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Hu Y, Pan G, Zhao M, Yin H, Wang Y, Sun J, Yu Z, Bai C, Xue Y. Suitable fermentation temperature of forage sorghum silage increases greenhouse gas production: Exploring the relationship between temperature, microbial community, and gas production. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 950:175325. [PMID: 39117229 DOI: 10.1016/j.scitotenv.2024.175325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Revised: 07/13/2024] [Accepted: 08/04/2024] [Indexed: 08/10/2024]
Abstract
Silage is an excellent method of feed preservation; however, carbon dioxide, methane and nitrous oxide produced during fermentation are significant sources of agricultural greenhouse gases. Therefore, determining a specific production method is crucial for reducing global warming. The effects of four temperatures (10 °C, 20 °C, 30 °C, and 40 °C) on silage quality, greenhouse gas yield and microbial community composition of forage sorghum were investigated. At 20 °C and 30 °C, the silage has a lower pH value and a higher lactic acid content, resulting in higher silage quality and higher total gas production. In the first five days of ensiling, there was a significant increase in the production of carbon dioxide, methane, and nitrous oxide. After that, the output remained relatively stable, and their production at 20 °C and 30 °C was significantly higher than that at 10 °C and 40 °C. Firmicutes and Proteobacteria were the predominant silage microorganisms at the phylum level. Under the treatment of 20 °C, 30 °C, and 40 °C, Lactobacillus had already dominated on the second day of silage. However, low temperatures under 10 °C slowed down the microbial community succession, allowing, bad microorganisms such as Chryseobacterium, Pantoea and Pseudomonas dominate the fermentation, in the early stage of ensiling, which also resulted in the highest bacterial network complexity. According to random forest and structural equation model analysis, the production of carbon dioxide, methane and nitrous oxide is mainly affected by microorganisms such as Lactobacillus, Klebsiella and Enterobacter, and temperature influences the activity of these microorganisms to mediate gas production in silage. This study helps reveal the relationship between temperature, microbial community and greenhouse gas production during silage fermentation, providing a reference for clean silage fermentation.
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Affiliation(s)
- Yifei Hu
- College of Horticulture, Shenyang Agricultural University, Shenyang 110161, China
| | - Gang Pan
- College of Horticulture, Shenyang Agricultural University, Shenyang 110161, China
| | - Meirong Zhao
- College of Horticulture, Shenyang Agricultural University, Shenyang 110161, China
| | - Hang Yin
- College of Horticulture, Shenyang Agricultural University, Shenyang 110161, China
| | - Yibo Wang
- College of Horticulture, Shenyang Agricultural University, Shenyang 110161, China
| | - Juanjuan Sun
- Institute of Grassland Research, Chinese Academy of Agricultural Sciences, Hohhot 010010, China
| | - Zhu Yu
- College of Grassland Science and Technology, China Agricultural University, Beijing 100193, China
| | - Chunsheng Bai
- College of Horticulture, Shenyang Agricultural University, Shenyang 110161, China.
| | - Yanlin Xue
- Inner Mongolia Engineering Research Center of Development and Utilization of Microbial Resources in Silage, Inner Mongolia Academy of Agriculture and Animal Husbandry Science, Hohhot 010031, China.
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Villanueva-Galindo E, Pérez-Rangel M, Moreno-Andrade I. Evaluation of individual and combined effect of lactic acid-consuming bacteria on mesophilic hydrogen production from lactic acid effluent from food waste treatment. BIORESOURCE TECHNOLOGY 2024; 408:131224. [PMID: 39111400 DOI: 10.1016/j.biortech.2024.131224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Revised: 07/12/2024] [Accepted: 08/04/2024] [Indexed: 08/10/2024]
Abstract
Lactic acid has been applied as a precursor for hydrogen (H2) production from substrates rich in lactic acid bacteria (LAB), focusing on microbial interactions between producing and consuming LAB tested with model substrates. Therefore, this study evaluated the effect of single and combined lactic acid-consuming bacteria on mesophilic H2 production in batch tests from lactic acid from fermented food waste (FW). Megasphaera elsdenii, Clostridium beijerinckii, and Clostridium butyricum were inoculated at different ratios (v/v). Additionally, thermal pretreated sludge (TPS) was added to the strain mixtures. The highest production was obtained with M. elsdenii, C. beijerinckii, and C. butyricum (17:66:17 ratio), obtaining 1629.0 mL/Lreactor. The optimal mixture (68:32:0 of M. elsdenii and C. beijerinckii) enriched with TPS reached 1739.3 ± 98.6 mL H2/Lreactor, consuming 98 % of lactic acid added. M. elsdenii and Clostridium strains enhance H2 production from lactic acid as they persist in a microbial community initially dominated by LAB.
