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Cha M, Kim JK, Lee WH, Song H, Lee TG, Kim SK, Kim SJ. Metabolic engineering of Caldicellulosiruptor bescii for hydrogen production. Appl Microbiol Biotechnol 2024; 108:65. [PMID: 38194138 PMCID: PMC10776719 DOI: 10.1007/s00253-023-12974-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 12/04/2023] [Accepted: 12/15/2023] [Indexed: 01/10/2024]
Abstract
Hydrogen is an alternative fuel for transportation vehicles because it is clean, sustainable, and highly flammable. However, the production of hydrogen from lignocellulosic biomass by microorganisms presents challenges. This microbial process involves multiple complex steps, including thermal, chemical, and mechanical treatment of biomass to remove hemicellulose and lignin, as well as enzymatic hydrolysis to solubilize the plant cell walls. These steps not only incur costs but also result in the production of toxic hydrolysates, which inhibit microbial growth. A hyper-thermophilic bacterium of Caldicellulosiruptor bescii can produce hydrogen by decomposing and fermenting plant biomass without the need for conventional pretreatment. It is considered as a consolidated bioprocessing (CBP) microorganism. This review summarizes the basic scientific knowledge and hydrogen-producing capacity of C. bescii. Its genetic system and metabolic engineering strategies to improve hydrogen production are also discussed. KEY POINTS: • Hydrogen is an alternative and eco-friendly fuel. • Caldicellulosiruptor bescii produces hydrogen with a high yield in nature. • Metabolic engineering can make C. bescii to improve hydrogen production.
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Affiliation(s)
- Minseok Cha
- Research Center for Biological Cybernetics, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - Jung Kon Kim
- Department of Animal Environment, National Institute of Animal Science, Wanju, 55365, Republic of Korea
| | - Won-Heong Lee
- Department of Integrative Food, Bioscience and Biotechnology, Chonnam National University, Gwangju, 61186, Republic of Korea
| | | | - Tae-Gi Lee
- Department of Food Science and Biotechnology, Chung-Ang University, Gyeonggi, 17546, Republic of Korea
| | - Sun-Ki Kim
- Department of Food Science and Biotechnology, Chung-Ang University, Gyeonggi, 17546, Republic of Korea
| | - Soo-Jung Kim
- Research Center for Biological Cybernetics, Chonnam National University, Gwangju, 61186, Republic of Korea.
- Department of Integrative Food, Bioscience and Biotechnology, Chonnam National University, Gwangju, 61186, Republic of Korea.
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2
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Hung JH, Zhang SM, Huang SL. Nitrate promotes the growth and the production of short-chain fatty acids and tryptophan from commensal anaerobe Veillonella dispar in the lactate-deficient environment by facilitating the catabolism of glutamate and aspartate. Appl Environ Microbiol 2024; 90:e0114824. [PMID: 39082806 PMCID: PMC11337843 DOI: 10.1128/aem.01148-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2024] [Accepted: 07/10/2024] [Indexed: 08/22/2024] Open
Abstract
Veillonella spp. are nitrate-reducing bacteria with anaerobic respiratory activity that reduce nitrate to nitrite. They are obligate anaerobic, Gram-negative cocci that ferment lactate as the main carbon source and produce short-chain fatty acids (SCFAs). Commensal Veillonella reside in the human body site where lactate level is, however, limited for Veillonella growth. In this study, nitrate was shown to promote the anaerobic growth of Veillonella in the lactate-deficient media. We aimed to investigate the underlying mechanisms and the metabolism involved in nitrate respiration. Nitrate (15 mM) was demonstrated to promote Veillonella dispar growth and viability in the tryptone-yeast extract medium containing 0.5 mM L-lactate. Metabolite and transcriptomic analyses revealed nitrate enabled V. dispar to actively utilize glutamate and aspartate from the medium and secrete tryptophan. Glutamate or aspartate was further supplemented to a medium to investigate individual catabolism during nitrate respiration. Notably, nitrate was demonstrated to elevate SCFA production in the glutamate-supplemented medium, and further increase tryptophan production in the aspartate-supplemented medium. We proposed that the increased consumption of glutamate provided reducing power for nitrate respiration and aspartate served as a substrate for fumarate formation. Both glutamate and aspartate were incorporated into the central metabolic pathways via reverse tricarboxylic acid cycle and were linked with the increased production of acetate, propionate, and tryptophan. This study provides further understanding of the promoted growth and metabolic mechanisms by commensal V. dispar utilizing nitrate and specific amino acids to adapt to the lactate-deficient environment.IMPORTANCENitrate is a pivotal ecological factor influencing microbial community and metabolism. Dietary nitrate provides health benefits including anti-diabetic and anti-hypertensive effects via microbial-derived metabolites such as nitrite. Unraveling the impacts of nitrate on the growth and metabolism of human commensal bacteria is imperative to comprehend the intricate roles of nitrate in regulating microbial metabolism, community, and human health. Veillonella are lactate-utilizing, nitrate-reducing bacteria that are frequently found in the human body site where lactate levels are low and nitrate is at millimolar levels. Here, we comprehensively described the metabolic strategies employed by V. dispar to thrive in the lactate-deficient environment using nitrate respiration and catabolism of specific amino acids. The elevated production of SCFAs and tryptophan from amino acids during nitrate respiration of V. dispar further suggested the potential roles of nitrate and Veillonella in the promotion of human health.
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Affiliation(s)
- Jia-He Hung
- School of Medicine, National Yang Ming Chiao Tung University, Yangming Campus, Taipei, Taiwan
| | - Shi-Min Zhang
- Program in Molecular Medicine, National Yang Ming Chiao Tung University, Yangming Campus, Taipei, Taiwan
| | - Shir-Ly Huang
- Institute of Microbiology and Immunology, National Yang Ming Chiao Tung University, Yangming Campus, Taipei, Taiwan
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Brame JE, Liddicoat C, Abbott CA, Cando‐Dumancela C, Fickling NW, Robinson JM, Breed MF. Urban sports fields support higher levels of soil butyrate and butyrate-producing bacteria than urban nature parks. Ecol Evol 2024; 14:e70057. [PMID: 39041015 PMCID: PMC11262829 DOI: 10.1002/ece3.70057] [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: 05/07/2024] [Revised: 07/03/2024] [Accepted: 07/10/2024] [Indexed: 07/24/2024] Open
Abstract
Butyrate-producing bacteria colonise the gut of humans and non-human animals, where they produce butyrate, a short-chain fatty acid with known health benefits. Butyrate-producing bacteria also reside in soils and soil bacteria can drive the assembly of airborne bacterial communities (the aerobiome). Aerobiomes in urban greenspaces are important reservoirs of butyrate-producing bacteria as they supplement the human microbiome, but soil butyrate producer communities have rarely been examined in detail. Here, we studied soil metagenome taxonomic and functional profiles and soil physicochemical data from two urban greenspace types: sports fields (n = 11) and nature parks (n = 22). We also developed a novel method to quantify soil butyrate and characterised the in situ activity of butyrate-producing bacteria. We show that soil butyrate was higher in sports fields than nature parks and that sports fields also had significantly higher relative abundances of the terminal butyrate production genes buk and butCoAT than nature parks. Soil butyrate positively correlated with buk gene abundance (but not butCoAT). Soil moisture (r = .50), calcium (r = -.62), iron (ρ = .54), ammonium nitrogen (ρ = .58) and organic carbon (r = .45) had the strongest soil abiotic effects on soil butyrate concentrations and iron (ρ = .56) and calcium (ρ = -.57) had the strongest soil abiotic effects on buk read abundances. Overall, our findings contribute important new insights into the role of sports fields as key exposure reservoirs of butyrate producing bacteria, with important implications for the provision of microbiome-mediated human health benefits via butyrate.
