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Ji X, Chen Z, Shen Y, Liu L, Chen R, Zhu J. Hexanoic acid production and microbial community in anaerobic fermentation: Effects of inorganic carbon addition. BIORESOURCE TECHNOLOGY 2024; 403:130881. [PMID: 38788806 DOI: 10.1016/j.biortech.2024.130881] [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: 03/23/2024] [Revised: 05/20/2024] [Accepted: 05/21/2024] [Indexed: 05/26/2024]
Abstract
Carbon dioxide (CO2) plays a crucial role in carbon chain elongation with ethanol serving as an electron donor. In this study, the impacts of various carbonates on CO2 concentration, hexanoic acid production, and microbial communities during ethanol-butyric acid fermentation were explored. The results showed that the addition of MgCO3 provided sustained inorganic carbon and facilitated interspecific electron transfer, thereby increasing hexanoic acid yield by 58%. MgCO3 and NH4HCO3 inhibited the excessive ethanol oxidation and decreased the yield of acetic acid by 51% and 42%, respectively. The yields of hexanoic acid and acetic acid in the CaCO3 group increased by 19% and 15%, respectively. The NaHCO3 group exhibited high headspace CO2 concentration, promoting acetogenic bacteria enrichment while reducing the abundance of Clostridium_sensu_stricto_12. The batch addition of NaHCO3 accelerated the synthesis of hexanoic acid and increased its production by 26%. The relative abundance of Clostridium_sensus_stricto_12 was positively correlated with hexanoic acid production.
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Affiliation(s)
- Xiaofeng Ji
- School of Agricultural Engineering and Food Science, Shandong University of Technology, Zibo 255000, China
| | - Zhengang Chen
- School of Agricultural Engineering and Food Science, Shandong University of Technology, Zibo 255000, China
| | - Yingmeng Shen
- School of Agricultural Engineering and Food Science, Shandong University of Technology, Zibo 255000, China
| | - Longlong Liu
- School of Agricultural Engineering and Food Science, Shandong University of Technology, Zibo 255000, China
| | - Ranran Chen
- School of Agricultural Engineering and Food Science, Shandong University of Technology, Zibo 255000, China
| | - Jiying Zhu
- School of Agricultural Engineering and Food Science, Shandong University of Technology, Zibo 255000, China.
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2
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Liu Y, Chen L, Duan Y, Li R, Yang Z, Liu S, Li G. Recent progress and prospects for chain elongation of transforming biomass waste into medium-chain fatty acids. CHEMOSPHERE 2024; 355:141823. [PMID: 38552798 DOI: 10.1016/j.chemosphere.2024.141823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Revised: 03/18/2024] [Accepted: 03/26/2024] [Indexed: 04/06/2024]
Abstract
Chain elongation technology utilises microorganisms in anaerobic digestion to transform waste biomass into medium-chain fatty acids that have greater economic value. This innovative technology expands upon traditional anaerobic digestion methods, requiring abundant substrates that serve as electron donors and acceptors, and inoculating microorganisms with chain elongation functions. While this process may result in the production of by-products and elicit competitive responses, toxicity suppression of microorganisms by substrates and products remains a significant obstacle to the industrialisation of chain elongation technology. This study provides a comprehensive overview of existing research on widely employed electron donors and their synthetic reactions, competitive reactions, inoculum selection, toxicity inhibition of substrates and products, and increased chain elongation approaches. Additionally, it presents actionable recommendations for future research and development endeavours in this domain, intending to inspire and guide researchers in advancing the frontiers of chain elongation technology.
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Affiliation(s)
- Yuhao Liu
- School of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou, 450046, Henan Province, China.
| | - Long Chen
- School of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou, 450046, Henan Province, China
| | - Yacong Duan
- School of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou, 450046, Henan Province, China
| | - Ruihua Li
- School of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou, 450046, Henan Province, China
| | - Ziyan Yang
- School of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou, 450046, Henan Province, China
| | - Shuli Liu
- School of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou, 450046, Henan Province, China
| | - Guoting Li
- School of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou, 450046, Henan Province, China
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3
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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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Villegas-Rodríguez SB, Arreola-Vargas J, Buitrón G. Influence of pH and temperature on the performance and microbial community during the production of medium-chain carboxylic acids using winery effluents as substrate. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024:10.1007/s11356-024-33103-5. [PMID: 38558339 DOI: 10.1007/s11356-024-33103-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 03/22/2024] [Indexed: 04/04/2024]
Abstract
Winery effluents containing high ethanol concentrations and diverse organic matter are ideal substrates for producing medium-chain carboxylic acids via fermentation and chain elongation. However, the process needs to be better understood. This study presents novel insights into the bioconversion mechanisms of medium-chain carboxylic acids by correlating fermentation and chain elongation kinetic profiles with the study of microbial communities at different pH (5 to 7) conditions and temperatures (30 to 40 °C). It was found that high productivities of MCCA were obtained using a native culture and winery effluents as a natural substrate. Minor pH variations significantly affected the metabolic pathway of the microorganisms for MCCA production. The maximal productivities of hexanoic (715 mg/L/d) and octanoic (350 mg/L/d) acids were found at pH 6 and 35 °C. Results evidence that the presence of Clostridium, Bacteroides, and Negativicutes promotes the high productions of MCCA. The formation of heptanoic acid was favor when Mogibacterium and Burkholderia were present.
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Affiliation(s)
- Sharon B Villegas-Rodríguez
- Laboratory for Research On Advanced Processes for Water Treatment, Unidad Académica Juriquilla, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Blvd. Juriquilla 3001, 76230, Queretaro, Mexico
| | - Jorge Arreola-Vargas
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, 77843, USA
| | - Germán Buitrón
- Laboratory for Research On Advanced Processes for Water Treatment, Unidad Académica Juriquilla, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Blvd. Juriquilla 3001, 76230, Queretaro, Mexico.
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5
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Montecchio D, Gazzola G, Gallipoli A, Gianico A, Braguglia CM. Medium chain Fatty acids production from Food Waste via homolactic fermentation and lactate/ethanol elongation: Electron balance and thermodynamic assessment. WASTE MANAGEMENT (NEW YORK, N.Y.) 2024; 177:289-297. [PMID: 38359509 DOI: 10.1016/j.wasman.2024.01.049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 01/08/2024] [Accepted: 01/29/2024] [Indexed: 02/17/2024]
Abstract
This study explored the potential of Food Waste (FW) extract as a suitable substrate for Medium Chain Fatty Acids (MCFAs) production, in a single-phase reactor, where both fermentation and Chain Elongation (CE) processes occurred simultaneously. A continuous experiment was conducted with an Organic Loading Rate (OLR) = 20 gCOD L-1 d-1 and was fed in batch mode twice a week with pH = 6. In addition, four batch tests were performed, to assess the effects on the MCFAs production of caproate inhibition, hydrogen partial pressure (PH2) and different lactate/acetate ratios. Thermodynamics and electron flux were calculated to gain insights into the process pathways. Due to the presence of aminoacids, fermentation was mostly homolactic and both lactate and ethanol were produced as Electron Donors (EDs); the average MCFAs production efficiency was ∼ 12 %, although after 4 weeks the elongation process was halted, resulting in EDs accumulation. This occurred regardless of inoculum selection and the presence of caproate as a possible inhibitor, suggesting that EDs accumulation was due to the elongation process kinetics being slower than those of the fermentation step, thus calling for a longer Hydraulic Retention Time (HRT). It's worth noting that lactate was prevalently self-elongated to butyrate, whereas ethanol elongation only took place after lactate depletion, but was more efficient since it required other Electron Acceptors (EAs) such as butyrate, propionate or valerate. Moreover, the selected pH limited the acrylate pathway to a reasonable extent, whereas the high PH2 prevented both ethanol and lactate oxydation to acetate.
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Affiliation(s)
- Daniele Montecchio
- Istituto di Ricerca sulle Acque-CNR, Area della Ricerca RM1, 00015 Monterotondo, Roma, Italy.
| | - Giulio Gazzola
- Istituto di Ricerca sulle Acque-CNR, Area della Ricerca RM1, 00015 Monterotondo, Roma, Italy.
| | - Agata Gallipoli
- Istituto di Ricerca sulle Acque-CNR, Area della Ricerca RM1, 00015 Monterotondo, Roma, Italy.
| | - Andrea Gianico
- Istituto di Ricerca sulle Acque-CNR, Area della Ricerca RM1, 00015 Monterotondo, Roma, Italy.
| | - Camilla M Braguglia
- Istituto di Ricerca sulle Acque-CNR, Area della Ricerca RM1, 00015 Monterotondo, Roma, Italy.
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Fernández-Blanco C, Veiga MC, Kennes C. Carbon dioxide as key player in chain elongation and growth of Clostridium kluyveri: Insights from batch and bioreactor studies. BIORESOURCE TECHNOLOGY 2024; 394:130192. [PMID: 38081469 DOI: 10.1016/j.biortech.2023.130192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/07/2023] [Accepted: 12/08/2023] [Indexed: 02/04/2024]
Abstract
Chain elongation technology allows medium-chain fatty acids (MCFAs) production as an alternative to fossil resources. Clostridium kluyveri generates n-caproate primarily from ethanol and acetate, presumably requiring CO2 for growth. Here, the impact of CO2 on C. kluyveri was explored. Bottle studies revealed the bacterium's adaptability to low CO2 levels, even in conditions with minimal dissolved NaHCO3 (0.0003 M) and unfavorable pH (below 6) under 1 bar CO2. Bioreactor investigations demonstrated a direct correlation between CO2 availability and bacterial growth. The highest n-caproate production (11.0 g/L) with 90.1 % selectivity was achieved in a bioreactor with continuous CO2 supply at 3 mL/min. Additional bottle experiments pressurized with 1 bar CO2 and varying ethanol:acetate ratios (1:1, 2:1, 4:1) also confirmed CO2 consumption by C. kluyveri. However, increasing the ethanol:acetate ratio did not enhance n-caproate selectivity, likely due to overly acidic pH conditions. These findings provide insights into chain-elongators responses under diverse conditions.
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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
| | - 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.
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Lago A, Greses S, Aboudi K, Moreno I, González-Fernández C. Effect of decoupling hydraulic and solid retention times on carbohydrate-rich residue valorization into carboxylic acids. Sci Rep 2023; 13:20590. [PMID: 37996698 PMCID: PMC10667524 DOI: 10.1038/s41598-023-48097-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 11/22/2023] [Indexed: 11/25/2023] Open
Abstract
This research assessed the effect of decoupling hydraulic retention time (HRT) and solid retention time (SRT) on the production of volatile fatty acids (VFAs) via anaerobic fermentation of beet molasses. The performance of a continuous stirred tank reactor (CSTR, STR = HTR = 30 days) and two anaerobic sequencing batch reactors (AnSBR) with decoupled STR (30 days) and HRT (20 and 10 days) was compared. Previously, a temperature study in batch reactors (25, 35, and 55 °C) revealed 25 °C as the optimal temperature to maximize the VFAs yield and the long-chain VFAs (> C4) production, being selected for the continuous reactors operation. An HRT of 20 days in AnSBR led to an enhancement in bioconversion efficiency into VFAs (55.5% chemical oxygen demand basis) compared to the CSTR (34.9%). In contrast, the CSTR allowed the production of valuable caproic acid (25.4% vs 4.1% w/w of total VFAs in AnSBR). Decreasing further the HRT to 10 days in AnSBR was detrimental in terms of bioconversion efficiency (21.7%) due to primary intermediates (lactate) accumulation. By decoupling HRT and SRT, VFAs were maximized, revealing HRT as an effective tool to drive specific conversion routes (butyrate- or lactate-fermentation).
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Affiliation(s)
- Adrián Lago
- Biotechnological Processes Unit, IMDEA Energy, Avda. Ramón de la Sagra 3, 28935, Móstoles, Madrid, Spain
- Thermochemical Processes Unit, IMDEA Energy, Avda. Ramón de la Sagra 3, 28935, Móstoles, Madrid, Spain
| | - Silvia Greses
- Biotechnological Processes Unit, IMDEA Energy, Avda. Ramón de la Sagra 3, 28935, Móstoles, Madrid, Spain
| | - Kaoutar Aboudi
- Biotechnological Processes Unit, IMDEA Energy, Avda. Ramón de la Sagra 3, 28935, Móstoles, Madrid, Spain
- Department of Chemical Engineering and Food Technology, Faculty of Sciences (Wine and Agri-Food Research Institute-IVAGRO and International Campus of Excellence-ceiA3), University of Cádiz, Republic Saharawi Avenue, P.O. Box No. 40, 11510, Puerto Real, Cádiz, Spain
| | - Inés Moreno
- Thermochemical Processes Unit, IMDEA Energy, Avda. Ramón de la Sagra 3, 28935, Móstoles, Madrid, Spain
- Chemical and Environmental Engineering Group, ESCET, Rey Juan Carlos University, 28933, Móstoles, Madrid, Spain
| | - Cristina González-Fernández
- Biotechnological Processes Unit, IMDEA Energy, Avda. Ramón de la Sagra 3, 28935, Móstoles, Madrid, Spain.
