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Wang WY, Wang BP, Su HS, Wei MM, Wei YT, Niu FX. Key role of K + and Ca 2+ in high-yield ethanol production by S. Cerevisiae from concentrated sugarcane molasses. Microb Cell Fact 2024; 23:123. [PMID: 38724968 PMCID: PMC11080136 DOI: 10.1186/s12934-024-02401-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2024] [Accepted: 04/23/2024] [Indexed: 05/13/2024] Open
Abstract
BACKGROUND Saccharomyces cerevisiae is an important microorganism in ethanol synthesis, and with sugarcane molasses as the feedstock, ethanol is being synthesized sustainably to meet growing demands. However, high-concentration ethanol fermentation based on high-concentration sugarcane molasses-which is needed for reduced energy consumption of ethanol distillation at industrial scale-is yet to be achieved. RESULTS In the present study, to identify the main limiting factors of this process, adaptive laboratory evolution and high-throughput screening (Py-Fe3+) based on ARTP (atmospheric and room-temperature plasma) mutagenesis were applied. We identified high osmotic pressure, high temperature, high alcohol levels, and high concentrations of K+, Ca2+, K+ and Ca2+ (K+&Ca2+), and sugarcane molasses as the main limiting factors. The robust S. cerevisiae strains of NGT-F1, NGW-F1, NGC-F1, NGK+, NGCa2+ NGK+&Ca2+-F1, and NGTM-F1 exhibited high tolerance to the respective limiting factor and exhibited increased yield. Subsequently, ethanol synthesis, cell morphology, comparative genomics, and gene ontology (GO) enrichment analysis were performed in a molasses broth containing 250 g/L total fermentable sugars (TFS). Additionally, S. cerevisiae NGTM-F1 was used with 250 g/L (TFS) sugarcane molasses to synthesize ethanol in a 5-L fermenter, giving a yield of 111.65 g/L, the conversion of sugar to alcohol reached 95.53%. It is the highest level of physical mutagenesis yield at present. CONCLUSION Our results showed that K+ and Ca2+ ions primarily limited the efficient production of ethanol. Then, subsequent comparative transcriptomic GO and pathway analyses showed that the co-presence of K+ and Ca2+ exerted the most prominent limitation on efficient ethanol production. The results of this study might prove useful by promoting the development and utilization of green fuel bio-manufactured from molasses.
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Affiliation(s)
- Wei-Yang Wang
- Guangxi Key Laboratory of Green Processing of Sugar Resources, Guangxi University of Science and Technology, Liuzhou, 545006, China
- Guangxi Microorganism and Enzyme Research Center of Engineering Technology, College of Life Science and Technology, Guangxi University, Nanning, 530004, Guangxi, China
| | - Bei-Ping Wang
- Guangxi Key Laboratory of Green Processing of Sugar Resources, Guangxi University of Science and Technology, Liuzhou, 545006, China
| | - Hai-Song Su
- Guangxi Key Laboratory of Green Processing of Sugar Resources, Guangxi University of Science and Technology, Liuzhou, 545006, China
| | - Mei-Ming Wei
- Guangxi Key Laboratory of Green Processing of Sugar Resources, Guangxi University of Science and Technology, Liuzhou, 545006, China
| | - Yu-Tuo Wei
- Guangxi Microorganism and Enzyme Research Center of Engineering Technology, College of Life Science and Technology, Guangxi University, Nanning, 530004, Guangxi, China
| | - Fu-Xing Niu
- Guangxi Key Laboratory of Green Processing of Sugar Resources, Guangxi University of Science and Technology, Liuzhou, 545006, China.
