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Wang D, Candry P, Hunt KA, Flinkstrom Z, Shi Z, Liu Y, Wofford NQ, McInerney MJ, Tanner RS, De Leόn KB, Zhou J, Winkler MKH, Stahl DA, Pan C. Metaproteomics-informed stoichiometric modeling reveals the responses of wetland microbial communities to oxygen and sulfate exposure. NPJ Biofilms Microbiomes 2024; 10:55. [PMID: 38961111 PMCID: PMC11222425 DOI: 10.1038/s41522-024-00525-5] [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: 01/04/2024] [Accepted: 06/07/2024] [Indexed: 07/05/2024] Open
Abstract
Climate changes significantly impact greenhouse gas emissions from wetland soil. Specifically, wetland soil may be exposed to oxygen (O2) during droughts, or to sulfate (SO42-) as a result of sea level rise. How these stressors - separately and together - impact microbial food webs driving carbon cycling in the wetlands is still not understood. To investigate this, we integrated geochemical analysis, proteogenomics, and stoichiometric modeling to characterize the impact of elevated SO42- and O2 levels on microbial methane (CH4) and carbon dioxide (CO2) emissions. The results uncovered the adaptive responses of this community to changes in SO42- and O2 availability and identified altered microbial guilds and metabolic processes driving CH4 and CO2 emissions. Elevated SO42- reduced CH4 emissions, with hydrogenotrophic methanogenesis more suppressed than acetoclastic. Elevated O2 shifted the greenhouse gas emissions from CH4 to CO2. The metabolic effects of combined SO42- and O2 exposures on CH4 and CO2 emissions were similar to those of O2 exposure alone. The reduction in CH4 emission by increased SO42- and O2 was much greater than the concomitant increase in CO2 emission. Thus, greater SO42- and O2 exposure in wetlands is expected to reduce the aggregate warming effect of CH4 and CO2. Metaproteomics and stoichiometric modeling revealed a unique subnetwork involving carbon metabolism that converts lactate and SO42- to produce acetate, H2S, and CO2 when SO42- is elevated under oxic conditions. This study provides greater quantitative resolution of key metabolic processes necessary for the prediction of CH4 and CO2 emissions from wetlands under future climate scenarios.
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Affiliation(s)
- Dongyu Wang
- School of Biological Sciences, University of Oklahoma, Norman, OK, USA
| | - Pieter Candry
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, USA
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Wageningen, The Netherlands
| | - Kristopher A Hunt
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, USA
| | - Zachary Flinkstrom
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, USA
| | - Zheng Shi
- School of Biological Sciences, University of Oklahoma, Norman, OK, USA
- Institute for Environmental Genomics, University of Oklahoma, Norman, OK, USA
| | - Yunlong Liu
- School of Computer Science, University of Oklahoma, Norman, OK, USA
| | - Neil Q Wofford
- School of Biological Sciences, University of Oklahoma, Norman, OK, USA
| | | | - Ralph S Tanner
- School of Biological Sciences, University of Oklahoma, Norman, OK, USA
| | - Kara B De Leόn
- School of Biological Sciences, University of Oklahoma, Norman, OK, USA
| | - Jizhong Zhou
- School of Biological Sciences, University of Oklahoma, Norman, OK, USA
- Institute for Environmental Genomics, University of Oklahoma, Norman, OK, USA
- School of Computer Science, University of Oklahoma, Norman, OK, USA
- School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, USA
- Earth and Environmental Sciences, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | | | - David A Stahl
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, USA
| | - Chongle Pan
- School of Biological Sciences, University of Oklahoma, Norman, OK, USA.
- School of Computer Science, University of Oklahoma, Norman, OK, USA.
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Gaur S, Kaur M, Kalra R, Rene ER, Goel M. Application of microbial resources in biorefineries: Current trend and future prospects. Heliyon 2024; 10:e28615. [PMID: 38628756 PMCID: PMC11019186 DOI: 10.1016/j.heliyon.2024.e28615] [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: 04/14/2023] [Revised: 03/21/2024] [Accepted: 03/21/2024] [Indexed: 04/19/2024] Open
Abstract
The recent growing interest in sustainable and alternative sources of energy and bio-based products has driven the paradigm shift to an integrated model termed "biorefinery." Biorefinery framework implements the concepts of novel eco-technologies and eco-efficient processes for the sustainable production of energy and value-added biomolecules. The utilization of microbial resources for the production of various value-added products has been documented in the literatures. However, the appointment of these microbial resources in integrated resource management requires a better understanding of their status. The main of aim of this review is to provide an overview on the defined positioning and overall contribution of the microbial resources, i.e., algae, fungi and bacteria, for various bioprocesses and generation of multiple products from a single biorefinery. By utilizing waste material as a feedstock, biofuels can be generated by microalgae while sequestering environmental carbon and producing value added compounds as by-products. In parallel, fungal biorefineries are prolific producers of lignocellulose degrading enzymes along with pharmaceutically important novel products. Conversely, bacterial biorefineries emerge as a preferred platform for the transformation of standard cells into proficient bio-factories, developing chassis and turbo cells for enhanced target compound production. This comprehensive review is poised to offer an intricate exploration of the current trends, obstacles, and prospective pathways of microbial biorefineries, for the development of future biorefineries.
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Affiliation(s)
- Suchitra Gaur
- Sustainable Agriculture Program, The Energy and Resources Institute, TERI-Gram, Gurugram, 122001, Haryana, India
| | - Mehak Kaur
- Sustainable Agriculture Program, The Energy and Resources Institute, TERI-Gram, Gurugram, 122001, Haryana, India
| | - Rishu Kalra
- Sustainable Agriculture Program, The Energy and Resources Institute, TERI-Gram, Gurugram, 122001, Haryana, India
| | - Eldon R. Rene
- Department of Water Supply, Sanitation and Environmental Engineering, IHE Delft Institute for Water Education, Westvest 7, Delft, 2601DA, the Netherlands
| | - Mayurika Goel
- Sustainable Agriculture Program, The Energy and Resources Institute, TERI-Gram, Gurugram, 122001, Haryana, India
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Xu T, Tao X, He H, Kempher ML, Zhang S, Liu X, Wang J, Wang D, Ning D, Pan C, Ge H, Zhang N, He YX, Zhou J. Functional and structural diversification of incomplete phosphotransferase system in cellulose-degrading clostridia. THE ISME JOURNAL 2023; 17:823-835. [PMID: 36899058 PMCID: PMC10203250 DOI: 10.1038/s41396-023-01392-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 02/21/2023] [Accepted: 02/23/2023] [Indexed: 05/24/2023]
Abstract
Carbohydrate utilization is critical to microbial survival. The phosphotransferase system (PTS) is a well-documented microbial system with a prominent role in carbohydrate metabolism, which can transport carbohydrates through forming a phosphorylation cascade and regulate metabolism by protein phosphorylation or interactions in model strains. However, those PTS-mediated regulated mechanisms have been underexplored in non-model prokaryotes. Here, we performed massive genome mining for PTS components in nearly 15,000 prokaryotic genomes from 4,293 species and revealed a high prevalence of incomplete PTSs in prokaryotes with no association to microbial phylogeny. Among these incomplete PTS carriers, a group of lignocellulose degrading clostridia was identified to have lost PTS sugar transporters and carry a substitution of the conserved histidine residue in the core PTS component, HPr (histidine-phosphorylatable phosphocarrier). Ruminiclostridium cellulolyticum was then selected as a representative to interrogate the function of incomplete PTS components in carbohydrate metabolism. Inactivation of the HPr homolog reduced rather than increased carbohydrate utilization as previously indicated. In addition to regulating distinct transcriptional profiles, PTS associated CcpA (Catabolite Control Protein A) homologs diverged from previously described CcpA with varied metabolic relevance and distinct DNA binding motifs. Furthermore, the DNA binding of CcpA homologs is independent of HPr homolog, which is determined by structural changes at the interface of CcpA homologs, rather than in HPr homolog. These data concordantly support functional and structural diversification of PTS components in metabolic regulation and bring novel understanding of regulatory mechanisms of incomplete PTSs in cellulose-degrading clostridia.
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Affiliation(s)
- Tao Xu
- Section on Pathophysiology and Molecular Pharmacology, Joslin Diabetes Center, Boston, MA, USA
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA
- Institute for Environmental Genomics, and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA
| | - Xuanyu Tao
- Institute for Environmental Genomics, and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA
| | - Hongxi He
- School of Life Sciences, Anhui University, Hefei, 230601, PR China
- Institutes of Material Science and Information Technology, Anhui University, Hefei, 230601, PR China
| | - Megan L Kempher
- Institute for Environmental Genomics, and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA
| | - Siping Zhang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, PR China
| | - Xiaochun Liu
- School of Life Sciences, Anhui University, Hefei, 230601, PR China
- Institutes of Material Science and Information Technology, Anhui University, Hefei, 230601, PR China
| | - Jun Wang
- School of Life Sciences, Anhui University, Hefei, 230601, PR China
- Institutes of Material Science and Information Technology, Anhui University, Hefei, 230601, PR China
| | - Dongyu Wang
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA
| | - Daliang Ning
- Institute for Environmental Genomics, and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA
| | - Chongle Pan
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA
- School of computer science, University of Oklahoma, Norman, OK, USA
| | - Honghua Ge
- School of Life Sciences, Anhui University, Hefei, 230601, PR China
- Institutes of Material Science and Information Technology, Anhui University, Hefei, 230601, PR China
| | - Nannan Zhang
- School of Life Sciences, Anhui University, Hefei, 230601, PR China.
- Institutes of Material Science and Information Technology, Anhui University, Hefei, 230601, PR China.
| | - Yong-Xing He
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, PR China.
| | - Jizhong Zhou
- Institute for Environmental Genomics, and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA.
- School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, USA.
- Earth and Environmental Sciences, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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Tao X, Morgan JS, Liu J, Kempher ML, Xu T, Zhou J. Target integration of an exogenous β-glucosidase enhances cellulose degradation and ethanol production in Clostridium cellulolyticum. BIORESOURCE TECHNOLOGY 2023; 376:128849. [PMID: 36898565 DOI: 10.1016/j.biortech.2023.128849] [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: 02/06/2023] [Revised: 03/03/2023] [Accepted: 03/05/2023] [Indexed: 06/18/2023]
Abstract
The bacteria Clostridium cellulolyticum is a promising candidate for consolidated bioprocessing (CBP). However, genetic engineering is necessary to improve this organism's cellulose degradation and bioconversion efficiencies to meet standard industrial requirements. In this study, CRISPR-Cas9n was used to integrate an efficient β-glucosidase into the genome of C. cellulolyticum, disrupting lactate dehydrogenase (ldh) expression and reducing lactate production. The engineered strain showed a 7.4-fold increase in β-glucosidase activity, a 70% decrease in ldh expression, a 12% increase in cellulose degradation, and a 32% increase in ethanol production compared to wild type. Additionally, ldh was identified as a potential site for heterologous expression. These results demonstrate that simultaneous β-glucosidase integration and lactate dehydrogenase disruption is an effective strategy for increasing cellulose to ethanol bioconversion rates in C. cellulolyticum.
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Affiliation(s)
- Xuanyu Tao
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, USA
| | - Josiah S Morgan
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, USA
| | - Jiantao Liu
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, USA
| | - Megan L Kempher
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, USA
| | - Tao Xu
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, USA
| | - Jizhong Zhou
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, USA; Earth and Environmental Sciences, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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Development of an efficient ClosTron system for gene disruption in Ruminiclostridium papyrosolvens. Appl Microbiol Biotechnol 2023; 107:1801-1812. [PMID: 36808278 DOI: 10.1007/s00253-023-12427-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 01/17/2023] [Accepted: 02/07/2023] [Indexed: 02/20/2023]
Abstract
Ruminiclostridium papyrosolvens is an anaerobic, mesophilic, and cellulolytic clostridia, promising consolidated bioprocessing (CBP) candidate for producing renewable green chemicals from cellulose, but its metabolic engineering is limited by lack of genetic tools. Here, we firstly employed the endogenous xylan-inducible promoter to control ClosTron system for gene disruption of R. papyrosolvens. The modified ClosTron can be easily transformed into R. papyrosolvens and specifically disrupt targeting genes. Furthermore, a counter selectable system based on uracil phosphoribosyl-transferase (Upp) was successfully established and introduced into the ClosTron system, which resulted in plasmid curing rapidly. Thus, the combination of xylan-inducible ClosTron and upp-based counter selectable system makes the gene disruption more efficient and convenient for successive gene disruption in R. papyrosolvens. KEY POINTS: • Limiting expression of LtrA enhanced the transformation of ClosTron plasmids in R. papyrosolvens. • DNA targeting specificity can be improved by precise management of the expression of LtrA. • Curing of ClosTron plasmids was achieved by introducing the upp-based counter selectable system.
