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Isipato M, Dessì P, Sánchez C, Mills S, Ijaz UZ, Asunis F, Spiga D, De Gioannis G, Mascia M, Collins G, Muntoni A, Lens PNL. Propionate Production by Bioelectrochemically-Assisted Lactate Fermentation and Simultaneous CO 2 Recycling. Front Microbiol 2021; 11:599438. [PMID: 33384675 PMCID: PMC7769879 DOI: 10.3389/fmicb.2020.599438] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 11/23/2020] [Indexed: 11/17/2022] Open
Abstract
Production of volatile fatty acids (VFAs), fundamental building blocks for the chemical industry, depends on fossil fuels but organic waste is an emerging alternative substrate. Lactate produced from sugar-containing waste streams can be further processed to VFAs. In this study, electrofermentation (EF) in a two-chamber cell is proposed to enhance propionate production via lactate fermentation. At an initial pH of 5, an applied potential of −1 V vs. Ag/AgCl favored propionate production over butyrate from 20 mM lactate (with respect to non-electrochemical control incubations), due to the pH buffering effect of the cathode electrode, with production rates up to 5.9 mM d–1 (0.44 g L–1 d–1). Microbial community analysis confirmed the enrichment of propionate-producing microorganisms, such as Tyzzerella sp. and Propionibacterium sp. Organisms commonly found in microbial electrosynthesis reactors, such as Desulfovibrio sp. and Acetobacterium sp., were also abundant at the cathode, indicating their involvement in recycling CO2 produced by lactate fermentation into acetate, as confirmed by stoichiometric calculations. Propionate was the main product of lactate fermentation at substrate concentrations up to 150 mM, with a highest production rate of 12.9 mM d–1 (0.96 g L–1 d–1) and a yield of 0.48 mol mol–1 lactate consumed. Furthermore, as high as 81% of the lactate consumed (in terms of carbon) was recovered as soluble product, highlighting the potential for EF application with high-carbon waste streams, such as cheese whey or other food wastes. In summary, EF can be applied to control lactate fermentation toward propionate production and to recycle the resulting CO2 into acetate, increasing the VFA yield and avoiding carbon emissions and addition of chemicals for pH control.
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Affiliation(s)
- Marco Isipato
- Department of Civil and Environmental Engineering and Architecture, University of Cagliari, Cagliari, Italy.,Microbiology, School of Natural Sciences and Ryan Institute, National University of Ireland Galway, Galway, Ireland
| | - Paolo Dessì
- Microbiology, School of Natural Sciences and Ryan Institute, National University of Ireland Galway, Galway, Ireland
| | - Carlos Sánchez
- Microbiology, School of Natural Sciences and Ryan Institute, National University of Ireland Galway, Galway, Ireland
| | - Simon Mills
- Microbiology, School of Natural Sciences and Ryan Institute, National University of Ireland Galway, Galway, Ireland
| | - Umer Z Ijaz
- Infrastructure and Environment Research Division, School of Engineering, University of Glasgow, Glasgow, United Kingdom
| | - Fabiano Asunis
- Department of Civil and Environmental Engineering and Architecture, University of Cagliari, Cagliari, Italy
| | - Daniela Spiga
- Department of Civil and Environmental Engineering and Architecture, University of Cagliari, Cagliari, Italy
| | - Giorgia De Gioannis
- Department of Civil and Environmental Engineering and Architecture, University of Cagliari, Cagliari, Italy.,IGAG-CNR, Environmental Geology and Geoengineering Institute of the National Research Council-Piazza D'Armi 1, Cagliari, Italy
| | - Michele Mascia
- Dipartimento di Ingegneria Meccanica, Chimica, e dei Materiali, Università degli Studi di Cagliari, Cagliari, Italy
| | - Gavin Collins
- Microbiology, School of Natural Sciences and Ryan Institute, National University of Ireland Galway, Galway, Ireland
| | - Aldo Muntoni
- Department of Civil and Environmental Engineering and Architecture, University of Cagliari, Cagliari, Italy.,IGAG-CNR, Environmental Geology and Geoengineering Institute of the National Research Council-Piazza D'Armi 1, Cagliari, Italy
| | - Piet N L Lens
- Microbiology, School of Natural Sciences and Ryan Institute, National University of Ireland Galway, Galway, Ireland
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Wang K, Nan X, Chu K, Tong J, Yang L, Zheng S, Zhao G, Jiang L, Xiong B. Shifts of Hydrogen Metabolism From Methanogenesis to Propionate Production in Response to Replacement of Forage Fiber With Non-forage Fiber Sources in Diets in vitro. Front Microbiol 2018; 9:2764. [PMID: 30524394 PMCID: PMC6262304 DOI: 10.3389/fmicb.2018.02764] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 10/29/2018] [Indexed: 12/31/2022] Open
Abstract