- Department of Chemical Engineering and Environmental Technology, School of Industrial Engineering, University of Valladolid, Dr. Mergelina, S/N, 47011, Valladolid, Spain.
- Institute of Sustainable Processes, Dr. Mergelina, S/N, 47011, Valladolid, Spain.
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Seid N, Ochsenreither K, Neumann A. Caproate production from Enset fiber in one-pot two-step fermentation using anaerobic fungi (Neocallimastix cameroonii strain G341) and Clostridium kluyveri DSM 555. Microb Cell Fact 2023; 22:216. [PMID: 37864174 PMCID: PMC10588050 DOI: 10.1186/s12934-023-02224-w] [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: 08/10/2023] [Accepted: 10/06/2023] [Indexed: 10/22/2023] Open
Abstract
BACKGROUND Lignocellulosic biomass plays a crucial role in creating a circular bioeconomy and minimizing environmental impact. Enset biomass is a byproduct of traditional Ethiopian Enset food processing that is thrown away in huge quantities. This study aimed to produce caproate from Enset fiber using Neocallimastix cameroonii strain G341 and Clostridium kluyveri DSM 555 in one-pot two-step fermentation. RESULTS The process started by growing N. cameroonii on Enset fiber as a carbon source for 7 days. Subsequently, the fungal culture was inoculated with active C. kluyveri preculture and further incubated. The results showed that N. cameroonii grew on 0.25 g untreated Enset fiber as the sole carbon source and produced 1.16 mmol acetate, 0.51 mmol hydrogen, and 1.34 mmol formate. In addition, lactate, succinate, and ethanol were detected in small amounts, 0.17 mmol, 0.08 mmol, and 0.7 mmol, respectively. After inoculating with C. kluyveri, 0.3 mmol of caproate and 0.48 mmol of butyrate were produced, and hydrogen production also increased to 0.95 mmol compared to sole N. cameroonii fermentation. Moreover, after the culture was supplemented with 2.18 mmol of ethanol during C. kluyveri inoculation, caproate, and hydrogen production was further increased to 1.2 and 1.36 mmol, respectively, and the consumption of acetate also increased. CONCLUSION A novel microbial cell factory was developed to convert untreated lignocellulosic Enset fiber into the medium chain carboxylic acid caproate and H2 by a co-culture of the anaerobic fungi N. cameroonii and C. kluyveri. This opens a new value chain for Enset farmers, as the process requires only locally available raw materials and low-price fermenters. As the caproate production was mainly limited by the available ethanol, the addition of locally produced ethanol-containing fermentation broth ("beer") would further increase the titer.
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Affiliation(s)
- Nebyat Seid
- Electrobiotechnology, Institute of Process Engineering in Life Science 2, Karlsruhe Institute of Technology (KIT), 76131, Karlsruhe, Germany.
- School of Chemical and Bio Engineering, Addis Ababa Institute of Technology, Addis Ababa University, P.O.B: 1176, Addis Ababa, Ethiopia.
| | - Katrin Ochsenreither
- Department of Chemical and Process Engineering, Karlsruhe Institute of Technology (KIT), 76131, Karlsruhe, Germany
| | - Anke Neumann
- Electrobiotechnology, Institute of Process Engineering in Life Science 2, Karlsruhe Institute of Technology (KIT), 76131, Karlsruhe, Germany.
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Chatzis A, Orellana E, Gaspari M, Kontogiannopoulos K, Treu L, Zouboulis A, Kougias PG. Comparative study on packing materials for improved biological methanation in trickle Bed reactors. BIORESOURCE TECHNOLOGY 2023; 385:129456. [PMID: 37406828 DOI: 10.1016/j.biortech.2023.129456] [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: 05/29/2023] [Revised: 06/29/2023] [Accepted: 07/02/2023] [Indexed: 07/07/2023]
Abstract
Packing materials improve biological methanation efficiency in Trickle Bed Reactors. The present study, which lies in the field of energy production and biotechnology, entailed the evaluation of commercial pelletized activated carbon and Raschig rings as packing materials. The evaluation focused on monitoring process indicators and examining the composition of the microbial community. Activated carbon resulted in enhanced methane purity, achieving a two-fold higher methane percentage than Raschig rings, maintaining a stable pH level within a range of 7-8 and reducing gas retention time from 6 h to 90 min. Additionally, the digestate derived from biogas plant was found to be a sufficient nutrient source for the process. Fermentative species with genes for β-oxidation, such as Amaricoccus sp. and Caloramator australicus could explain the production of hexanoic and valerate acids during reactor operation. Based on the physical properties of packing materials, the efficiency of biological methanation could be maximized.
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Affiliation(s)
- Alexandros Chatzis
- Laboratory of Chemical and Environmental Technology, Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece; Soil and Water Resources Institute, Hellenic Agricultural Organisation Dimitra, Thermi-Thessaloniki 57001, Greece
| | - Esteban Orellana
- Department of Biology, University of Padova, Via U. Bassi 58/b, 35121 Padua, Italy
| | - Maria Gaspari
- Soil and Water Resources Institute, Hellenic Agricultural Organisation Dimitra, Thermi-Thessaloniki 57001, Greece
| | | | - Laura Treu
- Department of Biology, University of Padova, Via U. Bassi 58/b, 35121 Padua, Italy
| | - Anastasios Zouboulis
- Laboratory of Chemical and Environmental Technology, Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Panagiotis G Kougias
- Soil and Water Resources Institute, Hellenic Agricultural Organisation Dimitra, Thermi-Thessaloniki 57001, Greece.
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10
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Wang Q, Yang N, Cai Y, Zhang R, Wu Y, Ma W, Fu C, Zhang P, Zhang G. Advances in understanding entire process of medium chain carboxylic acid production from organic wastes via chain elongation. CHEMOSPHERE 2023; 339:139723. [PMID: 37543231 DOI: 10.1016/j.chemosphere.2023.139723] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 07/22/2023] [Accepted: 08/01/2023] [Indexed: 08/07/2023]
Abstract
Chain elongation is an environmentally friendly biological technology capable of converting organic wastes into medium chain carboxylic acids (MCCAs). This review aims to offer a comprehensive analysis of MCCA production from organic wastes via chain elongation. Seven kinds of organic wastes are introduced and classified as easily degradable and hardly degradable. Among them, food waste, fruit and vegetable waste are the most potential organic wastes for MCCA production. Combined pretreatment technologies should be encouraged for the pretreatment of hardly degradable organic wastes. Furthermore, the mechanisms during MCCA production are analyzed, and the key influencing factors are evaluated, which affect the MCCA production and chain elongation efficiency indirectly. Extracting MCCA simultaneously is the most important way to improve MCCA production efficiency, and technologies for sequentially extracting different kinds of MCCAs are recommended. Finally, some perspectives for future chain elongation researches are proposed to promote the large-scale application of chain elongation.
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Affiliation(s)
- Qingyan Wang
- Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing, 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing, 100083, China
| | - Nan Yang
- Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing, 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing, 100083, China
| | - Yajing Cai
- Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing, 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing, 100083, China
| | - Ru Zhang
- Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing, 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing, 100083, China
| | - Yan Wu
- School of Environmental and Chemical Engineering, Chongqing Three Gorges University, Chongqing, 404632, China
| | - Weifang Ma
- Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing, 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing, 100083, China
| | - Chuan Fu
- School of Environmental and Chemical Engineering, Chongqing Three Gorges University, Chongqing, 404632, China
| | - Panyue Zhang
- Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing, 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing, 100083, China; School of Environmental and Chemical Engineering, Chongqing Three Gorges University, Chongqing, 404632, China.
| | - Guangming Zhang
- School of Energy & Environmental Engineering, Hebei University of Technology, Tianjin, 300130, China.
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11
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Sabbe K, D'Haen L, Boon N, Ganigué R. Predicting the performance of chain elongating microbiomes through flow cytometric fingerprinting. WATER RESEARCH 2023; 243:120323. [PMID: 37459796 DOI: 10.1016/j.watres.2023.120323] [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: 03/23/2023] [Revised: 06/29/2023] [Accepted: 07/06/2023] [Indexed: 09/07/2023]
Abstract
As part of the circular bio-economy paradigm shift, waste management and valorisation practices have moved away from sanitation and towards the production of added-value compounds. Recently, the development of mixed culture bioprocess for the conversion of waste(water) to platform chemicals, such as medium chain carboxylic acids, has attracted significant interest. Often, the microbiology of these novel bioprocesses is less diverse and more prone to disturbances, which can lead to process failure. This issue can be tackled by implementing an advanced monitoring strategy based on the microbiology of the process. In this study, flow cytometry was used to monitor the microbiology of lactic acid chain elongation for the production of caproic acid, and assess its performance both qualitatively and quantitatively. Two continuous stirred tank reactors for chain elongation were monitored flow cytometrically for over 336 days. Through community typing, four specific community types could be identified and correlated to both a specific functionality and genotypic diversity. Additionally, the machine-learning algorithms trained in this study demonstrated the ability to predict production rates of, amongst others, caproic acid with high accuracy in the present (R² > 0.87) and intermediate accuracy in the near future (R² > 0.63). The identification of specific community types and the development of predictive algorithms form the basis of advanced bioprocess monitoring based on flow cytometry, and have the potential to improve bioprocess control and optimization, leading to better product quality and yields.
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Affiliation(s)
- Kevin Sabbe
- 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, 9052 Ghent, Belgium
| | - Liese D'Haen
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - Nico Boon
- 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, 9052 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, 9052 Ghent, Belgium.
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12
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Strik DPBTB, Heusschen B. Microbial Recycling of Polylactic Acid Food Packaging Waste into Carboxylates via Hydrolysis and Mixed-Culture Fermentation. Microorganisms 2023; 11:2103. [PMID: 37630663 PMCID: PMC10458239 DOI: 10.3390/microorganisms11082103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 08/09/2023] [Accepted: 08/15/2023] [Indexed: 08/27/2023] Open
Abstract
To establish a circular economy, waste streams should be used as a resource to produce valuable products. Biodegradable plastic waste represents a potential feedstock to be microbially recycled via a carboxylate platform. Bioplastics such as polylactic acid food packaging waste (PLA-FPW) are theoretically suitable feedstocks for producing carboxylates. Once feasible, carboxylates such as acetate, n-butyrate, or n-caproate can be used for various applications like lubricants or building blocks for making new bioplastics. In this study, pieces of industrial compostable PLA-FPW material (at 30 or 60 g/L) were added to a watery medium with microbial growth nutrients. This broth was exposed to 70 °C for a pretreatment process to support the hydrolysis of PLA into lactic acid at a maximum rate of 3.0 g/L×d. After 21 days, the broths of the hydrolysis experiments were centrifugated and a part of the supernatant was extracted and prepared for anaerobic fermentation. The mixed microbial culture, originating from a food waste fermentation bioprocess, successfully fermented the hydrolyzed PLA into a spectrum of new C2-C6 multi-carbon carboxylates. n-butyrate was the major product for all fermentations and, on average, 6.5 g/L n-butyrate was obtained from 60 g/L PLA-FPW materials. The wide array of products were likely due to various microbial processes, including lactate conversion into acetate and propionate, as well as lactate-based chain elongation to produce medium-chain carboxylates. The fermentation process did not require pH control. Overall, we showed a proof-of-concept in using real bioplastic waste as feedstock to produce valuable C2-C6 carboxylates via microbial recycling.