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Cross-Feedings, Competition, and Positive and Negative Synergies in a Four-Species Synthetic Community for Anaerobic Degradation of Cellulose to Methane. mBio 2023; 14:e0318922. [PMID: 36847519 PMCID: PMC10128006 DOI: 10.1128/mbio.03189-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
Abstract
Complex interactions exist among microorganisms in a community to carry out ecological processes and adapt to changing environments. Here, we constructed a quad-culture consisting of a cellulolytic bacterium (Ruminiclostridium cellulolyticum), a hydrogenotrophic methanogen (Methanospirillum hungatei), an acetoclastic methanogen (Methanosaeta concilii), and a sulfate-reducing bacterium (Desulfovibrio vulgaris). The four microorganisms in the quad-culture cooperated via cross-feeding to produce methane using cellulose as the only carbon source and electron donor. The community metabolism of the quad-culture was compared with those of the R. cellulolyticum-containing tri-cultures, bi-cultures, and mono-culture. Methane production was higher in the quad-culture than the sum of the increases in the tri-cultures, which was attributed to a positive synergy of four species. In contrast, cellulose degradation by the quad-culture was lower than the additive effects of the tri-cultures which represented a negative synergy. The community metabolism of the quad-culture was compared between a control condition and a treatment condition with sulfate addition using metaproteomics and metabolic profiling. Sulfate addition enhanced sulfate reduction and decreased methane and CO2 productions. The cross-feeding fluxes in the quad-culture in the two conditions were modeled using a community stoichiometric model. Sulfate addition strengthened metabolic handoffs from R. cellulolyticum to M. concilii and D. vulgaris and intensified substrate competition between M. hungatei and D. vulgaris. Overall, this study uncovered emergent properties of higher-order microbial interactions using a four-species synthetic community. IMPORTANCE A synthetic community was designed using four microbial species that together performed distinct key metabolic processes in the anaerobic degradation of cellulose to methane and CO2. The microorganisms exhibited expected interactions, such as cross-feeding of acetate from a cellulolytic bacterium to an acetoclastic methanogen and competition of H2 between a sulfate reducing bacterium and a hydrogenotrophic methanogen. This validated our rational design of the interactions between microorganisms based on their metabolic roles. More interestingly, we also found positive and negative synergies as emergent properties of high-order microbial interactions among three or more microorganisms in cocultures. These microbial interactions can be quantitatively measured by adding and removing specific members. A community stoichiometric model was constructed to represent the fluxes in the community metabolic network. This study paved the way toward a more predictive understanding of the impact of environmental perturbations on microbial interactions sustaining geochemically significant processes in natural systems.
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Kolasinliler G, Aagre MM, Akkale C, Kaya HB. The use of CRISPR-Cas-based systems in bacterial cell factories. Biochem Eng J 2023. [DOI: 10.1016/j.bej.2023.108880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
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Yang Z, Leero DD, Yin C, Yang L, Zhu L, Zhu Z, Jiang L. Clostridium as microbial cell factory to enable the sustainable utilization of three generations of feedstocks. BIORESOURCE TECHNOLOGY 2022; 361:127656. [PMID: 35872277 DOI: 10.1016/j.biortech.2022.127656] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 07/15/2022] [Accepted: 07/16/2022] [Indexed: 06/15/2023]
Abstract
The sustainable production of chemicals and biofuels from non-fossil carbon sources is considered key to reducing greenhouse gas (GHG) emissions. Clostridium sp. can convert various substrates, including the 1st-generation (biomass crops), the 2nd-generation (lignocellulosic biomass), and the 3rd-generation (C1 gases) feedstocks, into high-value products, which makes Clostridia attractive for biorefinery applications. However, the complexity of lignocellulosic catabolism and C1 gas utilization make it difficult to construct efficient production routes. Accordingly, this review highlights the advances in the development of three generations of feedstocks with Clostridia as cell factories. At the same time, more attention was given to using agro-industrial wastes (lignocelluloses and C1 gases) as the feedstocks, for which metabolic and process engineering efforts were comprehensively analyzed. In addition, the challenges of using agro-industrial wastes are also discussed. Lastly, several new synthetic biology tools and regulatory strategies are emphasized as promising technologies to be developed to address the aforementioned challenges in Clostridia and realize the efficient utilization of agro-industrial wastes.
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Affiliation(s)
- Zhihan Yang
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Donald Delano Leero
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China
| | - Chengtai Yin
- College of Overseas Education, Nanjing Tech University, Nanjing 211816, China
| | - Lei Yang
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Liying Zhu
- College of Chemical and Molecular Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Zhengming Zhu
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China
| | - Ling Jiang
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China; State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, China.
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Re A, Mazzoli R. Current progress on engineering microbial strains and consortia for production of cellulosic butanol through consolidated bioprocessing. Microb Biotechnol 2022; 16:238-261. [PMID: 36168663 PMCID: PMC9871528 DOI: 10.1111/1751-7915.14148] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 08/01/2022] [Accepted: 09/07/2022] [Indexed: 01/27/2023] Open
Abstract
In the last decades, fermentative production of n-butanol has regained substantial interest mainly owing to its use as drop-in-fuel. The use of lignocellulose as an alternative to traditional acetone-butanol-ethanol fermentation feedstocks (starchy biomass and molasses) can significantly increase the economic competitiveness of biobutanol over production from non-renewable sources (petroleum). However, the low cost of lignocellulose is offset by its high recalcitrance to biodegradation which generally requires chemical-physical pre-treatment and multiple bioreactor-based processes. The development of consolidated processing (i.e., single-pot fermentation) can dramatically reduce lignocellulose fermentation costs and promote its industrial application. Here, strategies for developing microbial strains and consortia that feature both efficient (hemi)cellulose depolymerization and butanol production will be depicted, that is, rational metabolic engineering of native (hemi)cellulolytic or native butanol-producing or other suitable microorganisms; protoplast fusion of (hemi)cellulolytic and butanol-producing strains; and co-culture of (hemi)cellulolytic and butanol-producing microbes. Irrespective of the fermentation feedstock, biobutanol production is inherently limited by the severe toxicity of this solvent that challenges process economic viability. Hence, an overview of strategies for developing butanol hypertolerant strains will be provided.
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Affiliation(s)
- Angela Re
- Centre for Sustainable Future TechnologiesFondazione Istituto Italiano di TecnologiaTorinoItaly,Department of Applied Science and TechnologyPolitecnico di TorinoTurinItaly
| | - Roberto Mazzoli
- Structural and Functional Biochemistry, Laboratory of Proteomics and Metabolic Engineering of Prokaryotes, Department of Life Sciences and Systems BiologyUniversity of TorinoTorinoItaly
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Tao X, Liu J, Kempher ML, Xu T, Zhou J. In vivo Functional Characterization of Hydrophilic X2 Modules in the Cellulosomal Scaffolding Protein. Front Microbiol 2022; 13:861549. [PMID: 35464986 PMCID: PMC9022034 DOI: 10.3389/fmicb.2022.861549] [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: 01/24/2022] [Accepted: 03/10/2022] [Indexed: 11/30/2022] Open
Abstract
As part of free cellulases or scaffolding proteins in cellulosomes, the hydrophilic non-catalytic X2 module is widely distributed in cellulolytic Clostridia or other Firmicutes bacteria. Previous biochemical studies suggest that X2 modules might increase the solubility and substrate binding affinity of X2-bearing proteins. However, their in vivo biological functions remain elusive. Here we employed CRISPR-Cas9 editing to genetically modify X2 modules by deleting the conserved motif (NGNT) from the CipC scaffoldin. Both single and double X2 mutants (X2-N: near the N terminus of CipC; X2-C: near the C terminus of CipC) presented similar stoichiometric compositions in isolated cellulosomes as the wildtype strain (WT). These X2 mutants had an elongated adaptation stage during growth on cellulose compared to cellobiose. Compared to WT, the double mutant ΔX2-NC reduced cellulose degradation by 15% and the amount of released soluble sugars by 63%. Since single X2 mutants did not present such obvious physiological changes as ΔX2-NC, there seems to be a functional redundancy between X2 modules in CipC. The in vivo adhesion assay revealed that ΔX2-NC decreased cell attachment to cellulose by 70% but a weaker effect was also overserved in single X2 mutants. These results highlight the in vivo biological role of X2 in increasing cellulose degradation efficiency by enhancing the binding affinity between cells and cellulose, which provides new perspectives for microbial engineering.
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Affiliation(s)
- Xuanyu Tao
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, United States
| | - Jiantao Liu
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, United States
- School of Life Sciences, Jiangxi Science & Technology Normal University, Nanchang, China
| | - Megan L. Kempher
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, United States
| | - Tao Xu
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, United States
- Section on Pathophysiology and Molecular Pharmacology, Joslin Diabetes Center, Boston, MA, United States
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, United States
- *Correspondence: Tao Xu,
| | - Jizhong Zhou
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, United States
- Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Jizhong Zhou,
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Ali SM, Soliman NA, Abdal-Aziz SAA, Abdel-Fattah YR. Cloning of cellulase gene using metagenomic approach of soils collected from Wadi El Natrun, an extremophilic desert valley in Egypt. JOURNAL OF GENETIC ENGINEERING AND BIOTECHNOLOGY 2022; 20:20. [PMID: 35137293 PMCID: PMC8825895 DOI: 10.1186/s43141-022-00312-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 01/30/2022] [Indexed: 02/22/2023]
Abstract
Background Wadi El Natrun microorganisms have been considered as a new resource for natural products due to its extreme condition of salinity and alkalinity. Therefore, this study was devoted to generate metagemic library from soils collected from such an extreme environment in order to clone a novel cellulase for physique industrial applications. Results Total soil-DNA was successfully extracted, and then digested by different restriction enzymes. Purified fragments ranged ~ 200–6500 bp were ligated and were cloned into plasmid cloning vector (pUC19) by using Escherichia coli DH5α (E. coli) host cells. A constructed metagenomic library composed of 270 clones was screened on carboxymethylcellulose (CMC) agar plate where the active clones had been characterized by the formation of the yellowish halo zone. Thereafter, clone 1 was selected as the most active as being based on cellulase activity quantification (19 μ/ml). Plasmid related to clone 1 encoded cellSNSY gene of approximately 1.5 kb was subjected to molecular characterization; the obtained partial sequence of 861 bps encoded 287 amino acids showing 76% similarity to the endoglucanase gene of Bacillus amyloliquefaciens. The recombinant cellSNSY was expressed under lacz promoter at 1 mM of isopropyl β-d-1-thiogalactopyranoside (IPTG), giving 21 μ/ml cellulase after ~ 27 h. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) and an activity staining of the recombinant cellSNSY which revealed an active band with a molecular mass ~ 59 kDa appeared in the induced sample. The maximum enzyme activity of crude cellSNSY was observed at 45 °C and for a pH of 8.5. Interestingly, the enzyme activity was slightly inhibited by ethylenediamine tetraacetic acid (EDTA) and methanol. It showed high resistance to the tested heavy metals and the surfactant which ordered Zn> (SDS,Fe)>Mn>Cu. Conclusions This study established an easy and a skillful way to clone/express a new found cellulase gene(s) under lacZ promoter. The isolated recombinant cellSNSY showed 76% similarity to endoglucanase gene, and the enzyme showed tolerance to the mostly tested agents including heavy metals, surfactant, solvents, and EDTA. Additionally, the studied recombinant showed a high stability up to 55 °C and for alkaline pH 8.5. These features make it an ample and viable for many applications.
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Xu T, Tao X, Kempher ML, Zhou J. Cas9 Nickase-Based Genome Editing in Clostridium cellulolyticum. Methods Mol Biol 2022; 2479:227-243. [PMID: 35583742 DOI: 10.1007/978-1-0716-2233-9_15] [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] [Indexed: 06/15/2023]
Abstract
Clostridium cellulolyticum is a model mesophilic, cellulolytic bacterium, with the potential to produce biofuels from lignocellulose. However, the natural cellulose utilization efficiency is quite low and, therefore, metabolically engineered strains with increased efficiency can decrease both the overall cost and time required for biofuel production. Traditional genetic tools are inefficient, expensive, and time-consuming, but recent developments in the use of CRISPR-Cas genetic editing systems have greatly expanded our ability to reprogram cells. Here we describe an established protocol enabling one-step versatile genome editing in C. cellulolyticum. It integrates Cas9 nickase (Cas9n) which introduces a single nick that triggers repair via homologous recombination (SNHR) to edit genomic loci with high efficiency and accuracy. This one-step editing is achieved by transforming an all-in-one vector to coexpress Cas9n and a single guide RNA (gRNA) and carries a user-defined homologous donor template to promote SNHR at a desired target site. Additionally, this system has high specificity and allows for various types of genomic editing, including markerless insertions, deletions, substitutions, and even multiplex editing.
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Affiliation(s)
- Tao Xu
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA
- Section on Pathophysiology and Molecular Pharmacology, Joslin Diabetes Center, Boston, MA, USA
| | - Xuanyu Tao
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA
| | - Megan L Kempher
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA
| | - Jizhong Zhou
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA.
