooperation/competition and potentialities of bacterial communities involved in the long-term lactate-based chain elongation process from food waste extract were evaluated under different operating conditions by DNA/RNA amplicon sequencing and functional profile prediction. The feeding strategies and the applied organic loading rates strongly affected the microbial community composition. The use of food waste extract promoted the selection of primary fermenters (i.e., Olsenella, Lactobacillus) responsible for the in situ production of electron donors (i.e., lactate). The discontinuous feeding and the organic loading rate 15 gCOD L-1 d-1 selected the best performing microbiome in which microbes coexist and cooperate to complete the chain elongation process. Both at DNA and RNA level, this microbiome was composed by the lactate producer Olsenella, the short chain fatty acids producers Anaerostipes, Clostridium sensu stricto 7, C. sensu stricto 12, Corynebacterium, Erysipelotrichaceae UCG-004, F0332, Leuconostoc, and the chain elongator Caproiciproducens. This microbiome also showed the highest predicted abundance of short-chain acyl-CoA dehydrogenase, the functional enzyme responsible for the chain elongation process. The combined approach herein used allowed to study the microbial ecology of chain elongation process from food waste by identifying the main functional groups, establishing the presence of potential biotic interactions within the microbiomes, and predicting metabolic potentialities. This study provided pivotal indications for the selection of high-performance microbiome involved in caproate production from food waste that can serve as a basis for further improving system performance and engineering the process scale-up.
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20
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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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21
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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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22
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Meinel M, Delgado AG, Ilhan ZE, Aguero ML, Aguiar S, Krajmalnik-Brown R, Torres CI. Organic carbon metabolism is a main determinant of hydrogen demand and dynamics in anaerobic soils. CHEMOSPHERE 2022; 303:134877. [PMID: 35577129 DOI: 10.1016/j.chemosphere.2022.134877] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 04/29/2022] [Accepted: 05/04/2022] [Indexed: 06/15/2023]
Abstract
Hydrogen (H2) is a crucial electron donor for many processes in the environment including nitrate-, sulfate- and, iron-reduction, homoacetogenesis, and methanogenesis, and is a major determinant of microbial competition and metabolic pathways in groundwater, sediments, and soils. Despite the importance of H2 for many microbial processes in the environment, the total H2 consuming capacity (or H2 demand) of soils is generally unknown. Using soil microcosms with added H2, the aims of this study were 1) to measure the H2 demand of geochemically diverse soils and 2) to define the processes leading to this demand. Study results documented a large range of H2 demand in soil (0.034-1.2 millielectron equivalents H2 g-1 soil). The measured H2 demand greatly exceeded the theoretical demand predicted based on measured concentrations of common electron acceptors initially present in a library of 15 soils. While methanogenesis accounted for the largest fraction of H2 demand, humic acid reduction and acetogenesis were also significant contributing H2-consuming processes. Much of the H2 demand could be attributed to CO2 produced during incubation from fermentation and/or acetoclastic methanogenesis. The soil initial total organic carbon showed the strongest correlation to H2 demand. Besides external additions, H2 was likely generated or cycled in the microcosms. Apart from fermentative H2 production, carboxylate elongation to produce C4-C7 fatty acids may have accounted for additional H2 production in these soils. Many of these processes, especially the organic carbon contribution is underestimated in microbial models for H2 consumption in natural soil ecosystems or during bioremediation of contaminants in soils.