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Soares LW, King CG, Fernando CM, Roth A, Breaker RR. Genetic disruption of the bacterial raiA motif noncoding RNA causes defects in sporulation and aggregation. Proc Natl Acad Sci U S A 2024; 121:e2318008121. [PMID: 38306478 PMCID: PMC10861870 DOI: 10.1073/pnas.2318008121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 12/02/2023] [Indexed: 02/04/2024] Open
Abstract
Several structured noncoding RNAs in bacteria are essential contributors to fundamental cellular processes. Thus, discoveries of additional ncRNA classes provide opportunities to uncover and explore biochemical mechanisms relevant to other major and potentially ancient processes. A candidate structured ncRNA named the "raiA motif" has been found via bioinformatic analyses in over 2,500 bacterial species. The gene coding for the RNA typically resides between the raiA and comFC genes of many species of Bacillota and Actinomycetota. Structural probing of the raiA motif RNA from the Gram-positive anaerobe Clostridium acetobutylicum confirms key features of its sophisticated secondary structure model. Expression analysis of raiA motif RNA reveals that the RNA is constitutively produced but reaches peak abundance during the transition from exponential growth to stationary phase. The raiA motif RNA becomes the fourth most abundant RNA in C. acetobutylicum, excluding ribosomal RNAs and transfer RNAs. Genetic disruption of the raiA motif RNA causes cells to exhibit substantially decreased spore formation and diminished ability to aggregate. Restoration of normal cellular function in this knock-out strain is achieved by expression of a raiA motif gene from a plasmid. These results demonstrate that raiA motif RNAs normally participate in major cell differentiation processes by operating as a trans-acting factor.
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Affiliation(s)
- Lucas W. Soares
- Department of Microbial Pathogenesis, Yale University, New Haven, CT06536
| | - Christopher G. King
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT06511-8103
| | - Chrishan M. Fernando
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT06511-8103
| | - Adam Roth
- HHMI, Yale University, New Haven, CT06511-8103
| | - Ronald R. Breaker
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT06511-8103
- HHMI, Yale University, New Haven, CT06511-8103
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT06511-8103
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3
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Rivera Vazquez J, Trujillo E, Williams J, She F, Getahun F, Callaghan MM, Coon JJ, Amador-Noguez D. Lipid membrane remodeling and metabolic response during isobutanol and ethanol exposure in Zymomonas mobilis. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:14. [PMID: 38281959 PMCID: PMC10823705 DOI: 10.1186/s13068-023-02450-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Accepted: 12/16/2023] [Indexed: 01/30/2024]
Abstract
BACKGROUND Recent engineering efforts have targeted the ethanologenic bacterium Zymomonas mobilis for isobutanol production. However, significant hurdles remain due this organism's vulnerability to isobutanol toxicity, adversely affecting its growth and productivity. The limited understanding of the physiological impacts of isobutanol on Z. mobilis constrains our ability to overcome these production barriers. RESULTS We utilized a systems-level approach comprising LC-MS/MS-based lipidomics, metabolomics, and shotgun proteomics, to investigate how exposure to ethanol and isobutanol impact the lipid membrane composition and overall physiology of Z. mobilis. Our analysis revealed significant and distinct alterations in membrane phospholipid and fatty acid composition resulting from ethanol and isobutanol exposure. Notably, ethanol exposure increased membrane cyclopropane fatty acid content and expression of cyclopropane fatty acid (CFA) synthase. Surprisingly, isobutanol decreased cyclopropane fatty acid content despite robust upregulation of CFA synthase. Overexpression of the native Z. mobilis' CFA synthase increased cyclopropane fatty acid content in all phospholipid classes and was associated with a significant improvement in growth rates in the presence of added ethanol and isobutanol. Heterologous expression of CFA synthase from Clostridium acetobutylicum resulted in a near complete replacement of unsaturated fatty acids with cyclopropane fatty acids, affecting all lipid classes. However, this did not translate to improved growth rates under isobutanol exposure. Correlating with its greater susceptibility to isobutanol, Z. mobilis exhibited more pronounced alterations in its proteome, metabolome, and overall cell morphology-including cell swelling and formation of intracellular protein aggregates -when exposed to isobutanol compared to ethanol. Isobutanol triggered a broad stress response marked by the upregulation of heat shock proteins, efflux transporters, DNA repair systems, and the downregulation of cell motility proteins. Isobutanol also elicited widespread dysregulation of Z. mobilis' primary metabolism evidenced by increased levels of nucleotide degradation intermediates and the depletion of biosynthetic and glycolytic intermediates. CONCLUSIONS This study provides a comprehensive, systems-level evaluation of the impact of ethanol and isobutanol exposure on the lipid membrane composition and overall physiology of Z. mobilis. These findings will guide engineering of Z. mobilis towards the creation of isobutanol-tolerant strains that can serve as robust platforms for the industrial production of isobutanol from lignocellulosic sugars.