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Affiliation(s)
- David P. B. T. B. Strik
- Environmental Technology, Wageningen University & Research, 6708 WG Wageningen, The Netherlands
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13
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Fuchs W, Rachbauer L, Rittmann SKMR, Bochmann G, Ribitsch D, Steger F. Eight Up-Coming Biotech Tools to Combat Climate Crisis. Microorganisms 2023; 11:1514. [PMID: 37375016 DOI: 10.3390/microorganisms11061514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 06/02/2023] [Accepted: 06/05/2023] [Indexed: 06/29/2023] Open
Abstract
Biotechnology has a high potential to substantially contribute to a low-carbon society. Several green processes are already well established, utilizing the unique capacity of living cells or their instruments. Beyond that, the authors believe that there are new biotechnological procedures in the pipeline which have the momentum to add to this ongoing change in our economy. Eight promising biotechnology tools were selected by the authors as potentially impactful game changers: (i) the Wood-Ljungdahl pathway, (ii) carbonic anhydrase, (iii) cutinase, (iv) methanogens, (v) electro-microbiology, (vi) hydrogenase, (vii) cellulosome and, (viii) nitrogenase. Some of them are fairly new and are explored predominantly in science labs. Others have been around for decades, however, with new scientific groundwork that may rigorously expand their roles. In the current paper, the authors summarize the latest state of research on these eight selected tools and the status of their practical implementation. We bring forward our arguments on why we consider these processes real game changers.
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Affiliation(s)
- Werner Fuchs
- Department IFA-Tulln, Institute of Environmental Biotechnology, University of Natural Resources and Life Sciences, Vienna, Konrad-Lorenz-Strasse 20, 3430 Tulln, Austria
| | - Lydia Rachbauer
- Lawrence Berkeley National Laboratory, Deconstruction Division at the Joint Bioenergy Institute, 5885 Hollis Street, Emeryville, CA 94608, USA
| | - Simon K-M R Rittmann
- Archaea Physiology & Biotechnology Group, Department of Functional and Evolutionary Ecology, Universität Wien, Djerassiplatz 1, 1030 Wien, Austria
| | - Günther Bochmann
- Department IFA-Tulln, Institute of Environmental Biotechnology, University of Natural Resources and Life Sciences, Vienna, Konrad-Lorenz-Strasse 20, 3430 Tulln, Austria
| | - Doris Ribitsch
- ACIB-Austrian Centre of Industrial Biotechnology, Krenngasse 37, 8010 Graz, Austria
| | - Franziska Steger
- Department IFA-Tulln, Institute of Environmental Biotechnology, University of Natural Resources and Life Sciences, Vienna, Konrad-Lorenz-Strasse 20, 3430 Tulln, Austria
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14
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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: 1] [Impact Index Per Article: 1.0] [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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15
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Li L, Liu C, Xu L, Zhuang H, He J, He Q, Zhang J. Acclimation of anaerobic fermentation microbiome with acetate and ethanol for chain elongation and the biochemical response. CHEMOSPHERE 2023; 320:138083. [PMID: 36754309 DOI: 10.1016/j.chemosphere.2023.138083] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 01/10/2023] [Accepted: 02/05/2023] [Indexed: 06/18/2023]
Abstract
Medium chain fatty acids (MCFAs) production is a promising method for resource recovery from organic wastes. In this study, the microbial community structure shift along the long-term acclimation experiment and the concomitant effect of H2 level on chain elongation performance was investigated. Chain elongation microbiome could be rapidly acclimated from traditional anaerobic fermentation consortia. Genera Caproiciproducens, Clostridium sensu stricto 12, Rummeliibacillus and Oscillibacter was found to be dominant during the operation. The H2 was accumulated in the headspace by increasing the ethanol input, which inhibited oxidation of caproate and butyrate immediately, while its inhibition effect on chain elongation was delayed. H2 level in the headspace was positively correlated to the MCFAs production related bacteria. However, too much H2 accumulated might be suppressive for MCFAs production in the long term. It might result from the thermodynamic barrier for discarding excess reducing equivalents under high H2 level, which further gave rise to ethanol accumulation in this system.
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Affiliation(s)
- Lin Li
- College of Environment and Ecology, Chongqing University, Chongqing 400044, China; State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Chang Liu
- College of Environment and Ecology, Chongqing University, Chongqing 400044, China
| | - Linji Xu
- College of Environment and Ecology, Chongqing University, Chongqing 400044, China.
| | - Huichuan Zhuang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Junguo He
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China; School of Civil Engineering, Guangzhou University, Guangzhou 510006, China.
| | - Qiang He
- College of Environment and Ecology, Chongqing University, Chongqing 400044, China
| | - Jie Zhang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
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16
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Wang C, Wang Y, Chen Z, Wei W, Chen X, Mannina G, Ni BJ. A novel strategy for efficiently transforming waste activated sludge into medium-chain fatty acid using free nitrous acid. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 862:160826. [PMID: 36502988 DOI: 10.1016/j.scitotenv.2022.160826] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/30/2022] [Accepted: 12/06/2022] [Indexed: 06/17/2023]
Abstract
The global energy crisis is approaching due to rapid population growth and overexploitation of fossil fuels. Therefore, the development and use of new and renewable energy sources is already in the extreme urgency. This work developed a novel technology to efficiently produce renewable liquid bioenergy from discarded wastes, by effectively transforming sewage sludge into high-value medium chain fatty acids (MCFA). The maximum MCFA yield in the anaerobic sludge fermentation was revealed to be 10.6 times of control when utilizing sewage sludge with 1.78 mg-N/L free nitrous acid (FNA) pretreatment. The carbon flow from sewage sludge into MCFA in the fermentation system was significantly enhanced with appropriate levels (0.71-1.78 mg-N/L) of FNA pretreatment. Compared to FNA pretreatment, however, its direct addition severely inhibited total products (i.e., carboxylates and complex alcohols) generation because of the toxicity on live cells (decreasing to 8.3 %-13.9 %) in sludge. Kinetic models (one-substrate and two-substrate) were utilized to investigate the mechanism of MCFA promotion by FNA pretreatment on anaerobic sludge fermentation, in which linear relationship analysis between FNA-derived organic release and the fitted parameters were also performed. The results indicated that the conversion of refractory materials into rapidly bioavailable substrates for MCFA production contributed to increasing MCFA production rate and potential. Moreover, the relative abundances of functional microorganisms related to hydrolysis-acidification and chain elongation process increased under FNA pretreatment, further favoring the MCFA production. This study provides a novel and effective technology of sludge energy recovery that can achieve the next-generation sustainable sewage sludge management.
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Affiliation(s)
- 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
| | - Zhijie Chen
- School of Civil and Environmental Engineering, Centre for Technology in Water and Wastewater, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Wei Wei
- School of Civil and Environmental Engineering, Centre for Technology in Water and Wastewater, University of Technology Sydney, Sydney, NSW 2007, Australia.
| | - Xueming Chen
- Fujian Provincial Engineering Research Center of Rural Waste Recycling Technology, College of Environment and Safety Engineering, Fuzhou University, Fujian 350116, China
| | - Giorgio Mannina
- Engineering Department, Palermo University, Ed. 8 Viale delle Scienze, 90128 Palermo, Italy
| | - Bing-Jie Ni
- School of Civil and Environmental Engineering, Centre for Technology in Water and Wastewater, University of Technology Sydney, Sydney, NSW 2007, Australia
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17
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Shrestha S, Xue S, Raskin L. Competitive Reactions during Ethanol Chain Elongation Were Temporarily Suppressed by Increasing Hydrogen Partial Pressure through Methanogenesis Inhibition. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:3369-3379. [PMID: 36790331 PMCID: PMC9979639 DOI: 10.1021/acs.est.2c09014] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/16/2023] [Accepted: 01/27/2023] [Indexed: 05/29/2023]
Abstract
Organic waste streams can be converted into high-value platform chemicals such as medium-chain carboxylic acids (MCCAs) using mixed microbial communities via chain elongation. However, the heterogeneity of waste streams and the use of complex microbial communities can lead to undesirable reactions, thus decreasing process efficiency. We explored suppressing excessive ethanol oxidation to acetate (EEO) by increasing the hydrogen partial pressure (PH2) through hydrogenotrophic methanogenesis inhibition by periodically adding 2-bromoethanesulfonate (2-BES) to an MCCA-producing bioreactor to reach 10 mM of 2-BES upon addition. The bioreactor was fed with pretreated food waste and brewery waste containing high concentrations of short-chain carboxylic acids and ethanol, respectively. While 2-BES addition initially reduced EEO, some methanogens (Methanobrevibacter spp.) persisted and resistant populations were selected over time. Besides changing the methanogenic community structure, adding 2-BES also changed the bacterial community structure due to its impact on PH2. While we demonstrated that PH2 could be manipulated using 2-BES to control EEO, methods that do not require the addition of a chemical inhibitor should be explored to maintain optimum PH2 for long-term suppression of EEO.
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Affiliation(s)
| | - Siqi Xue
- Department of Civil and Environmental
Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Lutgarde Raskin
- Department of Civil and Environmental
Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
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18
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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: 4] [Impact Index Per Article: 4.0] [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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19
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Vidal-Antich C, Peces M, Perez-Esteban N, Mata-Alvarez J, Dosta J, Astals S. Impact of food waste composition on acidogenic co-fermentation with waste activated sludge. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 849:157920. [PMID: 35952870 DOI: 10.1016/j.scitotenv.2022.157920] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 08/01/2022] [Accepted: 08/05/2022] [Indexed: 06/15/2023]
Abstract
The impact of food waste (FW) composition on co-fermentation performance was studied to elucidate if adjusting FW composition can be used to drive the fermentation yield and profile, which is relevant for biorefinery applications. First, the impact of individual FW components (i.e., fruit, vegetables, pasta, rice, meat, fish, and cellulose) was assessed. Subsequently, the effect of mixing a protein-rich component and a carbohydrate-rich component was studied (i.e., fish/fruit and fish/cellulose, and meat/rice and meat/vegetable). All experiments were carried out in mesophilic batch assays using waste activated sludge (WAS) as main substrate, the same mixture ratio (70 % WAS +30 % FW on VS basis), and no pH control. Results showed that each FW component had a distinct effect on VFA yield and profile, with protein-rich components reaching the highest VFA yields; 502 and 442 mgCOD/gVS for WAS/Fish and WAS/Meat, respectively. A positive interaction on VFA yield was observed when mixing a protein-rich and a carbohydrate-rich component. This interaction was not proportional to the co-substrates proportion in the mixtures. On the other hand, the VFA profile was clearly driven by the components in the mixture, including both WAS and FW composition. Overall, these results indicate that predicting the VFA yield of WAS/FW co-fermentation is not just related to FW composition, but FW composition could be used to adjust the VFA profile to a certain extent.
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Affiliation(s)
- C Vidal-Antich
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain; Water Research Institute, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
| | - M Peces
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
| | - N Perez-Esteban
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
| | - J Mata-Alvarez
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain; Water Research Institute, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
| | - J Dosta
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain; Water Research Institute, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
| | - S Astals
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain.
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20
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Wu L, Wei W, Liu X, Wang D, Ni BJ. Potentiality of recovering bioresource from food waste through multi-stage Co-digestion with enzymatic pretreatment. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 319:115777. [PMID: 35982572 DOI: 10.1016/j.jenvman.2022.115777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 07/15/2022] [Accepted: 07/15/2022] [Indexed: 06/15/2023]
Abstract
Food waste (FW) is not only a major social, nutritional and environmental issue, but also an underutilized resource with significant energy, which has not been fully explored currently. Considering co-digestion can adjust carbon to nitrogen ratio (C/N) of the feedstock and improve the synergetic interactions among microorganisms, anaerobic co-digestion (AnCoD) is then becoming an emerging approach to achieve higher energy recovery from FW while ensuring the stability of the system. To obtain higher economic gain from such biodegradable wastes, increasing attention has been paid on optimizing the system configuration or applying enzymatic hydrolysis before digesting FW. A better understanding on the potentiality of correlating enzymatic pretreatment and AnCoD operated in various system configuration would enhance the bioresource recovery from FW and increase revenue through treating this organic waste. Specifically, the biobased chemicals outputs from FW-related co-digestion system with different configuration were firstly compared in this review. A deep discussion concerning the challenges for achieving bioresources recovery from FW co-digestion systems with enzymatic pretreatment was then given. Recommendations for future studies regarding FW co-digestion were then proposed at last.
