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Cao Y, Liu H, Liu W, Guo J, Xian M. Debottlenecking the biological hydrogen production pathway of dark fermentation: insight into the impact of strain improvement. Microb Cell Fact 2022; 21:166. [PMID: 35986320 PMCID: PMC9389701 DOI: 10.1186/s12934-022-01893-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 07/26/2022] [Indexed: 11/26/2022] Open
Abstract
Confronted with the exhaustion of the earth’s fossil fuel reservoirs, bio-based process to produce renewable energy is receiving significant interest. Hydrogen is considered as an attractive energy carrier that can replace fossil fuels in the future mainly due to its high energy content, recyclability and environment-friendly nature. Biological hydrogen production from renewable biomass or waste materials by dark fermentation is a promising alternative to conventional routes since it is energy-saving and reduces environmental pollution. However, the current yield and evolution rate of fermentative hydrogen production are still low. Strain improvement of the microorganisms employed for hydrogen production is required to make the process competitive with traditional production methods. The present review summarizes recent progresses on the screening for highly efficient hydrogen-producing strains using various strategies. As the metabolic pathways for fermentative hydrogen production have been largely resolved, it is now possible to engineer the hydrogen-producing strains by rational design. The hydrogen yields and production rates by different genetically modified microorganisms are discussed. The key limitations and challenges faced in present studies are also proposed. We hope that this review can provide useful information for scientists in the field of fermentative hydrogen production. Hydrogen can be generated by microorganisms. Dark fermentation is efficient for biological hydrogen production. Strain improvement is critical to enhancing hydrogen-producing ability.
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Capson-Tojo G, Batstone DJ, Grassino M, Vlaeminck SE, Puyol D, Verstraete W, Kleerebezem R, Oehmen A, Ghimire A, Pikaar I, Lema JM, Hülsen T. Purple phototrophic bacteria for resource recovery: Challenges and opportunities. Biotechnol Adv 2020; 43:107567. [PMID: 32470594 DOI: 10.1016/j.biotechadv.2020.107567] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 05/11/2020] [Accepted: 05/14/2020] [Indexed: 10/24/2022]
Abstract
Sustainable development is driving a rapid focus shift in the wastewater and organic waste treatment sectors, from a "removal and disposal" approach towards the recovery and reuse of water, energy and materials (e.g. carbon or nutrients). Purple phototrophic bacteria (PPB) are receiving increasing attention due to their capability of growing photoheterotrophically under anaerobic conditions. Using light as energy source, PPB can simultaneously assimilate carbon and nutrients at high efficiencies (with biomass yields close to unity (1 g CODbiomass·g CODremoved-1)), facilitating the maximum recovery of these resources as different value-added products. The effective use of infrared light enables selective PPB enrichment in non-sterile conditions, without competition with other phototrophs such as microalgae if ultraviolet-visible wavelengths are filtered. This review reunites results systematically gathered from over 177 scientific articles, aiming at producing generalized conclusions. The most critical aspects of PPB-based production and valorisation processes are addressed, including: (i) the identification of the main challenges and potentials of different growth strategies, (ii) a critical analysis of the production of value-added compounds, (iii) a comparison of the different value-added products, (iv) insights into the general challenges and opportunities and (v) recommendations for future research and development towards practical implementation. To date, most of the work has not been executed under real-life conditions, relevant for full-scale application. With the savings in wastewater discharge due to removal of organics, nitrogen and phosphorus as an important economic driver, priorities must go to using PPB-enriched cultures and real waste matrices. The costs associated with artificial illumination, followed by centrifugal harvesting/dewatering and drying, are estimated to be 1.9, 0.3-2.2 and 0.1-0.3 $·kgdry biomass-1. At present, these costs are likely to exceed revenues. Future research efforts must be carried out outdoors, using sunlight as energy source. The growth of bulk biomass on relatively clean wastewater streams (e.g. from food processing) and its utilization as a protein-rich feed (e.g. to replace fishmeal, 1.5-2.0 $·kg-1) appears as a promising valorisation route.
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Affiliation(s)
- Gabriel Capson-Tojo
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD 4072, Australia; CRETUS Institute, Department of Chemical Engineering, School of Engineering, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
| | - Damien J Batstone
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - María Grassino
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - Siegfried E Vlaeminck
- Research Group of Sustainable Energy, Air and Water Technology, Department of Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen, Belgium.
| | - Daniel Puyol
- Department of Chemical and Environmental Technology, ESCET, Rey Juan Carlos University, Móstoles, Spain.
| | - Willy Verstraete
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000 Gent, Belgium; Avecom NV, Industrieweg 122P, 9032 Wondelgem, Belgium.
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, the Netherlands.
| | - Adrian Oehmen
- School of Chemical Engineering, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - Anish Ghimire
- Department of Environmental Science and Engineering, Kathmandu University, Dhulikhel, Nepal.
| | - Ilje Pikaar
- School of Civil Engineering, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - Juan M Lema
- CRETUS Institute, Department of Chemical Engineering, School of Engineering, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
| | - Tim Hülsen
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD 4072, Australia.
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Assessing New Biotechnologies by Combining TEA and TM-LCA for an Efficient Use of Biomass Resources. SUSTAINABILITY 2020. [DOI: 10.3390/su12093676] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
An efficient use of biomass resources is a key element of the bioeconomy. Ideally, options leading to the highest environmental and economic gains can be singled out for any given region. In this study, to achieve this goal of singling out an ideal technology for a given region, biotechnologies are assessed by a combination of techno-economic assessment (TEA) and territorial metabolism life cycle assessment (TM-LCA). Three technology variations for anaerobic digestion (AD) were assessed at two different scales (200 kW and 1 MW) and for two different regions. First, sustainable feedstock availability for two European regions was quantified. Then, the environmental impact and economic potential of each technology when scaled up to the regional level, considering all of the region’s unique sustainably available feedstock, was investigated. Multiple criteria decision analysis and internalized damage monetization were used to generate single scores for the assessments. Preference for the technology scenario producing the most energy was shown for all regions and scales, while producing bioplastic was less preferable since the value of the produced bioplastic plastic was not great enough to offset the resultant reduction in energy production. Assessing alternatives in a regional context provided valuable information about the influence of different types of feedstock on environmental performance.
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