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Affiliation(s)
- Joel E. Brame
- College of Science and EngineeringFlinders UniversityBedford ParkSouth AustraliaAustralia
- The Aerobiome Innovation and Research Hub (The AIR Hub), College of Science and EngineeringFlinders UniversityBedford ParkSouth AustraliaAustralia
| | - Craig Liddicoat
- College of Science and EngineeringFlinders UniversityBedford ParkSouth AustraliaAustralia
- The Aerobiome Innovation and Research Hub (The AIR Hub), College of Science and EngineeringFlinders UniversityBedford ParkSouth AustraliaAustralia
| | - Catherine A. Abbott
- College of Science and EngineeringFlinders UniversityBedford ParkSouth AustraliaAustralia
| | - Christian Cando‐Dumancela
- College of Science and EngineeringFlinders UniversityBedford ParkSouth AustraliaAustralia
- The Aerobiome Innovation and Research Hub (The AIR Hub), College of Science and EngineeringFlinders UniversityBedford ParkSouth AustraliaAustralia
| | - Nicole W. Fickling
- College of Science and EngineeringFlinders UniversityBedford ParkSouth AustraliaAustralia
- The Aerobiome Innovation and Research Hub (The AIR Hub), College of Science and EngineeringFlinders UniversityBedford ParkSouth AustraliaAustralia
| | - Jake M. Robinson
- College of Science and EngineeringFlinders UniversityBedford ParkSouth AustraliaAustralia
- The Aerobiome Innovation and Research Hub (The AIR Hub), College of Science and EngineeringFlinders UniversityBedford ParkSouth AustraliaAustralia
| | - Martin F. Breed
- College of Science and EngineeringFlinders UniversityBedford ParkSouth AustraliaAustralia
- The Aerobiome Innovation and Research Hub (The AIR Hub), College of Science and EngineeringFlinders UniversityBedford ParkSouth AustraliaAustralia
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Steuber J, Fritz G. The Na +-translocating NADH:quinone oxidoreductase (Na +-NQR): Physiological role, structure and function of a redox-driven, molecular machine. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2024; 1865:149485. [PMID: 38955304 DOI: 10.1016/j.bbabio.2024.149485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Accepted: 06/27/2024] [Indexed: 07/04/2024]
Abstract
Many bacterial processes are powered by the sodium motive force (smf) and in case of pathogens, the smf contributes to virulence. Vibrio cholerae, the causative agent of Cholera disease, possesses a Na+-translocating NADH:quinone oxidoreductase (NQR), a six-subunit membrane protein assembly. The 3D structure of NQR revealed the arrangement of the six subunits NqrABCDEF, the position of all redox cofactors (four flavins, two [2Fe-2S] centers) and the binding sites for the substrates NADH (in NqrF) and ubiquinone (in NqrB). Upon oxidation of NADH, electrons are shuttled twice across the membrane, starting with cytoplasmic FADNqrF and electron transfer to the [2Fe2S] clusterNqrF and from there to an intra-membranous [2Fe-2S] clusterNqrDE, periplasmic FMNNqrC, FMNNqrB and from there to riboflavinNqrB. This riboflavin is located at the cytoplasmic entry site of the sodium channel in NqrB, and it donates electrons to ubiquinone-8 positioned at the cytoplasmic side of NqrB. Targeting the substrate binding sites of NQR is a promising strategy to identify new inhibitors against many bacterial pathogens. Detailed structural information on the binding mode of natural inhibitors and small molecules in the active sites of NQR is now available, paving the way for the development of new antibiotics. The NQR shows different conformations as revealed in recent cryo-EM and crystallographic studies combined with spectroscopic analyses. These conformations represent distinct steps in the catalytic cycle. Considering the structural and functional data available, we propose a mechanism of Na+-NQR based on conformational coupling of electron transfer and Na+ translocation reaction steps.
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Affiliation(s)
- Julia Steuber
- Institute of Biology, Department of Cellular Microbiology, University of Hohenheim, Garbenstr. 30, 70599 Stuttgart, Germany.
| | - Günter Fritz
- Institute of Biology, Department of Cellular Microbiology, University of Hohenheim, Garbenstr. 30, 70599 Stuttgart, Germany.
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Laux M, Ciapina LP, de Carvalho FM, Gerber AL, Guimarães APC, Apolinário M, Paes JES, Jonck CR, de Vasconcelos ATR. Living in mangroves: a syntrophic scenario unveiling a resourceful microbiome. BMC Microbiol 2024; 24:228. [PMID: 38943070 PMCID: PMC11212195 DOI: 10.1186/s12866-024-03390-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 06/19/2024] [Indexed: 07/01/2024] Open
Abstract
BACKGROUND Mangroves are complex and dynamic coastal ecosystems under frequent fluctuations in physicochemical conditions related to the tidal regime. The frequent variation in organic matter concentration, nutrients, and oxygen availability, among other factors, drives the microbial community composition, favoring syntrophic populations harboring a rich and diverse, stress-driven metabolism. Mangroves are known for their carbon sequestration capability, and their complex and integrated metabolic activity is essential to global biogeochemical cycling. Here, we present a metabolic reconstruction based on the genomic functional capability and flux profile between sympatric MAGs co-assembled from a tropical restored mangrove. RESULTS Eleven MAGs were assigned to six Bacteria phyla, all distantly related to the available reference genomes. The metabolic reconstruction showed several potential coupling points and shortcuts between complementary routes and predicted syntrophic interactions. Two metabolic scenarios were drawn: a heterotrophic scenario with plenty of carbon sources and an autotrophic scenario with limited carbon sources or under inhibitory conditions. The sulfur cycle was dominant over methane and the major pathways identified were acetate oxidation coupled to sulfate reduction, heterotrophic acetogenesis coupled to carbohydrate catabolism, ethanol production and carbon fixation. Interestingly, several gene sets and metabolic routes similar to those described for wastewater and organic effluent treatment processes were identified. CONCLUSION The mangrove microbial community metabolic reconstruction reflected the flexibility required to survive in fluctuating environments as the microhabitats created by the tidal regime in mangrove sediments. The metabolic components related to wastewater and organic effluent treatment processes identified strongly suggest that mangrove microbial communities could represent a resourceful microbial model for biotechnological applications that occur naturally in the environment.
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Affiliation(s)
- Marcele Laux
- Laboratório de Bioinformática, Laboratório Nacional de Computação Científica, Avenida Getúlio Vargas 333, Quitandinha Petrópolis, Rio de Janeiro, 25651-075, Brazil
| | - Luciane Prioli Ciapina
- Laboratório de Bioinformática, Laboratório Nacional de Computação Científica, Avenida Getúlio Vargas 333, Quitandinha Petrópolis, Rio de Janeiro, 25651-075, Brazil.
| | - Fabíola Marques de Carvalho
- Laboratório de Bioinformática, Laboratório Nacional de Computação Científica, Avenida Getúlio Vargas 333, Quitandinha Petrópolis, Rio de Janeiro, 25651-075, Brazil
| | - Alexandra Lehmkuhl Gerber
- Laboratório de Bioinformática, Laboratório Nacional de Computação Científica, Avenida Getúlio Vargas 333, Quitandinha Petrópolis, Rio de Janeiro, 25651-075, Brazil
| | - Ana Paula C Guimarães
- Laboratório de Bioinformática, Laboratório Nacional de Computação Científica, Avenida Getúlio Vargas 333, Quitandinha Petrópolis, Rio de Janeiro, 25651-075, Brazil
| | - Moacir Apolinário
- Petróleo Brasileiro S. A., Centro de Pesquisa Leopoldo Américo Miguez de Mello, Rio de Janeiro, RJ, Brasil
| | - Jorge Eduardo Santos Paes
- Petróleo Brasileiro S. A., Centro de Pesquisa Leopoldo Américo Miguez de Mello, Rio de Janeiro, RJ, Brasil
| | - Célio Roberto Jonck
- Petróleo Brasileiro S. A., Centro de Pesquisa Leopoldo Américo Miguez de Mello, Rio de Janeiro, RJ, Brasil
| | - Ana Tereza R de Vasconcelos
- Laboratório de Bioinformática, Laboratório Nacional de Computação Científica, Avenida Getúlio Vargas 333, Quitandinha Petrópolis, Rio de Janeiro, 25651-075, Brazil
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6
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Rahmati F, Sethi D, Shu W, Asgari Lajayer B, Mosaferi M, Thomson A, Price GW. Advances in microbial exoenzymes bioengineering for improvement of bioplastics degradation. CHEMOSPHERE 2024; 355:141749. [PMID: 38521099 DOI: 10.1016/j.chemosphere.2024.141749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 03/06/2024] [Accepted: 03/16/2024] [Indexed: 03/25/2024]
Abstract
Plastic pollution has become a major global concern, posing numerous challenges for the environment and wildlife. Most conventional ways of plastics degradation are inefficient and cause great damage to ecosystems. The development of biodegradable plastics offers a promising solution for waste management. These plastics are designed to break down under various conditions, opening up new possibilities to mitigate the negative impact of traditional plastics. Microbes, including bacteria and fungi, play a crucial role in the degradation of bioplastics by producing and secreting extracellular enzymes, such as cutinase, lipases, and proteases. However, these microbial enzymes are sensitive to extreme environmental conditions, such as temperature and acidity, affecting their functions and stability. To address these challenges, scientists have employed protein engineering and immobilization techniques to enhance enzyme stability and predict protein structures. Strategies such as improving enzyme and substrate interaction, increasing enzyme thermostability, reinforcing the bonding between the active site of the enzyme and substrate, and refining enzyme activity are being utilized to boost enzyme immobilization and functionality. Recently, bioengineering through gene cloning and expression in potential microorganisms, has revolutionized the biodegradation of bioplastics. This review aimed to discuss the most recent protein engineering strategies for modifying bioplastic-degrading enzymes in terms of stability and functionality, including enzyme thermostability enhancement, reinforcing the substrate binding to the enzyme active site, refining with other enzymes, and improvement of enzyme surface and substrate action. Additionally, discovered bioplastic-degrading exoenzymes by metagenomics techniques were emphasized.