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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
| | - Wei Wei
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Xuran Liu
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Dongbo Wang
- Key Laboratory of Environmental Biology and Pollution Control, College of Environmental Science and Engineering, Hunan University, Changsha, 410082, 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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21
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Ji X, Zhu K, Zhang Y, Ullah F, Li A, Zhang L. Mixed culture chain elongation for consumption of acetate and ethanol in anaerobic fermentation: The impact of salt type, dosage and acclimation. WASTE MANAGEMENT (NEW YORK, N.Y.) 2022; 152:48-58. [PMID: 35973327 DOI: 10.1016/j.wasman.2022.08.005] [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: 03/09/2022] [Revised: 07/18/2022] [Accepted: 08/03/2022] [Indexed: 06/15/2023]
Abstract
Microbial chain elongation is a newly developed carboxylate platform-based bioprocess, which often encounters high salinity stress due to saline feedstock and pH adjustment. In this study, we systematically investigated the effects of salt types (Na+, K+, and NH4+), dosage, and salinity acclimation on microbial chain elongation, and identified the microbial community by high throughput 16S rRNA gene sequencing. The results showed that a high level of Na+ and NH4+ (12.5 g/L of cations) exerted seriously inhibitory effects without chain elongating activity, while K+ had the slightest inhibition only with a little longer lag phase and lower products yield. The chain elongating products yields and the selectivity of caproate decreased with the increasing Na+ concentration, and 8.6 g/L of Na+ was found to be the threshold value for un-acclimated inoculum used for chain elongation. The acclimation to high saline conditions greatly promoted the consumption of acetate and ethanol with a shorter lag phase, and recovered a robust elongating activity for butyrate production. Furthermore, the high throughput 16S rRNA gene sequencing analysis results indicated that six genera, such as Clostridium IV and Clostridium sensu stricto, closely relating chain elongation process were depressed by high salinity, and the salinity acclimation helped to enrich the functional microbes. These findings could provide useful information for engineering microbial chain elongation process under saline conditions.
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Affiliation(s)
- Xinran Ji
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environmental Science and Technology, Dalian University of Technology, Linggong Road 2, Dalian 116024, PR China
| | - Kongyun Zhu
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environmental Science and Technology, Dalian University of Technology, Linggong Road 2, Dalian 116024, PR China
| | - Yulin Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environmental Science and Technology, Dalian University of Technology, Linggong Road 2, Dalian 116024, PR China
| | - Fahim Ullah
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environmental Science and Technology, Dalian University of Technology, Linggong Road 2, Dalian 116024, PR China
| | - Aimin Li
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environmental Science and Technology, Dalian University of Technology, Linggong Road 2, Dalian 116024, PR China
| | - Lei Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environmental Science and Technology, Dalian University of Technology, Linggong Road 2, Dalian 116024, PR China.
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22
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Ma H, Wu W, Yu Z, Zhao J, Fu P, Xia C, Lam SS, Wang Q, Gao M. Medium-chain fatty acid production from Chinese liquor brewing yellow water by electro-fermentation: Division of fermentation process and segmented electrical stimulation. BIORESOURCE TECHNOLOGY 2022; 360:127510. [PMID: 35752258 DOI: 10.1016/j.biortech.2022.127510] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 06/20/2022] [Accepted: 06/21/2022] [Indexed: 06/15/2023]
Abstract
Electro-fermentation (EF) has been proposed as a method to improve the yield of medium-chain fatty acid (MCFA). In this study, MCFA production from Chinese liquor wastewater (yellow water) was investigated and corresponding composite electron donors (lactate and ethanol in yellow water) were investigated by different electrical stimulation modes. The caproate yield under whole period electrical stimulation increased by 250.9% compared with open circuit. The oxidation-dominated and reduction-dominated periods of the fermentation process were divided, and the segmented electrical stimulation experiment showed the caproate yield under reduction-dominated EF system further increased by 288.5% compared with open circuit. The microbial diversity analysis demonstrated that Clostridium 12 might be enriched better by keeping open circuit during EDs consumption, meanwhile the bacteria with potential negative effects on CE were inhibited. The electrical stimulation mode of EF process was optimized and provided a new way to recycle organic wastewater.
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Affiliation(s)
- Hongzhi Ma
- Department of Environmental Science and Engineering, University of Science and Technology Beijing 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China.
| | - Wenyu Wu
- Department of Environmental Science and Engineering, University of Science and Technology Beijing 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China
| | - Ziqiang Yu
- Department of Environmental Science and Engineering, University of Science and Technology Beijing 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China
| | - Jihua Zhao
- Department of Environmental Science and Engineering, University of Science and Technology Beijing 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China
| | - Penglu Fu
- Department of Environmental Science and Engineering, University of Science and Technology Beijing 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China
| | - Changlei Xia
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, College of Materials Science and Engineering, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
| | - Su Shiung Lam
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, College of Materials Science and Engineering, Nanjing Forestry University, Nanjing, Jiangsu 210037, China; Higher Institution Centre of Excellence (HICoE), Institute of Tropical Aquaculture and Fisheries (AKUATROP), University Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia
| | - Qunhui Wang
- Department of Environmental Science and Engineering, University of Science and Technology Beijing 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China
| | - Ming Gao
- Department of Environmental Science and Engineering, University of Science and Technology Beijing 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China
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Gazzola G, Maria Braguglia C, Crognale S, Gallipoli A, Mininni G, Piemonte V, Rossetti S, Tonanzi B, Gianico A. Biorefining food waste through the anaerobic conversion of endogenous lactate into caproate: A fragile balance between microbial substrate utilization and product inhibition. WASTE MANAGEMENT (NEW YORK, N.Y.) 2022; 150:328-338. [PMID: 35907330 DOI: 10.1016/j.wasman.2022.07.031] [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: 04/11/2022] [Revised: 06/27/2022] [Accepted: 07/21/2022] [Indexed: 06/15/2023]
Abstract
New technologies development and renewable source exploitation are key tools to realize the European Green Deal and to boost the bio-based economy. In this context, fermentation of organic residues as food waste is an efficient method to obtain marketable products such as carboxylic acids widely applied in industrial production. Under favourable thermodynamic conditions, short chain fatty acids deriving from primary fermentation could be biologically converted into medium-chain fatty acids as caproate via chain elongation (CE) process, by using ethanol or lactate as electron donors. This study evaluates the effectivity of producing caproate from Food Waste extract rich in organics with in situ electron donor production. The test carried out at OLR 15 gCOD L-1d-1 showed high Volatile Fatty Acids (from acetic to caproic acid) yields (0.37 g g-1CODfed), with a maximum caproate concentration of 8 g L-1. The associated microbiome was composed by lactate-producing bacteria (Corynebacterium, Lactobacillus, and Olsenella) and by chain elongators (Clostridiaceae and Caproiciproducens). By stressing the system with OLR increase up to 20 gCOD L-1d-1, the CE process was inhibited by the high concentration of caproate (low occurrence of Clostridiaceae and Caproiciproducens). Nevertheless, after few days of stop-feeding regime imposed to the system, the microbiome restored its capability to proceed with lactate-based CE pathways. Different batch tests carried out with the inhibited biomass at increasing initial caproate concentration confirmed its impact on lactate utilization kinetics.
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Affiliation(s)
- Giulio Gazzola
- Water Research Institute, National Research Council of Italy, CNR-IRSA, Area della Ricerca RM1, Via Salaria km 29.300, 00015 Monterotondo, Roma, Italy
| | - Camilla Maria Braguglia
- Water Research Institute, National Research Council of Italy, CNR-IRSA, Area della Ricerca RM1, Via Salaria km 29.300, 00015 Monterotondo, Roma, Italy
| | - Simona Crognale
- Water Research Institute, National Research Council of Italy, CNR-IRSA, Area della Ricerca RM1, Via Salaria km 29.300, 00015 Monterotondo, Roma, Italy
| | - Agata Gallipoli
- Water Research Institute, National Research Council of Italy, CNR-IRSA, Area della Ricerca RM1, Via Salaria km 29.300, 00015 Monterotondo, Roma, Italy
| | - Giuseppe Mininni
- Water Research Institute, National Research Council of Italy, CNR-IRSA, Area della Ricerca RM1, Via Salaria km 29.300, 00015 Monterotondo, Roma, Italy
| | - Vincenzo Piemonte
- Faculty of Engineering, University Campus Bio-Medico, Via Alvaro del Portillo, 21, 00128 Roma, Italy
| | - Simona Rossetti
- Water Research Institute, National Research Council of Italy, CNR-IRSA, Area della Ricerca RM1, Via Salaria km 29.300, 00015 Monterotondo, Roma, Italy
| | - Barbara Tonanzi
- Water Research Institute, National Research Council of Italy, CNR-IRSA, Area della Ricerca RM1, Via Salaria km 29.300, 00015 Monterotondo, Roma, Italy
| | - Andrea Gianico
- Water Research Institute, National Research Council of Italy, CNR-IRSA, Area della Ricerca RM1, Via Salaria km 29.300, 00015 Monterotondo, Roma, Italy.
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24
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Zhang Y, Pan X, Zuo J, Hu J. Production of n-caproate using food waste through thermophilic fermentation without addition of external electron donors. BIORESOURCE TECHNOLOGY 2022; 343:126144. [PMID: 34673194 DOI: 10.1016/j.biortech.2021.126144] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/04/2021] [Accepted: 09/07/2021] [Indexed: 06/13/2023]
Abstract
The effectiveness of producing n-caproate from food waste without external electron donors (EDs) was investigated through batch and semi-continuous fermentation. The maximum concentration of n-caproate reached 10,226.28 mg COD/L during semi-continuous fermentation. The specificity for n-caproate was the highest at 40.19 ± 3.95%, and the soluble COD conversion rate of n-caproate reached up to 22.50 ± 1.09% at the end of batch fermentation. The production of n-caproate was coupled with the generation of lactate as an ED to facilitate chain elongation reactions. When lactate was used as the only substrate, n-butyrate (64.12 ± 20.11%) markedly dominated the products, instead of n-caproate (0.63 ± 0.07%). Microbial community analysis revealed that Caproiciproducens, Rummeliibacillus, and Clostridium_sensu_stricto_12 were the key genera related to n-caproate production. In addition to n-caproate, n-butyrate dominated the products in batch and semi-continuous fermentation with a maximum specificity of 47.59 ± 3.39%. Clostridium_sensu_stricto_7 was committed to producing n-butyrate from lactate.
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Affiliation(s)
- Yanyan Zhang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Xinrong Pan
- College of Biology and Environmental Engineering, Zhejiang Shuren University, Hangzhou 310015, China
| | - Jiane Zuo
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; Tsinghua Shenzhen International Graduate School, Shenzhen 518055, China.
| | - Jiamin Hu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
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25
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Contreras-Dávila CA, Zuidema N, Buisman CJN, Strik DPBTB. Reactor microbiome enriches vegetable oil with n-caproate and n-caprylate for potential functionalized feed additive production via extractive lactate-based chain elongation. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:232. [PMID: 34872602 PMCID: PMC8647473 DOI: 10.1186/s13068-021-02084-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 11/21/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Biotechnological processes for efficient resource recovery from residual materials rely on complex conversions carried out by reactor microbiomes. Chain elongation microbiomes produce valuable medium-chain carboxylates (MCC) that can be used as biobased starting materials in the chemical, agriculture and food industry. In this study, sunflower oil is used as an application-compatible solvent to accumulate microbially produced MCC during extractive lactate-based chain elongation. The MCC-enriched solvent is harvested as a potential novel product for direct application without further MCC purification, e.g., direct use for animal nutrition. Sunflower oil biocompatibility, in situ extraction performance and effects on chain elongation were evaluated in batch and continuous experiments. Microbial community composition and dynamics of continuous experiments were analyzed based on 16S rRNA gene sequencing data. Potential applications of MCC-enriched solvents along with future research directions are discussed. RESULTS Sunflower oil showed high MCC extraction specificity and similar biocompatibility to oleyl alcohol in batch extractive fermentation of lactate and food waste. Continuous chain elongation microbiomes produced the MCC n-caproate (nC6) and n-caprylate (nC8) from L-lactate and acetate at pH 5.0 standing high undissociated n-caproic acid concentrations (3 g L-1). Extractive chain elongation with sunflower oil relieved apparent toxicity of MCC and production rates and selectivities reached maximum values of 5.16 ± 0.41 g nC6 L-1 d-1 (MCC: 11.5 g COD L-1 d-1) and 84 ± 5% (e- eq MCC per e- eq products), respectively. MCC were selectively enriched in sunflower oil to concentrations up to 72 g nC6 L-1 and 3 g nC8 L-1, equivalent to 8.3 wt% in MCC-enriched sunflower oil. Fermentation at pH 7.0 produced propionate and n-butyrate instead of MCC. Sunflower oil showed stable linoleic and oleic acids composition during extractive chain elongation regardless of pH conditions. Reactor microbiomes showed reduced diversity at pH 5.0 with MCC production linked to Caproiciproducens co-occurring with Clostridium tyrobutyricum, Clostridium luticellarii and Lactobacillus species. Abundant taxa at pH 7.0 were Anaerotignum, Lachnospiraceae and Sporoanaerobacter. CONCLUSIONS Sunflower oil is a suitable biobased solvent to selectively concentrate MCC. Extractive reactor microbiomes produced MCC with improved selectivity and production rate, while downstream processing complexity was reduced. Potential applications of MCC-enriched solvents may include feed, food and biofuels purposes.
