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Robazza A, Baleeiro FCF, Kleinsteuber S, Neumann A. Two-stage conversion of syngas and pyrolysis aqueous condensate into L-malate. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:85. [PMID: 38907325 PMCID: PMC11191387 DOI: 10.1186/s13068-024-02532-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Accepted: 06/13/2024] [Indexed: 06/23/2024]
Abstract
Hybrid thermochemical-biological processes have the potential to enhance the carbon and energy recovery from organic waste. This work aimed to assess the carbon and energy recovery potential of multifunctional processes to simultaneously sequestrate syngas and detoxify pyrolysis aqueous condensate (PAC) for short-chain carboxylates production. To evaluate relevant process parameters for mixed culture co-fermentation of syngas and PAC, two identical reactors were run under mesophilic (37 °C) and thermophilic (55 °C) conditions at increasing PAC loading rates. Both the mesophilic and the thermophilic process recovered at least 50% of the energy in syngas and PAC into short-chain carboxylates. During the mesophilic syngas and PAC co-fermentation, methanogenesis was completely inhibited while acetate, ethanol and butyrate were the primary metabolites. Over 90% of the amplicon sequencing variants based on 16S rRNA were assigned to Clostridium sensu stricto 12. During the thermophilic process, on the other hand, Symbiobacteriales, Syntrophaceticus, Thermoanaerobacterium, Methanothermobacter and Methanosarcina likely played crucial roles in aromatics degradation and methanogenesis, respectively, while Moorella thermoacetica and Methanothermobacter marburgensis were the predominant carboxydotrophs in the thermophilic process. High biomass concentrations were necessary to maintain stable process operations at high PAC loads. In a second-stage reactor, Aspergillus oryzae converted acetate, propionate and butyrate from the first stage into L-malate, confirming the successful detoxification of PAC below inhibitory levels. The highest L-malate yield was 0.26 ± 2.2 molL-malate/molcarboxylates recorded for effluent from the mesophilic process at a PAC load of 4% v/v. The results highlight the potential of multifunctional reactors where anaerobic mixed cultures perform simultaneously diverse process roles, such as carbon fixation, wastewater detoxification and carboxylates intermediate production. The recovered energy in the form of intermediate carboxylates allows for their use as substrates in subsequent fermentative stages.
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Affiliation(s)
- Alberto Robazza
- Institute of Process Engineering in Life Sciences 2: Electro Biotechnology, Karlsruhe Institute of Technology - KIT, 76131, Karlsruhe, Germany
| | - Flávio C F Baleeiro
- Department of Microbial Biotechnology, Helmholtz Centre for Environmental Research - UFZ, 04318, Leipzig, Germany
| | - Sabine Kleinsteuber
- Department of Microbial Biotechnology, Helmholtz Centre for Environmental Research - UFZ, 04318, Leipzig, Germany
| | - Anke Neumann
- Institute of Process Engineering in Life Sciences 2: Electro Biotechnology, Karlsruhe Institute of Technology - KIT, 76131, Karlsruhe, Germany.
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Singh A, Moestedt J, Berg A, Schnürer A. Microbiological Surveillance of Biogas Plants: Targeting Acetogenic Community. Front Microbiol 2021; 12:700256. [PMID: 34484143 PMCID: PMC8415747 DOI: 10.3389/fmicb.2021.700256] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Accepted: 07/21/2021] [Indexed: 11/15/2022] Open
Abstract
Acetogens play a very important role in anaerobic digestion and are essential in ensuring process stability. Despite this, targeted studies of the acetogenic community in biogas processes remain limited. Some efforts have been made to identify and understand this community, but the lack of a reliable molecular analysis strategy makes the detection of acetogenic bacteria tedious. Recent studies suggest that screening of bacterial genetic material for formyltetrahydrofolate synthetase (FTHFS), a key marker enzyme in the Wood-Ljungdahl pathway, can give a strong indication of the presence of putative acetogens in biogas environments. In this study, we applied an acetogen-targeted analyses strategy developed previously by our research group for microbiological surveillance of commercial biogas plants. The surveillance comprised high-throughput sequencing of FTHFS gene amplicons and unsupervised data analysis with the AcetoScan pipeline. The results showed differences in the acetogenic community structure related to feed substrate and operating parameters. They also indicated that our surveillance method can be helpful in the detection of community changes before observed changes in physico-chemical profiles, and that frequent high-throughput surveillance can assist in management towards stable process operation, thus improving the economic viability of biogas plants. To our knowledge, this is the first study to apply a high-throughput microbiological surveillance approach to visualise the potential acetogenic population in commercial biogas digesters.