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Affiliation(s)
- Megan Meinel
- Arizona State University, Biodesign Swette Center for Environmental Biotechnology, 1001 S McAllister Ave, Tempe, AZ, USA; Arizona State University, School of Sustainable Engineering and the Built Environment, 1001 S McAllister Ave, Tempe, AZ, USA; Arizona State University, Engineering Research Center for Bio-mediated and Bio-inspired Geotechnics (CBBG), 1001 S McAllister Ave, Tempe, AZ, USA
| | - Anca G Delgado
- Arizona State University, Biodesign Swette Center for Environmental Biotechnology, 1001 S McAllister Ave, Tempe, AZ, USA; Arizona State University, School of Sustainable Engineering and the Built Environment, 1001 S McAllister Ave, Tempe, AZ, USA; Arizona State University, Engineering Research Center for Bio-mediated and Bio-inspired Geotechnics (CBBG), 1001 S McAllister Ave, Tempe, AZ, USA
| | - Zehra Esra Ilhan
- Arizona State University, Biodesign Swette Center for Environmental Biotechnology, 1001 S McAllister Ave, Tempe, AZ, USA
| | - Marisol Luna Aguero
- Arizona State University, Biodesign Swette Center for Environmental Biotechnology, 1001 S McAllister Ave, Tempe, AZ, USA; Arizona State University, School of Sustainable Engineering and the Built Environment, 1001 S McAllister Ave, Tempe, AZ, USA; Arizona State University, Engineering Research Center for Bio-mediated and Bio-inspired Geotechnics (CBBG), 1001 S McAllister Ave, Tempe, AZ, USA
| | - Samuel Aguiar
- Arizona State University, Biodesign Swette Center for Environmental Biotechnology, 1001 S McAllister Ave, Tempe, AZ, USA; Arizona State University, Engineering Research Center for Bio-mediated and Bio-inspired Geotechnics (CBBG), 1001 S McAllister Ave, Tempe, AZ, USA
| | - Rosa Krajmalnik-Brown
- Arizona State University, Biodesign Swette Center for Environmental Biotechnology, 1001 S McAllister Ave, Tempe, AZ, USA; Arizona State University, School of Sustainable Engineering and the Built Environment, 1001 S McAllister Ave, Tempe, AZ, USA; Arizona State University, Engineering Research Center for Bio-mediated and Bio-inspired Geotechnics (CBBG), 1001 S McAllister Ave, Tempe, AZ, USA; Arizona State University, Biodesign Center for Health Through Microbiomes, 1001 S McAllister Ave, Tempe, AZ, USA.
| | - César I Torres
- Arizona State University, Biodesign Swette Center for Environmental Biotechnology, 1001 S McAllister Ave, Tempe, AZ, USA; Arizona State University, Engineering Research Center for Bio-mediated and Bio-inspired Geotechnics (CBBG), 1001 S McAllister Ave, Tempe, AZ, USA; Arizona State University, School for Engineering of Matter, Transport & Energy, 1001 S McAllister Ave, Tempe, AZ, USA.
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23
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Sarkar O, Rova U, Christakopoulos P, Matsakas L. Effect of metals on the regulation of acidogenic metabolism enhancing biohydrogen and carboxylic acids production from brewery spent grains: Microbial dynamics and biochemical analysis. Eng Life Sci 2022; 22:650-661. [PMID: 36247830 PMCID: PMC9550736 DOI: 10.1002/elsc.202200030] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 08/09/2022] [Accepted: 08/18/2022] [Indexed: 11/07/2022] Open
Abstract
The present study reports the mixed culture acidogenic production of biohydrogen and carboxylic acids (CA) from brewery spent grains (BSG) in the presence of high concentrations of cobalt, iron, nickel, and zinc. The metals enhanced biohydrogen output by 2.39 times along with CA biosynthesis by 1.73 times. Cobalt and iron promoted the acetate and butyrate pathways, leading to the accumulation of 5.14 gCOD/L of acetic and 11.36 gCOD/L of butyric acid. The production of solvents (ethanol + butanol) was higher with zinc (4.68 gCOD/L) and cobalt (4.45 gCOD/L). A combination of all four metals further enhanced CA accumulation to 42.98 gCOD/L, thus surpassing the benefits accrued from supplementation with individual metals. Additionally, 0.36 and 0.31 mol green ammonium were obtained from protein‐rich brewery spent grain upon supplementation with iron and cobalt, respectively. Metagenomic analysis revealed the high relative abundance of Firmicutes (>90%), of which 85.02% were Clostridium, in mixed metal‐containing reactors. Finally, a significant correlation of dehydrogenase activity with CA and biohydrogen evolution was observed upon metal addition.