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Affiliation(s)
- Farzad Rahmati
- Department of Microbiology, Faculty of Science, Qom Branch, Islamic Azad University (IAU), Qom 37185364, Iran
| | - Debadatta Sethi
- Sugarcane Research Station, Odisha University of Agriculture and Technology, Nayagarh, India
| | - Weixi Shu
- Faculty of Agriculture, Dalhousie University, Truro, NS, B2N 5E3, Canada
| | | | - Mohammad Mosaferi
- Health and Environment Research Center, Tabriz Health Services Management Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Allan Thomson
- Perennia Food and Agriculture Corporation., 173 Dr. Bernie MacDonald Dr., Bible Hill, Truro, NS, B6L 2H5, Canada
| | - G W Price
- Faculty of Agriculture, Dalhousie University, Truro, NS, B2N 5E3, Canada.
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7
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Ipiales RP, Lelli G, Diaz E, Diaz-Portuondo E, Mohedano AF, de la Rubia MA. Study of two approaches for the process water management from hydrothermal carbonization of swine manure: Anaerobic treatment and nutrient recovery. ENVIRONMENTAL RESEARCH 2024; 246:118098. [PMID: 38184062 DOI: 10.1016/j.envres.2024.118098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/29/2023] [Accepted: 01/02/2024] [Indexed: 01/08/2024]
Abstract
Hydrothermal carbonization (HTC) is a promising alternative to transform biomass waste into a solid carbonaceous material (hydrochar) and a process water with potential for material and energy recovery. In this study, two alternatives for process water treatment by conventional and acid-assisted HTC of swine manure are discussed. Process water from conventional HTC at 180 °C showed high biodegradability (55% COD removal) and methane production (∼290 mL STP CH4 g-1 CODadded) and the treatment in an upflow anaerobic sludge blanket reactor allowed obtaining a high methane production yield (1.3 L CH4 L-1 d-1) and COD removal (∼70%). The analysis of the microbiota showed a high concentration of Synergistota and Firmicutes phyla, with high degradation of organic nitrogen-containing organic compounds. Acid-assisted HTC proved to be a viable option for nutrient recovery (migration of 83% of the P to the process water), which allowed obtaining a solid salt by chemical precipitation with Mg(OH)2 (NPK of 4/4/0.4) and MgCl2 (NPK 8/17/0.5), with a negligible content of heavy metals. The characteristics of the precipitated solid complied with the requirements of European Regulation (2019)/1009 for fertilizers and amendments in agricultural soils, being a suitable alternative for the recycling of nutrients from wastes.
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Affiliation(s)
- R P Ipiales
- Chemical Engineering Department, Universidad Autonoma de Madrid, 28049, Madrid, Spain; Arquimea Agrotech, 28400, Collado Villalba, Madrid, Spain
| | - G Lelli
- Chemical Engineering Department, Universidad Autonoma de Madrid, 28049, Madrid, Spain
| | - E Diaz
- Chemical Engineering Department, Universidad Autonoma de Madrid, 28049, Madrid, Spain
| | | | - A F Mohedano
- Chemical Engineering Department, Universidad Autonoma de Madrid, 28049, Madrid, Spain
| | - M A de la Rubia
- Chemical Engineering Department, Universidad Autonoma de Madrid, 28049, Madrid, Spain.
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Thweatt JL, Harman CE, Araújo MN, Marlow JJ, Oliver GC, Sabuda MC, Sevgen S, Wilpiszeki RL. Chapter 6: The Breadth and Limits of Life on Earth. ASTROBIOLOGY 2024; 24:S124-S142. [PMID: 38498824 DOI: 10.1089/ast.2021.0131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
Scientific ideas about the potential existence of life elsewhere in the universe are predominantly informed by knowledge about life on Earth. Over the past ∼4 billion years, life on Earth has evolved into millions of unique species. Life now inhabits nearly every environmental niche on Earth that has been explored. Despite the wide variety of species and diverse biochemistry of modern life, many features, such as energy production mechanisms and nutrient requirements, are conserved across the Tree of Life. Such conserved features help define the operational parameters required by life and therefore help direct the exploration and evaluation of habitability in extraterrestrial environments. As new diversity in the Tree of Life continues to expand, so do the known limits of life on Earth and the range of environments considered habitable elsewhere. The metabolic processes used by organisms living on the edge of habitability provide insights into the types of environments that would be most suitable to hosting extraterrestrial life, crucial for planning and developing future astrobiology missions. This chapter will introduce readers to the breadth and limits of life on Earth and show how the study of life at the extremes can inform the broader field of astrobiology.
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Affiliation(s)
- Jennifer L Thweatt
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, Pennsylvania, USA. (Former)
| | - C E Harman
- Planetary Systems Branch, NASA Ames Research Center, Moffett Field, California, USA
| | - M N Araújo
- Biochemistry Department, University of São Paulo, São Carlos, Brazil
| | - Jeffrey J Marlow
- Department of Biology, Boston University, Boston, Massachusetts, USA
| | - Gina C Oliver
- Department of Geology, San Bernardino Valley College, San Bernardino, California, USA
| | - Mary C Sabuda
- Department of Earth and Environmental Sciences, University of Minnesota-Twin Cities, Minneapolis, Minnesota, USA
- Biotechnology Institute, University of Minnesota-Twin Cities, St. Paul, Minnesota, USA
| | - Serhat Sevgen
- Institute of Marine Sciences, Middle East Technical University, Erdemli, Mersin, Turkey
- Blue Marble Space Institute of Science, Seattle, Washington, USA
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9
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Banchi E, Corre E, Del Negro P, Celussi M, Malfatti F. Genome-resolved metagenomics of Venice Lagoon surface sediment bacteria reveals high biosynthetic potential and metabolic plasticity as successful strategies in an impacted environment. MARINE LIFE SCIENCE & TECHNOLOGY 2024; 6:126-142. [PMID: 38433960 PMCID: PMC10902248 DOI: 10.1007/s42995-023-00192-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 09/05/2023] [Indexed: 03/05/2024]
Abstract
Bacteria living in sediments play essential roles in marine ecosystems and deeper insights into the ecology and biogeochemistry of these largely unexplored organisms can be obtained from 'omics' approaches. Here, we characterized metagenome-assembled-genomes (MAGs) from the surface sediment microbes of the Venice Lagoon (northern Adriatic Sea) in distinct sub-basins exposed to various natural and anthropogenic pressures. MAGs were explored for biodiversity, major marine metabolic processes, anthropogenic activity-related functions, adaptations at the microscale, and biosynthetic gene clusters. Starting from 126 MAGs, a non-redundant dataset of 58 was compiled, the majority of which (35) belonged to (Alpha- and Gamma-) Proteobacteria. Within the broad microbial metabolic repertoire (including C, N, and S metabolisms) the potential to live without oxygen emerged as one of the most important features. Mixotrophy was also found as a successful lifestyle. Cluster analysis showed that different MAGs encoded the same metabolic patterns (e.g., C fixation, sulfate oxidation) thus suggesting metabolic redundancy. Antibiotic and toxic compounds resistance genes were coupled, a condition that could promote the spreading of these genetic traits. MAGs showed a high biosynthetic potential related to antimicrobial and biotechnological classes and to organism defense and interactions as well as adaptive strategies for micronutrient uptake and cellular detoxification. Our results highlighted that bacteria living in an impacted environment, such as the surface sediments of the Venice Lagoon, may benefit from metabolic plasticity as well as from the synthesis of a wide array of secondary metabolites, promoting ecosystem resilience and stability toward environmental pressures. Supplementary Information The online version contains supplementary material available at 10.1007/s42995-023-00192-z.