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Affiliation(s)
- Abhijeet Singh
- Anaerobic Microbiology and Biotechnology Group, Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Jan Moestedt
- Tekniska Verken i Linköping AB, Department R&D, Linköping, Sweden
| | | | - Anna Schnürer
- Anaerobic Microbiology and Biotechnology Group, Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
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Wotton A, Yeung T, Jennepalli S, Teh ZL, Pickford R, Huang S, Conibeer G, Stride JA, Patterson RJ. Simultaneous Fe 3O 4 Nanoparticle Formation and Catalyst-Driven Hydrothermal Cellulose Degradation. ACS OMEGA 2021; 6:10790-10800. [PMID: 34056233 PMCID: PMC8153760 DOI: 10.1021/acsomega.1c00393] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 03/19/2021] [Indexed: 06/12/2023]
Abstract
Breakdown and utilization of cellulose are critical for the bioenergy sector; however, current cellulose-to-energy conversion schemes often consume large quantities of unrecoverable chemicals, or are expensive, due to the need for enzymes or high temperatures. In this paper, we demonstrate a new method for converting cellulose into soluble compounds using a mixture of Fe2+ and Fe3+ as catalytic centers for the breakdown, yielding Fe3O4 nanoparticles during the hydrothermal process. Iron precursors transformed more than 61% of microcrystalline cellulose into solutes, with the composition of the solute changing with the initial Fe3+ concentration. The primary products of the breakdown of cellulose were a range of aldaric acids with different molecular weights. The nanoparticles have concentration-dependent tuneable sizes between 6.7 and 15.8 nm in diameter. The production of value-added nanomaterials at low temperatures improves upon the economics of traditional cellulose-to-energy conversion schemes with the precursor value increasing rather than deteriorating over time.
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Affiliation(s)
- Alexander Wotton
- School
of Photovoltaic and Renewable Engineering, University of New South Wales, Anzac Parade, Kensington, NSW 2052, Australia
| | - Tracey Yeung
- School
of Photovoltaic and Renewable Engineering, University of New South Wales, Anzac Parade, Kensington, NSW 2052, Australia
| | - Sreenu Jennepalli
- School
of Chemistry, University of New South Wales, Anzac Parade, Kensington, NSW 2052, Australia
| | - Zhi Li Teh
- School
of Photovoltaic and Renewable Engineering, University of New South Wales, Anzac Parade, Kensington, NSW 2052, Australia
| | - Russell Pickford
- School
of Chemistry, University of New South Wales, Anzac Parade, Kensington, NSW 2052, Australia
| | - Shujuan Huang
- School
of Photovoltaic and Renewable Engineering, University of New South Wales, Anzac Parade, Kensington, NSW 2052, Australia
| | - Gavin Conibeer
- School
of Photovoltaic and Renewable Engineering, University of New South Wales, Anzac Parade, Kensington, NSW 2052, Australia
| | - John A. Stride
- School
of Chemistry, University of New South Wales, Anzac Parade, Kensington, NSW 2052, Australia
| | - Robert John Patterson
- School
of Photovoltaic and Renewable Engineering, University of New South Wales, Anzac Parade, Kensington, NSW 2052, Australia
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Ferguson RMW, Coulon F, Villa R. Understanding microbial ecology can help improve biogas production in AD. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 642:754-763. [PMID: 29920462 DOI: 10.1016/j.scitotenv.2018.06.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 06/01/2018] [Accepted: 06/01/2018] [Indexed: 06/08/2023]
Abstract
454-Pyrosequencing and lipid fingerprinting were used to link anaerobic digestion (AD) process parameters (pH, alkalinity, volatile fatty acids (VFAs), biogas production and methane content) with the reactor microbial community structure and composition. AD microbial communities underwent stress conditions after changes in organic loading rate and digestion substrates. 454-Pyrosequencing analysis showed that, irrespectively of the substrate digested, methane content and pH were always significantly, and positively, correlated with community evenness. In AD, microbial communities with more even distributions of diversity are able to use parallel metabolic pathways and have greater functional stability; hence, they are capable of adapting and responding to disturbances. In all reactors, a decrease in methane content to <30% was always correlated with a 50% increase of Firmicutes sequences (particularly in operational taxonomic units (OTUs) related to Ruminococcaceae and Veillonellaceae). Whereas digesters producing higher methane content (above 60%), contained a high number of sequences related to Synergistetes and unidentified bacterial OTUs. Finally, lipid fingerprinting demonstrated that, under stress, the decrease in archaeal biomass was higher than the bacterial one, and that archaeal Phospholipid etherlipids (PLEL) levels were correlated to reactor performances. These results demonstrate that, across a number of parameters such as lipids, alpha and beta diversity, and OTUs, knowledge of the microbial community structure can be used to predict, monitor, or optimise AD performance.