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Affiliation(s)
- Omprakash Sarkar
- Biochemical Process Engineering Division of Chemical Engineering Department of Civil, Environmental, and Natural Resources Engineering Luleå University of Technology Luleå Sweden
| | - Ulrika Rova
- Biochemical Process Engineering Division of Chemical Engineering Department of Civil, Environmental, and Natural Resources Engineering Luleå University of Technology Luleå Sweden
| | - Paul Christakopoulos
- Biochemical Process Engineering Division of Chemical Engineering Department of Civil, Environmental, and Natural Resources Engineering Luleå University of Technology Luleå Sweden
| | - Leonidas Matsakas
- Biochemical Process Engineering Division of Chemical Engineering Department of Civil, Environmental, and Natural Resources Engineering Luleå University of Technology Luleå Sweden
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24
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Strik DPBTB, Ganigué R, Angenent LT. Editorial: Microbial Chain Elongation- Close the Carbon Loop by Connecting-Communities. Front Bioeng Biotechnol 2022; 10:894490. [PMID: 35880097 PMCID: PMC9307487 DOI: 10.3389/fbioe.2022.894490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 06/20/2022] [Indexed: 11/25/2022] Open
Affiliation(s)
- David P. B. T. B. Strik
- Environmental Technology, Wageningen University and Research, Wageningen, Netherlands
- *Correspondence: David P. B. T. B. Strik,
| | - Ramon Ganigué
- Center for Microbial Ecology and Technology, Ghent University, Ghent, Belgium
- Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Gent, Belgium
| | - Largus T. Angenent
- Environmental Biotechnology Group, Center of Applied Geosciences, University of Tübingen, Tübingen, Germany
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25
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Mariën Q, Ulčar B, Verleyen J, Vanthuyne B, Ganigué R. High-rate conversion of lactic acid-rich streams to caproic acid in a fermentative granular system. BIORESOURCE TECHNOLOGY 2022; 355:127250. [PMID: 35562021 DOI: 10.1016/j.biortech.2022.127250] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 04/26/2022] [Accepted: 04/27/2022] [Indexed: 06/15/2023]
Abstract
Lactic acid-driven chain elongation enables upgrading low-value organic streams into caproic acid. Recently, volumetric production rates over 0.5 g L-1 h-1have been reported for carbohydrate-rich streams in expanded granular sludge bed (EGSB) reactors. However, many target streams contain mixtures of carbohydrates and lactic acid, and little is known about their impact on product profile and microbial ecology, or the importance of carbohydrates as substrate to achieve high rates. This manuscript investigated varying glucose-to-lactate ratios and observed that decreasing glucose-content eliminated odd-chain by-products, while glucose omission required acetic acid addition to support lactic acid conversion. Decreasing the glucose-content fed resulted in decreasing amounts of granular biomass, with the disappearance of granules when no glucose was fed. Lowering the HRT to 0.3 days while feeding only lactic and acetic acid likely triggered re-granulation, enabling the highest lactic acid-driven caproic acid production rates reported thus far at 16.4 ± 1.7 g L-1 d-1.
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Affiliation(s)
- Quinten Mariën
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000 Ghent, Belgium; Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Frieda Saeysstraat 1, 9000 Ghent, Belgium
| | - Barbara Ulčar
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000 Ghent, Belgium; Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Frieda Saeysstraat 1, 9000 Ghent, Belgium
| | - Jesper Verleyen
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - Benjamin Vanthuyne
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - Ramon Ganigué
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000 Ghent, Belgium; Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Frieda Saeysstraat 1, 9000 Ghent, Belgium.
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26
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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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27
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Katakojwala R, Tharak A, Sarkar O, Venkata Mohan S. Design and evaluation of gas fermentation systems for CO 2 reduction to C2 and C4 fatty acids: Non-genetic metabolic regulation with pressure, pH and reaction time. BIORESOURCE TECHNOLOGY 2022; 351:126937. [PMID: 35248708 DOI: 10.1016/j.biortech.2022.126937] [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: 01/22/2022] [Revised: 02/26/2022] [Accepted: 02/28/2022] [Indexed: 06/14/2023]
Abstract
Addressing the carbon emissions through microbial mediated fermentation is an emerging interest. Custom designed and fabricated gas fermentation (GF) systems were evaluated to optimize the headspace pressure, pH (6.5, 7.5, and 8.5), fermentation time, and substrate concentration by employing enriched homoacetogenic chemolithoautotrophs in non-genetic approach. Headspace pressure showed marked influence on the metabolic conversion of inorganic carbon to acetic and butyric acids with 26% higher productivity than the control (atmospheric pressure). Maximum volatile fatty acid (VFA) yield of 3.7 g/L was observed at alkaline pH (8.5) under 2 bar pressure at carbon load of 10 g/L, 96 h). Acetic (3.0 g/L) and butyric (0.7 g/L) acids were the major products upon conversion of 85% of the inorganic substrate. A better in-situ buffering (β = 0.048) at pH 8.5 along with higher reductive current (RCC: -4.4 mA) depicted better performance of GF towards CO2 reduction.