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Affiliation(s)
- Elisa Banchi
- National Institute of Oceanography and Applied Geophysics OGS, Trieste, Italy
| | - Erwan Corre
- FR2424, Station Biologique de Roscoff, Plateforme ABiMS (Analysis and Bioinformatics for Marine Science), Sorbonne Université CNRS, 29680 Roscoff, France
| | - Paola Del Negro
- National Institute of Oceanography and Applied Geophysics OGS, Trieste, Italy
| | - Mauro Celussi
- National Institute of Oceanography and Applied Geophysics OGS, Trieste, Italy
| | - Francesca Malfatti
- National Institute of Oceanography and Applied Geophysics OGS, Trieste, Italy
- Department of Life Sciences, University of Trieste, Trieste, Italy
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10
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Ma JY, Yan Z, Sun XD, Jiang YQ, Duan JL, Feng LJ, Zhu FP, Liu XY, Xia PF, Yuan XZ. A hybrid photocatalytic system enables direct glucose utilization for methanogenesis. Proc Natl Acad Sci U S A 2024; 121:e2317058121. [PMID: 38232281 PMCID: PMC10823229 DOI: 10.1073/pnas.2317058121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 11/20/2023] [Indexed: 01/19/2024] Open
Abstract
Integration of methanogenic archaea with photocatalysts presents a sustainable solution for solar-driven methanogenesis. However, maximizing CH4 conversion efficiency remains challenging due to the intrinsic energy conservation and strictly restricted substrates of methanogenic archaea. Here, we report a solar-driven biotic-abiotic hybrid (biohybrid) system by incorporating cadmium sulfide (CdS) nanoparticles with a rationally designed methanogenic archaeon Methanosarcina acetivorans C2A, in which the glucose synergist protein and glucose kinase, an energy-efficient route for glucose transport and phosphorylation from Zymomonas mobilis, were implemented to facilitate nonnative substrate glucose for methanogenesis. We demonstrate that the photo-excited electrons facilitate membrane-bound electron transport chain, thereby augmenting the Na+ and H+ ion gradients across membrane to enhance adenosine triphosphate (ATP) synthesis. Additionally, this biohybrid system promotes the metabolism of pyruvate to acetyl coenzyme A (AcCoA) and inhibits the flow of AcCoA to the tricarboxylic acid (TCA) cycle, resulting in a 1.26-fold augmentation in CH4 production from glucose-derived carbon. Our results provide a unique strategy for enhancing methanogenesis through rational biohybrid design and reprogramming, which gives a promising avenue for sustainably manufacturing value-added chemicals.
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Affiliation(s)
- Jing-Ya Ma
- Shandong Key Laboratory of Environmental Processes and Health, School of Environmental Science and Engineering, Shandong University, Qingdao266237, People’s Republic of China
| | - Zhen Yan
- Shandong Key Laboratory of Environmental Processes and Health, School of Environmental Science and Engineering, Shandong University, Qingdao266237, People’s Republic of China
| | - Xiao-Dong Sun
- Shandong Key Laboratory of Environmental Processes and Health, School of Environmental Science and Engineering, Shandong University, Qingdao266237, People’s Republic of China
| | - Yu-Qian Jiang
- Shandong Key Laboratory of Environmental Processes and Health, School of Environmental Science and Engineering, Shandong University, Qingdao266237, People’s Republic of China
| | - Jian-Lu Duan
- Shandong Key Laboratory of Environmental Processes and Health, School of Environmental Science and Engineering, Shandong University, Qingdao266237, People’s Republic of China
| | - Li-Juan Feng
- College of Geography and Environment, Shandong Normal University, Jinan250014, People’s Republic of China
| | - Fan-Ping Zhu
- Shandong Key Laboratory of Environmental Processes and Health, School of Environmental Science and Engineering, Shandong University, Qingdao266237, People’s Republic of China
| | - Xiao-Yu Liu
- Shandong Key Laboratory of Environmental Processes and Health, School of Environmental Science and Engineering, Shandong University, Qingdao266237, People’s Republic of China
| | - Peng-Fei Xia
- Shandong Key Laboratory of Environmental Processes and Health, School of Environmental Science and Engineering, Shandong University, Qingdao266237, People’s Republic of China
| | - Xian-Zheng Yuan
- Shandong Key Laboratory of Environmental Processes and Health, School of Environmental Science and Engineering, Shandong University, Qingdao266237, People’s Republic of China
- Sino-French Research Institute for Ecology and Environment, Shandong University, Qingdao266237, People’s Republic of China
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11
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Nguyen TTM, Badhan AK, Reid ID, Ribeiro G, Gruninger R, Tsang A, Guan LL, McAllister T. Comparative analysis of functional diversity of rumen microbiome in bison and beef heifers. Appl Environ Microbiol 2023; 89:e0132023. [PMID: 38054735 PMCID: PMC10734544 DOI: 10.1128/aem.01320-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 09/17/2023] [Indexed: 12/07/2023] Open
Abstract
IMPORTANCE Ruminants play a key role in the conversion of cellulolytic plant material into high-quality meat and milk protein for humans. The rumen microbiome is the driver of this conversion, yet there is little information on how gene expression within the microbiome impacts the efficiency of this conversion process. The current study investigates gene expression in the rumen microbiome of beef heifers and bison and how transplantation of ruminal contents from bison to heifers alters gene expression. Understanding interactions between the host and the rumen microbiome is the key to developing informed approaches to rumen programming that will enhance production efficiency in ruminants.
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Affiliation(s)
- Thi Truc Minh Nguyen
- Centre for Structural and Functional Genomics, Concordia University, Montreal, Quebec, Canada
| | - Ajay Kumar Badhan
- Lethbridge Research and Development Centre, Lethbridge, Alberta, Canada
| | - Ian D. Reid
- Centre for Structural and Functional Genomics, Concordia University, Montreal, Quebec, Canada
| | - Gabriel Ribeiro
- Department of Animal and Poultry Science, College of Agriculture and Bioresource, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Robert Gruninger
- Lethbridge Research and Development Centre, Lethbridge, Alberta, Canada
| | - Adrian Tsang
- Centre for Structural and Functional Genomics, Concordia University, Montreal, Quebec, Canada
| | - Le Luo Guan
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Tim McAllister
- Lethbridge Research and Development Centre, Lethbridge, Alberta, Canada
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12
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Hau JL, Schleicher L, Herdan S, Simon J, Seifert J, Fritz G, Steuber J. Functionality of the Na +-translocating NADH:quinone oxidoreductase and quinol:fumarate reductase from Prevotella bryantii inferred from homology modeling. Arch Microbiol 2023; 206:32. [PMID: 38127130 PMCID: PMC10739449 DOI: 10.1007/s00203-023-03769-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 11/20/2023] [Accepted: 11/23/2023] [Indexed: 12/23/2023]
Abstract
Members of the family Prevotellaceae are Gram-negative, obligate anaerobic bacteria found in animal and human microbiota. In Prevotella bryantii, the Na+-translocating NADH:quinone oxidoreductase (NQR) and quinol:fumarate reductase (QFR) interact using menaquinone as electron carrier, catalyzing NADH:fumarate oxidoreduction. P. bryantii NQR establishes a sodium-motive force, whereas P. bryantii QFR does not contribute to membrane energization. To elucidate the possible mode of function, we present 3D structural models of NQR and QFR from P. bryantii to predict cofactor-binding sites, electron transfer routes and interaction with substrates. Molecular docking reveals the proposed mode of menaquinone binding to the quinone site of subunit NqrB of P. bryantii NQR. A comparison of the 3D model of P. bryantii QFR with experimentally determined structures suggests alternative pathways for transmembrane proton transport in this type of QFR. Our findings are relevant for NADH-dependent succinate formation in anaerobic bacteria which operate both NQR and QFR.