- Earth and Environmental Sciences, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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13
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Cheng Y, Jiang Y, Ren Z, Fu Y, Xu C. Development of an in vivo methylation system for transformation of Ruminiclostridium cellulolyticum. J Appl Microbiol 2021; 132:1926-1935. [PMID: 34787948 DOI: 10.1111/jam.15367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Revised: 09/06/2021] [Accepted: 10/04/2021] [Indexed: 11/30/2022]
Abstract
AIMS Ruminiclostridium cellulolyticum, an anaerobic cellulolytic bacterium producing an efficient cellulolytic extracellular complex named cellulosome, is a promising host for biofuel production from lignocellulose. This study aims to develop a rapid transformation method for R. cellulolyticum avoiding its restriction system. METHODS AND RESULTS The CceI restriction system is a major barrier to introduction of foreign DNA into R. cellulolyticum cells. To improve the transformation efficiency of R. cellulolyticum, the gene encoding CceI methyltransferase (M.CceI) of R. cellulolyticum H10 was functionally expressed in Escherichia coli, resulting in an in vivo methylation system for transformation of R. cellulolyticum. The electrotransformation experiments of R. cellulolyticum H10 with the E. coli-Clostridium shuttle plasmid pMTC6 showed that the transformation efficiency reached up to 2.6 × 103 ±0.23 × 103 CFU per μg plasmid DNA. The results demonstrated that the system is able to confer the M.CceI-specific DNA methylation pattern to its resident plasmid, which makes the plasmid resistant to the CceI restriction and efficiently transferred into R. cellulolyticum. CONCLUSIONS In this study, we generated an in vivo methylation system of R. cellulolyticum, allowing interspecies DNA transfer and improving transformation efficiency. SIGNIFICANCE AND IMPACT OF THE STUDY This research result will greatly facilitate the metabolic engineering of R. cellulolyticum for biofuel production directly from cellulose.
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Affiliation(s)
- Ying Cheng
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, Shanxi Province, China
| | - Yuanyuan Jiang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, Shanxi Province, China
| | - Zhenxing Ren
- Institute of Applied Chemistry, Shanxi University, Taiyuan, Shanxi Province, China
| | - Yuejun Fu
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, Shanxi Province, China
| | - Chenggang Xu
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, Shanxi Province, China
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Abstract
An accelerating global energy demand, paired with the harmful environmental effects of fossil fuels, has triggered the search for alternative, renewable energy sources. Biofuels are arguably a potential renewable energy source in the transportation industry as they can be used within current infrastructures and require less technological advances than other renewable alternatives, such as electric vehicles and nuclear power. The literature suggests biofuels can negatively impact food security and production; however, this is dependent on the type of feedstock used in biofuel production. Advanced biofuels, derived from inedible biomass, are heavily favoured but require further research and development to reach their full commercial potential. Replacing fossil fuels by biofuels can substantially reduce particulate matter (PM), carbon monoxide (CO) emissions, but simultaneously increase emissions of nitrogen oxides (NOx), acetaldehyde (CH3CHO) and peroxyacetyl nitrate (PAN), resulting in debates concerning the way biofuels should be implemented. The potential biofuel blends (FT-SPK, HEFA-SPK, ATJ-SPK and HFS-SIP) and their use as an alternative to kerosene-type fuels in the aviation industry have also been assessed. Although these fuels are currently more costly than conventional aviation fuels, possible reduction in production costs has been reported as a potential solution. A preliminary study shows that i-butanol emissions (1.8 Tg/year) as a biofuel can increase ozone levels by up to 6% in the upper troposphere, highlighting a potential climate impact. However, a larger number of studies will be needed to assess the practicalities and associated cost of using the biofuel in existing vehicles, particularly in terms of identifying any modifications to existing engine infrastructure, the impact of biofuel emissions, and their chemistry on the climate and human health, to fully determine their suitability as a potential renewable energy source.
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15
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Strategies towards Reduction of Cellulases Consumption: Debottlenecking the Economics of Lignocellulosics Valorization Processes. POLYSACCHARIDES 2021. [DOI: 10.3390/polysaccharides2020020] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Lignocellulosic residues have been receiving growing interest as a promising source of polysaccharides, which can be converted into a variety of compounds, ranging from biofuels to bioplastics. Most of these can replace equivalent products traditionally originated from petroleum, hence representing an important environmental advantage. Lignocellulosic materials are theoretically unlimited, cheaper and may not compete with food crops. However, the conversion of these materials to simpler sugars usually requires cellulolytic enzymes. Being still associated with a high cost of production, cellulases are commonly considered as one of the main obstacles in the economic valorization of lignocellulosics. This work provides a brief overview of some of the most studied strategies that can allow an important reduction of cellulases consumption, hence improving the economy of lignocellulosics conversion. Cellulases recycling is initially discussed regarding the main processes to recover active enzymes and the most important factors that may affect enzyme recyclability. Similarly, the potential of enzyme immobilization is analyzed with a special focus on the contributions that some elements of the process can offer for prolonged times of operation and improved enzyme stability and robustness. Finally, the emergent concept of consolidated bioprocessing (CBP) is also described in the particular context of a potential reduction of cellulases consumption.
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16
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Rajesh RO, Godan TK, Sindhu R, Pandey A, Binod P. Bioengineering advancements, innovations and challenges on green synthesis of 2, 5-furan dicarboxylic acid. Bioengineered 2020; 11:19-38. [PMID: 31880190 PMCID: PMC6961589 DOI: 10.1080/21655979.2019.1700093] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 10/30/2019] [Accepted: 10/31/2019] [Indexed: 12/20/2022] Open
Abstract
The major drawback of chemical transformations for the production of 2, 5-furan dicarboxylic acid (FDCA) implies the usage of hazardous chemicals, high temperature and high pressure from nonrenewable resources. Alternate to chemical methods, biological methods are promising. Microbial FDCA production is improved through engineering approaches of media conditions, homologous and heterologous expression of genes, genetic and metabolic engineering, etc. The highest FDCA production of 41.29 g/L is observed by an engineered Raultella ornitholytica BF 60 from 35 g/L HMF in sodium phosphate buffer with a 95.14% yield in 72 h. Also, an enzyme cascade system of recombinant and wild enzymes like periplasmic aldehyde oxidase ABC, galactose oxidase M3-5, HRP and catalase have transformed 6.3 g/L HMF to 7.81 g/L FDCA in phosphate buffer with 100% yield in 6 h. Still, these processes are emerging for fulfilling the industrial needs due to the challenges in 'green FDCA production'.
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Affiliation(s)
- Rajendran Omana Rajesh
- Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST), Thiruvananthapuram, India
- Academy of Scientific and Innovative Research (AcSIR), CSIR-National Institute for Interdisciplinary Science and Technology (NIIST), Thiruvananthapuram, India
| | - Tharangattumana Krishnan Godan
- Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST), Thiruvananthapuram, India
- Academy of Scientific and Innovative Research (AcSIR), CSIR-National Institute for Interdisciplinary Science and Technology (NIIST), Thiruvananthapuram, India
| | - Raveendran Sindhu
- Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST), Thiruvananthapuram, India
| | - Ashok Pandey
- Centre for Innovation and Translational Research, CSIR-Indian Institute of Toxicology Research (CSIR-IITR), Lucknow, India
| | - Parameswaran Binod
- Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST), Thiruvananthapuram, India
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Sharma S, Kundu A, Basu S, Shetti NP, Aminabhavi TM. Sustainable environmental management and related biofuel technologies. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 273:111096. [PMID: 32734892 DOI: 10.1016/j.jenvman.2020.111096] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 07/07/2020] [Accepted: 07/13/2020] [Indexed: 05/06/2023]
Abstract
Environmental sustainability criteria and rising energy demands, exhaustion of conventional resources of energy followed by environmental degradation due to abrupt climate changes have shifted the attention of scientists to seek renewable sources of green and clean energy for sustainable development. Bioenergy is an excellent alternative since it can be applied for several energy-requirements after utilizing suitable conversion methodology. This review elucidates all aspects of biofuels (bioethanol, biodiesel, and butanol) and their sustainability criteria. The principal focus is on the latest developments in biofuel production chiefly stressing on the role of nanotechnology. A plethora of investigations regarding the emerging techniques for process improvement like integration methods, less energy-intensive distillation techniques, and bioengineering of microorganisms are discussed. This can assist in making biofuel-production in a real-world market more economically and environmentally viable.
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Affiliation(s)
- Surbhi Sharma
- School of Chemistry and Biochemistry, Thapar Institute of Engineering and Technology, Patiala, 147004, India
| | - Aayushi Kundu
- School of Chemistry and Biochemistry, Thapar Institute of Engineering and Technology, Patiala, 147004, India; Affiliate Faculty-TIET-Virginia Tech Center of Excellence in Emerging Materials, India
| | - Soumen Basu
- School of Chemistry and Biochemistry, Thapar Institute of Engineering and Technology, Patiala, 147004, India; Affiliate Faculty-TIET-Virginia Tech Center of Excellence in Emerging Materials, India.
| | - Nagaraj P Shetti
- Center for Electrochemical Science and Materials, Department of Chemistry, K.L.E. Institute of Technology, Hubballi, 580 027, India.
| | - Tejraj M Aminabhavi
- Pharmaceutical Engineering, SET's College of Pharmacy, Dharwad, 580 002, Karnataka, India.
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18
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Tao X, Xu T, Kempher ML, Liu J, Zhou J. Precise promoter integration improves cellulose bioconversion and thermotolerance in Clostridium cellulolyticum. Metab Eng 2020; 60:110-118. [PMID: 32294528 DOI: 10.1016/j.ymben.2020.03.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 03/22/2020] [Accepted: 03/30/2020] [Indexed: 11/15/2022]
Abstract
Lignocellulose has been used for production of sustainable biofuels and value-added chemicals. However, the low-efficiency bioconversion of lignocellulose greatly contributes to a high production cost. Here, we employed CRISPR-Cas9 editing to improve cellulose degradation efficiency by editing a regulatory element of the cip-cel gene cluster in Clostridium cellulolyticum. Insertion of a synthetic promoter (P4) and an endogenous promoter (P2) in the mspI-deficient parental strain (Δ2866) created chromosomal integrants, P4-2866 and P2-2866, respectively. Both engineered strains increased the transcript abundance of downstream polycistronic genes and enhanced in vitro cellulolytic activities of isolated cellulosomes. A high cellulose load of 20 g/L suppressed cellulose degradation in the parental strain in the first 150 h fermentation; whereas P4-2866 and P2-2866 hydrolyzed 29% and 53% of the cellulose, respectively. Both engineered strains also demonstrated a greater growth rate and a higher cell biomass yield. Interestingly, the Δ2866 parental strain demonstrated better thermotolerance than the wildtype strain, and promoter insertion further enhanced thermotolerance. Similar improvements in cell growth and cellulose degradation were reproduced by promoter insertion in the wildtype strain and a lactate production-defective mutant (LM). P2 insertion in LM increased ethanol titer by 65%. Together, the editing of regulatory elements of catabolic gene clusters provides new perspectives on improving cellulose bioconversion in microbes.
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Affiliation(s)
- Xuanyu Tao
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, USA
| | - Tao Xu
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, USA; Section on Pathophysiology and Molecular Pharmacology, Joslin Diabetes Center, Boston, MA, USA; Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA.
| | - Megan L Kempher
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, USA
| | - Jiantao Liu
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, USA
| | - Jizhong Zhou
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, USA; Earth and Environmental Sciences, Lawrence Berkeley National Laboratory, Berkeley, CA, USA; State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China.
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19
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In Vivo Thermodynamic Analysis of Glycolysis in Clostridium thermocellum and Thermoanaerobacterium saccharolyticum Using 13C and 2H Tracers. mSystems 2020; 5:5/2/e00736-19. [PMID: 32184362 PMCID: PMC7380578 DOI: 10.1128/msystems.00736-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Thermodynamics constitutes a key determinant of flux and enzyme efficiency in metabolic networks. Here, we provide new insights into the divergent thermodynamics of the glycolytic pathways of C. thermocellum and T. saccharolyticum, two industrially relevant thermophilic bacteria whose metabolism still is not well understood. We report that while the glycolytic pathway in T. saccharolyticum is as thermodynamically favorable as that found in model organisms, such as E. coli or Saccharomyces cerevisiae, the glycolytic pathway of C. thermocellum operates near equilibrium. The use of a near-equilibrium glycolytic pathway, with potentially increased ATP yield, by this cellulolytic microbe may represent an evolutionary adaptation to growth on cellulose, but it has the drawback of being highly susceptible to product feedback inhibition. The results of this study will facilitate future engineering of high-performance strains capable of transforming cellulosic biomass to biofuels at high yields and titers. Clostridium thermocellum and Thermoanaerobacterium saccharolyticum are thermophilic anaerobic bacteria with complementary metabolic capabilities that utilize distinct glycolytic pathways for the conversion of cellulosic sugars to biofuels. We integrated quantitative metabolomics with 2H and 13C metabolic flux analysis to investigate the in vivo reversibility and thermodynamics of the central metabolic networks of these two microbes. We found that the glycolytic pathway in C. thermocellum operates remarkably close to thermodynamic equilibrium, with an overall drop in Gibbs free energy 5-fold lower than that of T. saccharolyticum or anaerobically grown Escherichia coli. The limited thermodynamic driving force of glycolysis in C. thermocellum could be attributed in large part to the small free energy of the phosphofructokinase reaction producing fructose bisphosphate. The ethanol fermentation pathway was also substantially more reversible in C. thermocellum than in T. saccharolyticum. These observations help explain the comparatively low ethanol titers of C. thermocellum and suggest engineering interventions that can be used to increase its ethanol productivity and glycolytic rate. In addition to thermodynamic analysis, we used our isotope tracer data to reconstruct the T. saccharolyticum central metabolic network, revealing exclusive use of the Embden-Meyerhof-Parnas (EMP) pathway for glycolysis, a bifurcated tricarboxylic acid (TCA) cycle, and a sedoheptulose bisphosphate bypass active within the pentose phosphate pathway. IMPORTANCE Thermodynamics constitutes a key determinant of flux and enzyme efficiency in metabolic networks. Here, we provide new insights into the divergent thermodynamics of the glycolytic pathways of C. thermocellum and T. saccharolyticum, two industrially relevant thermophilic bacteria whose metabolism still is not well understood. We report that while the glycolytic pathway in T. saccharolyticum is as thermodynamically favorable as that found in model organisms, such as E. coli or Saccharomyces cerevisiae, the glycolytic pathway of C. thermocellum operates near equilibrium. The use of a near-equilibrium glycolytic pathway, with potentially increased ATP yield, by this cellulolytic microbe may represent an evolutionary adaptation to growth on cellulose, but it has the drawback of being highly susceptible to product feedback inhibition. The results of this study will facilitate future engineering of high-performance strains capable of transforming cellulosic biomass to biofuels at high yields and titers.