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Affiliation(s)
- Ranaprathap Katakojwala
- Bioengineering and Environmental Sciences Lab, Department of Energy and Environmental Engineering, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad 500 007, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Athmakuri Tharak
- Bioengineering and Environmental Sciences Lab, Department of Energy and Environmental Engineering, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad 500 007, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Omprakash Sarkar
- Bioengineering and Environmental Sciences Lab, Department of Energy and Environmental Engineering, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad 500 007, India
| | - S Venkata Mohan
- Bioengineering and Environmental Sciences Lab, Department of Energy and Environmental Engineering, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad 500 007, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
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28
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Calvo DC, Luna HJ, Arango JA, Torres CI, Rittmann BE. Determining global trends in syngas fermentation research through a bibliometric analysis. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 307:114522. [PMID: 35066199 DOI: 10.1016/j.jenvman.2022.114522] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 01/10/2022] [Accepted: 01/13/2022] [Indexed: 06/14/2023]
Abstract
Syngas fermentation, in which microorganisms convert H2, CO, and CO2 to acids and alcohols, is a promising alternative for carbon cycling and valorization. The intellectual landscape of the topic was characterized through a bibliometric analysis using a search query (SQ) that included all relevant documents on syngas fermentation available through the Web of Science database up to December 31st, 2021. The SQ was validated with a preliminary analysis in bibliometrix and a review of titles and abstracts of all sources. Although syngas fermentation began in the early 1980s, it grew rapidly beginning in 2008, with 92.5% of total publications and 87.3% of total citations from 2008 to 2021. The field has been steadily moving from fundamentals towards applications, suggesting that the field is maturing scientifically. The greatest number of publications and citations are from the USA, and researchers in China, Germany, and Spain also are highly active. Although collaborations have increased in the past few years, author-cluster analysis shows specialized research domains with little collaboration between groups. Based on topic trends, the main challenges to be address are related to mass-transfer limitations, and researchers are starting to explore mixed cultures, genetic engineering, microbial chain elongation, and biorefineries.
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Affiliation(s)
- Diana C Calvo
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ, PO Box 85287-3005, USA; Biodesign Center for Health Through Microbiomes, Arizona State University, Tempe, AZ, PO Box 85287-3005, USA.
| | - Hector J Luna
- Grupo GRESIA, Department of Environmental Engineering, Universidad Antonio Nariño, Bogotá, 110231, Colombia; Environmental and Chemical Technology Group, Department of Chemistry, Federal University of Ouro Preto, Campus University, Campus Universitario, Brazil
| | - Jineth A Arango
- Pontificia Universidad Católica de Valparaíso, Valparaíso, 2362803, Chile.
| | - Cesar I Torres
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ, PO Box 85287-3005, USA.
| | - Bruce E Rittmann
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ, PO Box 85287-3005, USA.
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29
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Metagenome-Assembled Genomes from a Microbiome Converting Xylose to Medium-Chain Carboxylic Acids. Microbiol Resour Announc 2022; 11:e0115121. [PMID: 35343806 PMCID: PMC9022542 DOI: 10.1128/mra.01151-21] [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] [Indexed: 12/02/2022] Open
Abstract
There is growing interest in producing beneficial products from wastes using microbiomes. We previously performed multiomic analyses of a bioreactor microbiome that converted carbohydrate-rich lignocellulosic residues to medium-chain carboxylic acids. Here, we present draft metagenome-assembled genomes from this microbiome, obtained from reactors in which xylose was the primary carbon source.
