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Haque S, Singh R, Pal DB, Faidah H, Ashgar SS, Areeshi MY, Almalki AH, Verma B, Srivastava N, Gupta VK. Thermophilic biohydrogen production strategy using agro industrial wastes: Current update, challenges, and sustainable solutions. CHEMOSPHERE 2022; 307:136120. [PMID: 35995181 DOI: 10.1016/j.chemosphere.2022.136120] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 07/31/2022] [Accepted: 08/16/2022] [Indexed: 06/15/2023]
Abstract
Continuously increasing wastes management issues and the high demand of fuels to fulfill the current societal requirements is not satisfactory. In addition, severe environmental pollution caused by generated wastes and the massive consumption of fossil fuels are the main causes of global warming. In this scenario, production of hydrogen from organic wastes is a potential and one of the most feasible alternatives to resolve these issues. However, sensitivity of H2 production at higher temperature and lack of potential substrates are the main issues which are strongly associated with such kinds of biofuels. Therefore, the present review is targeted towards the evaluation and enhancement of thermophilic biohydrogen production using organic, cellulosic wastes as promising bioresources. This review discusses about the current status, development in the area of thermophilic biohydrogen production wherein organic wastes as key substrate are being employed. The combinations of suitable organic and cellulose rich substrates, thermo-tolerant microbes, high enzymes stability may support to enhance the biohydrogen production, significantly. Further, various factors which may significantly contribute to enhance biohydrogen production have been discussed thoroughly in reference to the thermophilic biohydrogen production technology. Additionally, existing obstacles such as unfavorable thermophilic biohydrogen pathways, inefficiency of thermophilic microbiomes, genetic modifications, enzymes stability have been discussed in context to the possible limitations of thermophilic biohydrogen production strategy. Structural and functional microbiome analysis, fermentation pathway modifications via genetic engineering and the application of nanotechnology to enhance the thermophilic biohydrogen production have been discussed as the future prospective.
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Affiliation(s)
- Shafiul Haque
- Research and Scientific Studies Unit, College of Nursing and Allied Health Sciences, Jazan University, Jazan, 45142, Saudi Arabia
| | - Rajeev Singh
- Department of Environmental Studies, Satyawati College, University of Delhi, Delhi, 110052, India
| | - Dan Bahadur Pal
- Department of Chemical Engineering, Birla Institute of Technology, Mesra Ranchi, 835215, Jharkhand, India; Department of Chemical Engineering, Harcourt Butler Technical University, Nawabganj, Kanpur, 208002, Uttar Pradesh, India
| | - Hani Faidah
- Department of Microbiology, Faculty of Medicine, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Sami S Ashgar
- Department of Microbiology, Faculty of Medicine, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Mohammed Y Areeshi
- Research and Scientific Studies Unit, College of Nursing and Allied Health Sciences, Jazan University, Jazan, 45142, Saudi Arabia; Medical Laboratory Technology Department, College of Applied Medical Sciences, Jazan University, Jazan, 45142, Saudi Arabia
| | - Atiah H Almalki
- Department of Pharmaceutical Chemistry, College of Pharmacy, Taif University, P.O. Box 11099, Taif, 21944, Saudi Arabia; Addiction and Neuroscience Research Unit, College of Pharmacy, Taif University, Al-Hawiah, Taif, 21944, Saudi Arabia
| | - Bhawna Verma
- Department of Chemical Engineering & Technology, Indian Institute of Technology (BHU) Varanasi Varanasi, 221005, Uttar Pradesh, India
| | - Neha Srivastava
- Department of Chemical Engineering & Technology, Indian Institute of Technology (BHU) Varanasi Varanasi, 221005, Uttar Pradesh, India.
| | - Vijai Kumar Gupta
- Biorefining and Advanced Materials Research Center, Scotland's Rural College (SRUC), Kings Buildings, West Mains Road, Edinburgh, EH9 3JG, UK; Center for Safe and Improved Food, Scotland's Rural College (SRUC), Kings Buildings, West Mains Road, Edinburgh, EH9 3JG, UK.