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20
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Mazzoli R. Metabolic engineering strategies for consolidated production of lactic acid from lignocellulosic biomass. Biotechnol Appl Biochem 2020; 67:61-72. [DOI: 10.1002/bab.1869] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 12/05/2019] [Indexed: 01/04/2023]
Affiliation(s)
- Roberto Mazzoli
- Structural and Functional BiochemistryLaboratory of Proteomics and Metabolic Engineering of ProkaryotesDepartment of Life Sciences and Systems BiologyUniversity of Torino Torino Italy
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21
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Xie M, Zhang J, Singan VR, McGranahan MJ, LaFayette PR, Jawdy SS, Engle N, Doeppke C, Tschaplinski TJ, Davis MF, Lindquist E, Barry K, Schmutz J, Parrott WA, Chen F, Tuskan GA, Chen J, Muchero W. Identification of functional single nucleotide polymorphism of Populus trichocarpa PtrEPSP-TF and determination of its transcriptional effect. PLANT DIRECT 2020; 4:e00178. [PMID: 31911959 PMCID: PMC6941116 DOI: 10.1002/pld3.178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 09/17/2019] [Accepted: 10/02/2019] [Indexed: 06/10/2023]
Abstract
In plants, the phenylpropanoid pathway is responsible for the synthesis of a diverse array of secondary metabolites that include lignin monomers, flavonoids, and coumarins, many of which are essential for plant structure, biomass recalcitrance, stress defense, and nutritional quality. Our previous studies have demonstrated that Populus trichocarpa PtrEPSP-TF, an isoform of 5-enolpyruvylshikimate 3-phosphate (EPSP) synthase, has transcriptional activity and regulates phenylpropanoid biosynthesis in Populus. In this study, we report the identification of single nucleotide polymorphism (SNP) of PtrEPSP-TF that defines its functionality. Populus natural variants carrying this SNP were shown to have reduced lignin content. Here, we demonstrated that the SNP-induced substitution of 142nd amino acid (PtrEPSP-TFD142E) dramatically impairs the DNA-binding and transcriptional activity of PtrEPSP-TF. When introduced to a monocot species rice (Oryza sativa) in which an EPSP synthase isoform with the DNA-binding helix-turn-helix (HTH) motif is absent, the PtrEPSP-TF, but not PtrEPSP-TFD142E, activated genes in the phenylpropanoid pathway. More importantly, heterologous expression of PtrEPSP-TF uncovered five new transcriptional regulators of phenylpropanoid biosynthesis in rice. Collectively, this study identifies the key amino acid required for PtrEPSP-TF functionality and provides a strategy to uncover new transcriptional regulators in phenylpropanoid biosynthesis.
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Affiliation(s)
- Meng Xie
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTNUSA
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTNUSA
- Department of Plant SciencesUniversity of TennesseeKnoxvilleTNUSA
| | - Jin Zhang
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTNUSA
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTNUSA
| | | | | | | | - Sara S. Jawdy
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTNUSA
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTNUSA
| | - Nancy Engle
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTNUSA
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTNUSA
| | - Crissa Doeppke
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTNUSA
- National Renewable Energy LaboratoryGoldenCOUSA
| | - Timothy J. Tschaplinski
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTNUSA
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTNUSA
| | - Mark F. Davis
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTNUSA
- National Renewable Energy LaboratoryGoldenCOUSA
| | - Erika Lindquist
- U.S. Department of EnergyJoint Genome InstituteWalnut CreekCAUSA
| | - Kerrie Barry
- U.S. Department of EnergyJoint Genome InstituteWalnut CreekCAUSA
| | - Jeremy Schmutz
- U.S. Department of EnergyJoint Genome InstituteWalnut CreekCAUSA
- HudsonAlpha Institute for BiotechnologyHuntsvilleALUSA
| | - Wayne A. Parrott
- Department of Crop and Soil SciencesUniversity of GeorgiaAthensGAUSA
| | - Feng Chen
- Department of Plant SciencesUniversity of TennesseeKnoxvilleTNUSA
| | - Gerald A. Tuskan
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTNUSA
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTNUSA
| | - Jin‐Gui Chen
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTNUSA
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTNUSA
| | - Wellington Muchero
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTNUSA
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTNUSA
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22
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Holwerda EK, Olson DG, Ruppertsberger NM, Stevenson DM, Murphy SJL, Maloney MI, Lanahan AA, Amador-Noguez D, Lynd LR. Metabolic and evolutionary responses of Clostridium thermocellum to genetic interventions aimed at improving ethanol production. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:40. [PMID: 32175007 PMCID: PMC7063780 DOI: 10.1186/s13068-020-01680-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 02/10/2020] [Indexed: 05/06/2023]
Abstract
BACKGROUND Engineering efforts targeted at increasing ethanol by modifying the central fermentative metabolism of Clostridium thermocellum have been variably successful. Here, we aim to understand this variation by a multifaceted approach including genomic and transcriptomic analysis combined with chemostat cultivation and high solids cellulose fermentation. Three strain lineages comprising 16 strains total were examined. Two strain lineages in which genes involved in pathways leading to organic acids and/or sporulation had been knocked out resulted in four end-strains after adaptive laboratory evolution (ALE). A third strain lineage recapitulated mutations involving adhE that occurred spontaneously in some of the engineered strains. RESULTS Contrary to lactate dehydrogenase, deleting phosphotransacetylase (pta, acetate) negatively affected steady-state biomass concentration and caused increased extracellular levels of free amino acids and pyruvate, while no increase in ethanol was detected. Adaptive laboratory evolution (ALE) improved growth and shifted elevated levels of amino acids and pyruvate towards ethanol, but not for all strain lineages. Three out of four end-strains produced ethanol at higher yield, and one did not. The occurrence of a mutation in the adhE gene, expanding its nicotinamide-cofactor compatibility, enabled two end-strains to produce more ethanol. A disruption in the hfsB hydrogenase is likely the reason why a third end-strain was able to make more ethanol. RNAseq analysis showed that the distribution of fermentation products was generally not regulated at the transcript level. At 120 g/L cellulose loadings, deletions of spo0A, ldh and pta and adaptive evolution did not negatively influence cellulose solubilization and utilization capabilities. Strains with a disruption in hfsB or a mutation in adhE produced more ethanol, isobutanol and 2,3-butanediol under these conditions and the highest isobutanol and ethanol titers reached were 5.1 and 29.9 g/L, respectively. CONCLUSIONS Modifications in the organic acid fermentative pathways in Clostridium thermocellum caused an increase in extracellular pyruvate and free amino acids. Adaptive laboratory evolution led to improved growth, and an increase in ethanol yield and production due a mutation in adhE or a disruption in hfsB. Strains with deletions in ldh and pta pathways and subjected to ALE demonstrated undiminished cellulolytic capabilities when cultured on high cellulose loadings.
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Affiliation(s)
- Evert K. Holwerda
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755 USA
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Daniel G. Olson
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755 USA
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | | | - David M. Stevenson
- Department of Bacteriology, University of Wisconsin, Madison, WI 53706 USA
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Sean J. L. Murphy
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755 USA
| | - Marybeth I. Maloney
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755 USA
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Anthony A. Lanahan
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755 USA
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Daniel Amador-Noguez
- Department of Bacteriology, University of Wisconsin, Madison, WI 53706 USA
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Lee R. Lynd
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755 USA
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
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23
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Clostridium sp. as Bio-Catalyst for Fuels and Chemicals Production in a Biorefinery Context. Catalysts 2019. [DOI: 10.3390/catal9110962] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Clostridium sp. is a genus of anaerobic bacteria capable of metabolizing several substrates (monoglycerides, diglycerides, glycerol, carbon monoxide, cellulose, and more), into valuable products. Biofuels, such as ethanol and butanol, and several chemicals, such as acetone, 1,3-propanediol, and butyric acid, can be produced by these organisms through fermentation processes. Among the most well-known species, Clostridium carboxidivorans, C. ragsdalei, and C. ljungdahlii can be highlighted for their ability to use gaseous feedstocks (as syngas), obtained from the gasification or pyrolysis of waste material, to produce ethanol and butanol. C. beijerinckii is an important species for the production of isopropanol and butanol, with the advantage of using hydrolysate lignocellulosic material, which is produced in large amounts by first-generation ethanol industries. High yields of 1,3 propanediol by C. butyricum are reported with the use of another by-product from fuel industries, glycerol. In this context, several Clostridium wild species are good candidates to be used as biocatalysts in biochemical or hybrid processes. In this review, literature data showing the technical viability of these processes are presented, evidencing the opportunity to investigate them in a biorefinery context.
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Banerjee S, Mishra G, Roy A. Metabolic Engineering of Bacteria for Renewable Bioethanol Production from Cellulosic Biomass. BIOTECHNOL BIOPROC E 2019. [DOI: 10.1007/s12257-019-0134-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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25
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COMPUTER RECOGNITION OF CHEMICAL SUBSTANCES BASED ON THEIR ELECTROPHYSIOLOGICAL CHARACTERISTICS. BIOTECHNOLOGIA ACTA 2019. [DOI: 10.15407/biotech12.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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26
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Uehling JK, Entler MR, Meredith HR, Millet LJ, Timm CM, Aufrecht JA, Bonito GM, Engle NL, Labbé JL, Doktycz MJ, Retterer ST, Spatafora JW, Stajich JE, Tschaplinski TJ, Vilgalys RJ. Microfluidics and Metabolomics Reveal Symbiotic Bacterial-Fungal Interactions Between Mortierella elongata and Burkholderia Include Metabolite Exchange. Front Microbiol 2019; 10:2163. [PMID: 31632357 PMCID: PMC6779839 DOI: 10.3389/fmicb.2019.02163] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 09/03/2019] [Indexed: 01/12/2023] Open
Abstract
We identified two poplar (Populus sp.)-associated microbes, the fungus, Mortierella elongata strain AG77, and the bacterium, Burkholderia strain BT03, that mutually promote each other’s growth. Using culture assays in concert with a novel microfluidic device to generate time-lapse videos, we found growth specific media differing in pH and pre-conditioned by microbial growth led to increased fungal and bacterial growth rates. Coupling microfluidics and comparative metabolomics data results indicated that observed microbial growth stimulation involves metabolic exchange during two ordered events. The first is an emission of fungal metabolites, including organic acids used or modified by bacteria. A second signal of unknown nature is produced by bacteria which increases fungal growth rates. We find this symbiosis is initiated in part by metabolic exchange involving fungal organic acids.