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Affiliation(s)
- Edith Villanueva-Galindo
- Laboratory for Research on Advanced Processes for Water Treatment, Unidad Académica Juriquilla, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Blvd. Juriquilla 3001, Querétaro 76230, Mexico
| | - Marisol Pérez-Rangel
- Laboratory for Research on Advanced Processes for Water Treatment, Unidad Académica Juriquilla, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Blvd. Juriquilla 3001, Querétaro 76230, Mexico
| | - Iván Moreno-Andrade
- Laboratory for Research on Advanced Processes for Water Treatment, Unidad Académica Juriquilla, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Blvd. Juriquilla 3001, Querétaro 76230, Mexico.
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Martínez-Fraile C, Muñoz R, Teresa Simorte M, Sanz I, García-Depraect O. Biohydrogen production by lactate-driven dark fermentation of real organic wastes derived from solid waste treatment plants. BIORESOURCE TECHNOLOGY 2024; 403:130846. [PMID: 38754561 DOI: 10.1016/j.biortech.2024.130846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 05/13/2024] [Accepted: 05/14/2024] [Indexed: 05/18/2024]
Abstract
This study evaluated the hydrogen production potential through lactate-driven dark fermentation (LD-DF) of organic wastes from solid waste treatment plants, including the organic fraction of municipal solid waste (OFMSW), mixed sewage sludge, and two OFMSW leachates. In initial batch fermentations, only OFMSW supported a significant hydrogen yield (70.1 ± 7.7 NmL-H2/g-VS added) among the tested feedstocks. Lactate acted as an important hydrogen precursor, requiring the presence of carbohydrates for sequential two-step lactate-type fermentation. The impact of operational pH (5.5-6.5) and initial total solids (TS) concentration (5-12.5 % w/w) was also evaluated using OFMSW as substrate, obtaining hydrogen yields ranging from 6.6 to 55.9 NmL-H2/g-VSadded. The highest yield occurred at 6.5 pH and 7.5 % TS. The LD-DF pathway was indicated to be present under diverse pH and TS conditions, supported by employing a specialized microbial consortium capable of performing LD-DF, along with the observed changes in lactate levels during fermentation.
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Affiliation(s)
- Cristina Martínez-Fraile
- Institute of Sustainable Processes, Dr. Mergelina s/n, 47011 Valladolid, Spain; Department of Chemical Engineering and Environmental Technology, School of Industrial Engineering, University of Valladolid, Dr. Mergelina, s/n, 47011 Valladolid, Spain
| | - Raúl Muñoz
- Institute of Sustainable Processes, Dr. Mergelina s/n, 47011 Valladolid, Spain; Department of Chemical Engineering and Environmental Technology, School of Industrial Engineering, University of Valladolid, Dr. Mergelina, s/n, 47011 Valladolid, Spain
| | - María Teresa Simorte
- FCC Medio Ambiente, Avenida Camino de Santiago 40, CTR de Valladolid, Madrid 2850, Spain
| | - Inmaculada Sanz
- FCC Medio Ambiente, Avenida Camino de Santiago 40, CTR de Valladolid, Madrid 2850, Spain
| | - Octavio García-Depraect
- Institute of Sustainable Processes, Dr. Mergelina s/n, 47011 Valladolid, Spain; Department of Chemical Engineering and Environmental Technology, School of Industrial Engineering, University of Valladolid, Dr. Mergelina, s/n, 47011 Valladolid, Spain.
