1
|
Bühlmann CH, Mickan BS, Tait S, Batstone DJ, Bahri PA. Lactic acid production from food waste at an anaerobic digestion biorefinery: effect of digestate recirculation and sucrose supplementation. Front Bioeng Biotechnol 2023; 11:1177739. [PMID: 37251566 PMCID: PMC10214416 DOI: 10.3389/fbioe.2023.1177739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 04/27/2023] [Indexed: 05/31/2023] Open
Abstract
Low lactic acid (LA) yields from direct food waste (FW) fermentation restrict this production pathway. However, nitrogen and other nutrients within FW digestate, in combination with sucrose supplementation, may enhance LA production and improve feasibility of fermentation. Therefore, this work aimed to improve LA fermentation from FWs by supplementing nitrogen (0-400 mgN·L-1) as NH4Cl or digestate and dosing sucrose (0-150 g·L-1) as a low-cost carbohydrate. Overall, NH4Cl and digestate led to similar improvements in the rate of LA formation (0.03 ± 0.02 and 0.04 ± 0.02 h-1 for NH4Cl and digestate, respectively), but NH4Cl also improved the final concentration, though effects varied between treatments (5.2 ± 4.6 g·L-1). While digestate altered the community composition and increased diversity, sucrose minimised community diversion from LA, promoted Lactobacillus growth at all dosages, and enhanced the final LA concentration from 25 to 30 g·L-1 to 59-68 g·L-1, depending on nitrogen dosage and source. Overall, the results highlighted the value of digestate as a nutrient source and sucrose as both community controller and means to enhance the LA concentration in future LA biorefinery concepts.
Collapse
Affiliation(s)
| | - Bede S. Mickan
- School of Agriculture and Environment, The University of Western Australia, Perth, WA, Australia
- Institute of Agriculture, The University of Western Australia, Perth, WA, Australia
- Richgro Garden Products, Jandakot, WA, Australia
| | - Stephan Tait
- Centre for Agricultural Engineering, University of Southern Queensland, Toowoomba, QLD, Australia
| | - Damien J. Batstone
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St Lucia, Brisbane, QLD, Australia
| | - Parisa A. Bahri
- Discipline of Engineering and Energy, Murdoch University, Perth, WA, Australia
| |
Collapse
|
2
|
Ceron-Chafla P, de Vrieze J, Rabaey K, van Lier JB, Lindeboom REF. Steering the product spectrum in high-pressure anaerobic processes: CO 2 partial pressure as a novel tool in biorefinery concepts. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:27. [PMID: 36803622 PMCID: PMC9938588 DOI: 10.1186/s13068-023-02262-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 01/05/2023] [Indexed: 02/19/2023]
Abstract
BACKGROUND Elevated CO2 partial pressure (pCO2) has been proposed as a potential steering parameter for selective carboxylate production in mixed culture fermentation. It is anticipated that intermediate product spectrum and production rates, as well as changes in the microbial community, are (in)directly influenced by elevated pCO2. However, it remains unclear how pCO2 interacts with other operational conditions, namely substrate specificity, substrate-to-biomass (S/X) ratio and the presence of an additional electron donor, and what effect pCO2 has on the exact composition of fermentation products. Here, we investigated possible steering effects of elevated pCO2 combined with (1) mixed substrate (glycerol/glucose) provision; (2) subsequent increments in substrate concentration to increase the S/X ratio; and (3) formate as an additional electron donor. RESULTS Metabolite predominance, e.g., propionate vs. butyrate/acetate, and cell density, depended on interaction effects between pCO2-S/X ratio and pCO2-formate. Individual substrate consumption rates were negatively impacted by the interaction effect between pCO2-S/X ratio and were not re-established after lowering the S/X ratio and adding formate. The product spectrum was influenced by the microbial community composition, which in turn, was modified by substrate type and the interaction effect between pCO2-formate. High propionate and butyrate levels strongly correlated with Negativicutes and Clostridia predominance, respectively. After subsequent pressurized fermentation phases, the interaction effect between pCO2-formate enabled a shift from propionate towards succinate production when mixed substrate was provided. CONCLUSIONS Overall, interaction effects between elevated pCO2, substrate specificity, high S/X ratio and availability of reducing equivalents from formate, rather than an isolated pCO2 effect, modified the proportionality of propionate, butyrate and acetate in pressurized mixed substrate fermentations at the expense of reduced consumption rates and increased lag-phases. The interaction effect between elevated pCO2 and formate was beneficial for succinate production and biomass growth with a glycerol/glucose mixture as the substrate. The positive effect may be attributed to the availability of extra reducing equivalents, likely enhanced carbon fixating activity and hindered propionate conversion due to increased concentration of undissociated carboxylic acids.