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Affiliation(s)
- Jessie K Uehling
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States.,Department of Biology, Duke University, Durham, NC, United States
| | - Matthew R Entler
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Hannah R Meredith
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States.,Department of Biomedical Engineering, Duke University, Durham, NC, United States
| | - Larry J Millet
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States.,The Bredesen Center, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Collin M Timm
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Jayde A Aufrecht
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Gregory M Bonito
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI, United States
| | - Nancy L Engle
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Jessy L Labbé
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States.,Genome Science & Technology, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Mitchel J Doktycz
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States.,Genome Science & Technology, The University of Tennessee, Knoxville, Knoxville, TN, United States.,Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Scott T Retterer
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States.,Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Joseph W Spatafora
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
| | - Jason E Stajich
- Department of Microbiology and Plant Pathology, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA, United States
| | | | - Rytas J Vilgalys
- Department of Biology, Duke University, Durham, NC, United States
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28
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Engineering Clostridium for improved solvent production: recent progress and perspective. Appl Microbiol Biotechnol 2019; 103:5549-5566. [DOI: 10.1007/s00253-019-09916-7] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 05/15/2019] [Accepted: 05/15/2019] [Indexed: 01/07/2023]
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29
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Sahoo K, Sahoo RK, Gaur M, Subudhi E. Cellulolytic thermophilic microorganisms in white biotechnology: a review. Folia Microbiol (Praha) 2019; 65:25-43. [DOI: 10.1007/s12223-019-00710-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 04/15/2019] [Indexed: 10/26/2022]
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30
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Sander K, Chung D, Hyatt D, Westpheling J, Klingeman DM, Rodriguez M, Engle NL, Tschaplinski TJ, Davison BH, Brown SD. Rex in Caldicellulosiruptor bescii: Novel regulon members and its effect on the production of ethanol and overflow metabolites. Microbiologyopen 2019; 8:e00639. [PMID: 29797457 PMCID: PMC6391272 DOI: 10.1002/mbo3.639] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 03/03/2018] [Accepted: 03/05/2018] [Indexed: 11/23/2022] Open
Abstract
Rex is a global redox-sensing transcription factor that senses and responds to the intracellular [NADH]/[NAD+ ] ratio to regulate genes for central metabolism, and a variety of metabolic processes in Gram-positive bacteria. We decipher and validate four new members of the Rex regulon in Caldicellulosiruptor bescii; a gene encoding a class V aminotransferase, the HydG FeFe Hydrogenase maturation protein, an oxidoreductase, and a gene encoding a hypothetical protein. Structural genes for the NiFe and FeFe hydrogenases, pyruvate:ferredoxin oxidoreductase, as well as the rex gene itself are also members of this regulon, as has been predicted previously in different organisms. A C. bescii rex deletion strain constructed in an ethanol-producing strain made 54% more ethanol (0.16 mmol/L) than its genetic parent after 36 hr of fermentation, though only under nitrogen limited conditions. Metabolomic interrogation shows this rex-deficient ethanol-producing strain synthesizes other reduced overflow metabolism products likely in response to more reduced intracellular redox conditions and the accumulation of pyruvate. These results suggest ethanol production is strongly dependent on the native intracellular redox state in C. bescii, and highlight the combined promise of using this gene and manipulation of culture conditions to yield strains capable of producing ethanol at higher yields and final titer.
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Affiliation(s)
- Kyle Sander
- Department of Chemical and Biomolecular EngineeringUniversity of TennesseeKnoxvilleTennessee
- Bredesen Center for Interdisciplinary Graduate Research and EducationUniversity of TennesseeKnoxvilleTennessee
- BioEnergy Sciences CenterOak Ridge National LaboratoryOak RidgeTennessee
| | - Daehwan Chung
- BioEnergy Sciences CenterOak Ridge National LaboratoryOak RidgeTennessee
- Department of GeneticsUniversity of GeorgiaAthensGeorgia
- Present address:
National Renewable Energy LaboratoryGoldenCO
| | - Doug Hyatt
- BioEnergy Sciences CenterOak Ridge National LaboratoryOak RidgeTennessee
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTennessee
| | - Janet Westpheling
- BioEnergy Sciences CenterOak Ridge National LaboratoryOak RidgeTennessee
- Department of GeneticsUniversity of GeorgiaAthensGeorgia
| | - Dawn M. Klingeman
- BioEnergy Sciences CenterOak Ridge National LaboratoryOak RidgeTennessee
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTennessee
| | - Miguel Rodriguez
- BioEnergy Sciences CenterOak Ridge National LaboratoryOak RidgeTennessee
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTennessee
| | - Nancy L. Engle
- BioEnergy Sciences CenterOak Ridge National LaboratoryOak RidgeTennessee
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTennessee
| | - Timothy J. Tschaplinski
- BioEnergy Sciences CenterOak Ridge National LaboratoryOak RidgeTennessee
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTennessee
| | - Brian H. Davison
- Department of Chemical and Biomolecular EngineeringUniversity of TennesseeKnoxvilleTennessee
- Bredesen Center for Interdisciplinary Graduate Research and EducationUniversity of TennesseeKnoxvilleTennessee
- BioEnergy Sciences CenterOak Ridge National LaboratoryOak RidgeTennessee
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTennessee
| | - Steven D. Brown
- Bredesen Center for Interdisciplinary Graduate Research and EducationUniversity of TennesseeKnoxvilleTennessee
- BioEnergy Sciences CenterOak Ridge National LaboratoryOak RidgeTennessee
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTennessee
- Present address:
LanzaTechSkokieIL
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31
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Furches A, Kainer D, Weighill D, Large A, Jones P, Walker AM, Romero J, Gazolla JGFM, Joubert W, Shah M, Streich J, Ranjan P, Schmutz J, Sreedasyam A, Macaya-Sanz D, Zhao N, Martin MZ, Rao X, Dixon RA, DiFazio S, Tschaplinski TJ, Chen JG, Tuskan GA, Jacobson D. Finding New Cell Wall Regulatory Genes in Populus trichocarpa Using Multiple Lines of Evidence. FRONTIERS IN PLANT SCIENCE 2019; 10:1249. [PMID: 31649710 PMCID: PMC6791931 DOI: 10.3389/fpls.2019.01249] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 09/09/2019] [Indexed: 05/05/2023]
Abstract
Understanding the regulatory network controlling cell wall biosynthesis is of great interest in Populus trichocarpa, both because of its status as a model woody perennial and its importance for lignocellulosic products. We searched for genes with putatively unknown roles in regulating cell wall biosynthesis using an extended network-based Lines of Evidence (LOE) pipeline to combine multiple omics data sets in P. trichocarpa, including gene coexpression, gene comethylation, population level pairwise SNP correlations, and two distinct SNP-metabolite Genome Wide Association Study (GWAS) layers. By incorporating validation, ranking, and filtering approaches we produced a list of nine high priority gene candidates for involvement in the regulation of cell wall biosynthesis. We subsequently performed a detailed investigation of candidate gene GROWTH-REGULATING FACTOR 9 (PtGRF9). To investigate the role of PtGRF9 in regulating cell wall biosynthesis, we assessed the genome-wide connections of PtGRF9 and a paralog across data layers with functional enrichment analyses, predictive transcription factor binding site analysis, and an independent comparison to eQTN data. Our findings indicate that PtGRF9 likely affects the cell wall by directly repressing genes involved in cell wall biosynthesis, such as PtCCoAOMT and PtMYB.41, and indirectly by regulating homeobox genes. Furthermore, evidence suggests that PtGRF9 paralogs may act as transcriptional co-regulators that direct the global energy usage of the plant. Using our extended pipeline, we show multiple lines of evidence implicating the involvement of these genes in cell wall regulatory functions and demonstrate the value of this method for prioritizing candidate genes for experimental validation.
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Affiliation(s)
- Anna Furches
- Biosciences Division, and The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- The Bredesen Center for Interdisciplinary Research and Graduate Education, University of Tennessee, Knoxville, TN, United States
| | - David Kainer
- Biosciences Division, and The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Deborah Weighill
- Biosciences Division, and The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- The Bredesen Center for Interdisciplinary Research and Graduate Education, University of Tennessee, Knoxville, TN, United States
| | - Annabel Large
- Biosciences Division, and The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Oak Ridge Associated Universities (ORAU), Oak Ridge, TN, United States
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN, United States
| | - Piet Jones
- Biosciences Division, and The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- The Bredesen Center for Interdisciplinary Research and Graduate Education, University of Tennessee, Knoxville, TN, United States
| | - Angelica M. Walker
- Biosciences Division, and The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Oak Ridge Associated Universities (ORAU), Oak Ridge, TN, United States
- Department of Computer Science, Johns Hopkins University, Baltimore, MD, United States
- Department of Biology, Johns Hopkins University, Baltimore, MD, United States
| | - Jonathon Romero
- Biosciences Division, and The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- The Bredesen Center for Interdisciplinary Research and Graduate Education, University of Tennessee, Knoxville, TN, United States
| | | | - Wayne Joubert
- Oak Ridge Leadership Computing Facility, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Manesh Shah
- Biosciences Division, and The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Jared Streich
- Biosciences Division, and The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Priya Ranjan
- Biosciences Division, and The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Department of Plant Sciences, The University of Tennessee Institute of Agriculture, University of Tennessee, Knoxville, TN, United States
| | - Jeremy Schmutz
- Joint Genome Institute, Walnut Creek, CA, United States
- HudsonAlpha Institute for Biotechnology, Huntsville, AL, United States
| | | | - David Macaya-Sanz
- Department of Biology, West Virginia University, Morgantown, WV, United States
| | - Nan Zhao
- Department of Plant Sciences, The University of Tennessee Institute of Agriculture, University of Tennessee, Knoxville, TN, United States
| | - Madhavi Z. Martin
- Biosciences Division, and The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Xiaolan Rao
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, TX, United States
| | - Richard A. Dixon
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, TX, United States
| | - Stephen DiFazio
- Department of Biology, West Virginia University, Morgantown, WV, United States
| | - Timothy J. Tschaplinski
- Biosciences Division, and The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Jin-Gui Chen
- Biosciences Division, and The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Gerald A. Tuskan
- Biosciences Division, and The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Daniel Jacobson
- Biosciences Division, and The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- The Bredesen Center for Interdisciplinary Research and Graduate Education, University of Tennessee, Knoxville, TN, United States
- *Correspondence: Daniel Jacobson,
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32
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Cecchini NM, Roychoudhry S, Speed DJ, Steffes K, Tambe A, Zodrow K, Konstantinoff K, Jung HW, Engle NL, Tschaplinski TJ, Greenberg JT. Underground Azelaic Acid-Conferred Resistance to Pseudomonas syringae in Arabidopsis. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:86-94. [PMID: 30156481 DOI: 10.1094/mpmi-07-18-0185-r] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Local interactions between individual plant organs and diverse microorganisms can lead to whole plant immunity via the mobilization of defense signals. One such signal is the plastid lipid-derived oxylipin azelaic acid (AZA). Arabidopsis lacking AZI1 or EARLI1, related lipid transfer family proteins, exhibit reduced AZA transport among leaves and cannot mount systemic immunity. AZA has been detected in roots as well as leaves. Therefore, the present study addresses the effects on plants of AZA application to roots. AZA but not the structurally related suberic acid inhibits root growth when directly in contact with roots. Treatment of roots with AZA also induces resistance to Pseudomonas syringae in aerial tissues. These effects of AZA on root growth and disease resistance depend, at least partially, on AZI1 and EARLI1. AZI1 in roots localizes to plastids, similar to its known location in leaves. Interestingly, kinases previously shown to modify AZI1 in vitro, MPK3 and MPK6, are also needed for AZA-induced root-growth inhibition and aboveground immunity. Finally, deuterium-labeled AZA applied to the roots does not move to aerial tissues. Thus, AZA application to roots triggers systemic immunity through an AZI1/EARLI1/MPK3/MPK6-dependent pathway and AZA effects may involve one or more additional mobile signals.
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Affiliation(s)
- Nicolás M Cecchini
- 1 Department of Molecular Genetics and Cell Biology, The University of Chicago, 929 East 57th Street GCIS 524W, Chicago, IL 60637, U.S.A
| | - Suruchi Roychoudhry
- 1 Department of Molecular Genetics and Cell Biology, The University of Chicago, 929 East 57th Street GCIS 524W, Chicago, IL 60637, U.S.A
| | - DeQuantarius J Speed
- 1 Department of Molecular Genetics and Cell Biology, The University of Chicago, 929 East 57th Street GCIS 524W, Chicago, IL 60637, U.S.A
| | - Kevin Steffes
- 1 Department of Molecular Genetics and Cell Biology, The University of Chicago, 929 East 57th Street GCIS 524W, Chicago, IL 60637, U.S.A
| | - Arjun Tambe
- 1 Department of Molecular Genetics and Cell Biology, The University of Chicago, 929 East 57th Street GCIS 524W, Chicago, IL 60637, U.S.A
| | - Kristin Zodrow
- 1 Department of Molecular Genetics and Cell Biology, The University of Chicago, 929 East 57th Street GCIS 524W, Chicago, IL 60637, U.S.A
| | - Katerina Konstantinoff
- 1 Department of Molecular Genetics and Cell Biology, The University of Chicago, 929 East 57th Street GCIS 524W, Chicago, IL 60637, U.S.A
| | - Ho Won Jung
- 2 Department of Molecular Genetics, Dong-A University, 37 Nakdong-Daero 550beon-gil, Saha-gu, Busan 49315, Korea; and
| | - Nancy L Engle
- 3 Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831, U.S.A
| | | | - Jean T Greenberg
- 1 Department of Molecular Genetics and Cell Biology, The University of Chicago, 929 East 57th Street GCIS 524W, Chicago, IL 60637, U.S.A
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Henson WR, Hsu FF, Dantas G, Moon TS, Foston M. Lipid metabolism of phenol-tolerant Rhodococcus opacus strains for lignin bioconversion. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:339. [PMID: 30607174 PMCID: PMC6309088 DOI: 10.1186/s13068-018-1337-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Accepted: 12/11/2018] [Indexed: 06/09/2023]
Abstract
BACKGROUND Lignin is a recalcitrant aromatic polymer that is a potential feedstock for renewable fuel and chemical production. Rhodococcus opacus PD630 is a promising strain for the biological upgrading of lignin due to its ability to tolerate and utilize lignin-derived aromatic compounds. To enhance its aromatic tolerance, we recently applied adaptive evolution using phenol as a sole carbon source and characterized a phenol-adapted R. opacus strain (evol40) and the wild-type (WT) strain by whole genome and RNA sequencing. While this effort increased our understanding of the aromatic tolerance, the tolerance mechanisms were not completely elucidated. RESULTS We hypothesize that the composition of lipids plays an important role in phenol tolerance. To test this hypothesis, we applied high-resolution mass spectrometry analysis to lipid samples obtained from the WT and evol40 strains grown in 1 g/L glucose (glucose), 0.75 g/L phenol (low phenol), or 1.5 g/L phenol (high phenol, evol40 only) as a sole carbon source. This analysis identified > 100 lipid species of mycolic acids, phosphatidylethanolamines (PEs), phosphatidylinositols (PIs), and triacylglycerols. In both strains, mycolic acids had fewer double bond numbers in phenol conditions than the glucose condition, and evol40 had significantly shorter mycolic acid chain lengths than the WT strain in phenol conditions. These results indicate that phenol adaptation affected mycolic acid membrane composition. In addition, the percentage of unsaturated phospholipids decreased for both strains in phenol conditions compared to the glucose condition. Moreover, the PI content increased for both strains in the low phenol condition compared to the glucose condition, and the PI content increased further for evol40 in the high phenol condition relative to the low phenol condition. CONCLUSIONS This work represents the first comprehensive lipidomic study on the membrane of R. opacus grown using phenol as a sole carbon source. Our results suggest that the alteration of the mycolic acid and phospholipid membrane composition may be a strategy of R. opacus for phenol tolerance.