The rumen microbial complex adaptive mechanism invalidates various methane (CH4) mitigation strategies. Shifting the hydrogen flow toward alternative electron acceptors, such as propionate, was considered to be a meaningful mitigation strategy. A completely randomized design was applied in in vitro incubation to investigate the effects of replacing forage fiber with non-forage fiber sources (NFFS) in diets on methanogenesis, hydrogen metabolism, propionate production and the methanogenic and bacterial community. There are two treatments in the current study, CON (a basic total mixed ration) and TRT (a modified total mixed ration). The dietary treatments were achieved by partly replacing forage fiber with NFFS (wheat bran and soybean hull) to decrease forage neutral detergent fiber (fNDF) content from 24.0 to 15.8%, with the composition and inclusion rate of other dietary ingredients remaining the same in total mixed rations. The concentrations of CH4, hydrogen (H2) and volatile fatty acids were determined using a gas chromatograph. The archaeal and bacterial 16S rRNA genes were sequenced by Miseq high-throughput sequencing and used to reveal the relative abundance of methanogenic and bacterial communities. The results revealed that the concentration of propionate was significantly increased, while the concentration of acetate and the acetate to propionate ratio were not affected by treatments. Compared with CON, the production of H2 increased by 8.45% and the production of CH4 decreased by 14.06%. The relative abundance of Methanomassiliicoccus was significantly increased, but the relative abundance of Methanobrevibacter tended to decrease in TRT group. At the bacterial phylum level, the TRT group significantly decreased the relative abundance of Firmicutes and tended to increase the relative abundance of Bacteroidetes. The replacement of forage fiber with NFFS in diets can affect methanogenesis by shifting the hydrogen flow toward propionate, and part is directed to H2 in vitro. The shift was achieved by a substitution of Firmicutes by Bacteroidetes, another substitution of Methanobrevibacter by Methanomassiliicoccus. Theoretical predictions of displacements of H2 metabolism from methanogenesis to propionate production was supported by the dietary intervention in vitro.
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Affiliation(s)
- Kun Wang
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China.,State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Xuemei Nan
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Kangkang Chu
- Beijing Dairy Cattle Center, Beijing Capital Agribusiness Group, Beijing, China
| | - Jinjin Tong
- Beijing Key Laboratory for Dairy Cow Nutrition, Beijing University of Agriculture, Beijing, China
| | - Liang Yang
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Shanshan Zheng
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Guangyong Zhao
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Linshu Jiang
- Beijing Key Laboratory for Dairy Cow Nutrition, Beijing University of Agriculture, Beijing, China
| | - Benhai Xiong
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
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Mamuad LL, Kim SH, Choi YJ, Soriano AP, Cho KK, Lee K, Bae GS, Lee SS. Increased propionate concentration in Lactobacillus mucosae-fermented wet brewers grains and during in vitro rumen fermentation. J Appl Microbiol 2017; 123:29-40. [PMID: 28425572 DOI: 10.1111/jam.13475] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 04/03/2017] [Accepted: 04/07/2017] [Indexed: 01/15/2023]
Abstract
AIMS This study was conducted to isolate and identify propionate-producing bacteria that can be used as an inoculum in improving wet brewers grains and rumen fermentation via increasing propionate concentration. METHODS AND RESULTS A strain of Lactobacillus that exhibits high levels of propionate production was identified and characterized as Lactobacillus mucosae 521129 by 16S rRNA gene sequencing and phylogenetic analyses. Wet brewers grains were fermented through L. mucosae inoculation and resulted in an increase in propionate concentration. Fermented wet brewers grains were used in in vitro rumen fermentation and revealed that L. mucosae-fermented wet brewers grains produced more gas and had higher accumulations propionate and total volatile fatty acid (VFA) than the control. The fewest methanogen DNA copies were detected in L. mucosae-fermented wet brewers grains. CONCLUSION Identified L. mucosae improved the fermentation of wet brewers grains and the in vitro rumen fermentation via increasing propionate and total VFA concentrations. SIGNIFICANCE AND IMPACT OF THE STUDY The presented research provided the identification of L. mucosae 521129 as a propionate producer and was metabolically profiled. Furthermore, data present the putative application of this organism in improving the fermentation of wet brewers grains and in vitro rumen fermentation.