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30
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Gao J, Qin J, Ye F, Ding F, Liu G, Li A, Ren C, Xu Y. Constructing simplified microbial consortia to improve the key flavour compounds during strong aroma-type Baijiu fermentation. Int J Food Microbiol 2022; 369:109594. [DOI: 10.1016/j.ijfoodmicro.2022.109594] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 02/08/2022] [Accepted: 02/22/2022] [Indexed: 11/25/2022]
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31
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Wang H, Gu Y, Zhao D, Qiao Z, Zheng J, Gao J, Ren C, Xu Y. Caproicibacterium lactatifermentans sp. nov., isolated from pit clay used for the production of Chinese strong aroma-type liquor. Int J Syst Evol Microbiol 2022; 72. [PMID: 35085065 DOI: 10.1099/ijsem.0.005206] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Two recently reported bacterial strains that were identified as the dominant caproate-producing bacteria in pit clay, were further characterized to determine their phylogeny and taxonomy. The two strains, designated as LBM19010T and JNU-WLY1368, were short rod-shaped, Gram-stain-positive, non-motile and strictly anaerobic. Analysis of the 16S rRNA gene sequences revealed that strains LBM19010T and JNU-WLY1368 shared a 16S rRNA gene sequence similarity of 99.93 % and belonged to a recent proposed genus Caproicibacterium in the family Oscillospiraceae. The proposed type strain, LBM19010T, showed the highest 16S rRNA gene sequence similarity to Caproicibacterium amylolyticum LBM18003T (96.34%), followed by Caproiciproducens galactitolivorans JCM 30532T (94.14 %). The pairwise average nucleotide identity and average amino acid identity values between strains LBM19010T and LBM18003T were 74.84 and 76.18 %, respectively. Growth of strain LBM19010T occurred at pH 4.5-7.5 (optimum, pH 5.0-5.5), 20-40 °C (optimum, 35 °C) and with 0-1 % (w/v) NaCl (optimum, 0 %). Strains LBM19010T and JNU-WLY1368 were both able to ferment several hexoses, disaccharides, starch and lactate but not pentoses. Caproate and butyrate were the major end-products from glucose. The predominant cellular fatty acids (>10 %) of strain LBM19010T were C16 : 0 (56.3 %), C14 : 0 DMA (19.5 %) and C14 : 0 (14.9 %). The identified polar lipids of strain LBM19010T were diphosphatidylglycerol, phosphatidylglycerol, three unidentified phospholipids and nine unidentified glycolipids. Based on phylogenetic, phenotypic and chemotaxonomic evidence, strains LBM19010T and JNU-WLY1368 belong to a novel species of the genus Caproicibacterium, for which the name Caproicibacterium lactatifermentans sp. nov. is proposed. The type strain is LBM19010T (=GDMCC 1.1627T=JCM 33782T).
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Affiliation(s)
- Huilin Wang
- Lab of Brewing Microbiology and Applied Enzymology, Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, PR China
| | - Yang Gu
- Lab of Brewing Microbiology and Applied Enzymology, Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, PR China
| | - Dong Zhao
- China Light Industry Key Laboratory of Solid-state Fermentation for Strong Aroma-type Liquor, Yibin 644007, PR China
| | - Zongwei Qiao
- China Light Industry Key Laboratory of Solid-state Fermentation for Strong Aroma-type Liquor, Yibin 644007, PR China
| | - Jia Zheng
- China Light Industry Key Laboratory of Solid-state Fermentation for Strong Aroma-type Liquor, Yibin 644007, PR China
| | - Jiangjing Gao
- Lab of Brewing Microbiology and Applied Enzymology, Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, PR China
| | - Cong Ren
- Lab of Brewing Microbiology and Applied Enzymology, Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, PR China
| | - Yan Xu
- Lab of Brewing Microbiology and Applied Enzymology, Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, PR China
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32
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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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33
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Santhosh J, Sarkar O, Venkata Mohan S. Green Hydrogen-Compressed natural gas (bio-H-CNG) production from food waste: Organic load influence on hydrogen and methane fusion. BIORESOURCE TECHNOLOGY 2021; 340:125643. [PMID: 34375791 DOI: 10.1016/j.biortech.2021.125643] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/17/2021] [Accepted: 07/19/2021] [Indexed: 06/13/2023]
Abstract
Biogenic hydrogen (bioH2) enriched compressed natural gas (bio-H-CNG or biohythane) is emerging interest due to its feasibility to use in the existing transportation infrastructure with induced environmental benefits. This study evaluated the production of bioH2and biomethane (bioCH4) towards bio-H-CNG formation at a varying organic load (OL: 30,40,50 g COD/L) of food waste (FW). Acidogenic reactor operated with FW at 40 g COD/L showed the highest cumulative bioH2production while elevated OL (50 g COD/L)showedhigher cumulative bioCH4production (CMP: 11.92 L) from the methanogenic reactor. BioH2 and bioCH4 produced at different time intervals were combined to assess bio-H-CNG. The nature of biocatalyst and OLsignificantly regulated the composition of bio-H-CNG varying between 0.1 and 0.3 of H2/(H2+CH4) ratio accounting for5-12.6 kJ/g COD. Chain elongation, converting short (C2-C4) to medium-chain fatty acids(Caproic acid,1.16 g/L) was specifically observed during the acidogenic process.