Collapse
Affiliation(s)
- Pamela Ceron-Chafla
- Sanitary Engineering Section, Department of Water Management, Delft University of Technology, Stevinweg 1, 2628 CN, Delft, The Netherlands.
| | - Jo de Vrieze
- grid.5342.00000 0001 2069 7798Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - Korneel Rabaey
- grid.5342.00000 0001 2069 7798Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000 Ghent, Belgium ,grid.510907.aCenter for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Coupure Links 653, 9000 Ghent, Belgium
| | - Jules B. van Lier
- grid.5292.c0000 0001 2097 4740Sanitary Engineering Section, Department of Water Management, Delft University of Technology, Stevinweg 1, 2628 CN Delft, The Netherlands
| | - Ralph E. F. Lindeboom
- grid.5292.c0000 0001 2097 4740Sanitary Engineering Section, Department of Water Management, Delft University of Technology, Stevinweg 1, 2628 CN Delft, The Netherlands
| |
Collapse
|
3
|
Krohn C, Khudur L, Dias DA, van den Akker B, Rees CA, Crosbie ND, Surapaneni A, O'Carroll DM, Stuetz RM, Batstone DJ, Ball AS. The role of microbial ecology in improving the performance of anaerobic digestion of sewage sludge. Front Microbiol 2022; 13:1079136. [PMID: 36590430 PMCID: PMC9801413 DOI: 10.3389/fmicb.2022.1079136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 11/28/2022] [Indexed: 12/15/2022] Open
Abstract
The use of next-generation diagnostic tools to optimise the anaerobic digestion of municipal sewage sludge has the potential to increase renewable natural gas recovery, improve the reuse of biosolid fertilisers and help operators expand circular economies globally. This review aims to provide perspectives on the role of microbial ecology in improving digester performance in wastewater treatment plants, highlighting that a systems biology approach is fundamental for monitoring mesophilic anaerobic sewage sludge in continuously stirred reactor tanks. We further highlight the potential applications arising from investigations into sludge ecology. The principal limitation for improvements in methane recoveries or in process stability of anaerobic digestion, especially after pre-treatment or during co-digestion, are ecological knowledge gaps related to the front-end metabolism (hydrolysis and fermentation). Operational problems such as stable biological foaming are a key problem, for which ecological markers are a suitable approach. However, no biomarkers exist yet to assist in monitoring and management of clade-specific foaming potentials along with other risks, such as pollutants and pathogens. Fundamental ecological principles apply to anaerobic digestion, which presents opportunities to predict and manipulate reactor functions. The path ahead for mapping ecological markers on process endpoints and risk factors of anaerobic digestion will involve numerical ecology, an expanding field that employs metrics derived from alpha, beta, phylogenetic, taxonomic, and functional diversity, as well as from phenotypes or life strategies derived from genetic potentials. In contrast to addressing operational issues (as noted above), which are effectively addressed by whole population or individual biomarkers, broad improvement and optimisation of function will require enhancement of hydrolysis and acidogenic processes. This will require a discovery-based approach, which will involve integrative research involving the proteome and metabolome. This will utilise, but overcome current limitations of DNA-centric approaches, and likely have broad application outside the specific field of anaerobic digestion.