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Affiliation(s)
- Julio Rivera Vazquez
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, 53726, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
| | - Edna Trujillo
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, 53726, USA
- Genome Center of Wisconsin, Madison, WI, USA
| | - Jonathan Williams
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, 53726, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
| | - Fukang She
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
| | - Fitsum Getahun
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, 53726, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
| | - Melanie M Callaghan
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, 53726, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
| | - Joshua J Coon
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, 53726, USA
- Morgridge Institute for Research, Madison, WI, USA
- National Center for Quantitative Biology of Complex Systems, University of Wisconsin-Madison, Madison, WI, USA
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Daniel Amador-Noguez
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, 53726, USA.
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA.
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4
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Linney JA, Routledge SJ, Connell SD, Larson TR, Pitt AR, Jenkinson ER, Goddard AD. Identification of membrane engineering targets for increased butanol tolerance in Clostridium saccharoperbutylacetonicum. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184217. [PMID: 37648011 DOI: 10.1016/j.bbamem.2023.184217] [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: 05/10/2023] [Revised: 07/17/2023] [Accepted: 08/17/2023] [Indexed: 09/01/2023]
Abstract
There is a growing interest in the use of microbial cell factories to produce butanol, an industrial solvent and platform chemical. Biobutanol can also be used as a biofuel and represents a cleaner and more sustainable alternative to the use of conventional fossil fuels. Solventogenic Clostridia are the most popular microorganisms used due to the native expression of butanol synthesis pathways. A major drawback to the wide scale implementation and development of these technologies is the toxicity of butanol. Various membrane properties and related functions are perturbed by the interaction of butanol with the cell membrane, causing lower yields and higher purification costs. This is ultimately why the technology remains underemployed. This study aimed to develop a deeper understanding of butanol toxicity at the membrane to determine future targets for membrane engineering. Changes to the lipidome in Clostridium saccharoperbutylacetonicum N1-4 (HMT) throughout butanol fermentation were investigated with thin layer chromatography and mass spectrometry. By the end of fermentation, levels of phosphatidylglycerol lipids had increased significantly, suggesting an important role of these lipid species in tolerance to butanol. Using membrane models and in vitro assays to investigate characteristics such as permeability, fluidity, and swelling, it was found that altering the composition of membrane models can convey tolerance to butanol, and that modulating membrane fluidity appears to be a key factor. Data presented here will ultimately help to inform rational strain engineering efforts to produce more robust strains capable of producing higher butanol titres.
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Affiliation(s)
- John A Linney
- School of Health and Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Sarah J Routledge
- School of Health and Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Simon D Connell
- School of Physics and Astronomy and The Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Tony R Larson
- Department of Biology, University of York, York YO10 5DD, UK
| | - Andrew R Pitt
- Manchester Institute of Biotechnology, University of Manchester, Manchester M1 7DN, UK
| | | | - Alan D Goddard
- School of Health and Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK.