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Affiliation(s)
- Robert M W Ferguson
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK
| | - Frédéric Coulon
- School of Water, Energy and Environment, Cranfield University, Cranfield, MK43 0AL, UK
| | - Raffaella Villa
- School of Water, Energy and Environment, Cranfield University, Cranfield, MK43 0AL, UK.
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Xu R, Yang ZH, Zheng Y, Liu JB, Xiong WP, Zhang YR, Lu Y, Xue WJ, Fan CZ. Organic loading rate and hydraulic retention time shape distinct ecological networks of anaerobic digestion related microbiome. BIORESOURCE TECHNOLOGY 2018; 262:184-193. [PMID: 29705610 DOI: 10.1016/j.biortech.2018.04.083] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 04/19/2018] [Accepted: 04/20/2018] [Indexed: 05/27/2023]
Abstract
Understanding of how anaerobic digestion (AD)-related microbiomes are constructed by operational parameters or their interactions within the biochemical process is limited. Using high-throughput sequencing and molecular ecological network analysis, this study shows the succession of AD-related microbiome hosting diverse members of the phylum Actinobacteria, Bacteroidetes, Euryarchaeota, and Firmicutes, which were affected by organic loading rate (OLR) and hydraulic retention time (HRT). OLR formed finer microbial network modules than HRT (12 vs. 6), suggesting the further subdivision of functional components. Biomarkers were also identified in OLR or HRT groups (e.g. the family Actinomycetaceae, Methanosaetaceae and Aminiphilaceae). The most pair-wise link between Firmicutes and biogas production indicates the keystone members based on network features can be considered as markers in the regulation of AD. A set of 40% species ("core microbiome") were similar across different digesters. Such noteworthy overlap of microbiomes indicates they are generalists in maintaining the ecological stability of digesters.
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Affiliation(s)
- Rui Xu
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Zhao-Hui Yang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
| | - Yue Zheng
- Department of Chemical Engineering, University of Washington, Seattle, WA 98195, United States
| | - Jian-Bo Liu
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Wei-Ping Xiong
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Yan-Ru Zhang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Yue Lu
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Wen-Jing Xue
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Chang-Zheng Fan
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
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Ferguson RMW, Coulon F, Villa R. Organic loading rate: A promising microbial management tool in anaerobic digestion. WATER RESEARCH 2016; 100:348-356. [PMID: 27214347 DOI: 10.1016/j.watres.2016.05.009] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 04/25/2016] [Accepted: 05/02/2016] [Indexed: 06/05/2023]
Abstract
This study investigated the effect of changes in organic loading rate (OLR) and feedstock on the volatile fatty acids (VFAs) production and their potential use as a bioengineering management tool to improve stability of anaerobic digesters. Digesters were exposed to one or two changes in OLR using the same or different co-substrates (Fat Oil and Grease waste (FOG) and/or glycerol). Although all the OLR fluctuations produced a decrease in biogas and methane production, the digesters exposed twice to glycerol showed faster recovery towards stable conditions after the second OLR change. This was correlated with the composition of the VFAs produced and their mode of production, from parallel to sequential, resulting in a more efficient recovery from inhibition of methanogenesis. The change in acids processing after the first OLR increase induced a shift in the microbial community responsible of the process optimisation when the digesters were exposed to a subsequent OLR increase with the same feedstock. When the digesters were exposed to an OLR change with a different feedstock (FOG), the recovery took 7d longer than with the same one (glycerol). However, the microbial community showed functional resilience and was able to perform similarly to pre-exposure conditions. Thus, changes in operational conditions can be used to influence microbial community structure for anaerobic digestion (AD) optimisation. Finally, shorter recovery times and increased resilience of digesters were linked to higher numbers of Clostridia incertae sedis XV, suggesting that this group may be a good candidate for AD bioaugmentation to speed up recovery after process instability or OLR increase.
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Affiliation(s)
- Robert M W Ferguson
- Cranfield University, School of Water, Energy and Environment, Cranfield, MK43 0AL, UK
| | - Frédéric Coulon
- Cranfield University, School of Water, Energy and Environment, Cranfield, MK43 0AL, UK
| | - Raffaella Villa
- Cranfield University, School of Water, Energy and Environment, Cranfield, MK43 0AL, UK.
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