Collapse
Affiliation(s)
- Christian Krohn
- ARC Training Centre for the Transformation of Australia's Biosolids Resource, RMIT University, Bundoora, VIC, Australia,*Correspondence: Christian Krohn,
| | - Leadin Khudur
- ARC Training Centre for the Transformation of Australia's Biosolids Resource, RMIT University, Bundoora, VIC, Australia
| | - Daniel Anthony Dias
- School of Health and Biomedical Sciences, Discipline of Laboratory Medicine, STEM College, RMIT University, Bundoora, VIC, Australia
| | | | | | | | - Aravind Surapaneni
- ARC Training Centre for the Transformation of Australia's Biosolids Resource, RMIT University, Bundoora, VIC, Australia
| | - Denis M. O'Carroll
- Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Richard M. Stuetz
- Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Damien J. Batstone
- ARC Training Centre for the Transformation of Australia's Biosolids Resource, RMIT University, Bundoora, VIC, Australia,Australian Centre for Water and Environmental Biotechnology, Gehrmann Building, The University of Queensland, Brisbane, QLD, Australia
| | - Andrew S. Ball
- ARC Training Centre for the Transformation of Australia's Biosolids Resource, RMIT University, Bundoora, VIC, Australia
| |
Collapse
|
4
|
Virdis B, Hoelzle R, Marchetti A, Boto ST, Rosenbaum MA, Blasco-Gómez R, Puig S, Freguia S, Villano M. Electro-fermentation: Sustainable bioproductions steered by electricity. Biotechnol Adv 2022; 59:107950. [PMID: 35364226 DOI: 10.1016/j.biotechadv.2022.107950] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 02/22/2022] [Accepted: 03/24/2022] [Indexed: 01/06/2023]
Abstract
The market of biobased products obtainable via fermentation processes is steadily increasing over the past few years, driven by the need to create a decarbonized economy. To date, industrial fermentation (IF) employs either pure or mixed microbial cultures (MMC) whereby the type of the microbial catalysts and the used feedstock affect metabolic pathways and, in turn, the type of product(s) generated. In many cases, especially when dealing with MMC, the economic viability of IF is hindered by factors such as the low attained product titer and selectivity, which ultimately challenge the downstream recovery and purification steps. In this context, electro-fermentation (EF) represents an innovative approach, based on the use of a polarized electrode interface to trigger changes in the rate, yield, titer or product distribution deriving from traditional fermentation processes. In principle, the electrode in EF can act as an electron acceptor (i.e., anodic electro-fermentation, AEF) or donor (i.e., cathodic electro-fermentation, CEF), or simply as a mean to control the oxidation-reduction potential of the fermentation broth. However, the molecular and biochemical basis underlying the EF process are still largely unknown. This review paper provides a comprehensive overview of recent literature studies including both AEF and CEF examples with either pure or mixed microbial cultures. A critical analysis of biochemical, microbiological, and engineering aspects which presently hamper the transition of the EF technology from the laboratory to the market is also presented.
Collapse
Affiliation(s)
- Bernardino Virdis
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, Brisbane, QLD 4072, Australia
| | - Robert Hoelzle
- School of Earth and Environmental Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Angela Marchetti
- Department of Chemistry, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Santiago T Boto
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute (HKI), 07745 Jena, Germany; Faculty of Biological Sciences, Friedrich Schiller University (FSU), 07743 Jena, Germany
| | - Miriam A Rosenbaum
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute (HKI), 07745 Jena, Germany; Faculty of Biological Sciences, Friedrich Schiller University (FSU), 07743 Jena, Germany
| | - Ramiro Blasco-Gómez
- LEQUIA, Institute of the Environment, University of Girona, Maria Aurèlia Capmany 69, 17003 Girona, Spain
| | - Sebastià Puig
- LEQUIA, Institute of the Environment, University of Girona, Maria Aurèlia Capmany 69, 17003 Girona, Spain
| | - Stefano Freguia
- Department of Chemical Engineering, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Marianna Villano
- Department of Chemistry, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy.
| |
Collapse
|
5
|
Ceron-Chafla P, García-Timermans C, de Vrieze J, Ganigué R, Boon N, Rabaey K, van Lier JB, Lindeboom REF. Pre-incubation conditions determine the fermentation pattern and microbial community structure in fermenters at mild hydrostatic pressure. Biotechnol Bioeng 2022; 119:1792-1807. [PMID: 35312065 PMCID: PMC9325544 DOI: 10.1002/bit.28085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 02/08/2022] [Accepted: 03/05/2022] [Indexed: 11/11/2022]
Abstract
Fermentation at elevated hydrostatic pressure is a novel strategy targeting product selectivity. However, the role of inoculum history and cross-resistance, that is, acquired tolerance from incubation under distinctive environmental stress, remains unclear in high-pressure operation. In our here presented work, we studied fermentation and microbial community responses of halotolerant marine sediment inoculum (MSI) and anaerobic digester inoculum (ADI), pre-incubated in serum bottles at different temperatures and subsequently exposed to mild hydrostatic pressure (MHP; < 10 MPa) in stainless steel reactors. Results showed that MHP effects on microbial growth, activity, and community structure were strongly temperature-dependent. At moderate temperature (20°C), biomass yield and fermentation were not limited by MHP; suggesting a cross-resistance effect from incubation temperature and halotolerance. Low temperatures (10°C) and MHP imposed kinetic and bioenergetic limitations, constraining growth and product formation. Fermentation remained favorable in MSI at 28°C and ADI at 37°C, despite reduced biomass yield resulting from maintenance and decay proportionally increasing with temperature. Microbial community structure was modified by temperature during the enrichment, and slight differences observed after MHP-exposure did not compromise functionality. Results showed that the relation incubation temperature-halotolerance proved to be a modifier of microbial responses to MHP and could be potentially exploited in fermentations to modulate product/biomass ratio.