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Zhang H, Zhang C, Nie X, Wu Y, Yang C, Jiang W, Gu Y. Pleiotropic Regulator GssR Positively Regulates Autotrophic Growth of Gas-Fermenting Clostridium ljungdahlii. Microorganisms 2023; 11:1968. [PMID: 37630531 PMCID: PMC10458427 DOI: 10.3390/microorganisms11081968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 07/29/2023] [Accepted: 07/30/2023] [Indexed: 08/27/2023] Open
Abstract
Clostridium ljungdahlii is a representative autotrophic acetogen capable of producing multiple chemicals from one-carbon gases (CO2/CO). The metabolic and regulatory networks of this carbon-fixing bacterium are interesting, but still remain minimally explored. Here, based on bioinformatics analysis followed by functional screening, we identified a RpiR family transcription factor (TF) that can regulate the autotrophic growth and carbon fixation of C. ljungdahlii. After deletion of the corresponding gene, the resulting mutant strain exhibited significantly impaired growth in gas fermentation, thus reducing the production of acetic acid and ethanol. In contrast, the overexpression of this TF gene could promote cell growth, indicating a positive regulatory effect of this TF in C. ljungdahlii. Thus, we named the TF as GssR (growth and solvent synthesis regulator). Through the following comparative transcriptomic analysis and biochemical verification, we discovered three important genes (encoding pyruvate carboxylase, carbon hunger protein CstA, and a BlaI family transcription factor) that were directly regulated by GssR. Furthermore, an upstream regulator, BirA, that could directly bind to gssR was found; thus, these two regulators may form a cascade regulation and jointly affect the physiology and metabolism of C. ljungdahlii. These findings substantively expand our understanding on the metabolic regulation of carbon fixation in gas-fermenting Clostridium species.
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Affiliation(s)
- Huan Zhang
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Can Zhang
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaoqun Nie
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuwei Wu
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chen Yang
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
| | - Weihong Jiang
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
| | - Yang Gu
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
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6
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Omorotionmwan BB, Wang H, Baker JP, Gizynski K, Yoo M, Akaluka C, Zhang Y, Minton NP. Chromosomal engineering of inducible isopropanol- butanol-ethanol production in Clostridium acetobutylicum. Front Bioeng Biotechnol 2023; 11:1218099. [PMID: 37397966 PMCID: PMC10312008 DOI: 10.3389/fbioe.2023.1218099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 06/05/2023] [Indexed: 07/04/2023] Open
Abstract
The use of environmentally damaging petrochemical feedstocks can be displaced by fermentation processes based on engineered microbial chassis that recycle biomass-derived carbon into chemicals and fuels. The stable retention of introduced genes, designed to extend product range and/or increase productivity, is essential. Accordingly, we have created multiply marked auxotrophic strains of Clostridium acetobutylicum that provide distinct loci (pyrE, argH, purD, pheA) at which heterologous genes can be rapidly integrated using allele-coupled exchange (ACE). For each locus, ACE-mediated insertion is conveniently selected on the basis of the restoration of prototrophy on minimal media. The Clostridioides difficile gene (tcdR) encoding an orthogonal sigma factor (TcdR) was integrated at the pyrE locus under the control of the lactose-inducible, bgaR::PbgaL promoter to allow the simultaneous control of genes/operons inserted at other disparate loci (purD and pheA) that had been placed under the control of the PtcdB promoter. In control experiments, dose-dependent expression of a catP reporter gene was observed with increasing lactose concentration. At the highest doses tested (10 mM) the level of expression was over 10-fold higher than if catP was placed directly under the control of bgaR::PbgaL and over 2-fold greater than achieved using the strong Pfdx promoter of the Clostridium sporogenes ferredoxin gene. The utility of the system was demonstrated in the production of isopropanol by the C. acetobutylicum strain carrying an integrated copy of tcdR following the insertion of a synthetic acetone operon (ctfA/B, adc) at the purD locus and a gene (sadh) encoding a secondary dehydrogenase at pheA. Lactose induction (10 mM) resulted in the production of 4.4 g/L isopropanol and 19.8 g/L Isopropanol-Butanol-Ethanol mixture.