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Affiliation(s)
- Jann-Louis Hau
- Institute of Biology, University of Hohenheim, Garbenstraße 30, 70599, Stuttgart, Germany
| | - Lena Schleicher
- Institute of Biology, University of Hohenheim, Garbenstraße 30, 70599, Stuttgart, Germany
- HoLMiR-Hohenheim Center for Livestock Microbiome Research, University of Hohenheim, Leonore-Blosser-Reisen-Weg 3, 70599, Stuttgart, Germany
| | - Sebastian Herdan
- Institute of Biology, University of Hohenheim, Garbenstraße 30, 70599, Stuttgart, Germany
- HoLMiR-Hohenheim Center for Livestock Microbiome Research, University of Hohenheim, Leonore-Blosser-Reisen-Weg 3, 70599, Stuttgart, Germany
| | - Jörg Simon
- Microbial Energy Conservation and Biotechnology, Department of Biology, Technical University of Darmstadt, Schnittspahnstraße 10, 64287, Darmstadt, Germany
| | - Jana Seifert
- HoLMiR-Hohenheim Center for Livestock Microbiome Research, University of Hohenheim, Leonore-Blosser-Reisen-Weg 3, 70599, Stuttgart, Germany
- Institute of Animal Science, University of Hohenheim, Emil-Wolff-Straße 8, 70599, Stuttgart, Germany
| | - Günter Fritz
- Institute of Biology, University of Hohenheim, Garbenstraße 30, 70599, Stuttgart, Germany
| | - Julia Steuber
- Institute of Biology, University of Hohenheim, Garbenstraße 30, 70599, Stuttgart, Germany.
- HoLMiR-Hohenheim Center for Livestock Microbiome Research, University of Hohenheim, Leonore-Blosser-Reisen-Weg 3, 70599, Stuttgart, Germany.
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13
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Ge X, Schut GJ, Tran J, Poole II FL, Niks D, Menjivar K, Hille R, Adams MWW. Characterization of the Membrane-Associated Electron-Bifurcating Flavoenzyme EtfABCX from the Hyperthermophilic Bacterium Thermotoga maritima. Biochemistry 2023; 62:3554-3567. [PMID: 38061393 PMCID: PMC10734219 DOI: 10.1021/acs.biochem.3c00473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 11/20/2023] [Accepted: 11/20/2023] [Indexed: 12/20/2023]
Abstract
Electron bifurcation is an energy-conservation mechanism in which a single enzyme couples an exergonic reaction with an endergonic one. Heterotetrameric EtfABCX drives the reduction of low-potential ferredoxin (E°' ∼ -450 mV) by oxidation of the midpotential NADH (E°' = -320 mV) by simultaneously coupling the reaction to reduction of the high-potential menaquinone (E°' = -74 mV). Electron bifurcation occurs at the NADH-oxidizing bifurcating-flavin adenine dinucleotide (BF-FAD) in EtfA, which has extremely crossed half-potentials and passes the first, high-potential electron to an electron-transferring FAD and via two iron-sulfur clusters eventually to menaquinone. The low-potential electron on the BF-FAD semiquinone simultaneously reduces ferredoxin. We have expressed the genes encodingThermotoga maritimaEtfABCX in E. coli and purified the EtfABCX holoenzyme and the EtfAB subcomplex. The bifurcation activity of EtfABCX was demonstrated by using electron paramagnetic resonance (EPR) to follow accumulation of reduced ferredoxin. To elucidate structural factors that impart the bifurcating ability, EPR and NADH titrations monitored by visible spectroscopy and dye-linked enzyme assays have been employed to characterize four conserved residues, R38, P239, and V242 in EtfA and R140 in EtfB, in the immediate vicinity of the BF-FAD. The R38, P239, and V242 variants showed diminished but still significant bifurcation activity. Despite still being partially reduced by NADH, the R140 variant had no bifurcation activity, and electron transfer to its two [4Fe-4S] clusters was prevented. The role of R140 is discussed in terms of the bifurcation mechanism in EtfABCX and in the other three families of bifurcating enzymes.
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Affiliation(s)
- Xiaoxuan Ge
- Department
of Biochemistry and Molecular Biology, University
of Georgia, Athens, Georgia 30602, United States
| | - Gerrit J. Schut
- Department
of Biochemistry and Molecular Biology, University
of Georgia, Athens, Georgia 30602, United States
| | - Jessica Tran
- Department
of Biochemistry, University of California,
Riverside, Riverside, California 92507, United States
| | - Farris L. Poole II
- Department
of Biochemistry and Molecular Biology, University
of Georgia, Athens, Georgia 30602, United States
| | - Dimitri Niks
- Department
of Biochemistry, University of California,
Riverside, Riverside, California 92507, United States
| | - Kevin Menjivar
- Department
of Biochemistry, University of California,
Riverside, Riverside, California 92507, United States
| | - Russ Hille
- Department
of Biochemistry, University of California,
Riverside, Riverside, California 92507, United States
| | - Michael W. W. Adams
- Department
of Biochemistry and Molecular Biology, University
of Georgia, Athens, Georgia 30602, United States
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14
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Liu GH, Yang S, Han S, Xie CJ, Liu X, Rensing C, Zhou SG. Nitrogen fixation and transcriptome of a new diazotrophic Geomonas from paddy soils. mBio 2023; 14:e0215023. [PMID: 37855611 PMCID: PMC10746287 DOI: 10.1128/mbio.02150-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 09/07/2023] [Indexed: 10/20/2023] Open
Abstract
IMPORTANCE The ability of Geomonas species to fix nitrogen gas (N2) is an important metabolic feature for its application as a plant growth-promoting rhizobacterium. This research is of great importance as it provides the first comprehensive direct experimental evidence of nitrogen fixation by the genus Geomonas in pure culture. We isolated a number of Geomonas strains from paddy soils and determined that nifH was present in these strains. This study demonstrated that these Geomonas species harbored genes encoding nitrogenase, as do Geobacter and Anaeromyxobacter in the same class of Deltaproteobacteria. We demonstrated N2-dependent growth of Geomonas and determined regulation of gene expression associated with nitrogen fixation. The research establishes and advances our understanding of nitrogen fixation in Geomonas.
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Affiliation(s)
- Guo-Hong Liu
- Institute of Resources, Environment and Soil Fertilizer, Fujian Academy of Agricultural Sciences, Fuzhou City, Fujian Province, China
| | - Shang Yang
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou City, Fujian Province, China
| | - Shuang Han
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou City, Fujian Province, China
| | - Cheng-Jie Xie
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou City, Fujian Province, China
| | - Xing Liu
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou City, Fujian Province, China
| | - Christopher Rensing
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou City, Fujian Province, China
| | - Shun-Gui Zhou
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou City, Fujian Province, China
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15
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Jia D, Deng W, Hu P, Jiang W, Gu Y. Thermophilic Moorella thermoacetica as a platform microorganism for C1 gas utilization: physiology, engineering, and applications. BIORESOUR BIOPROCESS 2023; 10:61. [PMID: 38647965 PMCID: PMC10992200 DOI: 10.1186/s40643-023-00682-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 08/29/2023] [Indexed: 04/25/2024] Open
Abstract
In the context of the rapid development of low-carbon economy, there has been increasing interest in utilizing naturally abundant and cost-effective one-carbon (C1) substrates for sustainable production of chemicals and fuels. Moorella thermoacetica, a model acetogenic bacterium, has attracted significant attention due to its ability to utilize carbon dioxide (CO2) and carbon monoxide (CO) via the Wood-Ljungdahl (WL) pathway, thereby showing great potential for the utilization of C1 gases. However, natural strains of M. thermoacetica are not yet fully suitable for industrial applications due to their limitations in carbon assimilation and conversion efficiency as well as limited product range. Over the past decade, progresses have been made in the development of genetic tools for M. thermoacetica, accelerating the understanding and modification of this acetogen. Here, we summarize the physiological and metabolic characteristics of M. thermoacetica and review the recent advances in engineering this bacterium. Finally, we propose the future directions for exploring the real potential of M. thermoacetica in industrial applications.