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Affiliation(s)
- William R. Henson
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130 USA
| | - Fong-Fu Hsu
- Mass Spectrometry Resource, Division of Endocrinology, Diabetes, Metabolism, and Lipid Research, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110 USA
| | - Gautam Dantas
- Department of Pathology and Immunology, Washington University in St. Louis School of Medicine, St. Louis, MO 63108 USA
- The Edison Family Center for Genome Sciences and Systems Biology, Washington University in St. Louis School of Medicine, St. Louis, MO 63110 USA
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130 USA
- Department of Molecular Microbiology, Washington University in St. Louis, St. Louis, MO 63108 USA
| | - Tae Seok Moon
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130 USA
| | - Marcus Foston
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130 USA
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Leistra AN, Curtis NC, Contreras LM. Regulatory non-coding sRNAs in bacterial metabolic pathway engineering. Metab Eng 2018; 52:190-214. [PMID: 30513348 DOI: 10.1016/j.ymben.2018.11.013] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 10/31/2018] [Accepted: 11/29/2018] [Indexed: 12/11/2022]
Abstract
Non-coding RNAs (ncRNAs) are versatile and powerful controllers of gene expression that have been increasingly linked to cellular metabolism and phenotype. In bacteria, identified and characterized ncRNAs range from trans-acting, multi-target small non-coding RNAs to dynamic, cis-encoded regulatory untranslated regions and riboswitches. These native regulators have inspired the design and construction of many synthetic RNA devices. In this work, we review the design, characterization, and impact of ncRNAs in engineering both native and exogenous metabolic pathways in bacteria. We also consider the opportunities afforded by recent high-throughput approaches for characterizing sRNA regulators and their corresponding networks to showcase their potential applications and impact in engineering bacterial metabolism.
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Affiliation(s)
- Abigail N Leistra
- McKetta Department of Chemical Engineering, University of Texas at Austin, 200 E. Dean Keeton Street Stop C0400, Austin, TX 78712, USA
| | - Nicholas C Curtis
- McKetta Department of Chemical Engineering, University of Texas at Austin, 200 E. Dean Keeton Street Stop C0400, Austin, TX 78712, USA
| | - Lydia M Contreras
- McKetta Department of Chemical Engineering, University of Texas at Austin, 200 E. Dean Keeton Street Stop C0400, Austin, TX 78712, USA.
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35
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Xie M, Muchero W, Bryan AC, Yee K, Guo HB, Zhang J, Tschaplinski TJ, Singan VR, Lindquist E, Payyavula RS, Barros-Rios J, Dixon R, Engle N, Sykes RW, Davis M, Jawdy SS, Gunter LE, Thompson O, DiFazio SP, Evans LM, Winkeler K, Collins C, Schmutz J, Guo H, Kalluri U, Rodriguez M, Feng K, Chen JG, Tuskan GA. A 5-Enolpyruvylshikimate 3-Phosphate Synthase Functions as a Transcriptional Repressor in Populus. THE PLANT CELL 2018; 30:1645-1660. [PMID: 29891568 PMCID: PMC6096593 DOI: 10.1105/tpc.18.00168] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 04/17/2018] [Accepted: 06/05/2018] [Indexed: 05/21/2023]
Abstract
Long-lived perennial plants, with distinctive habits of inter-annual growth, defense, and physiology, are of great economic and ecological importance. However, some biological mechanisms resulting from genome duplication and functional divergence of genes in these systems remain poorly studied. Here, we discovered an association between a poplar (Populus trichocarpa) 5-enolpyruvylshikimate 3-phosphate synthase gene (PtrEPSP) and lignin biosynthesis. Functional characterization of PtrEPSP revealed that this isoform possesses a helix-turn-helix motif in the N terminus and can function as a transcriptional repressor that regulates expression of genes in the phenylpropanoid pathway in addition to performing its canonical biosynthesis function in the shikimate pathway. We demonstrated that this isoform can localize in the nucleus and specifically binds to the promoter and represses the expression of a SLEEPER-like transcriptional regulator, which itself specifically binds to the promoter and represses the expression of PtrMYB021 (known as MYB46 in Arabidopsis thaliana), a master regulator of the phenylpropanoid pathway and lignin biosynthesis. Analyses of overexpression and RNAi lines targeting PtrEPSP confirmed the predicted changes in PtrMYB021 expression patterns. These results demonstrate that PtrEPSP in its regulatory form and PtrhAT form a transcriptional hierarchy regulating phenylpropanoid pathway and lignin biosynthesis in Populus.
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Affiliation(s)
- Meng Xie
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Wellington Muchero
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Anthony C Bryan
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Kelsey Yee
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Hao-Bo Guo
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996
| | - Jin Zhang
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Timothy J Tschaplinski
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Vasanth R Singan
- U.S. Department of Energy Joint Genome Institute, Walnut Creek, California 94598
| | - Erika Lindquist
- U.S. Department of Energy Joint Genome Institute, Walnut Creek, California 94598
| | - Raja S Payyavula
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Jaime Barros-Rios
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, Texas 76203
| | - Richard Dixon
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, Texas 76203
| | - Nancy Engle
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Robert W Sykes
- Bioscience Center, National Renewable Energy Laboratory, Golden, Colorado 80401
| | - Mark Davis
- Bioscience Center, National Renewable Energy Laboratory, Golden, Colorado 80401
| | - Sara S Jawdy
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Lee E Gunter
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Olivia Thompson
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Stephen P DiFazio
- Department of Biology, West Virginia University, Morgantown, West Virginia 26506
| | - Luke M Evans
- Department of Biology, West Virginia University, Morgantown, West Virginia 26506
| | | | | | - Jeremy Schmutz
- U.S. Department of Energy Joint Genome Institute, Walnut Creek, California 94598
- HudsonAlpha Institute for Biotechnology, Huntsville, Alabama 35806
| | - Hong Guo
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996
| | - Udaya Kalluri
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Miguel Rodriguez
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Kai Feng
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Jin-Gui Chen
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Gerald A Tuskan
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
- U.S. Department of Energy Joint Genome Institute, Walnut Creek, California 94598
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Li T, Zhang C, Yang KL, He J. Unique genetic cassettes in a Thermoanaerobacterium contribute to simultaneous conversion of cellulose and monosugars into butanol. SCIENCE ADVANCES 2018; 4:e1701475. [PMID: 29740597 PMCID: PMC5938282 DOI: 10.1126/sciadv.1701475] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 02/07/2018] [Indexed: 05/25/2023]
Abstract
The demand for cellulosic biofuels is on the rise because of the anticipation for sustainable energy and less greenhouse gas emissions in the future. However, production of cellulosic biofuels, especially cellulosic butanol, has been hampered by the lack of potent microbes that are capable of converting cellulosic biomass into biofuels. We report a wild-type Thermoanaerobacterium thermosaccharolyticum strain TG57, which is capable of using microcrystalline cellulose directly to produce butanol (1.93 g/liter) as the only final product (without any acetone or ethanol produced), comparable to that of engineered microbes thus far. Strain TG57 exhibits significant advances including unique genes responsible for a new butyrate synthesis pathway, no carbon catabolite repression, and the absence of genes responsible for acetone synthesis (which is observed as the main by-product in most Clostridium strains known today). Furthermore, the use of glucose analog 2-deoxyglucose posed a selection pressure to facilitate isolation of strain TG57 with deletion/silencing of carbon catabolite repressor genes-the ccr and xylR genes-and thus is able to simultaneously ferment glucose, xylose, and arabinose to produce butanol (7.33 g/liter) as the sole solvent. Combined analysis of genomic and transcriptomic data revealed unusual aspects of genome organization, numerous determinants for unique bioconversions, regulation of central metabolic pathways, and distinct transcriptomic profiles. This study provides a genome-level understanding of how cellulose is metabolized by T. thermosaccharolyticum and sheds light on the potential of competitive and sustainable biofuel production.
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Affiliation(s)
- Tinggang Li
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576
| | - Chen Zhang
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576
| | - Kun-Lin Yang
- Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore 117576
| | - Jianzhong He
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576
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Abiotic Stresses Shift Belowground Populus-Associated Bacteria Toward a Core Stress Microbiome. mSystems 2018; 3:mSystems00070-17. [PMID: 29404422 PMCID: PMC5781258 DOI: 10.1128/msystems.00070-17] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 12/20/2017] [Indexed: 12/24/2022] Open
Abstract
The identification of a common “stress microbiome” indicates tightly controlled relationships between the plant host and bacterial associates and a conserved structure in bacterial communities associated with poplar trees under different growth conditions. The ability of the microbiome to buffer the plant from extreme environmental conditions coupled with the conserved stress microbiome observed in this study suggests an opportunity for future efforts aimed at predictably modulating the microbiome to optimize plant growth. Adverse growth conditions can lead to decreased plant growth, productivity, and survival, resulting in poor yields or failure of crops and biofeedstocks. In some cases, the microbial community associated with plants has been shown to alleviate plant stress and increase plant growth under suboptimal growing conditions. A systematic understanding of how the microbial community changes under these conditions is required to understand the contribution of the microbiome to water utilization, nutrient uptake, and ultimately yield. Using a microbiome inoculation strategy, we studied how the belowground microbiome of Populus deltoides changes in response to diverse environmental conditions, including water limitation, light limitation (shading), and metal toxicity. While plant responses to treatments in terms of growth, photosynthesis, gene expression and metabolite profiles were varied, we identified a core set of bacterial genera that change in abundance in response to host stress. The results of this study indicate substantial structure in the plant microbiome community and identify potential drivers of the phytobiome response to stress. IMPORTANCE The identification of a common “stress microbiome” indicates tightly controlled relationships between the plant host and bacterial associates and a conserved structure in bacterial communities associated with poplar trees under different growth conditions. The ability of the microbiome to buffer the plant from extreme environmental conditions coupled with the conserved stress microbiome observed in this study suggests an opportunity for future efforts aimed at predictably modulating the microbiome to optimize plant growth.
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Xu T, Li Y, He Z, Van Nostrand JD, Zhou J. Cas9 Nickase-Assisted RNA Repression Enables Stable and Efficient Manipulation of Essential Metabolic Genes in Clostridium cellulolyticum. Front Microbiol 2017; 8:1744. [PMID: 28936208 PMCID: PMC5594222 DOI: 10.3389/fmicb.2017.01744] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 08/28/2017] [Indexed: 11/16/2022] Open
Abstract
Essential gene functions remain largely underexplored in bacteria. Clostridium cellulolyticum is a promising candidate for consolidated bioprocessing; however, its genetic manipulation to reduce the formation of less-valuable acetate is technically challenging due to the essentiality of acetate-producing genes. Here we developed a Cas9 nickase-assisted chromosome-based RNA repression to stably manipulate essential genes in C. cellulolyticum. Our plasmid-based expression of antisense RNA (asRNA) molecules targeting the phosphotransacetylase (pta) gene successfully reduced the enzymatic activity by 35% in cellobiose-grown cells, metabolically decreased the acetate titer by 15 and 52% in wildtype transformants on cellulose and xylan, respectively. To control both acetate and lactate simultaneously, we transformed the repression plasmid into lactate production-deficient mutant and found the plasmid delivery reduced acetate titer by more than 33%, concomitant with negligible lactate formation. The strains with pta gene repression generally diverted more carbon into ethanol. However, further testing on chromosomal integrants that were created by double-crossover recombination exhibited only very weak repression because DNA integration dramatically lessened gene dosage. With the design of a tandem repetitive promoter-driven asRNA module and the use of a new Cas9 nickase genome editing tool, a chromosomal integrant (LM3P) was generated in a single step and successfully enhanced RNA repression, with a 27% decrease in acetate titer on cellulose in antibiotic-free medium. These results indicate the effectiveness of tandem promoter-driven RNA repression modules in promoting gene repression in chromosomal integrants. Our combinatorial method using a Cas9 nickase genome editing tool to integrate the gene repression module demonstrates easy-to-use and high-efficiency advantages, paving the way for stably manipulating genes, even essential ones, for functional characterization and microbial engineering.