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Affiliation(s)
- Bunmi B. Omorotionmwan
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), Biodiscovery Institute, School of Life Sciences, The University of Nottingham, Nottingham, United Kingdom
| | - Hengzheng Wang
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), Biodiscovery Institute, School of Life Sciences, The University of Nottingham, Nottingham, United Kingdom
| | - Jonathan P. Baker
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), Biodiscovery Institute, School of Life Sciences, The University of Nottingham, Nottingham, United Kingdom
| | - Krzysztof Gizynski
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), Biodiscovery Institute, School of Life Sciences, The University of Nottingham, Nottingham, United Kingdom
| | - Minyeong Yoo
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), Biodiscovery Institute, School of Life Sciences, The University of Nottingham, Nottingham, United Kingdom
| | - Cynthia Akaluka
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), Biodiscovery Institute, School of Life Sciences, The University of Nottingham, Nottingham, United Kingdom
| | - Ying Zhang
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), Biodiscovery Institute, School of Life Sciences, The University of Nottingham, Nottingham, United Kingdom
| | - Nigel P. Minton
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), Biodiscovery Institute, School of Life Sciences, The University of Nottingham, Nottingham, United Kingdom
- NIHR Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and the University of Nottingham, Nottingham, United Kingdom
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7
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Guo X, Zhang H, Feng J, Yang L, Luo K, Fu H, Wang J. De novo biosynthesis of butyl butyrate in engineered Clostridium tyrobutyricum. Metab Eng 2023; 77:64-75. [PMID: 36948242 DOI: 10.1016/j.ymben.2023.03.009] [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: 09/21/2022] [Revised: 03/07/2023] [Accepted: 03/20/2023] [Indexed: 03/24/2023]
Abstract
Butyl butyrate has broad applications in foods, cosmetics, solvents, and biofuels. Microbial synthesis of bio-based butyl butyrate has been regarded as a promising approach recently. Herein, we engineered Clostridium tyrobutyricum ATCC 25755 to achieve de novo biosynthesis of butyl butyrate from fermentable sugars. Through introducing the butanol synthetic pathway (enzyme AdhE2), screening alcohol acyltransferases (AATs), adjusting transcription of VAAT and adhE2 (i.e., optimizing promoter), and efficient supplying butyryl-CoA, an excellent engineered strain, named MUV3, was obtained with ability to produce 4.58 g/L butyl butyrate at 25 °C with glucose in serum bottles. More NADH is needed for butyl butyrate synthesis, thus mannitol (the more reduced substrate) was employed to produce butyl butyrate. Ultimately, 62.59 g/L butyl butyrate with a selectivity of 95.97%, and a yield of 0.21 mol/mol was obtained under mannitol with fed-batch fermentation in a 5 L bioreactor, which is the highest butyl butyrate titer reported so far. Altogether, this study presents an anaerobic fermentative platform for de novo biosynthesis of butyl butyrate in one step, which lays the foundation for butyl butyrate biosynthesis from renewable biomass feedstocks.
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Affiliation(s)
- Xiaolong Guo
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Huihui Zhang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Jun Feng
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Lu Yang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Kui Luo
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Hongxin Fu
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China; Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, South China University of Technology, Guangzhou, 510006, China.
| | - Jufang Wang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China; Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, South China University of Technology, Guangzhou, 510006, China.