Collapse
Affiliation(s)
- Pamela Ceron-Chafla
- Sanitary Engineering Section, Department of Water Management, Delft University of Technology, Delft, the Netherlands
| | - Cristina García-Timermans
- Faculty of Bioscience Engineering, Center for Microbial Ecology and Technology, Ghent University, Ghent, Belgium
| | - Jo de Vrieze
- Faculty of Bioscience Engineering, Center for Microbial Ecology and Technology, Ghent University, Ghent, Belgium.,Division of Soil and Water Management, Department of Earth and Environmental Sciences, KU Leuven, Leuven, Belgium.,Bio- and Chemical Systems Technology, Reactor Engineering and Safety (CREaS), Department of Chemical Engineering, KU Leuven, Leuven, Belgium
| | - Ramon Ganigué
- Faculty of Bioscience Engineering, Center for Microbial Ecology and Technology, Ghent University, Ghent, Belgium
| | - Nico Boon
- Faculty of Bioscience Engineering, Center for Microbial Ecology and Technology, Ghent University, Ghent, Belgium
| | - Korneel Rabaey
- Faculty of Bioscience Engineering, Center for Microbial Ecology and Technology, Ghent University, Ghent, Belgium.,Center for Advanced Process Technology for Urban Resource Recovery, Ghent, Belgium
| | - Jules B van Lier
- Sanitary Engineering Section, Department of Water Management, Delft University of Technology, Delft, the Netherlands
| | - Ralph E F Lindeboom
- Sanitary Engineering Section, Department of Water Management, Delft University of Technology, Delft, the Netherlands
| |
Collapse
|
6
|
Zhang Z, Tsapekos P, Alvarado-Morales M, Zhu X, Zervas A, Jacobsen CS, Angelidaki I. Enhanced fermentative lactic acid production from source-sorted organic household waste: Focusing on low-pH microbial adaptation and bio-augmentation strategy. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 808:152129. [PMID: 34863737 DOI: 10.1016/j.scitotenv.2021.152129] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Revised: 11/20/2021] [Accepted: 11/28/2021] [Indexed: 06/13/2023]
Abstract
Lactic acid (LA) production at low pH could significantly reduce the need for neutralizing agents, leading to reduction of operational costs. In the present study, LA production at acidic conditions was investigated using source-sorted organic household waste (SSOHW). Controlling the pH at low value (i.e. 5.0) and bio-augmenting with Pediococcus acidilactici led to a concentration of 39.3 ± 0.5 g-LA/L with a yield of 0.75 ± 0.02 g-LA/g-sugar. In contrast, secondary fermentation at higher pH level (i.e. 5.5 and 6.0) resulted in complete LA degradation. Subsequently, consecutive batch fermentations were conducted to adapt P. acidilactici to SSOHW and improve the LA production. Results showed that P. acidilactici could successively adapt in the SSOHW reaching a relative abundance above 2.8% at adaptation process. The added P. acidilactici ensured a high concentration of LA at three consecutive generations, achieving an increment above 18% compared to control test (abiotic augmentation). Moreover, adaptation processes (i.e. maintaining pH at 4.0 or stepwise decreasing the pH from 5.0 to 4.0) significantly improved LA concentration and productivity at the pH of 4.0. Overall, the results provide a promising method to reduce the LA production costs using residual resources.
Collapse
Affiliation(s)
- Zengshuai Zhang
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
| | - Panagiotis Tsapekos
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark.
| | - Merlin Alvarado-Morales
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
| | - Xinyu Zhu
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
| | - Athanasios Zervas
- Department of Environmental Science, Aarhus University, Frederiksborgvej 399, DK-4000 Roskilde, Denmark
| | - Carsten S Jacobsen
- Department of Environmental Science, Aarhus University, Frederiksborgvej 399, DK-4000 Roskilde, Denmark
| | - Irini Angelidaki
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
| |
Collapse
|