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Affiliation(s)
- Carlos A. Contreras-Dávila
- Environmental Technology, Wageningen University & Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
| | - Norwin Zuidema
- Environmental Technology, Wageningen University & Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
| | - Cees J. N. Buisman
- Environmental Technology, Wageningen University & Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
| | - David P. B. T. B. Strik
- Environmental Technology, Wageningen University & Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
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26
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Lu S, Jin H, Wang Y, Tao Y. Genome-Wide Transcriptomic Analysis of n-Caproic Acid Production in Ruminococcaceae Bacterium CPB6 with Lactate Supplementation. J Microbiol Biotechnol 2021; 31:1533-1544. [PMID: 34489376 PMCID: PMC9705837 DOI: 10.4014/jmb.2107.07009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 08/25/2021] [Accepted: 08/25/2021] [Indexed: 12/15/2022]
Abstract
n-Caproic acid (CA) is gaining increased attention due to its high value as a chemical feedstock. Ruminococcaceae bacterium strain CPB6 is an anaerobic mesophilic bacterium that is highly prolific in its ability to perform chain elongation of lactate to CA. However, little is known about the genome-wide transcriptional analysis of strain CPB6 for CA production triggered by the supplementation of exogenous lactate. In this study, cultivation of strain CPB6 was carried out in the absence and presence of lactate. Transcriptional profiles were analyzed using RNA-seq, and differentially expressed genes (DEGs) between the lactate-supplemented cells and control cells without lactate were analyzed. The results showed that lactate supplementation led to earlier CA p,roduction, and higher final CA titer and productivity. 295 genes were substrate and/or growth dependent, and these genes cover crucial functional categories. Specifically, 5 genes responsible for the reverse β-oxidation pathway, 11 genes encoding ATP-binding cassette (ABC) transporters, 6 genes encoding substrate-binding protein (SBP), and 4 genes encoding phosphotransferase system (PTS) transporters were strikingly upregulated in response to the addition of lactate. These genes would be candidates for future studies aiming at understanding the regulatory mechanism of lactate conversion into CA, as well as for the improvement of CA production in strain CPB6. The findings presented herein reveal unique insights into the biomolecular effect of lactate on CA production at the transcriptional level.
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Affiliation(s)
- Shaowen Lu
- CAS Key Laboratory of Environmental and Applied Microbiology and Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, P.R. China
| | - Hong Jin
- School of Basic Medical Science, Chengdu Medical College, Chengdu 610083, P.R. China
| | - Yi Wang
- Department of Biosystems Engineering, Auburn University, Auburn, Alabama, Alabama 36849, USA
| | - Yong Tao
- CAS Key Laboratory of Environmental and Applied Microbiology and Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, P.R. China,Faculty of Bioengineering, Sichuan University of Science and Engineering, Xueyuan Street 180#, Huixing Rd. Zigong 643000, P.R. China,Corresponding author Phone: 86-028-82890211 Fax: 86-028-82890211 E-mail:
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27
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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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28
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He J, Shi Z, Luo T, Zhang S, Liu Y, Luo G. Phenol promoted caproate production via two-stage batch anaerobic fermentation of organic substance with ethanol as electron donor for chain elongation. WATER RESEARCH 2021; 204:117601. [PMID: 34481286 DOI: 10.1016/j.watres.2021.117601] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 08/15/2021] [Accepted: 08/22/2021] [Indexed: 06/13/2023]
Abstract
The conversion of organic wastes/wastewater into medium chain fatty acids (MCFAs) such as caproate has attracted much attention, while the effects of toxic compounds on the process have rarely been studied. The present study investigated the effects of phenol (0-1.5 g/L), which is a toxicant and present in various organic wastes, on the caproate production in the chain elongation (CE) process with ethanol as electron donor via two-stage batch anaerobic fermentation of glucose. The results showed phenol ≤ 1 g/L did not affect short chain fatty acids (SCFAs) production, while 1 g/L phenol increased caproate production by 59.9% in the following CE process. The higher selectivity of caproate and higher consumption of ethanol contributed to the higher caproate production at 1 g/L phenol. It was also shown 1 g/L phenol had more positive effect on CE of butyrate than acetate. 1.5 g/L phenol inhibited both SCFAs production and CE processes. 16S rRNA genes analysis showed phenol had slight effect on the microbial communities for SCFAs production, while it obviously changed the dominant microbes in CE process. For CE process, metagenomic analysis was further conducted and phenol mainly affected fatty acid biosynthesis (FAB) pathway, but not reverse β-oxidization (RBO) pathway. 1 g/L phenol increased the abundances of genes in FAB pathway, which could be related with the higher caproate production. Genome reconstruction identified the dominant microbial species in CE process, which were changed with different concentrations of phenol. Most of the dominant species were new microbial species potentially involved in CE. The syntrophic cooperation between Petrimonas mucosa FDU058 and Methanofollis sp. FDU007 might play important role in increased caproate production at 1 g/L phenol, and their adaption to phenol could be due to the presence of genes relating with active efflux system and refolding of proteins.
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Affiliation(s)
- Jun He
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China; Shanghai Technical Service Platform for Pollution Control and Resource Utilization of Organic Wastes, Shanghai, 200438, China
| | - Zhijian Shi
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China; Shanghai Technical Service Platform for Pollution Control and Resource Utilization of Organic Wastes, Shanghai, 200438, China
| | - Tao Luo
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China; Shanghai Technical Service Platform for Pollution Control and Resource Utilization of Organic Wastes, Shanghai, 200438, China
| | - Shicheng Zhang
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China; Shanghai Technical Service Platform for Pollution Control and Resource Utilization of Organic Wastes, Shanghai, 200438, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Yan Liu
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China; Shanghai Technical Service Platform for Pollution Control and Resource Utilization of Organic Wastes, Shanghai, 200438, China.
| | - Gang Luo
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China; Shanghai Technical Service Platform for Pollution Control and Resource Utilization of Organic Wastes, Shanghai, 200438, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China.
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29
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de Leeuw KD, Ahrens T, Buisman CJN, Strik DPBTB. Open Culture Ethanol-Based Chain Elongation to Form Medium Chain Branched Carboxylates and Alcohols. Front Bioeng Biotechnol 2021; 9:697439. [PMID: 34485254 PMCID: PMC8416115 DOI: 10.3389/fbioe.2021.697439] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 07/30/2021] [Indexed: 11/18/2022] Open
Abstract
Chain elongation fermentation allows for the synthesis of biobased chemicals from complex organic residue streams. To expand the product spectrum of chain elongation technology and its application range we investigated 1) how to increase selectivity towards branched chain elongation and 2) whether alternative branched carboxylates such as branched valerates can be used as electron acceptors. Elongation of isobutyrate elongation towards 4-methyl-pentanoate was achieved with a selectivity of 27% (of total products, based on carbon atoms) in a continuous system that operated under CO2 and acetate limited conditions. Increasing the CO2 load led to more in situ acetate formation that increased overall chain elongation rate but decreased the selectivity of branched chain elongation. A part of this acetate formation was related to direct ethanol oxidation that seemed to be thermodynamically coupled to hydrogenotrophic carboxylate reduction to corresponding alcohols. Several alcohols including isobutanol and n-hexanol were formed. The microbiome from the continuous reactor was also able to form small amounts of 5-methyl-hexanoate likely from 3-methyl-butanoate and ethanol as substrate in batch experiments. The highest achieved concentration of isoheptanoate was 6.4 ± 0.9 mM Carbon, or 118 ± 17 mg/L, which contributed for 7% to the total amount of products (based on carbon atoms). The formation of isoheptanoate was dependent on the isoform of branched valerate. With 3-methyl-butanoate as substrate 5-methylhexanoate was formed, whereas a racemic mixture of L/D 2-methyl-butanoate did not lead to an elongated product. When isobutyrate and isovalerate were added simultaneously as substrates there was a large preference for elongation of isobutyrate over isovalerate. Overall, this work showed that chain elongation microbiomes can be further adapted with supplement of branched-electron acceptors towards the formation of iso-caproate and iso-heptanoate as well as that longer chain alcohol formation can be stimulated.
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Affiliation(s)
- Kasper D de Leeuw
- Environmental Technology, Wageningen University & Research, Wageningen, Netherlands
| | - Theresa Ahrens
- Environmental Technology, Wageningen University & Research, Wageningen, Netherlands
| | - Cees J N Buisman
- Environmental Technology, Wageningen University & Research, Wageningen, Netherlands
| | - David P B T B Strik
- Environmental Technology, Wageningen University & Research, Wageningen, Netherlands
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30
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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: 17] [Impact Index Per Article: 5.7] [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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31
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Wei Y, Ren B, Zheng S, Feng X, He Y, Zhu X, Zhou L, Li D. Effect of high concentration of ammonium on production of n-caproate: Recovery of a high-value biochemical from food waste via lactate-driven chain elongation. WASTE MANAGEMENT (NEW YORK, N.Y.) 2021; 128:25-35. [PMID: 33957431 DOI: 10.1016/j.wasman.2021.04.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 03/08/2021] [Accepted: 04/05/2021] [Indexed: 06/12/2023]
Abstract
Ammonium accumulation is inevitable during the fermentation of food waste (FW), challenging the application of chain elongation process upgrading FW into the high-value biochemical n-caproate, which is a medium chain carboxylate. This study is the first to investigate ammonium inhibition of lactate-driven chain elongation process. The short-term exposure of a Clostridium IV-dominated chain elongating reactor microbiome at an ammonium concentration of 1-4 g L-1 linearly decreased n-caproate production by 25-80%. High levels of ammonium (≥5 g L-1) could cause failure of chain elongation, shifting the product from n-caproate to propionate. The involved mechanisms revealed that ammonium reshaped the microbial community from Clostridium IV domination to Clostridium IV and Propionibacterium co-domination (based on 16S rRNA sequencing) and reduced the activities of key enzymes involved in the reversed β-oxidization pathway. We propose an effective strategy from our study, which is the first one to do in our knowledge, to upgrade raw FW without dilution to n-caproate: lowering the ammonium accumulation to 1.0 g L-1 at the setup phase for adaptation and prolonging the hydraulic retention time (10 days) during the operation phase for the colonization of chain-elongation bacteria. These findings lay a foundation for the implementation of the LCE process on FW, providing an alternative way to alleviate the global FW crisis.