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8
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Costa P, Usai G, Re A, Manfredi M, Mannino G, Bertea CM, Pessione E, Mazzoli R. Clostridium cellulovorans Proteomic Responses to Butanol Stress. Front Microbiol 2021; 12:674639. [PMID: 34367082 PMCID: PMC8336468 DOI: 10.3389/fmicb.2021.674639] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 06/14/2021] [Indexed: 12/16/2022] Open
Abstract
Combination of butanol-hyperproducing and hypertolerant phenotypes is essential for developing microbial strains suitable for industrial production of bio-butanol, one of the most promising liquid biofuels. Clostridium cellulovorans is among the microbial strains with the highest potential for direct production of n-butanol from lignocellulosic wastes, a process that would significantly reduce the cost of bio-butanol. However, butanol exhibits higher toxicity compared to ethanol and C. cellulovorans tolerance to this solvent is low. In the present investigation, comparative gel-free proteomics was used to study the response of C. cellulovorans to butanol challenge and understand the tolerance mechanisms activated in this condition. Sequential Window Acquisition of all Theoretical fragment ion spectra Mass Spectrometry (SWATH-MS) analysis allowed identification and quantification of differentially expressed soluble proteins. The study data are available via ProteomeXchange with the identifier PXD024183. The most important response concerned modulation of protein biosynthesis, folding and degradation. Coherent with previous studies on other bacteria, several heat shock proteins (HSPs), involved in protein quality control, were up-regulated such as the chaperones GroES (Cpn10), Hsp90, and DnaJ. Globally, our data indicate that protein biosynthesis is reduced, likely not to overload HSPs. Several additional metabolic adaptations were triggered by butanol exposure such as the up-regulation of V- and F-type ATPases (involved in ATP synthesis/generation of proton motive force), enzymes involved in amino acid (e.g., arginine, lysine, methionine, and branched chain amino acids) biosynthesis and proteins involved in cell envelope re-arrangement (e.g., the products of Clocel_4136, Clocel_4137, Clocel_4144, Clocel_4162 and Clocel_4352, involved in the biosynthesis of saturated fatty acids) and a redistribution of carbon flux through fermentative pathways (acetate and formate yields were increased and decreased, respectively). Based on these experimental findings, several potential gene targets for metabolic engineering strategies aimed at improving butanol tolerance in C. cellulovorans are suggested. This includes overexpression of HSPs (e.g., GroES, Hsp90, DnaJ, ClpC), RNA chaperone Hfq, V- and F-type ATPases and a number of genes whose function in C. cellulovorans is currently unknown.
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Affiliation(s)
- Paolo Costa
- Structural and Functional Biochemistry, Laboratory of Proteomics and Metabolic Engineering of Prokaryotes, Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy
| | - Giulia Usai
- Structural and Functional Biochemistry, Laboratory of Proteomics and Metabolic Engineering of Prokaryotes, Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy.,Centre for Sustainable Future Technologies, Fondazione Istituto Italiano di Tecnologia, Turin, Italy.,Department of Applied Science and Technology, Politecnico di Torino, Turin, Italy
| | - Angela Re
- Centre for Sustainable Future Technologies, Fondazione Istituto Italiano di Tecnologia, Turin, Italy
| | - Marcello Manfredi
- Center for Translational Research on Autoimmune and Allergic Diseases, Università del Piemonte Orientale, Novara, Italy.,Department of Translational Medicine, Università del Piemonte Orientale, Novara, Italy
| | - Giuseppe Mannino
- Plant Physiology Unit, Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy
| | - Cinzia Margherita Bertea
- Plant Physiology Unit, Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy
| | - Enrica Pessione
- Structural and Functional Biochemistry, Laboratory of Proteomics and Metabolic Engineering of Prokaryotes, Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy
| | - Roberto Mazzoli
- Structural and Functional Biochemistry, Laboratory of Proteomics and Metabolic Engineering of Prokaryotes, Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy
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9
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Mavrommati M, Daskalaki A, Papanikolaou S, Aggelis G. Adaptive laboratory evolution principles and applications in industrial biotechnology. Biotechnol Adv 2021; 54:107795. [PMID: 34246744 DOI: 10.1016/j.biotechadv.2021.107795] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 06/11/2021] [Accepted: 07/05/2021] [Indexed: 12/20/2022]
Abstract
Adaptive laboratory evolution (ALE) is an innovative approach for the generation of evolved microbial strains with desired characteristics, by implementing the rules of natural selection as presented in the Darwinian Theory, on the laboratory bench. New as it might be, it has already been used by several researchers for the amelioration of a variety of characteristics of widely used microorganisms in biotechnology. ALE is used as a tool for the deeper understanding of the genetic and/or metabolic pathways of evolution. Another important field targeted by ALE is the manufacturing of products of (high) added value, such as ethanol, butanol and lipids. In the current review, we discuss the basic principles and techniques of ALE, and then we focus on studies where it has been applied to bacteria, fungi and microalgae, aiming to improve their performance to biotechnological procedures and/or inspect the genetic background of evolution. We conclude that ALE is a promising and efficacious method that has already led to the acquisition of useful new microbiological strains in biotechnology and could possibly offer even more interesting results in the future.