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Affiliation(s)
- Tao Xu
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, NormanOK, United States
| | - Yongchao Li
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, NormanOK, United States
| | - Zhili He
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, NormanOK, United States
| | - Joy D. Van Nostrand
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, NormanOK, United States
| | - Jizhong Zhou
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, NormanOK, United States
- Earth Sciences Division, Lawrence Berkeley National Laboratory, BerkeleyCA, United States
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua UniversityBeijing, China
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Characterization of a novel, ubiquitous fungal endophyte from the rhizosphere and root endosphere of Populus trees. FUNGAL ECOL 2017. [DOI: 10.1016/j.funeco.2017.03.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Genome Editing in Clostridium saccharoperbutylacetonicum N1-4 with the CRISPR-Cas9 System. Appl Environ Microbiol 2017; 83:AEM.00233-17. [PMID: 28258147 DOI: 10.1128/aem.00233-17] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 02/26/2017] [Indexed: 12/12/2022] Open
Abstract
Clostridium saccharoperbutylacetonicum N1-4 is well known as a hyper-butanol-producing strain. However, the lack of genetic engineering tools hinders further elucidation of its solvent production mechanism and development of more robust strains. In this study, we set out to develop an efficient genome engineering system for this microorganism based on the clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated 9 (CRISPR-Cas9) system. First, the functionality of the CRISPR-Cas9 system previously customized for Clostridium beijerinckii was evaluated in C. saccharoperbutylacetonicum by targeting pta and buk, two essential genes for acetate and butyrate production, respectively. pta and buk single and double deletion mutants were successfully obtained based on this system. However, the genome engineering efficiency was rather low (the mutation rate is <20%). Therefore, the efficiency was further optimized by evaluating various promoters for guide RNA (gRNA) expression. With promoter P J23119 , we achieved a mutation rate of 75% for pta deletion without serial subculturing as suggested previously for C. beijerinckii Thus, this developed CRISPR-Cas9 system is highly desirable for efficient genome editing in C. saccharoperbutylacetonicum Batch fermentation results revealed that both the acid and solvent production profiles were altered due to the disruption of acid production pathways; however, neither acetate nor butyrate production was eliminated with the deletion of the corresponding gene. The butanol production, yield, and selectivity were improved in mutants, depending on the fermentation medium. In the pta buk double deletion mutant, the butanol production in P2 medium reached 19.0 g/liter, which is one of the highest levels ever reported from batch fermentations.IMPORTANCE An efficient CRISPR-Cas9 genome engineering system was developed for C. saccharoperbutylacetonicum N1-4. This paves the way for elucidating the solvent production mechanism in this hyper-butanol-producing microorganism and developing strains with desirable butanol-producing features. This tool can be easily adapted for use in closely related microorganisms. As also reported by others, here we demonstrated with solid data that the highly efficient expression of gRNA is the key factor determining the efficiency of CRISPR-Cas9 for genome editing. The protocol developed in this study can provide essential references for other researchers who work in the areas of metabolic engineering and synthetic biology. The developed mutants can be used as excellent starting strains for development of more robust ones for desirable solvent production.
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Ábrego U, Chen Z, Wan C. Consolidated Bioprocessing Systems for Cellulosic Biofuel Production. ADVANCES IN BIOENERGY 2017. [DOI: 10.1016/bs.aibe.2017.01.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Huang H, Chai C, Li N, Rowe P, Minton NP, Yang S, Jiang W, Gu Y. CRISPR/Cas9-Based Efficient Genome Editing in Clostridium ljungdahlii, an Autotrophic Gas-Fermenting Bacterium. ACS Synth Biol 2016; 5:1355-1361. [PMID: 27276212 DOI: 10.1021/acssynbio.6b00044] [Citation(s) in RCA: 126] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Acetogenic bacteria have the potential to convert single carbon gases (CO and CO2) into a range of bulk chemicals and fuels. Realization of their full potential is being impeded by the absence of effective genetic tools for high throughput genome modification. Here we report the development of a highly efficient CRISPR/Cas9 system for rapid genome editing of Clostridium ljungdahlii, a paradigm for the commercial production of ethanol from synthesis gas. Following the experimental selection of two promoters (Pthl and ParaE) for expression of cas9 and the requisite single guide RNA (sgRNA), the efficiency of system was tested by making precise deletions of four genes, pta, adhE1, ctf and pyrE. Deletion efficiencies were 100%, >75%, 100% and >50%, respectively. The system overcomes the deficiencies of currently available tools (more rapid, no added antibiotic resistance gene, scarless and minimal polar effects) and will find utility in other acetogens, including the pathogen Clostridium difficile.
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Affiliation(s)
- He Huang
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai 200032, China
| | - Changsheng Chai
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai 200032, China
| | - Ning Li
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai 200032, China
| | - Pete Rowe
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, University of Nottingham , Nottingham, NG7 2RD, U.K
| | - Nigel P Minton
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, University of Nottingham , Nottingham, NG7 2RD, U.K
| | - Sheng Yang
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai 200032, China
- Jiangsu National Synergetic Innovation Center for Advanced Materials, SICAM , 200 North Zhongshan Road, Nanjing 210009, China
| | - Weihong Jiang
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai 200032, China
- Jiangsu National Synergetic Innovation Center for Advanced Materials, SICAM , 200 North Zhongshan Road, Nanjing 210009, China
| | - Yang Gu
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai 200032, China
- Shanghai Collaborative Innovation Center for Biomanufacturing Technology , 130 Meilong Road, Shanghai 200237, China
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Metabolic Engineering of Raoultella ornithinolytica BF60 for Production of 2,5-Furandicarboxylic Acid from 5-Hydroxymethylfurfural. Appl Environ Microbiol 2016; 83:AEM.02312-16. [PMID: 27795308 DOI: 10.1128/aem.02312-16] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 09/17/2016] [Indexed: 01/15/2023] Open
Abstract
2,5-Furandicarboxylic acid (FDCA) is an important renewable biotechnological building block because it serves as an environmentally friendly substitute for terephthalic acid in the production of polyesters. Currently, FDCA is produced mainly via chemical oxidation, which can cause severe environmental pollution. In this study, we developed an environmentally friendly process for the production of FDCA from 5-hydroxymethyl furfural (5-HMF) using a newly isolated strain, Raoultella ornithinolytica BF60. First, R. ornithinolytica BF60 was identified by screening and was isolated. Its maximal FDCA titer was 7.9 g/liter, and the maximal molar conversion ratio of 5-HMF to FDCA was 51.0% (mol/mol) under optimal conditions (100 mM 5-HMF, 45 g/liter whole-cell biocatalyst, 30°C, and 50 mM phosphate buffer [pH 8.0]). Next, dcaD, encoding dicarboxylic acid decarboxylase, was mutated to block FDCA degradation to furoic acid, thus increasing FDCA production to 9.2 g/liter. Subsequently, aldR, encoding aldehyde reductase, was mutated to prevent the catabolism of 5-HMF to HMF alcohol, further increasing the FDCA titer, to 11.3 g/liter. Finally, the gene encoding aldehyde dehydrogenase 1 was overexpressed. The FDCA titer increased to 13.9 g/liter, 1.7 times that of the wild-type strain, and the molar conversion ratio increased to 89.0%. IMPORTANCE In this work, we developed an ecofriendly bioprocess for green production of FDCA in engineered R. ornithinolytica This report provides a starting point for further metabolic engineering aimed at a process for industrial production of FDCA using R. ornithinolytica.
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Bengelsdorf FR, Poehlein A, Flitsch SK, Linder S, Schiel-Bengelsdorf B, Stegmann BA, Krabben P, Green E, Zhang Y, Minton N, Dürre P. Host Organisms: Clostridium acetobutylicum/ Clostridium beijerinckiiand Related Organisms. Ind Biotechnol (New Rochelle N Y) 2016. [DOI: 10.1002/9783527807796.ch9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Frank R. Bengelsdorf
- Universität Ulm; Institut für Mikrobiologie und Biotechnologie; Albert-Einstein-Allee 11 89081 Ulm Germany
| | - Anja Poehlein
- Georg-August University; Genomic and Applied Microbiology and Göttingen Genomics Laboratory; Göttingen, Grisebachstr. 8 37077 Göttingen Germany
| | - Stefanie K. Flitsch
- Universität Ulm; Institut für Mikrobiologie und Biotechnologie; Albert-Einstein-Allee 11 89081 Ulm Germany
| | - Sonja Linder
- Universität Ulm; Institut für Mikrobiologie und Biotechnologie; Albert-Einstein-Allee 11 89081 Ulm Germany
| | - Bettina Schiel-Bengelsdorf
- Universität Ulm; Institut für Mikrobiologie und Biotechnologie; Albert-Einstein-Allee 11 89081 Ulm Germany
| | - Benjamin A. Stegmann
- Universität Ulm; Institut für Mikrobiologie und Biotechnologie; Albert-Einstein-Allee 11 89081 Ulm Germany
| | - Preben Krabben
- Green Biologics Limited; 45A Western Avenue, Milton Park Abingdon Oxfordshire OX14 4RU UK
| | - Edward Green
- CHAIN Biotechnology Limited; Imperial College Incubator, Imperial College London; Level 1 Bessemer Building London SW7 2AZ UK
| | - Ying Zhang
- University of Nottingham; BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences; University Park Nottingham NG7 2RD UK
| | - Nigel Minton
- University of Nottingham; BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences; University Park Nottingham NG7 2RD UK
| | - Peter Dürre
- Universität Ulm; Institut für Mikrobiologie und Biotechnologie; Albert-Einstein-Allee 11 89081 Ulm Germany
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Kalluri UC, Payyavula RS, Labbé JL, Engle N, Bali G, Jawdy SS, Sykes RW, Davis M, Ragauskas A, Tuskan GA, Tschaplinski TJ. Down-Regulation of KORRIGAN-Like Endo-β-1,4-Glucanase Genes Impacts Carbon Partitioning, Mycorrhizal Colonization and Biomass Production in Populus. FRONTIERS IN PLANT SCIENCE 2016; 7:1455. [PMID: 27757116 PMCID: PMC5047894 DOI: 10.3389/fpls.2016.01455] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 09/12/2016] [Indexed: 05/17/2023]
Abstract
A greater understanding of the genetic regulation of plant cell wall remodeling and the impact of modified cell walls on plant performance is important for the development of sustainable biofuel crops. Here, we studied the impact of down-regulating KORRIGAN-like cell wall biosynthesis genes, belonging to the endo-β-1,4-glucanase gene family, on Populus growth, metabolism and the ability to interact with symbiotic microbes. The reductions in cellulose content and lignin syringyl-to-guaiacyl unit ratio, and increase in cellulose crystallinity of cell walls of PdKOR RNAi plants corroborated the functional role of PdKOR in cell wall biosynthesis. Altered metabolism and reduced growth characteristics of RNAi plants revealed new implications on carbon allocation and partitioning. The distinctive metabolome phenotype comprised of a higher phenolic and salicylic acid content, and reduced lignin, shikimic acid and maleic acid content relative to control. Plant sustainability implications of modified cell walls on beneficial plant-microbe interactions were explored via co-culture with an ectomycorrhizal fungus, Laccaria bicolor. A significant increase in the mycorrhization rate was observed in transgenic plants, leading to measurable beneficial growth effects. These findings present new evidence for functional interconnectedness of cellulose biosynthesis pathway, metabolism and mycorrhizal association in plants, and further emphasize the consideration of the sustainability implications of plant trait improvement efforts.
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Affiliation(s)
- Udaya C. Kalluri
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak RidgeTN, USA
| | - Raja S. Payyavula
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak RidgeTN, USA
| | - Jessy L. Labbé
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak RidgeTN, USA
| | - Nancy Engle
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak RidgeTN, USA
| | - Garima Bali
- BioEnergy Science Center, School of Chemistry and Biochemistry, Institute of Paper Science and Technology, Georgia Institute of Technology, AtlantaGA, USA
| | - Sara S. Jawdy
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak RidgeTN, USA
| | - Robert W. Sykes
- The Biosciences Center, National Renewable Energy Laboratory, GoldenCO, USA
| | - Mark Davis
- The Biosciences Center, National Renewable Energy Laboratory, GoldenCO, USA
| | - Arthur Ragauskas
- Oak Ridge National Laboratory – Department of Chemical and Biomolecular Engineering and Department of Forestry, Wildlife and Fisheries, University of Tennessee, KnoxvilleTN, USA
| | - Gerald A. Tuskan
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak RidgeTN, USA
| | - Timothy J. Tschaplinski
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak RidgeTN, USA
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46
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Bryan AC, Jawdy S, Gunter L, Gjersing E, Sykes R, Hinchee MAW, Winkeler KA, Collins CM, Engle N, Tschaplinski TJ, Yang X, Tuskan GA, Muchero W, Chen JG. Knockdown of a laccase in Populus deltoides confers altered cell wall chemistry and increased sugar release. PLANT BIOTECHNOLOGY JOURNAL 2016; 14:2010-20. [PMID: 26997157 PMCID: PMC5043505 DOI: 10.1111/pbi.12560] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 03/01/2016] [Accepted: 03/12/2016] [Indexed: 05/07/2023]
Abstract
Plant laccases are thought to function in the oxidation of monolignols which leads to higher order lignin formation. Only a hand-full of laccases in plants have been functionally evaluated, and as such little is known about the breadth of their impact on cell wall chemistry or structure. Here, we describe a previously uncharacterized laccase from Populus, encoded by locus Potri.008G064000, whose reduced expression resulted in transgenic Populus trees with changes in syringyl/guaiacyl ratios as well as altered sugar release phenotypes. These phenotypes are consistent with plant biomass exhibiting reduced recalcitrance. Interestingly, the transgene effect on recalcitrance is dependent on a mild pretreatment prior to chemical extraction of sugars. Metabolite profiling suggests the transgene modulates phenolics that are associated with the cell wall structure. We propose that this particular laccase has a range of functions related to oxidation of phenolics and conjugation of flavonoids that interact with lignin in the cell wall.