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Affiliation(s)
- J Santhosh
- Bioengineering and Environmental Sciences Lab, Department of Energy and Environmental Engineering, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad-500 007, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Omprakash Sarkar
- Bioengineering and Environmental Sciences Lab, Department of Energy and Environmental Engineering, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad-500 007, India
| | - S Venkata Mohan
- Bioengineering and Environmental Sciences Lab, Department of Energy and Environmental Engineering, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad-500 007, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India.
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Scarborough MJ, Lawson CE, DeCola AC, Gois IM. Microbiomes for sustainable biomanufacturing. Curr Opin Microbiol 2021; 65:8-14. [PMID: 34700205 DOI: 10.1016/j.mib.2021.09.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 09/23/2021] [Accepted: 09/28/2021] [Indexed: 11/30/2022]
Affiliation(s)
- Matthew James Scarborough
- Department of Civil and Environmental Engineering, University of Vermont, Burlington, VT, United States.
| | - Christopher Evan Lawson
- Department of Chemical Engineering & Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Amy Camille DeCola
- Department of Civil and Environmental Engineering, University of Vermont, Burlington, VT, United States
| | - Ian Mateus Gois
- Department of Chemical Engineering & Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
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Adaptability of a caproate-producing bacterium contributes to its dominance in an anaerobic fermentation system. Appl Environ Microbiol 2021; 87:e0120321. [PMID: 34378978 DOI: 10.1128/aem.01203-21] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The transformation of diverse feedstocks into medium-chain fatty acids (MCFAs) by mixed cultures is a promising biorefinery route because of the high value of MCFAs. A particular concern is how to maintain the microbial consortia in mixed cultures to achieve stable MCFA production. Chinese strong aroma-type liquor (Baijiu) fermentation system continually produces caproic acid for decades through a spontaneous inoculation of anaerobes from pit mud into fermented grains. Therefore, illuminating the dominant caproate-producing bacterium (CPB) in pit mud and how the CPB sustains in the spontaneous fermentation system will benefit to reveal the microbiological mechanisms of the stable caproate production. Here, we examined pit mud samples across four Chinese strong aroma-type Baijiu producing areas and found that a caproate-producing Caproicibacterium sp. was widely distributed in these distilleries with relative abundance ranging from 1.4% to 35.5% and an average abundance of 11.4%. Through controlling carbon source availability, we achieved different simplified caproate-producing consortia and found that the growth advantage of Caproicibacterium sp. was highly dependent on glucose. Then two strains, named Caproicibacterium sp. LBM19010 and Caproicibacterium sp. JNU-WLY1368, were isolated from pit mud of two regions. The metabolic versatility of this bacterium utilizing starch, maltose, glucose and lactate reflected its adaptability to the fermentation environment where these carbon sources coexist. The simultaneous utilization of glucose and lactate contributed to the balance between cell growth and pH homeostasis. This study reveals that multiple adaptation strategies employed by the predominant CPB promotes its stability and dominance in a saccharide- and lactate-rich anaerobic habitat. IMPORTANCE Chinese strong aroma-type liquor (Baijiu) fermentation environment is a typical medium-chain fatty acid producing system with complex nutrients. Although several studies have revealed the correlation between microbial community composition and abiotic factors, the adaptation mechanisms of dominant species to abiotic environment are still unknown in this special anaerobic habitat. This study identified the predominant CPB in Chinese strong aroma-type Baijiu fermentation system. Metabolic versatility and flexibility of the dominant CPB with a small-size genome indicated that this bacterium can effectively exploit available carbon and nitrogen sources, which could be a key factor to promote its ecological success in a multi-species environment. The understanding of growth and metabolic features of CPB responsible for its dominance in microbial community will not only contribute to the improvement of Chinese strong aroma-type Baijiu production but also expand its potential industrial applications in caproate production.