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Kobayashi S, Kato J, Wada K, Takemura K, Kato S, Fujii T, Iwasaki Y, Aoi Y, Morita T, Matsushika A, Murakami K, Nakashimada Y. Reversible Hydrogenase Activity Confers Flexibility to Balance Intracellular Redox in Moorella thermoacetica. Front Microbiol 2022; 13:897066. [PMID: 35633713 PMCID: PMC9133594 DOI: 10.3389/fmicb.2022.897066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 04/19/2022] [Indexed: 11/13/2022] Open
Abstract
Hydrogen (H2) converted to reducing equivalents is used by acetogens to fix and metabolize carbon dioxide (CO2) to acetate. The utilization of H2 enables not only autotrophic growth, but also mixotrophic metabolism in acetogens, enhancing carbon utilization. This feature seems useful, especially when the carbon utilization efficiency of organic carbon sources is lowered by metabolic engineering to produce reduced chemicals, such as ethanol. The potential advantage was tested using engineered strains of Moorella thermoacetica that produce ethanol. By adding H2 to the fructose-supplied culture, the engineered strains produced increased levels of acetate, and a slight increase in ethanol was observed. The utilization of a knockout strain of the major acetate production pathway, aimed at increasing the carbon flux to ethanol, was unexpectedly hindered by H2-mediated growth inhibition in a dose-dependent manner. Metabolomic analysis showed a significant increase in intracellular NADH levels due to H2 in the ethanol-producing strain. Higher NADH level was shown to be the cause of growth inhibition because the decrease in NADH level by dimethyl sulfoxide (DMSO) reduction recovered the growth. When H2 was not supplemented, the intracellular NADH level was balanced by the reversible electron transfer from NADH oxidation to H2 production in the ethanol-producing strain. Therefore, reversible hydrogenase activity confers the ability and flexibility to balance the intracellular redox state of M. thermoacetica. Tuning of the redox balance is required in order to benefit from H2-supplemented mixotrophy, which was confirmed by engineering to produce acetone.
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Affiliation(s)
- Shunsuke Kobayashi
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashihiroshima, Japan
| | - Junya Kato
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashihiroshima, Japan
| | - Keisuke Wada
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - Kaisei Takemura
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashihiroshima, Japan
| | - Setsu Kato
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashihiroshima, Japan
| | - Tatsuya Fujii
- National Institute of Advanced Industrial Science and Technology (AIST), Higashihiroshima, Japan
| | - Yuki Iwasaki
- National Institute of Advanced Industrial Science and Technology (AIST), Higashihiroshima, Japan
| | - Yoshiteru Aoi
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashihiroshima, Japan
| | - Tomotake Morita
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - Akinori Matsushika
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashihiroshima, Japan
- National Institute of Advanced Industrial Science and Technology (AIST), Higashihiroshima, Japan
| | - Katsuji Murakami
- National Institute of Advanced Industrial Science and Technology (AIST), Higashihiroshima, Japan
| | - Yutaka Nakashimada
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashihiroshima, Japan
- *Correspondence: Yutaka Nakashimada,
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Bing RG, Straub CT, Sulis DB, Wang JP, Adams MWW, Kelly RM. Plant biomass fermentation by the extreme thermophile Caldicellulosiruptor bescii for co-production of green hydrogen and acetone: Technoeconomic analysis. BIORESOURCE TECHNOLOGY 2022; 348:126780. [PMID: 35093526 PMCID: PMC10560548 DOI: 10.1016/j.biortech.2022.126780] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 01/18/2022] [Accepted: 01/23/2022] [Indexed: 06/14/2023]
Abstract
A variety of chemical and biological processes have been proposed for conversion of sustainable low-cost feedstocks into industrial products. Here, a biorefinery concept is formulated, modeled, and analyzed in which a naturally (hemi)cellulolytic and extremely thermophilic bacterium, Caldicellulosiruptor bescii, is metabolically engineered to convert the carbohydrate content of lignocellulosic biomasses (i.e., soybean hulls, transgenic poplar) into green hydrogen and acetone. Experimental validation of C. bescii fermentative performance demonstrated 82% carbohydrate solubilization of soybean hulls and 55% for transgenic poplar. A detailed technical design, including equipment specifications, provides the basis for an economic analysis that establishes metabolic engineering targets. This robust industrial process leveraging metabolically engineered C. bescii yields 206 kg acetone and 25 kg H2 per metric ton of soybean hull, or 174 kg acetone and 21 kg H2 per metric ton transgenic poplar. Beyond this specific case, the model demonstrates industrial feasibility and economic advantages of thermophilic fermentation.
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Affiliation(s)
- Ryan G Bing
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, United States
| | - Christopher T Straub
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, United States
| | - Daniel B Sulis
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC 27695, United States
| | - Jack P Wang
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC 27695, United States
| | - Michael W W Adams
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, United States
| | - Robert M Kelly
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, United States.