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Affiliation(s)
- Dechen Jia
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Wangshuying Deng
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Peng Hu
- Shanghai GTLB Biotech Co., Ltd, 1688 North Guoquan Road, Shanghai, 200438, China
| | - Weihong Jiang
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Yang Gu
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China.
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16
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Kaewarsar E, Chaiyasut C, Lailerd N, Makhamrueang N, Peerajan S, Sirilun S. Optimization of Mixed Inulin, Fructooligosaccharides, and Galactooligosaccharides as Prebiotics for Stimulation of Probiotics Growth and Function. Foods 2023; 12:foods12081591. [PMID: 37107386 PMCID: PMC10137966 DOI: 10.3390/foods12081591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 03/30/2023] [Accepted: 04/03/2023] [Indexed: 04/29/2023] Open
Abstract
Prebiotics have become an important functional food because of their potential for modulating the gut microbiota and metabolic activities. However, different prebiotics can stimulate the growth of different probiotics. The optimization of prebiotics was focused on in this study in order to stimulate the representative probiotics' growth (Lacticaseibacillus rhamnosus (previously Lactobacillus rhamnosus) and Bifidobacterium animalis subsp. lactis) and their function. The culture medium was supplemented with three prebiotics, including inulin (INU), fructooligosaccharides (FOS), and galactooligosaccharides (GOS). All prebiotics can clearly stimulate the growth of probiotic strains in both monoculture and co-culture. The specific growth rates of L. rhamnosus and B. animalis subsp. lactis were shown in GOS (0.019 h-1) and FOS (0.023 h-1), respectively. The prebiotic index (PI) scores of INU (1.03), FOS (0.86), and GOS (0.84) in co-culture at 48 h were significantly higher than the control (glucose). The mixture of prebiotics to achieve high quality was optimized using the Box-Behnken design. The optimum prebiotic ratios of INU, FOS, and GOS were 1.33, 2.00, and 2.67% w/v, respectively, with the highest stimulated growth of probiotic strains occurring with the highest PI score (1.03) and total short chain fatty acid concentration (85.55 µmol/mL). The suitable ratio of mixed prebiotics will function as a potential ingredient for functional foods or colonic foods.
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Affiliation(s)
- Ekkachai Kaewarsar
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Chaiyavat Chaiyasut
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, Chiang Mai University, Chiang Mai 50200, Thailand
- Innovation Center for Holistic Health, Nutraceuticals and Cosmeceuticals, Faculty of Pharmacy, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Narissara Lailerd
- Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Netnapa Makhamrueang
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, Chiang Mai University, Chiang Mai 50200, Thailand
| | | | - Sasithorn Sirilun
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, Chiang Mai University, Chiang Mai 50200, Thailand
- Innovation Center for Holistic Health, Nutraceuticals and Cosmeceuticals, Faculty of Pharmacy, Chiang Mai University, Chiang Mai 50200, Thailand
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17
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Deng Z, Zhu H, Du W, Zhang H. Abdominal infection combined with pneumoperitoneum after renal transplantation: A case report. Medicine (Baltimore) 2023; 102:e32836. [PMID: 36749270 PMCID: PMC9901997 DOI: 10.1097/md.0000000000032836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
INTRODUCTION Abdominal infection combined with pneumoperitoneum after renal transplantation is rare, clinically confusing, and easily misdiagnosed by physicians as gastrointestinal perforation. PATIENT CONCERNS A 54-year-old man experienced abdominal pain and distension together with signs of peritoneal irritation after cadaveric renal transplantation. CT and standing abdominal plain film showed a large pneumoperitoneum in the abdominal cavity and the patient underwent an exploratory laparotomy but no gastrointestinal perforation was found. DIAGNOSIS No gastrointestinal perforation was found during the operation. In the search for the infectious agent, ascites culture was negative while next-generation sequencing was positive, suggesting the presence of intestinal flora ectopic to abdominal infection with anaerobic respiration fermentation leading to large amounts of gas. INTERVENTIONS The patient underwent exploratory laparotomy without gastrointestinal perforation, and then underwent abdominal lavage, placed abdominal drainage tube, and conducted culture and next-generation sequencing examination of ascites. OUTCOMES Postoperative symptoms were relieved and intestinal function recovered. After 3 months of outpatient follow-up, the patient had stable transplanted kidney function and was in good spirits and sleeping well, with a good appetite, soft and regular stools, no abdominal pain and distension, and no fever. CONCLUSION Patients after kidney transplantation should be wary of abdominal infection being misdiagnosed as gastrointestinal perforation.
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Affiliation(s)
- Zhiming Deng
- Organ Transplantation Department, The First People’s Hospital of Changde City, Changde, China
| | - Huachen Zhu
- Organ Transplantation Department, The First People’s Hospital of Changde City, Changde, China
| | - Wei Du
- Organ Transplantation Department, The First People’s Hospital of Changde City, Changde, China
| | - Hongwei Zhang
- Organ Transplantation Department, The First People’s Hospital of Changde City, Changde, China
- *Correspondence: Hongwei Zhang, Organ Transplantation Department, The First People’s Hospital of Changde City, # 818 Renmin Middle Road, Changde, Hunan 415003, China (e-mail: )
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18
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Purification and structural characterization of the Na +-translocating ferredoxin: NAD + reductase (Rnf) complex of Clostridium tetanomorphum. Nat Commun 2022; 13:6315. [PMID: 36274063 PMCID: PMC9588780 DOI: 10.1038/s41467-022-34007-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 10/05/2022] [Indexed: 12/25/2022] Open
Abstract
Various microbial metabolisms use H+/Na+-translocating ferredoxin:NAD+ reductase (Rnf) either to exergonically oxidize reduced ferredoxin by NAD+ for generating a transmembrane electrochemical potential or reversely to exploit the latter for producing reduced ferredoxin. For cryo-EM structural analysis, we elaborated a quick four-step purification protocol for the Rnf complex from Clostridium tetanomorphum and integrated the homogeneous and active enzyme into a nanodisc. The obtained 4.27 Å density map largely allows chain tracing and redox cofactor identification complemented by biochemical data from entire Rnf and single subunits RnfB, RnfC and RnfG. On this basis, we postulated an electron transfer route between ferredoxin and NAD via eight [4Fe-4S] clusters, one Fe ion and four flavins crossing the cell membrane twice related to the pathway of NADH:ubiquinone reductase. Redox-coupled Na+ translocation is provided by orchestrating Na+ uptake/release, electrostatic effects of the assumed membrane-integrated FMN semiquinone anion and accompanied polypeptide rearrangements mediated by different redox steps.
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19
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Occurrence of Capnophilic Lactic Fermentation in the Hyperthermophilic Anaerobic Bacterium Thermotoga sp. Strain RQ7. Int J Mol Sci 2022; 23:ijms231912049. [PMID: 36233345 PMCID: PMC9570489 DOI: 10.3390/ijms231912049] [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: 08/02/2022] [Revised: 10/03/2022] [Accepted: 10/06/2022] [Indexed: 11/17/2022] Open
Abstract
Capnophilic lactic fermentation (CLF) is an anaplerotic pathway exclusively identified in the anaerobic hyperthermophilic bacterium Thermotoga neapolitana, a member of the order Thermotogales. The CO2-activated pathway enables non-competitive synthesis of hydrogen and L-lactic acid at high yields, making it an economically attractive process for bioenergy production. In this work, we discovered and characterized CLF in Thermotoga sp. strain RQ7, a naturally competent strain, opening a new avenue for molecular investigation of the pathway. Evaluation of the fermentation products and expression analyses of key CLF-genes by RT-PCR revealed similar CLF-phenotypes between T. neapolitana and T. sp. strain RQ7, which were absent in the non-CLF-performing strain T. maritima. Key CLF enzymes, such as PFOR, HYD, LDH, RNF, and NFN, are up-regulated in the two CLF strains. Another important finding is the up-regulation of V-ATPase, which couples ATP hydrolysis to proton transport across the membranes, in the two CLF-performing strains. The fact that V-ATPase is absent in T. maritima suggested that this enzyme plays a key role in maintaining the necessary proton gradient to support high demand of reducing equivalents for simultaneous hydrogen and lactic acid synthesis in CLF.