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Dudek K, Guzmán CLÁ, Valdez-Vazquez I. Microbial activity of lactic acid bacteria and hydrogen producers mediated by pH and total solids during the consolidated bioprocessing of agave bagasse. World J Microbiol Biotechnol 2024; 40:70. [PMID: 38225443 PMCID: PMC10789659 DOI: 10.1007/s11274-024-03888-1] [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: 09/14/2023] [Accepted: 01/08/2024] [Indexed: 01/17/2024]
Abstract
Lactic acid bacteria (LAB) coexist with Clostridium spp. in hydrogen production processes from complex substrates; however, the role of LAB is still unclear. This study analyzed the fermentation products in a wide range of initial pH (pHi, 5.5-6.9) and total solids (TS%, 8-22%) to determine the activity of these two microbial groups over time (from 24 to 120 h). Agave bagasse served as the feedstock for hydrogen production via consolidated bioprocess (CBP), while the inoculum source was the indigenous mature microbiota. In the early stage of the CBP, hydrogen production from lactic acid occurred only at pHi ≥ 6.0 (ρ = 0.0004) with no effect of TS%; lactic acid accumulated below this pHi value. In this stage, lactic acid production positively correlated with a first cluster of LAB represented by Paucilactobacillus (r = 0.64) and Bacillus (r = 0.81). After 72 h, hydrogen production positively correlated with a second group of LAB led by Enterococcus (r = 0.71) together with the hydrogen producer Clostridium sensu stricto 1 (r = 0.8) and the acetogen Syntrophococcus (r = 0.52) with the influence of TS% (ρ < 0.0001). A further experiment showed that buffering the pH to 6.5 increased and lengthened the lactic acid production, doubling the hydrogen production from 20 to 41 mL H2/gTSadded. This study confirmed the prevalence of distinct groups of LAB over time, whose microbial activity promoted different routes of hydrogen production.
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Affiliation(s)
- Karol Dudek
- Instituto de Ingeniería, Unidad Académica Juriquilla, Universidad Nacional Autónoma de México, Blvd. Juriquilla 3001, Querétaro, 76230, Mexico
| | - Cecilia Lizeth Álvarez Guzmán
- Instituto de Ingeniería, Unidad Académica Juriquilla, Universidad Nacional Autónoma de México, Blvd. Juriquilla 3001, Querétaro, 76230, Mexico
| | - Idania Valdez-Vazquez
- Instituto de Ingeniería, Unidad Académica Juriquilla, Universidad Nacional Autónoma de México, Blvd. Juriquilla 3001, Querétaro, 76230, Mexico.
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Rasmey AHM, Abd-Alla MH, Tawfik MA, Bashandy SR, Salah M, Liu R, Sun C, Hassan EA. Synergistic strategy for the enhancement of biohydrogen production from molasses through coculture of Lactobacillus brevis and Clostridium saccharobutylicum. INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 2023; 48:25285-25299. [DOI: 10.1016/j.ijhydene.2023.03.323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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Regueira-Marcos L, Muñoz R, García-Depraect O. Continuous lactate-driven dark fermentation of restaurant food waste: Process characterization and new insights on transient feast/famine perturbations. BIORESOURCE TECHNOLOGY 2023:129385. [PMID: 37364653 DOI: 10.1016/j.biortech.2023.129385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 06/19/2023] [Accepted: 06/20/2023] [Indexed: 06/28/2023]
Abstract
The effect of hydraulic retention time (HRT) on the continuous lactate-driven dark fermentation (LD-DF) of food waste (FW) was investigated. The robustness of the bioprocess against feast/famine perturbations was also explored. The stepwise HRT decrease from 24 to 16 and 12 h in a continuously stirred tank fermenter fed with simulated restaurant FW impacted on hydrogen production rate (HPR). The optimal HRT of 16 h supported a HPR of 4.2 L H2/L-d. Feast/famine perturbations caused by 12-h feeding interruptions led to a remarkable peak in HPR up to 19.2 L H2/L-d, albeit the process became stable at 4.3 L H2/L-d following perturbation. The occurrence of LD-DF throughout the operation was endorsed by metabolites analysis. Particularly, hydrogen production positively correlated with lactate consumption and butyrate production. Overall, the FW LD-DF process was highly sensitive but resilient against transient feast/famine perturbations, supporting high-rate HPRs under optimal HRTs.