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Robles A, Yellowman TL, Joshi S, Mohana Rangan S, Delgado AG. Microbial Chain Elongation and Subsequent Fermentation of Elongated Carboxylates as H 2-Producing Processes for Sustained Reductive Dechlorination of Chlorinated Ethenes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:10398-10410. [PMID: 34283573 DOI: 10.1021/acs.est.1c01319] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In situ anaerobic groundwater bioremediation of trichloroethene (TCE) to nontoxic ethene is contingent on organohalide-respiring Dehalococcoidia, the most common strictly hydrogenotrophic Dehalococcoides mccartyi (D. mccartyi). The H2 requirement for D. mccartyi is fulfilled by adding various organic substrates (e.g., lactate, emulsified vegetable oil, and glucose/molasses), which require fermenting microorganisms to convert them to H2. The net flux of H2 is a crucial controlling parameter in the efficacy of bioremediation. H2 consumption by competing microorganisms (e.g., methanogens and homoacetogens) can diminish the rates of reductive dechlorination or stall the process altogether. Furthermore, some fermentation pathways do not produce H2 or having H2 as a product is not always thermodynamically favorable under environmental conditions. Here, we report on a novel application of microbial chain elongation as a H2-producing process for reductive dechlorination. In soil microcosms bioaugmented with dechlorinating and chain-elongating enrichment cultures, near stoichiometric conversion of TCE (0.07 ± 0.01, 0.60 ± 0.03, and 1.50 ± 0.20 mmol L-1 added sequentially) to ethene was achieved when initially stimulated by chain elongation of acetate and ethanol. Chain elongation initiated reductive dechlorination by liberating H2 in the conversion of acetate and ethanol to butyrate and caproate. Syntrophic fermentation of butyrate, a chain-elongation product, to H2 and acetate further sustained the reductive dechlorination activity. Methanogenesis was limited during TCE dechlorination in soil microcosms and absent in transfer cultures fed with chain-elongation substrates. This study provides critical fundamental knowledge toward the feasibility of chlorinated solvent bioremediation based on microbial chain elongation.
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Affiliation(s)
- Aide Robles
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, 1001 S. McAllister Ave., Tempe, Arizona 85287, United States
- School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, Arizona 85281, United States
- Engineering Research Center for Bio-mediated and Bio-inspired Geotechnics, Arizona State University, Tempe, Arizona 85281, United States
| | - Theodora L Yellowman
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, 1001 S. McAllister Ave., Tempe, Arizona 85287, United States
- Engineering Research Center for Bio-mediated and Bio-inspired Geotechnics, Arizona State University, Tempe, Arizona 85281, United States
| | - Sayalee Joshi
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, 1001 S. McAllister Ave., Tempe, Arizona 85287, United States
- School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, Arizona 85281, United States
- Engineering Research Center for Bio-mediated and Bio-inspired Geotechnics, Arizona State University, Tempe, Arizona 85281, United States
| | - Srivatsan Mohana Rangan
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, 1001 S. McAllister Ave., Tempe, Arizona 85287, United States
- School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, Arizona 85281, United States
- Engineering Research Center for Bio-mediated and Bio-inspired Geotechnics, Arizona State University, Tempe, Arizona 85281, United States
| | - Anca G Delgado
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, 1001 S. McAllister Ave., Tempe, Arizona 85287, United States
- School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, Arizona 85281, United States
- Engineering Research Center for Bio-mediated and Bio-inspired Geotechnics, Arizona State University, Tempe, Arizona 85281, United States
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Allaart MT, Stouten GR, Sousa DZ, Kleerebezem R. Product Inhibition and pH Affect Stoichiometry and Kinetics of Chain Elongating Microbial Communities in Sequencing Batch Bioreactors. Front Bioeng Biotechnol 2021; 9:693030. [PMID: 34235138 PMCID: PMC8256265 DOI: 10.3389/fbioe.2021.693030] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 05/25/2021] [Indexed: 11/13/2022] Open
Abstract
Anaerobic microbial communities can produce carboxylic acids of medium chain length (e.g., caproate, caprylate) by elongating short chain fatty acids through reversed β-oxidation. Ethanol is a common electron donor for this process. The influence of environmental conditions on the stoichiometry and kinetics of ethanol-based chain elongation remains elusive. Here, a sequencing batch bioreactor setup with high-resolution off-gas measurements was used to identify the physiological characteristics of chain elongating microbial communities enriched on acetate and ethanol at pH 7.0 ± 0.2 and 5.5 ± 0.2. Operation at both pH-values led to the development of communities that were highly enriched (>50%, based on 16S rRNA gene amplicon sequencing) in Clostridium kluyveri related species. At both pH-values, stably performing cultures were characterized by incomplete substrate conversion and decreasing biomass-specific hydrogen production rates during an operational cycle. The process stoichiometries obtained at both pH-values were different: at pH 7.0, 71 ± 6% of the consumed electrons were converted to caproate, compared to only 30 ± 5% at pH 5.5. Operating at pH 5.5 led to a decrease in the biomass yield, but a significant increase in the biomass-specific substrate uptake rate, suggesting that the organisms employ catabolic overcapacity to deal with energy losses associated to product inhibition. These results highlight that chain elongating conversions rely on a delicate balance between substrate uptake- and product inhibition kinetics.