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Uncoupling Fermentative Synthesis of Molecular Hydrogen from Biomass Formation in Thermotoga maritima. Appl Environ Microbiol 2018; 84:AEM.00998-18. [PMID: 29959252 DOI: 10.1128/aem.00998-18] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 06/24/2018] [Indexed: 01/08/2023] Open
Abstract
When carbohydrates are fermented by the hyperthermophilic anaerobe Thermotoga maritima, molecular hydrogen (H2) is formed in strict proportion to substrate availability. Excretion of the organic acids acetate and lactate provide an additional sink for removal of excess reductant. However, mechanisms controlling energy management of these metabolic pathways are largely unexplored. To investigate this topic, transient gene inactivation was used to block lactate production as a strategy to produce spontaneous mutant cell lines that overproduced H2 through mutation of unpredicted genetic targets. Single-crossover homologous chromosomal recombination was used to disrupt lactate dehydrogenase (encoded by ldh) with a truncated ldh fused to a kanamycin resistance cassette expressed from a native P groESL promoter. Passage of the unstable recombinant resulted in loss of the genetic marker and recovery of evolved cell lines, including strain Tma200. Relative to the wild type, and considering the mass balance of fermentation substrate and products, Tma200 grew more slowly, produced H2 at levels above the physiologic limit, and simultaneously consumed less maltose while oxidizing it more efficiently. Whole-genome resequencing indicated that the ABC maltose transporter subunit, encoded by malK3, had undergone repeated mutation, and high-temperature anaerobic [14C]maltose transport assays demonstrated that the rate of maltose transport was reduced. Transfer of the malK3 mutation into a clean genetic background also conferred increased H2 production, confirming that the mutant allele was sufficient for increased H2 synthesis. These data indicate that a reduced rate of maltose uptake was accompanied by an increase in H2 production, changing fermentation efficiency and shifting energy management.IMPORTANCE Biorenewable energy sources are of growing interest to mitigate climate change, but like other commodities with nominal value, require innovation to maximize yields. Energetic considerations constrain production of many biofuels, such as molecular hydrogen (H2) because of the competing needs for cell mass synthesis and metabolite formation. Here we describe cell lines of the extremophile Thermotoga maritima that exceed the physiologic limits for H2 formation arising from genetic changes in fermentative metabolism. These cell lines were produced using a novel method called transient gene inactivation combined with adaptive laboratory evolution. Genome resequencing revealed unexpected changes in a maltose transport protein. Reduced rates of sugar uptake were accompanied by lower rates of growth and enhanced productivity of H2.
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Nguyen PQ, Courchesne NMD, Duraj-Thatte A, Praveschotinunt P, Joshi NS. Engineered Living Materials: Prospects and Challenges for Using Biological Systems to Direct the Assembly of Smart Materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1704847. [PMID: 29430725 PMCID: PMC6309613 DOI: 10.1002/adma.201704847] [Citation(s) in RCA: 200] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 10/25/2017] [Indexed: 05/20/2023]
Abstract
Vast potential exists for the development of novel, engineered platforms that manipulate biology for the production of programmed advanced materials. Such systems would possess the autonomous, adaptive, and self-healing characteristics of living organisms, but would be engineered with the goal of assembling bulk materials with designer physicochemical or mechanical properties, across multiple length scales. Early efforts toward such engineered living materials (ELMs) are reviewed here, with an emphasis on engineered bacterial systems, living composite materials which integrate inorganic components, successful examples of large-scale implementation, and production methods. In addition, a conceptual exploration of the fundamental criteria of ELM technology and its future challenges is presented. Cradled within the rich intersection of synthetic biology and self-assembling materials, the development of ELM technologies allows the power of biology to be leveraged to grow complex structures and objects using a palette of bio-nanomaterials.