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Affiliation(s)
- Lois Regueira-Marcos
- Institute of Sustainable Processes, University of Valladolid, Dr. Mergelina, s/n, 47011 Valladolid, Spain; Department of Chemical Engineering and Environmental Technology, School of Industrial Engineering, University of Valladolid, Dr. Mergelina, s/n, 47011 Valladolid, Spain
| | - Raúl Muñoz
- Institute of Sustainable Processes, University of Valladolid, Dr. Mergelina, s/n, 47011 Valladolid, Spain; Department of Chemical Engineering and Environmental Technology, School of Industrial Engineering, University of Valladolid, Dr. Mergelina, s/n, 47011 Valladolid, Spain
| | - Octavio García-Depraect
- Institute of Sustainable Processes, University of Valladolid, Dr. Mergelina, s/n, 47011 Valladolid, Spain; Department of Chemical Engineering and Environmental Technology, School of Industrial Engineering, University of Valladolid, Dr. Mergelina, s/n, 47011 Valladolid, Spain.
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Xu M, Selvaraj GK, Lu H. Environmental sporobiota: Occurrence, dissemination, and risks. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 869:161809. [PMID: 36702282 DOI: 10.1016/j.scitotenv.2023.161809] [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: 11/22/2022] [Revised: 01/03/2023] [Accepted: 01/20/2023] [Indexed: 06/18/2023]
Abstract
Spore-forming bacteria known as sporobiota are widespread in diverse environments from terrestrial and aquatic habitats to industrial and healthcare systems. Studies on sporobiota have been mainly focused on food processing and clinical fields, while a large amount of sporobiota exist in natural environments. Due to their persistence and capabilities of transmitting virulence factors and antibiotic resistant genes, environmental sporobiota could pose significant health risks to humans. These risks could increase as global warming and environmental pollution has altered the life cycle of sporobiota. This review summarizes the current knowledge of environmental sporobiota, including their occurrence, characteristics, and functions. An interaction network among clinical-, food-related, and environment-related sporobiota is constructed. Recent and effective methods for detecting and disinfecting environmental sporobiota are also discussed. Key problems and future research needs for better understanding and reducing the risks of environmental sporobiota and sporobiome are proposed.
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Affiliation(s)
- Min Xu
- Key Laboratory of Environmental Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Ganesh-Kumar Selvaraj
- Department of Microbiology, St. Peter's Institute of Higher Education and Research, Chennai 600054, Tamil Nadu, India.
| | - Huijie Lu
- Key Laboratory of Environmental Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Key Laboratory of Water Pollution Control and Environmental Safety, Zhejiang, China.
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8
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Sivagurunathan P, Sahoo PC, Kumar M, Prakash Gupta R, Bhattacharyya D, Ramakumar SSV. Unrevealing the role of metal oxide nanoparticles on biohydrogen production by Lactobacillus delbrueckii. BIORESOURCE TECHNOLOGY 2023; 367:128260. [PMID: 36343775 DOI: 10.1016/j.biortech.2022.128260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 10/27/2022] [Accepted: 10/30/2022] [Indexed: 06/16/2023]
Abstract
The positive interaction between Clostridium sp. and lactic acid-producing bacteria (Lactobacillus sp) is commonly seen in various high-rate hydrogen production systems. However, the exact role of the hydrogen production ability of Lactobacillus sp in a dark fermentation production system is rarely studied. Lactobacillus delbrueckii was herein used for the first time, to the best of the author's knowledge, to demonstrate biohydrogen production under anaerobic conditions. At first, the pH condition was optimized, followed by the addition of nanoparticles for enhanced biohydrogen production. Under optimized conditions of pH 6.5, substrate concentration 10 g/L, and 100 mg/L of NiO/Fe2O3, the maximum hydrogen yield (HY) of 1.94 mol/mol hexose was obtained, which is 18 % more than the control. The enhanced H2 production upon the addition of nanoparticles is supported via the external electron transfer (EET) mechanism, which regulates the metabolic pathway regulation with increased production of acetate and butyrate and reduced formation of lactate.