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Affiliation(s)
- Anthony C Bryan
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Sara Jawdy
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Lee Gunter
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Erica Gjersing
- The Biosciences Center, National Renewable Energy Laboratory, Golden, CO, USA
| | - Robert Sykes
- The Biosciences Center, National Renewable Energy Laboratory, Golden, CO, USA
| | | | | | | | - Nancy Engle
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Timothy J Tschaplinski
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Xiaohan Yang
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Gerald A Tuskan
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Wellington Muchero
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
| | - Jin-Gui Chen
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
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Pyne ME, Liu X, Moo-Young M, Chung DA, Chou CP. Genome-directed analysis of prophage excision, host defence systems, and central fermentative metabolism in Clostridium pasteurianum. Sci Rep 2016; 6:26228. [PMID: 27641836 PMCID: PMC5027557 DOI: 10.1038/srep26228] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 04/29/2016] [Indexed: 11/09/2022] Open
Abstract
Clostridium pasteurianum is emerging as a prospective host for the production of biofuels and chemicals, and has recently been shown to directly consume electric current. Despite this growing biotechnological appeal, the organism’s genetics and central metabolism remain poorly understood. Here we present a concurrent genome sequence for the C. pasteurianum type strain and provide extensive genomic analysis of the organism’s defence mechanisms and central fermentative metabolism. Next generation genome sequencing produced reads corresponding to spontaneous excision of a novel phage, designated φ6013, which could be induced using mitomycin C and detected using PCR and transmission electron microscopy. Methylome analysis of sequencing reads provided a near-complete glimpse into the organism’s restriction-modification systems. We also unveiled the chief C. pasteurianum Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) locus, which was found to exemplify a Type I-B system. Finally, we show that C. pasteurianum possesses a highly complex fermentative metabolism whereby the metabolic pathways enlisted by the cell is governed by the degree of reductance of the substrate. Four distinct fermentation profiles, ranging from exclusively acidogenic to predominantly alcohologenic, were observed through redox consideration of the substrate. A detailed discussion of the organism’s central metabolism within the context of metabolic engineering is provided.
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Affiliation(s)
- Michael E Pyne
- Department of Chemical Engineering, University of Waterloo, Waterloo, Ontario, Canada
| | - Xuejia Liu
- Department of Chemical Engineering, University of Waterloo, Waterloo, Ontario, Canada
| | - Murray Moo-Young
- Department of Chemical Engineering, University of Waterloo, Waterloo, Ontario, Canada
| | - Duane A Chung
- Department of Chemical Engineering, University of Waterloo, Waterloo, Ontario, Canada.,Department of Pathology and Molecular Medicine, McMaster University, Ontario, Canada.,Algaeneers Inc. and Neemo Inc., Hamilton, Ontario, Canada
| | - C Perry Chou
- Department of Chemical Engineering, University of Waterloo, Waterloo, Ontario, Canada
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48
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Munir RI, Spicer V, Krokhin OV, Shamshurin D, Zhang X, Taillefer M, Blunt W, Cicek N, Sparling R, Levin DB. Transcriptomic and proteomic analyses of core metabolism in Clostridium termitidis CT1112 during growth on α-cellulose, xylan, cellobiose and xylose. BMC Microbiol 2016; 16:91. [PMID: 27215540 PMCID: PMC4877739 DOI: 10.1186/s12866-016-0711-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 05/16/2016] [Indexed: 01/15/2023] Open
Abstract
Background Clostridium termitidis CT1112 is an anaerobic, Gram-positive, mesophilic, spore-forming, cellulolytic bacterium, originally isolated from the gut of a wood feeding termite Nasusitermes lujae. It has the ability to hydrolyze both cellulose and hemicellulose, and ferment the degradation products to acetate, formate, ethanol, lactate, H2, and CO2. It is therefore ges in gene and gene product expression during growth of C. termitidis on cellobiose, xylose, xylan, and α–cellulose. Results Correlation of transcriptome and proteome data with growth and fermentation profiles identified putative carbon-catabolism pathways in C. termitidis. The majority of the proteins associated with central metabolism were detected in high abundance. While major differences were not observed in gene and gene-product expression for enzymes associated with metabolic pathways under the different substrate conditions, xylulokinase and xylose isomerase of the pentose phosphate pathway were found to be highly up-regulated on five carbon sugars compared to hexoses. In addition, genes and gene-products associated with a variety of cellulosome and non-cellulosome associated CAZymes were found to be differentially expressed. Specifically, genes for cellulosomal enzymes and components were highly expressed on α–cellulose, while xylanases and glucosidases were up-regulated on 5 carbon sugars with respect to cellobiose. Chitinase and cellobiophosphorylases were the predominant CAZymes expressed on cellobiose. In addition to growth on xylan, the simultaneous consumption of two important lignocellulose constituents, cellobiose and xylose was also demonstrated. Conclusion There are little changes in core-metabolic pathways under the different carbon sources compared. The most significant differences were found to be associated with the CAZymes, as well as specific up regulation of some key components of the pentose phosphate pathway in the presence of xylose and xylan. This study has enhanced our understanding of the physiology and metabolism of C. termitidis, and provides a foundation for future studies on metabolic engineering to optimize biofuel production from natural biomass. Electronic supplementary material The online version of this article (doi:10.1186/s12866-016-0711-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Riffat I Munir
- Department of Biosystems Engineering, University of Manitoba, R3T 5N6, Winnipeg, MB, Canada
| | - Victor Spicer
- Department of Physics and Astronomy, University of Manitoba, R3T 5N6, Winnipeg, MB, Canada.,Manitoba Centre for Proteomics and Systems Biology, University of Manitoba, R3T 5N6, Winnipeg, MB, Canada
| | - Oleg V Krokhin
- Manitoba Centre for Proteomics and Systems Biology, University of Manitoba, R3T 5N6, Winnipeg, MB, Canada
| | - Dmitry Shamshurin
- Manitoba Centre for Proteomics and Systems Biology, University of Manitoba, R3T 5N6, Winnipeg, MB, Canada
| | - XiangLi Zhang
- Department of Plant Science, University of Manitoba, R3T 5N6, Winnipeg, MB, Canada
| | - Marcel Taillefer
- Department of Microbiology, University of Manitoba, R3T 5N6, Winnipeg, MB, Canada
| | - Warren Blunt
- Department of Biosystems Engineering, University of Manitoba, R3T 5N6, Winnipeg, MB, Canada
| | - Nazim Cicek
- Department of Biosystems Engineering, University of Manitoba, R3T 5N6, Winnipeg, MB, Canada
| | - Richard Sparling
- Department of Microbiology, University of Manitoba, R3T 5N6, Winnipeg, MB, Canada
| | - David B Levin
- Department of Biosystems Engineering, University of Manitoba, R3T 5N6, Winnipeg, MB, Canada.
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Lal S, Levin DB. Comparative Genomics of Core Metabolism Genes of Cellulolytic and Non-cellulolytic Clostridium Species. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2016; 156:79-112. [PMID: 26907553 DOI: 10.1007/10_2015_5007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Microbial production of fuels such as ethanol, butanol, hydrogen (H2), and methane (CH4) from waste biomass has the potential to provide sustainable energy systems that can displace fossil fuel consumption. Screening for microbial diversity and genome sequencing of a wide-range of microorganisms can identify organisms with natural abilities to synthesize these alternative fuels and/or other biotechnological applications. Clostridium species are the most widely studied strict anaerobes capable of fermentative synthesis of ethanol, butanol, or hydrogen directly from waste biomass. Clostridium termitidis CT1112 is a mesophilic, cellulolytic species capable of direct cellulose fermentation to ethanol and organic acids, with concomitant synthesis of H2 and CO2. On the basis of 16S ribosomal RNA (rRNA) and chaperonin 60 (cpn60) gene sequence data, phylogenetic analyses revealed a close relationship between C. termitidis and C. cellobioparum. Comparative bioinformatic analyses of the C. termitidis genome with 18 cellulolytic and 10 non-cellulolytic Clostridium species confirmed this relationship, and further revealed that the majority of core metabolic pathway genes in C. termitidis and C. cellobioparum share more than 90% amino acid sequence identity. The gene loci and corresponding amino acid sequences of the encoded enzymes for each pathway were correlated by percentage identity, higher score (better alignment), and lowest e-value (most significant "hit"). In addition, the function of each enzyme was proposed by conserved domain analysis. In this chapter we discuss the comparative analysis of metabolic pathways involved in synthesis of various useful products by cellulolytic and non-cellulolytic biofuel and solvent producing Clostridium species. This study has generated valuable information concerning the core metabolism genes and pathways of C. termitidis CT1112, which is helpful in developing metabolic engineering strategies to enhance its natural capacity for better industrial applications.
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Affiliation(s)
- Sadhana Lal
- Department of Biosystems Engineering, University of Manitoba, Winnipeg, MB, Canada, R3T 5V6
| | - David B Levin
- Department of Biosystems Engineering, University of Manitoba, Winnipeg, MB, Canada, R3T 5V6.
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Gaida SM, Liedtke A, Jentges AHW, Engels B, Jennewein S. Metabolic engineering of Clostridium cellulolyticum for the production of n-butanol from crystalline cellulose. Microb Cell Fact 2016. [PMID: 26758196 DOI: 10.1186/s12934-12015-10406-12932] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2023] Open
Abstract
BACKGROUND Sustainable alternatives for the production of fuels and chemicals are needed to reduce our dependency on fossil resources and to avoid the negative impact of their excessive use on the global climate. Lignocellulosic feedstock from agricultural residues, energy crops and municipal solid waste provides an abundant and carbon-neutral alternative, but it is recalcitrant towards microbial degradation and must therefore undergo extensive pretreatment to release the monomeric sugar units used by biofuel-producing microbes. These pretreatment steps can be reduced by using microbes such as Clostridium cellulolyticum that naturally digest lignocellulose, but this limits the range of biofuels that can be produced. We therefore developed a metabolic engineering approach in C. cellulolyticum to expand its natural product spectrum and to fine tune the engineered metabolic pathways. RESULTS Here we report the metabolic engineering of C. cellulolyticum to produce n-butanol, a next-generation biofuel and important chemical feedstock, directly from crystalline cellulose. We introduced the CoA-dependent pathway for n-butanol synthesis from C. acetobutylicum and measured the expression of functional enzymes (using targeted proteomics) and the abundance of metabolic intermediates (by LC-MS/MS) to identify potential bottlenecks in the n-butanol biosynthesis pathway. We achieved yields of 40 and 120 mg/L n-butanol from cellobiose and crystalline cellulose, respectively, after cultivating the bacteria for 6 and 20 days. CONCLUSION The analysis of enzyme activities and key intracellular metabolites provides a robust framework to determine the metabolic flux through heterologous pathways in C. cellulolyticum, allowing further improvements by fine tuning individual steps to improve the yields of n-butanol.
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Affiliation(s)
- Stefan Marcus Gaida
- Department of Industrial Biotechnology, Fraunhofer Institute for Molecular Biology and Applied Ecology, Forckenbeckstrasse 6, 52074, Aachen, Germany.
| | - Andrea Liedtke
- Department of Industrial Biotechnology, Fraunhofer Institute for Molecular Biology and Applied Ecology, Forckenbeckstrasse 6, 52074, Aachen, Germany.
| | - Andreas Heinz Wilhelm Jentges
- Department of Industrial Biotechnology, Fraunhofer Institute for Molecular Biology and Applied Ecology, Forckenbeckstrasse 6, 52074, Aachen, Germany.
| | - Benedikt Engels
- Department of Industrial Biotechnology, Fraunhofer Institute for Molecular Biology and Applied Ecology, Forckenbeckstrasse 6, 52074, Aachen, Germany.
| | - Stefan Jennewein
- Department of Industrial Biotechnology, Fraunhofer Institute for Molecular Biology and Applied Ecology, Forckenbeckstrasse 6, 52074, Aachen, Germany.
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