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Affiliation(s)
- Maria Mavrommati
- Unit of Microbiology, Department of Biology, Division of Genetics, Cell Biology and Development, University of Patras, 26504 Patras, Greece; Laboratory of Food Microbiology and Biotechnology, Department of Food Science and Human Nutrition, Agricultural University of Athens, 75 Iera Odos, 11855 Athens, Greece
| | - Alexandra Daskalaki
- Unit of Microbiology, Department of Biology, Division of Genetics, Cell Biology and Development, University of Patras, 26504 Patras, Greece
| | - Seraphim Papanikolaou
- Laboratory of Food Microbiology and Biotechnology, Department of Food Science and Human Nutrition, Agricultural University of Athens, 75 Iera Odos, 11855 Athens, Greece
| | - George Aggelis
- Unit of Microbiology, Department of Biology, Division of Genetics, Cell Biology and Development, University of Patras, 26504 Patras, Greece.
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Grosse-Honebrink A, Little GT, Bean Z, Heldt D, Cornock RHM, Winzer K, Minton NP, Green E, Zhang Y. Development of Clostridium saccharoperbutylacetonicum as a Whole Cell Biocatalyst for Production of Chirally Pure ( R)-1,3-Butanediol. Front Bioeng Biotechnol 2021; 9:659895. [PMID: 34055760 PMCID: PMC8155681 DOI: 10.3389/fbioe.2021.659895] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 04/12/2021] [Indexed: 11/13/2022] Open
Abstract
Chirally pure (R)-1,3-butanediol ((R)-1,3-BDO) is a valuable intermediate for the production of fragrances, pheromones, insecticides and antibiotics. Biotechnological production results in superior enantiomeric excess over chemical production and is therefore the preferred production route. In this study (R)-1,3-BDO was produced in the industrially important whole cell biocatalyst Clostridium saccharoperbutylacetonicum through expression of the enantio-specific phaB gene from Cupriavidus necator. The heterologous pathway was optimised in three ways: at the transcriptional level choosing strongly expressed promoters and comparing plasmid borne with chromosomal gene expression, at the translational level by optimising the codon usage of the gene to fit the inherent codon adaptation index of C. saccharoperbutylacetonicum, and at the enzyme level by introducing point mutations which led to increased enzymatic activity. The resulting whole cell catalyst produced up to 20 mM (1.8 g/l) (R)-1,3-BDO in non-optimised batch fermentation which is a promising starting position for economical production of this chiral chemical.
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Affiliation(s)
- Alexander Grosse-Honebrink
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), Biodiscovery Institute, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Gareth T Little
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), Biodiscovery Institute, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Zak Bean
- CHAIN Biotechnology Ltd., MediCity, Nottingham, United Kingdom
| | - Dana Heldt
- CHAIN Biotechnology Ltd., MediCity, Nottingham, United Kingdom
| | - Ruth H M Cornock
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), Biodiscovery Institute, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Klaus Winzer
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), Biodiscovery Institute, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Nigel P Minton
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), Biodiscovery Institute, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Edward Green
- CHAIN Biotechnology Ltd., MediCity, Nottingham, United Kingdom
| | - Ying Zhang
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), Biodiscovery Institute, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
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11
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Monaghan TI, Baker JA, Robinson GK, Shepherd M. Parallel bioreactor system for accessible and reproducible anaerobic culture. Access Microbiol 2021; 3:000225. [PMID: 34151176 PMCID: PMC8208757 DOI: 10.1099/acmi.0.000225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 03/29/2021] [Indexed: 11/21/2022] Open
Abstract
When working with anaerobic bacteria it is important to have the capability to perform parallel bioreactor growth experiments that are both controllable and reproducible, although capital and consumables costs for commercially available systems are often prohibitively high. Hence, a three-vessel parallel bioreactor system was designed and constructed that has the capabilities for batch and fed batch processes and can also be set up for continuous culture at a fraction of the cost of commercial systems. This system carries over many of the same functionalities of those systems with a higher price point of entry, including in-line monitoring of temperature, pH, and redox poise. To validate the performance of this system Clostridium saccharoperbutylacetonicum was grown under conditions that promote ABE fermentation, an established industrial process used to produce the solvents acetone, butanol and ethanol. Measurements of cell density, pH, and redox poise all confirmed reproducible culture conditions for these parallel vessels, and solvent quantitation via GCMS verified consistent metabolic activities for the separate cultures. In future, this system will be of interest to researchers that require high performance parallel fermentation platforms but where commercial systems are not accessible.