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Affiliation(s)
- Peter Q. Nguyen
- School of Engineering and Applied Sciences, Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02138, USA
| | - Noémie-Manuelle Dorval Courchesne
- School of Engineering and Applied Sciences, Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02138, USA
| | - Anna Duraj-Thatte
- School of Engineering and Applied Sciences, Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02138, USA
| | - Pichet Praveschotinunt
- School of Engineering and Applied Sciences, Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02138, USA
| | - Neel S. Joshi
- School of Engineering and Applied Sciences, Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02138, USA
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Tian L, Perot SJ, Stevenson D, Jacobson T, Lanahan AA, Amador-Noguez D, Olson DG, Lynd LR. Metabolome analysis reveals a role for glyceraldehyde 3-phosphate dehydrogenase in the inhibition of C. thermocellum by ethanol. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:276. [PMID: 29213320 PMCID: PMC5708176 DOI: 10.1186/s13068-017-0961-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 11/06/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND Clostridium thermocellum is a promising microorganism for conversion of cellulosic biomass to biofuel, without added enzymes; however, the low ethanol titer produced by strains developed thus far is an obstacle to industrial application. RESULTS Here, we analyzed changes in the relative concentration of intracellular metabolites in response to gradual addition of ethanol to growing cultures. For C. thermocellum, we observed that ethanol tolerance, in experiments with gradual ethanol addition, was twofold higher than previously observed in response to a stepwise increase in the ethanol concentration, and appears to be due to a mechanism other than mutation. As ethanol concentrations increased, we found accumulation of metabolites upstream of the glyceraldehyde 3-phosphate dehydrogenase (GAPDH) reaction and depletion of metabolites downstream of that reaction. This pattern was not observed in the more ethanol-tolerant organism Thermoanaerobacterium saccharolyticum. We hypothesize that the Gapdh enzyme may have different properties in the two organisms. Our hypothesis is supported by enzyme assays showing greater sensitivity of the C. thermocellum enzyme to high levels of NADH, and by the increase in ethanol tolerance and production when the T. saccharolyticum gapdh was expressed in C. thermocellum. CONCLUSIONS We have demonstrated that a metabolic bottleneck occurs at the GAPDH reaction when the growth of C. thermocellum is inhibited by high levels of ethanol. We then showed that this bottleneck could be relieved by expression of the gapdh gene from T. saccharolyticum. This enzyme is a promising target for future metabolic engineering work.
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Affiliation(s)
- Liang Tian
- Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, NH 03755 USA
- Bioenergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Skyler J. Perot
- Dartmouth College, Hanover, NH 03755 USA
- Bioenergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - David Stevenson
- Bioenergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- University of Wisconsin-Madison, Madison, WI 53706 USA
| | - Tyler Jacobson
- Bioenergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- University of Wisconsin-Madison, Madison, WI 53706 USA
| | - Anthony A. Lanahan
- Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, NH 03755 USA
- Bioenergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Daniel Amador-Noguez
- Bioenergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- University of Wisconsin-Madison, Madison, WI 53706 USA
| | - Daniel G. Olson
- Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, NH 03755 USA
- Bioenergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Lee R. Lynd
- Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, NH 03755 USA
- Bioenergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
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Counts JA, Zeldes BM, Lee LL, Straub CT, Adams MWW, Kelly RM. Physiological, metabolic and biotechnological features of extremely thermophilic microorganisms. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2017; 9. [PMID: 28206708 DOI: 10.1002/wsbm.1377] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Revised: 11/23/2016] [Accepted: 11/30/2016] [Indexed: 12/12/2022]
Abstract
The current upper thermal limit for life as we know it is approximately 120°C. Microorganisms that grow optimally at temperatures of 75°C and above are usually referred to as 'extreme thermophiles' and include both bacteria and archaea. For over a century, there has been great scientific curiosity in the basic tenets that support life in thermal biotopes on earth and potentially on other solar bodies. Extreme thermophiles can be aerobes, anaerobes, autotrophs, heterotrophs, or chemolithotrophs, and are found in diverse environments including shallow marine fissures, deep sea hydrothermal vents, terrestrial hot springs-basically, anywhere there is hot water. Initial efforts to study extreme thermophiles faced challenges with their isolation from difficult to access locales, problems with their cultivation in laboratories, and lack of molecular tools. Fortunately, because of their relatively small genomes, many extreme thermophiles were among the first organisms to be sequenced, thereby opening up the application of systems biology-based methods to probe their unique physiological, metabolic and biotechnological features. The bacterial genera Caldicellulosiruptor, Thermotoga and Thermus, and the archaea belonging to the orders Thermococcales and Sulfolobales, are among the most studied extreme thermophiles to date. The recent emergence of genetic tools for many of these organisms provides the opportunity to move beyond basic discovery and manipulation to biotechnologically relevant applications of metabolic engineering. WIREs Syst Biol Med 2017, 9:e1377. doi: 10.1002/wsbm.1377 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- James A Counts