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Affiliation(s)
- Yong Wei
- School of Environmental and Safety Engineering, Changzhou University, Changzhou 213000, PR China
| | - Bing Ren
- School of Environmental and Safety Engineering, Changzhou University, Changzhou 213000, PR China; Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province; Chengdu Institute of Biology, Chinese Academy of Sciences. Chengdu, 610041, PR China; University of Chinese Academy of Sciences, Beijing 100864, PR China
| | - Shaorui Zheng
- Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province; Chengdu Institute of Biology, Chinese Academy of Sciences. Chengdu, 610041, PR China; University of Chinese Academy of Sciences, Beijing 100864, PR China; Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210014, PR China
| | - Xin Feng
- Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province; Chengdu Institute of Biology, Chinese Academy of Sciences. Chengdu, 610041, PR China; University of Chinese Academy of Sciences, Beijing 100864, PR China
| | - Yong He
- School of Environmental and Safety Engineering, Changzhou University, Changzhou 213000, PR China; Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province; Chengdu Institute of Biology, Chinese Academy of Sciences. Chengdu, 610041, PR China; University of Chinese Academy of Sciences, Beijing 100864, PR China
| | - Xiaoyu Zhu
- Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province; Chengdu Institute of Biology, Chinese Academy of Sciences. Chengdu, 610041, PR China; University of Chinese Academy of Sciences, Beijing 100864, PR China.
| | - Lixiang Zhou
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210014, PR China
| | - Dong Li
- Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province; Chengdu Institute of Biology, Chinese Academy of Sciences. Chengdu, 610041, PR China; University of Chinese Academy of Sciences, Beijing 100864, PR China
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Microbial Ecological Mechanism for Long-Term Production of High Concentrations of n-Caproate via Lactate-Driven Chain Elongation. Appl Environ Microbiol 2021; 87:AEM.03075-20. [PMID: 33741616 DOI: 10.1128/aem.03075-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 03/10/2021] [Indexed: 12/11/2022] Open
Abstract
Lactate-driven chain elongation (LCE) has emerged as a new biotechnology to upgrade organic waste streams into a valuable biochemical and fuel precursor, medium-chain carboxylate, n-caproate. Considering that a low cost of downstream extraction is critical for biorefinery technology, a high concentration of n-caproate production is very important to improve the scale-up of the LCE process. We report here that in a nonsterile open environment, the n-caproate concentration was increased from the previous record of 25.7 g·liter-1 to a new high level of 33.7 g·liter-1 (76.8 g chemical oxygen demand [COD]·liter - 1), with the highest production rate being 11.5 g·liter-1·day-1 (26.2 g COD·liter - 1·day-1). In addition, the LCE process remained stable, with an average concentration of n-caproate production of 20.2 ± 5.62 g·liter-1 (46.1 ± 12.8 g COD·liter - 1) for 780 days. Dynamic changes in taxonomic composition integrated with metagenomic data reveal the microbial ecology for long-term production of high concentrations of n-caproate: (i) the core microbiome is related to efficient functional groups, such as Ruminococcaceae (with functional strain CPB6); (ii) the core bacteria can maintain stability for long-term operation; (iii) the microbial network has relatively low microbe-microbe interaction strength; and (iv) low relative abundance and variety of competitors. The network structure could be shaped by hydraulic retention time (HRT) over time, and long-term operation at an HRT of 8 days displayed higher efficacy.IMPORTANCE Our research revealed the microbial network of the LCE reactor microbiome for n-caproate production at high concentrations, which will provide a foundation for designing or engineering the LCE reactor microbiome to recover n-caproate from organic waste streams in the future. In addition, the hypothetical model of the reactor microbiome that we proposed may offer guidance for researchers to find the underlying microbial mechanism when they encounter low-efficiency n-caproate production from the LCE process. We anticipate that our research will rapidly advance LCE biotechnology with the goal of promoting the sustainable development of human society.
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Baleeiro FCF, Kleinsteuber S, Sträuber H. Hydrogen as a Co-electron Donor for Chain Elongation With Complex Communities. Front Bioeng Biotechnol 2021; 9:650631. [PMID: 33898406 PMCID: PMC8059637 DOI: 10.3389/fbioe.2021.650631] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 03/12/2021] [Indexed: 01/04/2023] Open
Abstract
Electron donor scarcity is seen as one of the major issues limiting economic production of medium-chain carboxylates from waste streams. Previous studies suggest that co-fermentation of hydrogen in microbial communities that realize chain elongation relieves this limitation. To better understand how hydrogen co-feeding can support chain elongation, we enriched three different microbial communities from anaerobic reactors (A, B, and C with ascending levels of diversity) for their ability to produce medium-chain carboxylates from conventional electron donors (lactate or ethanol) or from hydrogen. In the presence of abundant acetate and CO2, the effects of different abiotic parameters (pH values in acidic to neutral range, initial acetate concentration, and presence of chemical methanogenesis inhibitors) were tested along with the enrichment. The presence of hydrogen facilitated production of butyrate by all communities and improved production of i-butyrate and caproate by the two most diverse communities (B and C), accompanied by consumption of acetate, hydrogen, and lactate/ethanol (when available). Under optimal conditions, hydrogen increased the selectivity of conventional electron donors to caproate from 0.23 ± 0.01 mol e-/mol e- to 0.67 ± 0.15 mol e-/mol e- with a peak caproate concentration of 4.0 g L-1. As a trade-off, the best-performing communities also showed hydrogenotrophic methanogenesis activity by Methanobacterium even at high concentrations of undissociated acetic acid of 2.9 g L-1 and at low pH of 4.8. According to 16S rRNA amplicon sequencing, the suspected caproate producers were assigned to the family Anaerovoracaceae (Peptostreptococcales) and the genera Megasphaera (99.8% similarity to M. elsdenii), Caproiciproducens, and Clostridium sensu stricto 12 (97-100% similarity to C. luticellarii). Non-methanogenic hydrogen consumption correlated to the abundance of Clostridium sensu stricto 12 taxa (p < 0.01). If a robust methanogenesis inhibition strategy can be found, hydrogen co-feeding along with conventional electron donors can greatly improve selectivity to caproate in complex communities. The lessons learned can help design continuous hydrogen-aided chain elongation bioprocesses.
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Affiliation(s)
- Flávio C F Baleeiro
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany.,Technical Biology, Institute of Process Engineering in Life Science II, Karlsruhe Institute of Technology - KIT, Karlsruhe, Germany
| | - Sabine Kleinsteuber
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
| | - Heike Sträuber
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
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Lactate Metabolism and Microbiome Composition Are Affected by Nitrogen Gas Supply in Continuous Lactate-Based Chain Elongation. FERMENTATION 2021. [DOI: 10.3390/fermentation7010041] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Chain elongation reactor microbiomes produce valuable medium-chain carboxylates (MCC) from non-sterile residual substrates where lactate is a relevant intermediate. Gas supply has been shown to impact chain elongation performance. In the present study, the effect of nitrogen gas (N2) supply on lactate metabolism, conversion rates, biomass growth, and microbiome composition was evaluated in a lactate-fed upflow anaerobic reactor with continuous or intermittent N2 gas supply. Successful MCC production was achieved with continuous N2 gas supply at low superficial gas velocities (SGV) of 0.22 m∙h−1. Supplying N2 at high SGV (>2 m∙h−1) either continuously (2.2 m∙h−1) or intermittently (3.6 m∙h−1) disrupted chain elongation, resulting in production of short-chain carboxylates (SCC), i.e., acetate, propionate, and n-butyrate. Caproiciproducens-dominated chain-elongating microbiomes enriched at low SGV were washed out at high SGV where Clostridium tyrobutyricum-dominated microbiomes thrived, by displaying higher lactate consumption rates. Suspended growth seemed to be dominant regardless of SGV and gas supply regime applied with no measurable sludge bed formed. The highest MCC production from lactate of 10 g COD∙L−1∙d−1 with electron selectivities of 72 ± 5%was obtained without N2 gas supply at a hydraulic retention time (HRT) of 1 day. The addition of 5 g∙L−1 of propionate did not inhibit chain elongation, but rather boosted lactate conversion rates towards MCC with n-heptylate reaching 1.8 g COD∙L−1∙d−1. N2 gas supply can be used for mixing purposes and to steer lactate metabolism to MCC or SCC production.
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Direct Conversion of Food Waste Extract into Caproate: Metagenomics Assessment of Chain Elongation Process. Microorganisms 2021; 9:microorganisms9020327. [PMID: 33562834 PMCID: PMC7915914 DOI: 10.3390/microorganisms9020327] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 02/01/2021] [Accepted: 02/03/2021] [Indexed: 12/30/2022] Open
Abstract
In a circular economy strategy, waste resources can be used for the biological production of high added-value substances, such as medium chain fatty acids (MCFAs), thus minimising waste and favouring a sustainable process. This study investigates single-stage fermentation processes for the production of MCFAs in a semi-continuous reactor treating the extract of real food waste (FW), without the addition of external electron donors. Two sequential acidogenic fermentation tests were carried out at an organic loading rate (OLR) of 5 and 15 gCOD L−1d−1 with a hydraulic retention time of 4 days and pH controlled at 6 ± 0.2. The highest level of caproate (4.8 g L−1) was observed at OLR of 15 gCOD L−1d−1 with a microbiome mainly composed by lactate-producing Actinomyces, Atopobium, and Olsenella species and caproate-producing Pseudoramibacter. Metagenomic analysis revealed the presence of key enzymes for the production of lactate, such as lactate dehydrogenase and pyruvate ferredoxin oxidoreductase, as well as several enzymes involved in the reverse β-oxidation pathway, thus suggesting the occurrence of a lactate-based chain elongation process.
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Saadoun L, Campitelli A, Kannengiesser J, Stanojkovski D, El Alaoui El Fels A, Mandi L, Ouazzani N. Potential of medium chain fatty acids production from municipal solid waste leachate: Effect of age and external electron donors. WASTE MANAGEMENT (NEW YORK, N.Y.) 2021; 120:503-512. [PMID: 33129653 DOI: 10.1016/j.wasman.2020.10.013] [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: 07/17/2020] [Revised: 10/06/2020] [Accepted: 10/08/2020] [Indexed: 06/11/2023]
Abstract
A large quantity of leachate is generated during municipal solid waste collection operation and in landfills due to the large amount of organic waste and high humidity. The content of medium chain fatty acids (MCFAs) in the leachate is a low cost feedstock for bio-based chemical and fuel production processes. The aim of this study is to investigate the MCFA production potential of three leachate ages through chain elongation process under uncontrolled pH batch test. Moreover, the effect of using different external electron donors (ethanol, methanol and a mixture of both) is studied. The experiment consists of characterizing the samples then adding external electron donors with a specific ratio to leachate samples under mesophilic temperature. For this investigation, also a statistical analysis is done, which shows the production of MCFAs is highly influenced by leachate age. The results indicate that the production of even-numbered acids increase from 600 to 1,000 mg/L by the end of the ethanol chain elongation experiment for young leachate. However, a higher MCFA production of more than 1,000 mg/L is achieved by using the mixture of methanol and ethanol as electron donor. Furthermore, all methanol chain elongation experiments lead to an odd-numbered production of MCFAs, such as pentanoic and heptanoic acids. These results confirm the potential improvement of MCFA production from leachate through choosing the optimal leachate age and electron donor. Overall, producing MCFAs from leachate is a good example of circular bio-economy because waste is used to produce biochemicals, which closes the material cycle.
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Affiliation(s)
- Lamia Saadoun
- Laboratory of Water, Biodiversity and Climate Change, Faculty of Sciences Semlalia, P.O. Box 2390, Cadi Ayyad University, Marrakech, Morocco; National Center for Studies and Research on Water and Energy (CNEREE), Cadi Ayyad University, P.O. Box 511, Marrakech, Morocco
| | - Alessio Campitelli
- Technical University of Darmstadt, Institute IWAR, Department of Material Flow Management and Resource Economy, Franziska-Braun-Straße 7, 64287 Darmstadt, Germany
| | - Jan Kannengiesser
- Technical University of Darmstadt, Institute IWAR, Department of Material Flow Management and Resource Economy, Franziska-Braun-Straße 7, 64287 Darmstadt, Germany
| | - Daniel Stanojkovski
- Technical University of Darmstadt, Institute IWAR, Department of Material Flow Management and Resource Economy, Franziska-Braun-Straße 7, 64287 Darmstadt, Germany
| | - Abdelhafid El Alaoui El Fels
- Laboratory of Water, Biodiversity and Climate Change, Faculty of Sciences Semlalia, P.O. Box 2390, Cadi Ayyad University, Marrakech, Morocco
| | - Laila Mandi
- Laboratory of Water, Biodiversity and Climate Change, Faculty of Sciences Semlalia, P.O. Box 2390, Cadi Ayyad University, Marrakech, Morocco; National Center for Studies and Research on Water and Energy (CNEREE), Cadi Ayyad University, P.O. Box 511, Marrakech, Morocco
| | - Naaila Ouazzani
- Laboratory of Water, Biodiversity and Climate Change, Faculty of Sciences Semlalia, P.O. Box 2390, Cadi Ayyad University, Marrakech, Morocco; National Center for Studies and Research on Water and Energy (CNEREE), Cadi Ayyad University, P.O. Box 511, Marrakech, Morocco.
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Ma H, Lin Y, Jin Y, Gao M, Li H, Wang Q, Ge S, Cai L, Huang Z, Van Le Q, Xia C. Effect of ultrasonic pretreatment on chain elongation of saccharified residue from food waste by anaerobic fermentation. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 268:115936. [PMID: 33158614 DOI: 10.1016/j.envpol.2020.115936] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 10/03/2020] [Accepted: 10/24/2020] [Indexed: 06/11/2023]
Abstract
Converting biowaste into value-added products has raised the researchers' interests. In this study, bioconversion was applied to produce chain acids from food waste by anaerobic fermentation. To improve the caproic acid production, different pretreatments (i.e., ultrasonic, hydrothermal, and alkaline-thermal) were used for investigating their effects on the acidogenic production and microbial communities. The results showed that ultrasonic and hydrothermal pretreatments (207.8 and 210.1 mg COD/g VS, respectively) were very efficient for enhancing the caproic acid production, compared to the alkaline-thermal pretreated samples and control samples (72.6 and 97.5 mg COD/g VS, respectively). The ultrasonic pretreatment was beneficial for reducing volatile fatty acids (VFAs) during the caproic acid production, resulting in converting more lactic acid to caproic acid by adding the hydrothermal pretreatment. The microbial community analysis showed that the acidogenic bacteria Caproiciproducens dominated the fermentation in this bioconversion process of food waste into chain acids. The Caproiciproducens mainly degraded the proteins and carbohydrates from the saccharified residues of food waste to produce caproic acids through chain elongation procedure. The investigation and optimized method may help develop the bioconversion technology for producing VFAs products from food wastes.