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Affiliation(s)
- Periyasamy Sivagurunathan
- Indian Oil Corporation Limited, Research & Development Centre, Sector 13, Faridabad 121007, Haryana, India
| | - Prakash C Sahoo
- Indian Oil Corporation Limited, Research & Development Centre, Sector 13, Faridabad 121007, Haryana, India
| | - Manoj Kumar
- Indian Oil Corporation Limited, Research & Development Centre, Sector 13, Faridabad 121007, Haryana, India.
| | - Ravi Prakash Gupta
- Indian Oil Corporation Limited, Research & Development Centre, Sector 13, Faridabad 121007, Haryana, India
| | - Debasis Bhattacharyya
- Indian Oil Corporation Limited, Research & Development Centre, Sector 13, Faridabad 121007, Haryana, India
| | - S S V Ramakumar
- Indian Oil Corporation Limited, Research & Development Centre, Sector 13, Faridabad 121007, Haryana, India
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Pérez-Rangel M, Valdez-Vazquez I, Martínez-Zavala SA, Casados-Vázquez LE, Bideshi DK, Barboza-Corona JE. Evaluation of inhibitory compounds produced by bacteria isolated from a hydrogen-producing bioreactor during the self-fermentation of wheat straw. J Appl Microbiol 2022; 133:1989-2001. [PMID: 35808847 DOI: 10.1111/jam.15708] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 06/29/2022] [Accepted: 07/05/2022] [Indexed: 11/28/2022]
Abstract
AIMS The objective of this study was to evaluate the inhibitory activity of compounds secreted by bacteria isolated from a hydrogen-producing bioreactor to understand how these microorganisms interact in this community. METHODS AND RESULTS In vitro inhibitory assays were performed using samples secreted by bacteria subject to different treatments to determine if their inhibitory effect was due to organic acids, non-proteinaceous compounds, or bacteriocin-like inhibitory substances (BLIS). Bacterial isolated were suppressed 43%, 30%, and 27% by neutralized, precipitated, and non-neutralized cell-free supernatants, respectively. Non-hydrogen producers (Non-H2 P) LAB (Lactobacillus plantarum LB1, L. pentosus LB7, Pediococcus acidilactici LB4) and hydrogen producers (H2 P) LAB (Enterococcus faecium F) were inhibited by the production of organic acids, non-proteinaceous compounds, and BLIS. Meanwhile, the obligate anaerobe H2 P (Clostridium beijerinckii B) inhibited by the production of non-proteinaceous compounds and BLIS. The presence of BLIS was confirmed when proteolytic enzymes affected the inhibitory activity of secreted proteins in values ranging from 20 to 42%. The BLIS produced by L. plantarum LB1, P. acidilactici LB4, L. pentosus LB7, and E. faecium F showed molecular masses of ~ 11 kDa, 25 kDa, 20 kDa, and 11 kDa, respectively. CONCLUSIONS It was demonstrated antagonistic interactions between Lactobacillus- Enterococcus, and Pediococcus-Enterococcus species, generated by the secretion of organic acids, non-proteinaceous compounds, and BLIS. SIGNIFICANCE AND IMPACT OF THE STUDY We report the interactions between LAB isolated from hydrogen-producing bioreactors. These interactions might impact the dynamics of the microbial population during hydrogen generation. Our work lays a foundation for strategies that allow controlling bacteria that can affect hydrogen production.