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, USA
| | - Benjamin M Zeldes
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, USA
| | - Laura L Lee
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, USA
| | - Christopher T Straub
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, USA
| | - Michael W W Adams
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA
| | - Robert M Kelly
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, USA
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van Lingen HJ, Plugge CM, Fadel JG, Kebreab E, Bannink A, Dijkstra J. Thermodynamic Driving Force of Hydrogen on Rumen Microbial Metabolism: A Theoretical Investigation. PLoS One 2016; 11:e0161362. [PMID: 27783615 PMCID: PMC5081179 DOI: 10.1371/journal.pone.0161362] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 08/04/2016] [Indexed: 01/26/2023] Open
Abstract
Hydrogen is a key product of rumen fermentation and has been suggested to thermodynamically control the production of the various volatile fatty acids (VFA). Previous studies, however, have not accounted for the fact that only thermodynamic near-equilibrium conditions control the magnitude of reaction rate. Furthermore, the role of NAD, which is affected by hydrogen partial pressure (PH2), has often not been considered. The aim of this study was to quantify the control of PH2 on reaction rates of specific fermentation pathways, methanogenesis and NADH oxidation in rumen microbes. The control of PH2 was quantified using the thermodynamic potential factor (FT), which is a dimensionless factor that corrects a predicted kinetic reaction rate for the thermodynamic control exerted. Unity FT was calculated for all glucose fermentation pathways considered, indicating no inhibition of PH2 on the production of a specific type of VFA (e.g., acetate, propionate and butyrate) in the rumen. For NADH oxidation without ferredoxin oxidation, increasing PH2 within the rumen physiological range decreased FT from unity to zero for different NAD+ to NADH ratios and pH of 6.2 and 7.0, which indicates thermodynamic control of PH2. For NADH oxidation with ferredoxin oxidation, increasing PH2 within the rumen physiological range decreased FT from unity at pH of 7.0 only. For the acetate to propionate conversion, FT increased from 0.65 to unity with increasing PH2, which indicates thermodynamic control. For propionate to acetate and butyrate to acetate conversions, FT decreased to zero below the rumen range of PH2, indicating full thermodynamic suppression. For methanogenesis by archaea without cytochromes, FT differed from unity only below the rumen range of PH2, indicating no thermodynamic control. This theoretical investigation shows that thermodynamic control of PH2 on individual VFA produced and associated yield of hydrogen and methane cannot be explained without considering NADH oxidation.
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Affiliation(s)
- Henk J. van Lingen
- TI Food and Nutrition, Wageningen, The Netherlands
- Animal Nutrition Group, Wageningen University, Wageningen, The Netherlands
- * E-mail:
| | - Caroline M. Plugge
- Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands
| | - James G. Fadel
- Department of Animal Sciences, University of California, Davis, Davis, California, United States of America
| | - Ermias Kebreab
- Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands
| | - André Bannink
- Animal Nutrition, Wageningen UR Livestock Research, Wageningen, the Netherlands
| | - Jan Dijkstra
- Animal Nutrition Group, Wageningen University, Wageningen, The Netherlands
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Pawar SS, Vongkumpeang T, Grey C, van Niel EWJ. Biofilm formation by designed co-cultures of Caldicellulosiruptor species as a means to improve hydrogen productivity. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:19. [PMID: 25722741 PMCID: PMC4342205 DOI: 10.1186/s13068-015-0201-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 01/08/2015] [Indexed: 05/08/2023]
Abstract
BACKGROUND Caldicellulosiruptor species have gained a reputation as being among the best microorganisms to produce hydrogen (H2) due to possession of a combination of appropriate features. However, due to their low volumetric H2 productivities (Q H2), Caldicellulosiruptor species cannot be considered for any viable biohydrogen production process yet. In this study, we evaluate biofilm forming potential of pure and co-cultures of Caldicellulosiruptor saccharolyticus and Caldicellulosiruptor owensensis in continuously stirred tank reactors (CSTR) and up-flow anaerobic (UA) reactors. We also evaluate biofilms as a means to retain biomass in the reactor and its influence on Q H2. Moreover, we explore the factors influencing the formation of biofilm. RESULTS Co-cultures of C. saccharolyticus and C. owensensis form substantially more biofilm than formed by C. owensensis alone. Biofilms improved substrate conversion in both of the reactor systems, but improved the Q H2 only in the UA reactor. When grown in the presence of each other's culture supernatant, both C. saccharolyticus and C. owensensis were positively influenced on their individual growth and H2 production. Unlike the CSTR, UA reactors allowed retention of C. saccharolyticus and C. owensensis when subjected to very high substrate loading rates. In the UA reactor, maximum Q H2 (approximately 20 mmol · L(-1) · h(-1)) was obtained only with granular sludge as the carrier material. In the CSTR, stirring negatively affected biofilm formation. Whereas, a clear correlation was observed between elevated (>40 μM) intracellular levels of the secondary messenger bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) and biofilm formation. CONCLUSIONS In co-cultures C. saccharolyticus fortified the trade of biofilm formation by C. owensensis, which was mediated by elevated levels of c-di-GMP in C. owensensis. These biofilms were effective in retaining biomass of both species in the reactor and improving Q H2 in a UA reactor using granular sludge as the carrier material. This concept forms a basis for further optimizing the Q H2 at laboratory scale and beyond.