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20
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Clostridioides difficile Modifies its Aromatic Compound Metabolism in Response to Amidochelocardin-Induced Membrane Stress. mSphere 2022; 7:e0030222. [PMID: 35993700 PMCID: PMC9599328 DOI: 10.1128/msphere.00302-22] [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] [Indexed: 11/20/2022] Open
Abstract
Amidochelocardin is a broad-spectrum antibiotic with activity against many Gram-positive and Gram-negative bacteria. According to recent data, the antibiotic effect of this atypical tetracycline is directed against the cytoplasmic membrane, which is associated with the dissipation of the membrane potential. Here, we investigated the effect of amidochelocardin on the proteome of Clostridioides difficile to gain insight into the membrane stress physiology of this important anaerobic pathogen. For the first time, the membrane-directed action of amidochelocardin was confirmed in an anaerobic pathogen. More importantly, our results revealed that aromatic compounds potentially play an important role in C. difficile upon dissipation of its membrane potential. More precisely, a simultaneously increased production of enzymes required for the synthesis of chorismate and two putative phenazine biosynthesis proteins point to the production of a hitherto unknown compound in response to membrane depolarization. Finally, increased levels of the ClnAB efflux system and its transcriptional regulator ClnR were found, which were previously found in response to cationic antimicrobial peptides like LL-37. Therefore, our data provide a starting point for a more detailed understanding of C. difficile's way to counteract membrane-active compounds. IMPORTANCE C. difficile is an important anaerobe pathogen causing mild to severe infections of the gastrointestinal tract. To avoid relapse of the infection following antibiotic therapy, antibiotics are needed that efficiently eradicate C. difficile from the intestinal tract. Since C. difficile was shown to be substantially sensitive to membrane-active antibiotics, it has been proposed that membrane-active antibiotics might be promising for the therapy of C. difficile infections. Therefore, we studied the response of C. difficile to amidochelocardin, a membrane-active antibiotic dissipating the membrane potential. Interestingly, C. difficile's response to amidochelocardin indicates a role of aromatic metabolites in mediating stress caused by dissipation of the membrane potential.
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21
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Schnizlein MK, Young VB. Capturing the environment of the Clostridioides difficile infection cycle. Nat Rev Gastroenterol Hepatol 2022; 19:508-520. [PMID: 35468953 DOI: 10.1038/s41575-022-00610-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/21/2022] [Indexed: 12/11/2022]
Abstract
Clostridioides difficile (formerly Clostridium difficile) infection is a substantial health and economic burden worldwide. Great strides have been made over the past several years in characterizing the physiology of C. difficile infection, particularly regarding how gut microorganisms and their host work together to provide colonization resistance. As mammalian hosts and their indigenous gut microbiota have co-evolved, they have formed a complex yet stable relationship that prevents invading microorganisms from establishing themselves. In this Review, we discuss the latest advances in our understanding of C. difficile physiology that have contributed to its success as a pathogen, including its versatile survival factors and ability to adapt to unique niches. Using discoveries regarding microorganism-host and microorganism-microorganism interactions that constitute colonization resistance, we place C. difficile within the fiercely competitive gut environment. A comprehensive understanding of these relationships is required to continue the development of precision medicine-based treatments for C. difficile infection.
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Affiliation(s)
- Matthew K Schnizlein
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Vincent B Young
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA.
- Department of Internal Medicine/Division of Infectious Diseases, University of Michigan Medical School, Ann Arbor, MI, USA.
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22
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McLeish AG, Greenfield P, Midgley DJ, Paulsen IT. Desulfuromonas sp. 'CSMB_57', isolation and genomic insights from the most abundant bacterial taxon in eastern Australian coals. Microb Genom 2022; 8. [PMID: 35997693 PMCID: PMC9484754 DOI: 10.1099/mgen.0.000857] [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] [Indexed: 11/18/2022] Open
Abstract
One of the most abundant and ubiquitous taxa observed in eastern Australian coal seams is an uncultured Desulfuromonas species and part of the Coal Seam Microbiome dataset assigned as 'CSMB_57'. Despite this abundance and ubiquity, knowledge about this taxon is limited. The present study aimed to generate an enrichment culture of Desulfuromonas sp. 'CSMB_57' using culturing strategies that exploit its sulphur-reducing capabilities by utilizing a polysulfide solution in a liquid medium. Using dilution to extinction methods, a highly enriched culture was successfully generated. The full-length 16S rRNA sequence revealed that all closely related taxa were observed in subsurface environments suggesting that D. sp. 'CSMB_57' may be a subsurface specialist. Subsequently, the DNA from the enrichment culture was sequenced and the genome of D. sp. 'CSMB_57' was assembled. Genomic annotation revealed a high number of CRISPR arrays for viral defence, a large array of ABC transporters for amino acid and peptide uptake, as well as genes likely associated with syntrophy such as genes associated with type-IVa pilus, often used for direct interspecies electron transfer, and multiple hydrogenases capable of producing hydrogen. From the various genomic observations, a conceptual ecological model was developed that explores its possible syntrophic roles with hydrogenotrophic methanogens and acetogenic bacteria within coal-seam environments.
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Affiliation(s)
- Andrew G McLeish
- Department of Molecular Sciences, Macquarie University, North Ryde, Sydney, Australia.,Department of Energy, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lindfield, Sydney, Australia
| | - Paul Greenfield
- Department of Energy, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lindfield, Sydney, Australia.,Department of Biological Sciences, Macquarie University, North Ryde, Sydney, Australia
| | - David J Midgley
- Department of Energy, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lindfield, Sydney, Australia
| | - Ian T Paulsen
- Department of Molecular Sciences, Macquarie University, North Ryde, Sydney, Australia
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Winiarska A, Hege D, Gemmecker Y, Kryściak-Czerwenka J, Seubert A, Heider J, Szaleniec M. Tungsten Enzyme Using Hydrogen as an Electron Donor to Reduce Carboxylic Acids and NAD . ACS Catal 2022; 12:8707-8717. [PMID: 35874620 PMCID: PMC9295118 DOI: 10.1021/acscatal.2c02147] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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Tungsten-dependent
aldehyde oxidoreductases (AORs) catalyze the
oxidation of aldehydes to acids and are the only known enzymes reducing
non-activated acids using electron donors with low redox potentials.
We report here that AOR from Aromatoleum aromaticum (AORAa) catalyzes the reduction of organic
acids not only with low-potential Eu(II) or Ti(III) complexes but
also with H2 as an electron donor. Additionally, AORAa catalyzes the H2-dependent reduction
of NAD+ or benzyl viologen. The rate of H2-dependent
NAD+ reduction equals to 10% of that of aldehyde oxidation,
representing the highest H2 turnover rate observed among
the Mo/W enzymes. As AORAa simultaneously
catalyzes the reduction of acids and NAD+, we designed
a cascade reaction utilizing a NAD(P)H-dependent alcohol dehydrogenase
to reduce organic acids to the corresponding alcohols with H2 as the only reductant. The newly discovered W-hydrogenase side activity
of AORAa may find applications in either
NADH recycling or conversion of carboxylic acids to more useful biochemicals.