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Affiliation(s)
- Hongzhi Ma
- Department of Environmental Engineering, University of Science and Technology Beijing, 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing, 100083, China
| | - Yujia Lin
- Department of Environmental Engineering, University of Science and Technology Beijing, 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing, 100083, China
| | - Yong Jin
- Department of Environmental Engineering, University of Science and Technology Beijing, 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing, 100083, China
| | - Ming Gao
- Department of Environmental Engineering, University of Science and Technology Beijing, 100083, China
| | - Hongai Li
- Department of Environmental Engineering, University of Science and Technology Beijing, 100083, China
| | - Qunhui Wang
- Department of Environmental Engineering, University of Science and Technology Beijing, 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing, 100083, China
| | - Shengbo Ge
- Co-Innovation Center of Efficient Processing and Utilization of Forestry Resources, College of Materials Science and Engineering, Nanjing Forestry University, Nanjing, Jiangsu, 210037, China
| | - Liping Cai
- Co-Innovation Center of Efficient Processing and Utilization of Forestry Resources, College of Materials Science and Engineering, Nanjing Forestry University, Nanjing, Jiangsu, 210037, China; Department of Mechanical Engineering, University of North Texas, Denton, TX, 76207, USA
| | - Zhenhua Huang
- Department of Mechanical Engineering, University of North Texas, Denton, TX, 76207, USA
| | - Quyet Van Le
- Institute of Research and Development, Duy Tan University, Da Nang, 550000, Viet Nam
| | - Changlei Xia
- Co-Innovation Center of Efficient Processing and Utilization of Forestry Resources, College of Materials Science and Engineering, Nanjing Forestry University, Nanjing, Jiangsu, 210037, China.
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Fermentation of Organic Residues to Beneficial Chemicals: A Review of Medium-Chain Fatty Acid Production. Processes (Basel) 2020. [DOI: 10.3390/pr8121571] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Medium-chain fatty acids (MCFAs) have a variety of uses in the production of industrial chemicals, food, and personal care products. These compounds are often produced through palm refining, but recent work has demonstrated that MCFAs can also be produced through the fermentation of complex organic substrates, including organic waste streams. While “chain elongation” offers a renewable platform for producing MCFAs, there are several limitations that need to be addressed before full-scale implementation becomes widespread. Here, we review the history of work on MCFA production by both pure and mixed cultures of fermenting organisms, and the unique metabolic features that lead to MCFA production. We also offer approaches to address the remaining challenges and increase MCFA production from renewable feedstocks.
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39
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Adjusting Organic Load as a Strategy to Direct Single-Stage Food Waste Fermentation from Anaerobic Digestion to Chain Elongation. Processes (Basel) 2020. [DOI: 10.3390/pr8111487] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Production of medium chain carboxylic acids (MCCA) as renewable feedstock bio-chemicals, from food waste (FW), requires complicated reactor configurations and supplementation of chemicals to achieve product selectivity. This study evaluated the manipulation of organic loading rate in an un-supplemented, single stage stirred tank reactor to steer an anaerobic digestion (AD) microbiome towards acidogenic fermentation (AF), and thence to chain elongation. Increasing substrate availability by switching to a FW feedstock with a higher COD stimulated chain elongation. The MCCA species n-caproic (10.1 ± 1.7 g L−1) and n-caprylic (2.9 ± 0.8 g L−1) acid were produced at concentrations comparable to more complex reactor set-ups. As a result, of the adjusted operating strategy, a more specialised microbiome developed containing several MCCA-producing bacteria, lactic acid-producing Olsenella spp. and hydrogenotrophic methanogens. By contrast, in an AD reactor that was operated in parallel to produce biogas, the retention times had to be doubled when fed with the high-COD FW to maintain biogas production. The AD microbiome comprised a diverse mixture of hydrolytic and acidogenic bacteria, and acetoclastic methanogens. The results suggest that manipulation of organic loading rate and food-to-microorganism ratio may be used as an operating strategy to direct an AD microbiome towards AF, and to stimulate chain elongation in FW fermentation, using a simple, un-supplemented stirred tank set-up. This outcome provides the opportunity to repurpose existing AD assets operating on food waste for biogas production, to produce potentially higher value MCCA products, via simple manipulation of the feeding strategy.
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Raes SMT, Jourdin L, Buisman CJN, Strik DPBTB. Bioelectrochemical Chain Elongation of Short‐Chain Fatty Acids Creates Steering Opportunities for Selective Formation ofn‐Butyrate,n‐Valerate orn‐Caproate. ChemistrySelect 2020. [DOI: 10.1002/slct.202002001] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Sanne M. T. Raes
- Environmental TechnologyWageningen University and Research, Axis-Z Bornse Weilanden 9 6708 WG Wageningen The Netherlands
| | - Ludovic Jourdin
- Environmental TechnologyWageningen University and Research, Axis-Z Bornse Weilanden 9 6708 WG Wageningen The Netherlands
| | - Cees J. N. Buisman
- Environmental TechnologyWageningen University and Research, Axis-Z Bornse Weilanden 9 6708 WG Wageningen The Netherlands
| | - David P. B. T. B. Strik
- Environmental TechnologyWageningen University and Research, Axis-Z Bornse Weilanden 9 6708 WG Wageningen The Netherlands
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Venkateswar Reddy M, Kumar G, Mohanakrishna G, Shobana S, Al-Raoush RI. Review on the production of medium and small chain fatty acids through waste valorization and CO 2 fixation. BIORESOURCE TECHNOLOGY 2020; 309:123400. [PMID: 32371319 DOI: 10.1016/j.biortech.2020.123400] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/15/2020] [Accepted: 04/16/2020] [Indexed: 06/11/2023]
Abstract
The developing approaches in the recovery of resources from biowastes for the production of renewable value-added products and fuels, using microbial cultures as bio-catalyst have now became promising aspect. In the path of anaerobic digestion, the microorganisms are assisting transformation of a complex organic feedstock/waste to biomass and biogas. This potentiality consequently leads to the production of intermediate precursors of renewable value-added products. Particularly, a set of anaerobic pathways in the fermentation process, yields small-chain fatty acids (SCFA), and medium-chain fatty acids (MCFA) via chain elongation pathways from waste valorization and CO2 fixation. This review focuses on the production of SCFA and MCFA from CO2, synthetic substrates and waste materials. Moreover, the review introduces the metabolic engineering of Escherichia coli and Saccharomyces cerevisiae for SCFAs/MCFAs production. Furtherly, it concludes that future critical research might target progress of this promising approach as a valorization of complex organic wastes.
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Affiliation(s)
- M Venkateswar Reddy
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms Universität, Corrensstr. 3, 48149 Münster, Germany
| | - Gopalakrishnan Kumar
- School of Civil and Environmental Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Gunda Mohanakrishna
- Department of Civil and Architectural Engineering, College of Engineering, Qatar University, P O Box 2713, Doha, Qatar.
| | - Sutha Shobana
- Department of Chemistry & Research Centre, Mohamed Sathak Engineering College, Kilakarai, 623 806 Ramanathapuram, Tamil Nadu, India
| | - Riyadh I Al-Raoush
- Department of Civil and Architectural Engineering, College of Engineering, Qatar University, P O Box 2713, Doha, Qatar
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Chatzipanagiotou K, Jourdin L, Buisman CJN, Strik DPBTB, Bitter JH. CO
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Conversion by Combining a Copper Electrocatalyst and Wild‐type Microorganisms. ChemCatChem 2020. [DOI: 10.1002/cctc.202000678] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Konstantina‐Roxani Chatzipanagiotou
- Biobased Chemistry and Technology Wageningen University & Research Bornse Weilanden 9 6708 WG Wageningen The Netherlands
- Environmental Technology Wageningen University & Research Bornse Weilanden 9 6708 WG Wageningen The Netherlands
| | - Ludovic Jourdin
- Environmental Technology Wageningen University & Research Bornse Weilanden 9 6708 WG Wageningen The Netherlands
- Department of Biotechnology Delft University of Technology van der Maasweg 9 2629 HZ Delft The Netherlands
| | - Cees J. N. Buisman
- Environmental Technology Wageningen University & Research Bornse Weilanden 9 6708 WG Wageningen The Netherlands
| | - David P. B. T. B. Strik
- Environmental Technology Wageningen University & Research Bornse Weilanden 9 6708 WG Wageningen The Netherlands
| | - Johannes H. Bitter
- Biobased Chemistry and Technology Wageningen University & Research Bornse Weilanden 9 6708 WG Wageningen The Netherlands
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Wang Q, Zhang P, Bao S, Liang J, Wu Y, Chen N, Wang S, Cai Y. Chain elongation performances with anaerobic fermentation liquid from sewage sludge with high total solid as electron acceptor. BIORESOURCE TECHNOLOGY 2020; 306:123188. [PMID: 32199398 DOI: 10.1016/j.biortech.2020.123188] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 03/08/2020] [Accepted: 03/11/2020] [Indexed: 06/10/2023]
Abstract
This work studied the effect of total solid (TS) of sewage sludge on VFA production and composition in anaerobic fermentation. Results revealed that VFA concentration reached the highest of 10.16 g/L and the ratio of acetic acid, propionic acid and n-butyric acid was 5:2:2 with the 8% TS sewage sludge. In subsequent chain elongation with sludge fermentation liquid, n-caproic acid concentration reached 43.45 mmol/L. The microbial community analysis indicated that relative abundance of Clostridium_sensu_stricto_12 for n-caproic acid production was high (52.41%). The chain elongation with sludge fermentation liquid had more pathways to produce n-caproic acid, and the chain elongation reactions were thermodynamically possible. The mixed VFAs and high concentration of n-butyric acid benefitted n-caproic acid production. Carbon balance revealed that the VFA composition of sludge fermentation liquid was beneficial to the chain elongation. This study will contribute to wasted sludge minimization and high-value material production.
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Affiliation(s)
- Qingyan Wang
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Panyue Zhang
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China; School of Environmental and Chemical Engineering, Chongqing Three Gorges University, Chongqing 404632, China.
| | - Shuai Bao
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Jinsong Liang
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Yan Wu
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China; School of Environmental and Chemical Engineering, Chongqing Three Gorges University, Chongqing 404632, China
| | - Na Chen
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Siqi Wang
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Yajing Cai
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
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San-Valero P, Abubackar HN, Veiga MC, Kennes C. Effect of pH, yeast extract and inorganic carbon on chain elongation for hexanoic acid production. BIORESOURCE TECHNOLOGY 2020; 300:122659. [PMID: 31893537 DOI: 10.1016/j.biortech.2019.122659] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 12/17/2019] [Accepted: 12/18/2019] [Indexed: 06/10/2023]
Abstract
Several anaerobic bioconversion technologies produce short chain volatile fatty acids and sometimes ethanol, which can together be elongated to hexanoic acid (C6 acid) by Clostridium kluyveri in a secondary fermentation process. Initiatives are needed to further optimize the process. Therefore, five strategies were tested aiming at elucidating their influence on hexanoic acid production from mixtures of acetic acid, butyric acid and ethanol. pH-regulated bioreactors, maintained at pH 7.5, 6.8 or 6.4 led to maximum C6 acid concentrations of, respectively, 19.4, 18.3 and 13.3 g L-1. At pH 6.8, yeast extract omission resulted in a decrease of the hexanoic acid concentration to 12.0 g L-1 while the addition of an inorganic carbon source, such as bicarbonate, for pH control, increased the C6 acid concentration up to 21.4 g L-1. This research provides guidelines for efficient improved production of hexanoic acid by pure cultures of C. kluyveri, contributing to the state of art.