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Affiliation(s)
- Marisol Pérez-Rangel
- Graduate Program in Biosciences, Life Science Division, University of Guanajuato Campus Irapuato-Salamanca. Irapuato, Guanajuato, México.,Unidad Académica Juriquilla, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Querétaro, Mexico
| | - Idania Valdez-Vazquez
- Unidad Académica Juriquilla, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Querétaro, Mexico
| | - Sheila A Martínez-Zavala
- Graduate Program in Biosciences, Life Science Division, University of Guanajuato Campus Irapuato-Salamanca. Irapuato, Guanajuato, México
| | - Luz E Casados-Vázquez
- Graduate Program in Biosciences, Life Science Division, University of Guanajuato Campus Irapuato-Salamanca. Irapuato, Guanajuato, México.,Food Department, Life Science División, University of Guanajuato Campus Irapuato-Salamanca. Irapuato, Guanajuato, México.,CONACyT-University of Guanajuato
| | - Dennis K Bideshi
- Department of Biological Sciences, California Baptist University, Riverside, California, USA
| | - José E Barboza-Corona
- Graduate Program in Biosciences, Life Science Division, University of Guanajuato Campus Irapuato-Salamanca. Irapuato, Guanajuato, México.,Food Department, Life Science División, University of Guanajuato Campus Irapuato-Salamanca. Irapuato, Guanajuato, México
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Logan M, Tan LC, Nzeteu CO, Lens PNL. Enhanced anaerobic digestion of dairy wastewater in a granular activated carbon amended sequential batch reactor. GLOBAL CHANGE BIOLOGY. BIOENERGY 2022; 14:840-857. [PMID: 35915605 PMCID: PMC9324911 DOI: 10.1111/gcbb.12947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 02/21/2022] [Accepted: 03/29/2022] [Indexed: 06/15/2023]
Abstract
This study investigated the potential of granular activated carbon (GAC) supplementation to enhance anaerobic degradation of dairy wastewater. Two sequential batch reactors (SBRs; 0.8 L working volume), one control and another amended with GAC, were operated at 37°C and 1.5-1.6 m/h upflow velocity for a total of 120 days (four cycles of 30 days each). The methane production at the end of each cycle run increased by about 68%, 503%, 110%, and 125% in the GAC-amended SBR, compared with the Control SBR. Lipid degradation was faster in the presence of GAC. Conversely, the organic compounds, especially lipids, accumulated in the absence of the conductive material. In addition, a reduction in lag phase duration by 46%-100% was observed at all four cycles in the GAC-amended SBR. The peak methane yield rate was at least 2 folds higher with GAC addition in all cycles. RNA-based bacterial analysis revealed enrichment of Synergistes (0.8% to 29.2%) and Geobacter (0.4% to 11.3%) in the GAC-amended SBR. Methanolinea (85.8%) was the dominant archaea in the biofilm grown on GAC, followed by Methanosaeta (11.3%), at RNA level. Overall, this study revealed that GAC supplementation in anaerobic digesters treating dairy wastewater can promote stable and efficient methane production, accelerate lipid degradation and might promote the activity of electroactive microorganisms.
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Affiliation(s)
| | - Lea Chua Tan
- National University of Ireland, GalwayGalwayIreland
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Enhanced Fermentative Hydrogen Production from Food Waste in Continuous Reactor after Butyric Acid Treatment. ENERGIES 2022. [DOI: 10.3390/en15114048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
End-product accumulation during dark fermentation leads to process instability and hydrogen production inhibition. To overcome this constraint, microbial community adaptation to butyric acid can induce acid tolerance and thus enhance the hydrogen yields; however, adaptation and selection of appropriate microbial communities remains uncertain when dealing with complex substrates in a continuous fermentation mode. To address this question, a reactor fed in continuous mode with food waste (organic loading rate of 60 gVS·L·d−1; 12 h hydraulic retention time) was first stressed for 48 h with increasing concentrations of butyric acid (up to 8.7 g·L−1). Performances were compared with a control reactor (unstressed) for 13 days. During 6 days in a steady-state, the pre-stressed reactor produced 2.2 ± 0.2 LH2·L·d−1, which was 48% higher than in the control reactor (1.5 ± 0.2 LH2·L·d−1). The pretreatment also affected the metabolites’ distribution. The pre-stressed reactor presented a higher production of butyric acid (+44%) achieving up to 3.8 ± 0.3 g·L−1, a lower production of lactic acid (−56%), and an enhancement of substrate conversion (+9%). The performance improvement was attributed to the promotion of Clostridium guangxiense, a hydrogen -producer, with a relative abundance increasing from 22% in the unstressed reactor to 52% in the stressed reactor.
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Dudek K, Molina-Guerrero CE, Valdez-Vazquez I. Profitability of single- and mixed-culture fermentations for the butyric acid production from a lignocellulosic substrate. Chem Eng Res Des 2022. [DOI: 10.1016/j.cherd.2022.04.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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