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Affiliation(s)
- Agnieszka Winiarska
- Jerzy Haber Institute of Catalysis and Surface Chemistry Polish Academy of Sciences, Kraków 30-239, Poland
| | - Dominik Hege
- Faculty of Biology, Philipps-Universität Marburg, Marburg D-35043, Germany
| | - Yvonne Gemmecker
- Faculty of Biology, Philipps-Universität Marburg, Marburg D-35043, Germany
| | - Joanna Kryściak-Czerwenka
- Jerzy Haber Institute of Catalysis and Surface Chemistry Polish Academy of Sciences, Kraków 30-239, Poland
| | - Andreas Seubert
- Faculty of Chemistry, Philipps-Universität Marburg, Marburg D-35043, Germany
| | - Johann Heider
- Faculty of Biology, Philipps-Universität Marburg, Marburg D-35043, Germany.,Center for Synthetic Microbiology, Philipps-Universität Marburg, Marburg D-35043, Germany
| | - Maciej Szaleniec
- Jerzy Haber Institute of Catalysis and Surface Chemistry Polish Academy of Sciences, Kraków 30-239, Poland
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24
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Schut GJ, Haja DK, Feng X, Poole FL, Li H, Adams MWW. An Abundant and Diverse New Family of Electron Bifurcating Enzymes With a Non-canonical Catalytic Mechanism. Front Microbiol 2022; 13:946711. [PMID: 35875533 PMCID: PMC9304861 DOI: 10.3389/fmicb.2022.946711] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 06/15/2022] [Indexed: 11/13/2022] Open
Abstract
Microorganisms utilize electron bifurcating enzymes in metabolic pathways to carry out thermodynamically unfavorable reactions. Bifurcating FeFe-hydrogenases (HydABC) reversibly oxidize NADH (E′∼−280 mV, under physiological conditions) and reduce protons to H2 gas (E°′−414 mV) by coupling this endergonic reaction to the exergonic reduction of protons by reduced ferredoxin (Fd) (E′∼−500 mV). We show here that HydABC homologs are surprisingly ubiquitous in the microbial world and are represented by 57 phylogenetically distinct clades but only about half are FeFe-hydrogenases. The others have replaced the hydrogenase domain with another oxidoreductase domain or they contain additional subunits, both of which enable various third reactions to be reversibly coupled to NAD+ and Fd reduction. We hypothesize that all of these enzymes carry out electron bifurcation and that their third substrates can include hydrogen peroxide, pyruvate, carbon monoxide, aldehydes, aryl-CoA thioesters, NADP+, cofactor F420, formate, and quinones, as well as many yet to be discovered. Some of the enzymes are proposed to be integral membrane-bound proton-translocating complexes. These different functionalities are associated with phylogenetically distinct clades and in many cases with specific microbial phyla. We propose that this new and abundant class of electron bifurcating enzyme be referred to as the Bfu family whose defining feature is a conserved bifurcating BfuBC core. This core contains FMN and six iron sulfur clusters and it interacts directly with ferredoxin (Fd) and NAD(H). Electrons to or from the third substrate are fed into the BfuBC core via BfuA. The other three known families of electron bifurcating enzyme (abbreviated as Nfn, EtfAB, and HdrA) contain a special FAD that bifurcates electrons to high and low potential pathways. The Bfu family are proposed to use a different electron bifurcation mechanism that involves a combination of FMN and three adjacent iron sulfur clusters, including a novel [2Fe-2S] cluster with pentacoordinate and partial non-Cys coordination. The absolute conservation of the redox cofactors of BfuBC in all members of the Bfu enzyme family indicate they have the same non-canonical mechanism to bifurcate electrons. A hypothetical catalytic mechanism is proposed as a basis for future spectroscopic analyses of Bfu family members.
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Affiliation(s)
- Gerrit J. Schut
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
| | - Dominik K. Haja
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
| | - Xiang Feng
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, United States
| | - Farris L. Poole
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
| | - Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, United States
| | - Michael W. W. Adams
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
- *Correspondence: Michael W. W. Adams, ; orcid.org/0000-0002-9796-5014
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25
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Buckel W, Beatrix B, Zelder O. Glutamate mutase and 2-methyleneglutarate mutase. Methods Enzymol 2022; 668:285-307. [PMID: 35589197 DOI: 10.1016/bs.mie.2021.12.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Wolfgang Buckel
- Department of Biology, Philipps University, Marburg, Germany.
| | - Birgitta Beatrix
- Gene Center, Department of Biochemistry, Ludwig Maximilian University, München, Germany
| | - Oskar Zelder
- Department of Biology, Philipps University, Marburg, Germany; Industrial Biotechnology I, BASF SE, Ludwigshafen am Rhein, Germany
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26
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Stickland metabolism in the gut. Nat Microbiol 2022; 7:603-604. [PMID: 35505246 DOI: 10.1038/s41564-022-01115-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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27
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ACETONE-BUTYL FERMENTATION PECULIARITIES OF THE BUTANOL STRAINS -PRODUCER. BIOTECHNOLOGIA ACTA 2022. [DOI: 10.15407/biotech15.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The aim of this review was to generalize and analyze the features of acetone-butyl fermentation as a type of butyric acid fermentation in the process of obtaining butanol as an alternative biofuel. Methods. The methods of analysis and generalization of analytical information and literature sources were used in the review. The results were obtained using the following methods such as microbiological (morphological properties of strains), chromatographic (determination of solvent concentration), spectrophotometric (determination of bacterial concentration), and molecular genetic (phylogenetic analysis of strains). Results. The process of acetone-butyl fermentation was analyzed, the main producer strains were considered, the features of the relationship between alcohol formation and sporulation were described, the possibility of butanol obtaining from synthesis gas was shown, and the features of the industrial production of butanol were considered. Conclusions. The features of the mechanism of acetone-butyl fermentation (the relationships between alcohol formation and sporulation, the duration of the acid-forming and alcohol-forming stages during batch fermentation depending on the change in the concentration of H2, CO, partial pressure, organic acids and mineral additives) and obtaining an enrichment culture during the production of butanol as an alternative fuel were shown. The possibility of using synthesis gas as a substrate for reducing atmospheric emissions during the fermentation process was shown. The direction of increasing the productivity of butanol-producing strains to create a competitive industrial biofuel technology was proposed.
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28
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Dittoe DK, Olson EG, Ricke SC. IMPACT OF THE GASTROINTESTINAL MICROBIOME AND FERMENTATION METABOLITES ON BROILER PERFORMANCE. Poult Sci 2022; 101:101786. [PMID: 35346496 PMCID: PMC9079343 DOI: 10.1016/j.psj.2022.101786] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 02/05/2022] [Indexed: 01/04/2023] Open
Affiliation(s)
- Dana K Dittoe
- Meat Science and Animal Biologics Discovery Program, Department of Animal and Dairy Sciences, University of Wisconsin, Madison, WI 53706, USA
| | - Elena G Olson
- Meat Science and Animal Biologics Discovery Program, Department of Animal and Dairy Sciences, University of Wisconsin, Madison, WI 53706, USA
| | - Steven C Ricke
- Meat Science and Animal Biologics Discovery Program, Department of Animal and Dairy Sciences, University of Wisconsin, Madison, WI 53706, USA.
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29
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Ameer A, Seleshe S, Kim BJ, Kang SN. Inoculation of Lactobacillus sakei on Quality Traits of Dry Fermented Sausages. Prev Nutr Food Sci 2021; 26:476-484. [PMID: 35047445 PMCID: PMC8747959 DOI: 10.3746/pnf.2021.26.4.476] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 08/31/2021] [Accepted: 09/09/2021] [Indexed: 11/22/2022] Open
Abstract
In this study, fermented sausage prepared by inoculating different strains of Lactobacillus sakei was assessed for their physiochemical, microbiological, and textural characteristics during fermentation and ripening. Five treatments were prepared: Control (commercial starter culture, C), L. sakei Korean Collection for Type Cultures (KCTC)-3802 (S1), L. sakei KCTC-3598 (S2), L. sakei KCTC-5053 (S3), and L. sakei KCTC-3603 (S4). The different strains of L. sakei did not show substantial differences (P>0.05) in pH values for dry fermented sausages at the end of the ripening period. Water activity (aw) values for all treatments were below 0.85 (P<0.05). Total viable count at the end of the study decreased in all L. sakei starter culture inoculated fermented sausages as S3> S2> S1> S4. High values of lactic acid bacteria (LAB) count and hardness were observed in the S2 batch as compared to other L. sakei inoculated treatments at the end of ripening (21st day). S3 inoculated with L. sakei strain exhibited significantly (P<0.05) higher value of a* (redness). A significant difference (P<0.05) in thiobarbituric acid reactive substances was exhibited in the following order: S4> S2> S1> S3> C. This study suggests that inoculation of S3 (L. sakei KCTC-5053) strain can improve the red color and reduce lipid oxidation while S2 enhances better microbiological quality as LAB. Incorporation of S3 and S2 strains accordingly can be helpful to enhance the quality of dry fermented sausages.
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Affiliation(s)
- Ammara Ameer
- Department of Animal Resource, Daegu University, Gyeongsan 38453, Korea
| | - Semeneh Seleshe
- Department of Animal Resource, Daegu University, Gyeongsan 38453, Korea
| | - Beom-Joon Kim
- Department of Animal Resource, Daegu University, Gyeongsan 38453, Korea
| | - Suk Nam Kang
- Department of Animal Resource, Daegu University, Gyeongsan 38453, Korea
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