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Affiliation(s)
| | | | - Diana Z Sousa
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands
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Kleerebezem R, Sousa DZ. Editorial overview: Microbial community engineering. Curr Opin Biotechnol 2021; 67:vi-ix. [PMID: 33745678 DOI: 10.1016/j.copbio.2021.02.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ Delft, The Netherlands.
| | - Diana Z Sousa
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708WE Wageningen, The Netherlands.
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39
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Calvo DC, Ontiveros-Valencia A, Krajmalnik-Brown R, Torres CI, Rittmann BE. Carboxylates and alcohols production in an autotrophic hydrogen-based membrane biofilm reactor. Biotechnol Bioeng 2021; 118:2338-2347. [PMID: 33675236 DOI: 10.1002/bit.27745] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 02/24/2021] [Accepted: 03/01/2021] [Indexed: 01/01/2023]
Abstract
Microbiological conversion of CO2 into biofuels and/or organic industrial feedstock is an excellent carbon-cycling strategy. Here, autotrophic anaerobic bacteria in the membrane biofilm reactor (MBfR) transferred electrons from hydrogen gas (H2 ) to inorganic carbon (IC) and produced organic acids and alcohols. We systematically varied the H2 -delivery, the IC concentration, and the hydraulic retention time in the MBfR. The relative availability of H2 versus IC was the determining factor for enabling microbial chain elongation (MCE). When the H2 :IC mole ratio was high (>2.0 mol H2 /mol C), MCE was an important process, generating medium-chain carboxylates up to octanoate (C8, 9.1 ± 1.3 mM C and 28.1 ± 4.1 mmol C m-2 d-1 ). Conversely, products with two carbons were the only ones present when the H2 :IC ratio was low (<2.0 mol H2 /mol C), so that H2 was the limiting factor. The biofilm microbial community was enriched in phylotypes most similar to the well-known acetogen Acetobacterium for all conditions tested, but phylotypes closely related with families capable of MCE (e.g., Bacteroidales, Rhodocyclaceae, Alcaligenaceae, Thermoanaerobacteriales, and Erysipelotrichaceae) became important when the H2 :IC ratio was high. Thus, proper management of IC availability and H2 supply allowed control over community structure and function, reflected by the chain length of the carboxylates and alcohols produced in the MBfR.
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Affiliation(s)
- Diana C Calvo
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, Arizona, USA.,School of Sustainable Engineering and the Built Environment, Ira A. Fulton Schools of Engineering, Design Annex, Tempe, Arizona, USA
| | - Aura Ontiveros-Valencia
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, Arizona, USA.,Department of Environmental Sciences, Instituto Potosino de Investigación Científica y Tecnológica, San Luis Potosí, Mexico
| | - Rosa Krajmalnik-Brown
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, Arizona, USA.,School of Sustainable Engineering and the Built Environment, Ira A. Fulton Schools of Engineering, Design Annex, Tempe, Arizona, USA.,Biodesign Center for Health Through Microbiome, Arizona State University, Tempe, Arizona, USA
| | - Cesar I Torres
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, Arizona, USA.,School for Engineering of Matter, Transport and Energy, Ira A. Fulton Schools of Engineering, Tempe, Arizona, USA
| | - Bruce E Rittmann
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, Arizona, USA.,School of Sustainable Engineering and the Built Environment, Ira A. Fulton Schools of Engineering, Design Annex, Tempe, Arizona, USA
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