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Affiliation(s)
- Sudhanshu S Pawar
- />Division of Applied Microbiology, Lund University, Getingevägen 60, PO Box 124, SE-221 00 Lund, Sweden
| | - Thitiwut Vongkumpeang
- />Division of Applied Microbiology, Lund University, Getingevägen 60, PO Box 124, SE-221 00 Lund, Sweden
| | - Carl Grey
- />Department of Biotechnology, Lund University, Getingevägen 60, PO Box 124, 221 00 Lund, Sweden
| | - Ed WJ van Niel
- />Division of Applied Microbiology, Lund University, Getingevägen 60, PO Box 124, SE-221 00 Lund, Sweden
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Pawar SS, van Niel EWJ. Evaluation of assimilatory sulphur metabolism in Caldicellulosiruptor saccharolyticus. BIORESOURCE TECHNOLOGY 2014; 169:677-685. [PMID: 25108266 DOI: 10.1016/j.biortech.2014.07.059] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2014] [Revised: 07/14/2014] [Accepted: 07/15/2014] [Indexed: 05/23/2023]
Abstract
Caldicellulosiruptor saccharolyticus has gained reputation as being among the best microorganisms to produce H2 due to possession of various appropriate features. The quest to develop an inexpensive cultivation medium led to determine a possible replacement of the expensive component cysteine, i.e. sulphate. C. saccharolyticus assimilated sulphate successfully in absence of a reducing agent without releasing hydrogen sulphide. A complete set of genes coding for enzymes required for sulphate assimilation were found in the majority of Caldicellulosiruptor species including C. saccharolyticus. C. saccharolyticus displayed indifferent physiological behaviour to source of sulphur when grown under favourable conditions in continuous cultures. Increasing the usual concentration of sulphur in the feed medium increased substrate conversion. Choice of sulphur source did not affect the tolerance of C. saccharolyticus to high partial pressures of H2. Thus, sulphate can be a principle sulphur source in an economically viable and more sustainable biohydrogen process using C. saccharolyticus.
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Affiliation(s)
- Sudhanshu S Pawar
- Division of Applied Microbiology, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden.
| | - Ed W J van Niel
- Division of Applied Microbiology, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden.
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Ciranna A, Pawar SS, Santala V, Karp M, van Niel EWJ. Assessment of metabolic flux distribution in the thermophilic hydrogen producer Caloramator celer as affected by external pH and hydrogen partial pressure. Microb Cell Fact 2014; 13:48. [PMID: 24678972 PMCID: PMC3986597 DOI: 10.1186/1475-2859-13-48] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 03/18/2014] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Caloramator celer is a strict anaerobic, alkalitolerant, thermophilic bacterium capable of converting glucose to hydrogen (H2), carbon dioxide, acetate, ethanol and formate by a mixed acid fermentation. Depending on the growth conditions C. celer can produce H2 at high yields. For a biotechnological exploitation of this bacterium for H2 production it is crucial to understand the factors that regulate carbon and electron fluxes and therefore the final distribution of metabolites to channel the metabolic flux towards the desired product. RESULTS Combining experimental results from batch fermentations with genome analysis, reconstruction of central carbon metabolism and metabolic flux analysis (MFA), this study shed light on glucose catabolism of the thermophilic alkalitolerant bacterium C. celer. Two innate factors pertaining to culture conditions have been identified to significantly affect the metabolic flux distribution: culture pH and partial pressures of H2 (PH2). Overall, at alkaline to neutral pH the rate of biomass synthesis was maximized, whereas at acidic pH the lower growth rate and the less efficient biomass formation are accompanied with more efficient energy recovery from the substrate indicating high cell maintenance possibly to sustain intracellular pH homeostasis. Higher H2 yields were associated with fermentation at acidic pH as a consequence of the lower synthesis of other reduced by-products such as formate and ethanol. In contrast, PH2 did not affect the growth of C. celer on glucose. At high PH2 the cellular redox state was balanced by rerouting the flow of carbon and electrons to ethanol and formate production allowing unaltered glycolytic flux and growth rate, but resulting in a decreased H2 synthesis. CONCLUSION C. celer possesses a flexible fermentative metabolism that allows redistribution of fluxes at key metabolic nodes to simultaneously control redox state and efficiently harvest energy from substrate even under unfavorable conditions (i.e. low pH and high PH2). With the H2 production in mind, acidic pH and low PH2 should be preferred for a high yield-oriented process, while a high productivity-oriented process can be achieved at alkaline pH and high PH2.