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Affiliation(s)
- L L Mamuad
- Ruminant Nutrition and Anaerobe Laboratory, Department of Animal Science and Technology, College of Bio-industry Science, Sunchon National University, Suncheon, Jeonnam, Korea
| | - S H Kim
- Ruminant Nutrition and Anaerobe Laboratory, Department of Animal Science and Technology, College of Bio-industry Science, Sunchon National University, Suncheon, Jeonnam, Korea
| | - Y J Choi
- Ruminant Nutrition and Anaerobe Laboratory, Department of Animal Science and Technology, College of Bio-industry Science, Sunchon National University, Suncheon, Jeonnam, Korea
| | - A P Soriano
- Ruminant Nutrition and Anaerobe Laboratory, Department of Animal Science and Technology, College of Bio-industry Science, Sunchon National University, Suncheon, Jeonnam, Korea.,Small Ruminant Center, Central Luzon State University, Science City of Muñoz, Nueva Ecija, Philippines
| | - K K Cho
- Department of Animal Resources Technology, Gyeongnam National University of Science and Technology, Jinju, Gyeongsang, Korea
| | - K Lee
- Department of Animal Sciences, Ohio State University, Columbus, OH, USA
| | - G S Bae
- Department of Animal Science and Technology, Chung-Ang University, Anseong, Korea
| | - S S Lee
- Ruminant Nutrition and Anaerobe Laboratory, Department of Animal Science and Technology, College of Bio-industry Science, Sunchon National University, Suncheon, Jeonnam, Korea
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Miceli JF, Torres CI, Krajmalnik-Brown R. Shifting the balance of fermentation products between hydrogen and volatile fatty acids: microbial community structure and function. FEMS Microbiol Ecol 2016; 92:fiw195. [PMID: 27633926 DOI: 10.1093/femsec/fiw195] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2016] [Indexed: 11/12/2022] Open
Abstract
Fermentation is a key process in many anaerobic environments. Varying the concentration of electron donor fed to a fermenting community is known to shift the distribution of products between hydrogen, fatty acids and alcohols. Work to date has focused mainly on the fermentation of glucose, and how the microbial community structure is affected has not been explored. We fed ethanol, lactate, glucose, sucrose or molasses at 100 me- eq. L-1, 200 me- eq. L-1 or 400 me- eq. L-1 to batch-fed cultures with fermenting, methanogenic communities. In communities fed high concentrations of electron donor, the fraction of electrons channeled to methane decreased, from 34% to 6%, while the fraction of electrons channeled to short chain fatty acids increased, from 52% to 82%, averaged across all electron donors. Ethanol-fed cultures did not produce propionate, but did show an increase in electrons directed to acetate as initial ethanol concentration increased. In glucose, sucrose, molasses and lactate-fed cultures, propionate accumulation co-occurred with known propionate producing organisms. Overall, microbial communities were determined by the substrate provided, rather than its initial concentration, indicating that a change in community function, rather than community structure, is responsible for shifts in the fermentation products produced.
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Affiliation(s)
- Joseph F Miceli
- Swette Center for Environmental Biotechnology, Arizona State University, 1001 S. McAllister Ave, Tempe 85287, Arizona, USA
| | - César I Torres
- Environmental Biotechnology, Arizona State University, 1001 S. McAllister Ave, Tempe 85287, Arizona, USA
| | - Rosa Krajmalnik-Brown
- Environmental Biotechnology, Arizona State University, 1001 S. McAllister Ave, Tempe 85287, Arizona, USA
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