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Affiliation(s)
- Pau San-Valero
- Chemical Engineering Laboratory, Faculty of Sciences and Center for Advanced Scientific Research (CICA), University of La Coruña, Rúa da Fraga 10, E - 15008 La Coruña, Spain
| | - Haris Nalakath Abubackar
- Chemical Engineering Laboratory, Faculty of Sciences and Center for Advanced Scientific Research (CICA), University of La Coruña, Rúa da Fraga 10, E - 15008 La Coruña, Spain
| | - María C Veiga
- Chemical Engineering Laboratory, Faculty of Sciences and Center for Advanced Scientific Research (CICA), University of La Coruña, Rúa da Fraga 10, E - 15008 La Coruña, Spain
| | - Christian Kennes
- Chemical Engineering Laboratory, Faculty of Sciences and Center for Advanced Scientific Research (CICA), University of La Coruña, Rúa da Fraga 10, E - 15008 La Coruña, Spain.
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Contreras-Dávila CA, Carrión VJ, Vonk VR, Buisman CNJ, Strik DPBTB. Consecutive lactate formation and chain elongation to reduce exogenous chemicals input in repeated-batch food waste fermentation. WATER RESEARCH 2020; 169:115215. [PMID: 31678751 DOI: 10.1016/j.watres.2019.115215] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 10/03/2019] [Accepted: 10/18/2019] [Indexed: 06/10/2023]
Abstract
The production of biochemicals from renewables through biorefinery processes is important to reduce the anthropogenic impact on the environment. Chain elongation processes based on microbiomes have been successfully developed to produce medium-chain fatty acids (MCFA) from organic waste streams. Yet, the sustainability of chain elongation can still be improved by reducing the use of electron donors and additional chemicals. This work aimed to couple lactate production and subsequent chain elongation to decrease chemicals input such as electron donors and hydroxide for pH control in repeated-batch food waste fermentation. Food waste with adjusted pH was used as substrate and fermentation proceeded without pH control. During fermentation, lactate was first formed through the homolactic pathway and then converted to fatty acids (FA), mainly n-butyrate and n-caproate. The highest n-caproate carbon selectivities (mmol C/mmol CFA) and production rates were 38% and 4.2 g COD/L-d, respectively. Hydroxide input was reduced over time to a minimum of 0.47 mol OH-/mol MCFA or 0.79 mol OH-/kg CODFA. Lactate was a key electron donor for chain elongation and its conversion was observed at pH as low as 4.3. The microbiome enriched in this work was dominated by Lactobacillus spp. and Caproiciproducens spp. The high abundance of Caproiciproducens spp. and their co-occurrence with Lactobacillus spp. suggest Caproiciproducens spp. used lactate as electron donor for chain elongation. This work shows the production of n-caproate from food waste with decreased use of hydroxide and no use of exogenous electron donors.
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Affiliation(s)
- Carlos A Contreras-Dávila
- Environmental Technology, Wageningen University & Research, Bornse Weilanden 9, 6708, WG, Wageningen, the Netherlands
| | - Víctor J Carrión
- Institute of Biology, Leiden University, Sylviusweg 72, 2333, BE, Leiden, the Netherlands; Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, the Netherlands
| | - Vincent R Vonk
- Environmental Technology, Wageningen University & Research, Bornse Weilanden 9, 6708, WG, Wageningen, the Netherlands
| | - Cees N J Buisman
- Environmental Technology, Wageningen University & Research, Bornse Weilanden 9, 6708, WG, Wageningen, the Netherlands
| | - David P B T B Strik
- Environmental Technology, Wageningen University & Research, Bornse Weilanden 9, 6708, WG, Wageningen, the Netherlands.
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Magdalena JA, González-Fernández C. Microalgae Biomass as a Potential Feedstock for the Carboxylate Platform. Molecules 2019; 24:molecules24234404. [PMID: 31810301 PMCID: PMC6930456 DOI: 10.3390/molecules24234404] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 11/26/2019] [Accepted: 11/30/2019] [Indexed: 11/16/2022] Open
Abstract
Volatile fatty acids (VFAs) are chemical building blocks for industries, and are mainly produced via the petrochemical pathway. However, the anaerobic fermentation (AF) process gives a potential alternative to produce these organic acids using renewable resources. For this purpose, waste streams, such as microalgae biomass, might constitute a cost-effective feedstock to obtain VFAs. The present review is intended to summarize the inherent potential of microalgae biomass for VFA production. Different strategies, such as the use of pretreatments to the inoculum and the manipulation of operational conditions (pH, temperature, organic loading rate or hydraulic retention time) to promote VFA production from different microalgae strains, are discussed. Microbial structure analysis using microalgae biomass as a substrate is pointed out in order to further comprehend the roles of bacteria and archaea in the AF process. Finally, VFA applications in different industry fields are reviewed.
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Han W, He P, Shao L, Lü F. Road to full bioconversion of biowaste to biochemicals centering on chain elongation: A mini review. J Environ Sci (China) 2019; 86:50-64. [PMID: 31787190 DOI: 10.1016/j.jes.2019.05.018] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Revised: 05/16/2019] [Accepted: 05/16/2019] [Indexed: 06/10/2023]
Abstract
Production of biochemicals from waste streams has been attracting increasing worldwide interest to achieve climate protection goals. Chain elongation (CE) for production of medium-chain carboxylic acids (MCCAs, especially caproate, enanthate and caprylate) from diverse biowaste has emerged as a potential economic and environmental technology for a sustainable society. The present mini review summarizes the research utilizing various synthetic or real waste-derived substrates available for MCCA production. Additionally, the microbial characteristics of the CE process are surveyed and discussed. Considering that a large proportion of recalcitrantly biodegradable biowaste and residues cannot be further utilized by CE systems and remain to be treated and disposed, we propose here a loop concept of bioconversion of biowaste to MCCAs making full use of the biowaste with zero emission. This could make possible an alternative technology for synthesis of value-added products from a wide range of biowaste, or even non-biodegradable waste (such as, plastics and rubbers). Meanwhile, the remaining scientific questions, unsolved problems, application potential and possible developments for this technology are discussed.
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Affiliation(s)
- Wenhao Han
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Pinjing He
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China; Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092, China; Centre for the Technology Research and Training on Household Waste in Small Towns & Rural Area, Ministry of Housing and Urban-Rural Development of China (MOHURD), China
| | - Liming Shao
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China; Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092, China; Centre for the Technology Research and Training on Household Waste in Small Towns & Rural Area, Ministry of Housing and Urban-Rural Development of China (MOHURD), China
| | - Fan Lü
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China; Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092, China.
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Jin Y, Lin Y, Wang P, Jin R, Gao M, Wang Q, Chang TC, Ma H. Volatile fatty acids production from saccharification residue from food waste ethanol fermentation: Effect of pH and microbial community. BIORESOURCE TECHNOLOGY 2019; 292:121957. [PMID: 31430672 DOI: 10.1016/j.biortech.2019.121957] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/02/2019] [Accepted: 08/03/2019] [Indexed: 06/10/2023]
Abstract
In this study, residue from saccharification and centrifugation of food waste ethanol fermentation was used as substrate to produce volatile fatty acids. The effects of different pH (5.5, 6.5, and uncontrolled) on the VFAs concentration, composition, acidogenic efficiency and microbial community distribution were investigated. The results showed that the highest concentration of VFAs was 267.8 ± 8.9 mg COD/g VS at pH of 6.5, and the highest percentage of butyric acid (79.8%) was followed by propionic acid and acetic acid at the end of the reaction. Microbial analysis showed that the contents of Vagococcus and Actinomyces increased, while the contents of Bacteroides and Fermentimonas decreased during anaerobic fermentation. The comparative high pH induced the accumulation of butyric acid. This study provides a new idea for the step anaerobic fermentation of food waste to produce alcohol and acid simultaneously.
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Affiliation(s)
- Yong Jin
- Department of Environmental Engineering, University of Science and Technology Beijing, 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China
| | - Yujia Lin
- Department of Environmental Engineering, University of Science and Technology Beijing, 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China
| | - Pan Wang
- Key Laboratory of Cleaner Production and Integrated Resource Utilization of China National Light Industry, Beijing Technology and Business University, Beijing 100048, China
| | - Runwen Jin
- Department of Environmental Engineering, University of Science and Technology Beijing, 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China
| | - Ming Gao
- Department of Environmental Engineering, University of Science and Technology Beijing, 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China
| | - Qunhui Wang
- Department of Environmental Engineering, University of Science and Technology Beijing, 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China
| | - Tien-Chin Chang
- Institute of Environmental Engineering and Management, National Taipei University of Technology, No. 1, Sec. 3, Chung-Hsiao E. Rd., Taipei 106, Taiwan
| | - Hongzhi Ma
- Department of Environmental Engineering, University of Science and Technology Beijing, 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China.
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San-Valero P, Fernández-Naveira Á, Veiga MC, Kennes C. Influence of electron acceptors on hexanoic acid production by Clostridium kluyveri. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2019; 242:515-521. [PMID: 31075646 DOI: 10.1016/j.jenvman.2019.04.093] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 04/12/2019] [Accepted: 04/22/2019] [Indexed: 05/12/2023]
Abstract
Clostridium kluyveri was used for chain elongation of C2C4 fatty acids in stirred tank bioreactors. The influence of different electron acceptors (acetic acid, butyric acid and the mixture of both) on C6 fatty acid production was evaluated in presence of ethanol using similar molar alcohol/acid ratios around 3.5. Bottle batch assays without pH regulation and with only acetic acid as electron acceptor yielded a final C6 fatty acid concentration of 6.8 ± 0.6 g L-1. Then, pH-regulated bioreactors were operated at constant pH of 6.8. Under such conditions, the maximum growth rate was 0.039 h-1 obtained using acetic acid and butyric acid as electron acceptors, whereas the lowest growth rate was 0.010 h-1 with only butyric acid as electron acceptor. The maximum growth rate with acetic acid only, was similar, though slightly lower, as with the mixture of C2C4 fatty acids. Besides, the maximum productions of hexanoic acid were 11.8 g L-1, 13.1 g L-1 and 21.2 g L-1 using, respectively, acetic acid, butyric acid and the mixture of both acids as electron acceptors. Thus, the use of a mixture of acetic acid and butyric acid in presence of ethanol for chain elongation, at constant pH, proved to be efficient for hexanoic acid production.
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Affiliation(s)
- P San-Valero
- Chemical Engineering Laboratory, Faculty of Sciences and Center for Advanced Scientific Research (CICA), University of La Coruña (UDC), Rúa da Fraga 10, E-15008, La Coruña, Spain
| | - Á Fernández-Naveira
- Chemical Engineering Laboratory, Faculty of Sciences and Center for Advanced Scientific Research (CICA), University of La Coruña (UDC), Rúa da Fraga 10, E-15008, La Coruña, Spain
| | - M C Veiga
- Chemical Engineering Laboratory, Faculty of Sciences and Center for Advanced Scientific Research (CICA), University of La Coruña (UDC), Rúa da Fraga 10, E-15008, La Coruña, Spain
| | - C Kennes
- Chemical Engineering Laboratory, Faculty of Sciences and Center for Advanced Scientific Research (CICA), University of La Coruña (UDC), Rúa da Fraga 10, E-15008, La Coruña, Spain.
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de Leeuw K, Buisman CJ, Strik DP. Branched Medium Chain Fatty Acids: Iso-Caproate Formation from Iso-Butyrate Broadens the Product Spectrum for Microbial Chain Elongation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:7704-7713. [PMID: 31244077 PMCID: PMC6610548 DOI: 10.1021/acs.est.8b07256] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 04/26/2019] [Accepted: 06/04/2019] [Indexed: 05/26/2023]
Abstract
Chain elongation fermentation can be used to convert organic residues into biobased chemicals. This research aimed to develop a bioprocess for branched medium chain fatty acids (MCFAs) production. A long-term continuous reactor experiment showed that iso-caproate (4-methyl pentanoate, i-C6) can be produced via ethanol based chain elongation. The enriched microbiome formed iso-caproate from iso-butyrate at a rate of 44 ± 6 mmol C L-1 day-1 during the last phase. This amounted to 20% of all formed compounds based on carbon atoms. The main fermentation product was n-caproate (55% of all carbon), as a result of acetate and subsequent n-butyrate elongation. The microbiome preferred straight-chain elongation over branched-chain elongation. Lowering the acetate concentration in the influent led to an increase of excessive ethanol oxidation (EEO) into electron equivalents (e.g., H2) and acetate. The formed acetate in turn stimulated straight chain elongation, but the resulting lower net acetate supply rate towards straight chain elongation led to an increased selectivity towards and productivity of i-C6. The electrons produced via oxidation routes and chain elongation were apparently utilized by hydrogenotrophic methanogens, homoacetogens, and carboxylate-to-alcohol reducing bacteria. Further improvements could be achieved if the acetate-producing EEO was minimized and limitations of ethanol and CO2 were prevented.
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