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Affiliation(s)
- Alessandro Ciranna
- Department of Chemistry and Bioengineering, Tampere University of Technology, Korkeakoulunkatu 8, FI-33720 Tampere, Finland
| | - Sudhanshu S Pawar
- Department of Applied Microbiology, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Ville Santala
- Department of Chemistry and Bioengineering, Tampere University of Technology, Korkeakoulunkatu 8, FI-33720 Tampere, Finland
| | - Matti Karp
- Department of Chemistry and Bioengineering, Tampere University of Technology, Korkeakoulunkatu 8, FI-33720 Tampere, Finland
| | - Ed WJ van Niel
- Department of Applied Microbiology, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
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Frascari D, Cappelletti M, Mendes JDS, Alberini A, Scimonelli F, Manfreda C, Longanesi L, Zannoni D, Pinelli D, Fedi S. A kinetic study of biohydrogen production from glucose, molasses and cheese whey by suspended and attached cells of Thermotoga neapolitana. BIORESOURCE TECHNOLOGY 2013; 147:553-561. [PMID: 24013293 DOI: 10.1016/j.biortech.2013.08.047] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 07/22/2013] [Accepted: 08/08/2013] [Indexed: 06/02/2023]
Abstract
Batch tests of H2 production from glucose, molasses and cheese whey by suspended and immobilized cells of Thermotoga neapolitana were conducted to develop a kinetic model of the process. H2 production was inhibited by neither H2 (up to 0.7 mg L(-1)) nor O2 (up to 0.2 mg L(-1)). The H2 specific rates obtained at different substrate concentrations were successfully interpolated with Andrew's inhibition model. With glucose and molasses, biofilms performed better than suspended cells. The suspended-cell process was successfully scaled-up to a 19-L bioreactor. Assays co-fed with molasses and cheese whey led to higher H2 productivities and H2/substrate yields than the single-substrate tests. The simulation of the suspended-cell continuous-flow process indicated the potential attainment of H2 productivities higher than those of the batch tests (up to 3.6 mmol H2 h(-1) L(-1) for molasses and 0.67 mmol H2 h(-1) L(-1) for cheese whey) and allowed the identification of the optimal dilution rate.
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Affiliation(s)
- Dario Frascari
- Department of Civil, Chemical, Environmental and Materials Engineering, University of Bologna, Via Terracini 28, Bologna, Italy.
| | - Martina Cappelletti
- Department of Pharmacy and BioTechnology, University of Bologna, Via Irnerio 42, Bologna, Italy
| | - Jocelia De Sousa Mendes
- Department of Civil, Chemical, Environmental and Materials Engineering, University of Bologna, Via Terracini 28, Bologna, Italy
| | - Andrea Alberini
- Department of Civil, Chemical, Environmental and Materials Engineering, University of Bologna, Via Terracini 28, Bologna, Italy
| | - Francesco Scimonelli
- Department of Civil, Chemical, Environmental and Materials Engineering, University of Bologna, Via Terracini 28, Bologna, Italy
| | - Chiara Manfreda
- Department of Pharmacy and BioTechnology, University of Bologna, Via Irnerio 42, Bologna, Italy
| | - Luca Longanesi
- Department of Civil, Chemical, Environmental and Materials Engineering, University of Bologna, Via Terracini 28, Bologna, Italy
| | - Davide Zannoni
- Department of Pharmacy and BioTechnology, University of Bologna, Via Irnerio 42, Bologna, Italy
| | - Davide Pinelli
- Department of Civil, Chemical, Environmental and Materials Engineering, University of Bologna, Via Terracini 28, Bologna, Italy
| | - Stefano Fedi
- Department of Pharmacy and BioTechnology, University of Bologna, Via Irnerio 42, Bologna, Italy
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Pawar SS, van Niel EWJ. Thermophilic biohydrogen production: how far are we? Appl Microbiol Biotechnol 2013; 97:7999-8009. [PMID: 23948723 PMCID: PMC3757257 DOI: 10.1007/s00253-013-5141-1] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 07/16/2013] [Accepted: 07/17/2013] [Indexed: 01/10/2023]
Abstract
Apart from being applied as an energy carrier, hydrogen is in increasing demand as a commodity. Currently, the majority of hydrogen (H2) is produced from fossil fuels, but from an environmental perspective, sustainable H2 production should be considered. One of the possible ways of hydrogen production is through fermentation, in particular, at elevated temperature, i.e. thermophilic biohydrogen production. This short review recapitulates the current status in thermophilic biohydrogen production through fermentation of commercially viable substrates produced from readily available renewable resources, such as agricultural residues. The route to commercially viable biohydrogen production is a multidisciplinary enterprise. Microbiological studies have pointed out certain desirable physiological characteristics in H2-producing microorganisms. More process-oriented research has identified best applicable reactor types and cultivation conditions. Techno-economic and life cycle analyses have identified key process bottlenecks with respect to economic feasibility and its environmental impact. The review has further identified current limitations and gaps in the knowledge, and also deliberates directions for future research and development of thermophilic biohydrogen production.
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Affiliation(s)
- Sudhanshu S Pawar
- Applied Microbiology, Lund University, Getingevägen 60, 222 41, Lund, Sweden.
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Talluri S, Raj SM, Christopher LP. Consolidated bioprocessing of untreated switchgrass to hydrogen by the extreme thermophile Caldicellulosiruptor saccharolyticus DSM 8903. BIORESOURCE TECHNOLOGY 2013; 139:272-9. [PMID: 23665687 DOI: 10.1016/j.biortech.2013.04.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 04/01/2013] [Accepted: 04/02/2013] [Indexed: 05/10/2023]
Abstract
The abilities of the extreme thermophilic bacterium Caldicellulosiruptor saccharolyticus DSM 8903 to ferment switchgrass (SWG), microcrystalline cellulose (MCC) and glucose to hydrogen (H2) in one-step were examined. Hydrogen production from glucose reached the theoretical maximum for dark fermentation of 4 mol H2/mol glucose. The H2 yield on MCC and SWG after 6 days of fermentation was 23.2 mmol H2/L or 9.4 mmol H2/g MCC and 14.3 mmol H2/L or 11.2 mmol H2/g SWG, respectively. The rate of H2 formation however was higher on MCC (0.7 mmol/Lh) than SWG (0.1 mmol/Lh). C. saccharolyticus DSM 8903 was able to produce H2 directly from mechanically-comminuted SWG without any physicochemical or biological pretreatment. Combining four processing steps (pretreatment, enzyme production, saccharification and fermentation) into a single biorefinery operation makes C. saccharolyticus DSM 8903 a promising candidate for consolidated bioprocessing (CBP) of lignocellulosic biomass.
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Affiliation(s)
- Suvarna Talluri
- Center for Bioprocessing Research and Development, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA
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Biohydrogen Production by the Thermophilic Bacterium Caldicellulosiruptor saccharolyticus: Current Status and Perspectives. Life (Basel) 2013; 3:52-85. [PMID: 25371332 PMCID: PMC4187192 DOI: 10.3390/life3010052] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 01/06/2013] [Accepted: 01/07/2013] [Indexed: 01/24/2023] Open
Abstract
Caldicellulosiruptor saccharolyticus is one of the most thermophilic cellulolytic organisms known to date. This Gram-positive anaerobic bacterium ferments a broad spectrum of mono-, di- and polysaccharides to mainly acetate, CO2 and hydrogen. With hydrogen yields approaching the theoretical limit for dark fermentation of 4 mol hydrogen per mol hexose, this organism has proven itself to be an excellent candidate for biological hydrogen production. This review provides an overview of the research on C. saccharolyticus with respect to the hydrolytic capability, sugar metabolism, hydrogen formation, mechanisms involved in hydrogen inhibition, and the regulation of the redox and carbon metabolism. Analysis of currently available fermentation data reveal decreased hydrogen yields under non-ideal cultivation conditions, which are mainly associated with the accumulation of hydrogen in the liquid phase. Thermodynamic considerations concerning the reactions involved in hydrogen formation are discussed with respect to the dissolved hydrogen concentration. Novel cultivation data demonstrate the sensitivity of C. saccharolyticus to increased hydrogen levels regarding substrate load and nitrogen limitation. In addition, special attention is given to the rhamnose metabolism, which represents an unusual type of redox balancing. Finally, several approaches are suggested to improve biohydrogen production by C. saccharolyticus.
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