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Affiliation(s)
- Taylor I Monaghan
- School of Biosciences, RAPID Group, University of Kent, Canterbury, CT2 7NJ, UK
| | - Joseph A Baker
- School of Biosciences, RAPID Group, University of Kent, Canterbury, CT2 7NJ, UK
| | - Gary K Robinson
- School of Biosciences, RAPID Group, University of Kent, Canterbury, CT2 7NJ, UK
| | - Mark Shepherd
- School of Biosciences, RAPID Group, University of Kent, Canterbury, CT2 7NJ, UK
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12
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Schalck T, den Bergh BV, Michiels J. Increasing Solvent Tolerance to Improve Microbial Production of Alcohols, Terpenoids and Aromatics. Microorganisms 2021; 9:249. [PMID: 33530454 PMCID: PMC7912173 DOI: 10.3390/microorganisms9020249] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 01/14/2021] [Accepted: 01/20/2021] [Indexed: 12/16/2022] Open
Abstract
Fuels and polymer precursors are widely used in daily life and in many industrial processes. Although these compounds are mainly derived from petrol, bacteria and yeast can produce them in an environment-friendly way. However, these molecules exhibit toxic solvent properties and reduce cell viability of the microbial producer which inevitably impedes high product titers. Hence, studying how product accumulation affects microbes and understanding how microbial adaptive responses counteract these harmful defects helps to maximize yields. Here, we specifically focus on the mode of toxicity of industry-relevant alcohols, terpenoids and aromatics and the associated stress-response mechanisms, encountered in several relevant bacterial and yeast producers. In practice, integrating heterologous defense mechanisms, overexpressing native stress responses or triggering multiple protection pathways by modifying the transcription machinery or small RNAs (sRNAs) are suitable strategies to improve solvent tolerance. Therefore, tolerance engineering, in combination with metabolic pathway optimization, shows high potential in developing superior microbial producers.
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Affiliation(s)
- Thomas Schalck
- VIB Center for Microbiology, Flanders Institute for Biotechnology, B-3001 Leuven, Belgium; (T.S.); (B.V.d.B.)
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20, B-3001 Leuven, Belgium
| | - Bram Van den Bergh
- VIB Center for Microbiology, Flanders Institute for Biotechnology, B-3001 Leuven, Belgium; (T.S.); (B.V.d.B.)
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20, B-3001 Leuven, Belgium
| | - Jan Michiels
- VIB Center for Microbiology, Flanders Institute for Biotechnology, B-3001 Leuven, Belgium; (T.S.); (B.V.d.B.)
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20, B-3001 Leuven, Belgium
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13
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Vasylkivska M, Branska B, Sedlar K, Jureckova K, Provaznik I, Patakova P. Phenotypic and Genomic Analysis of Clostridium beijerinckii NRRL B-598 Mutants With Increased Butanol Tolerance. Front Bioeng Biotechnol 2020; 8:598392. [PMID: 33224939 PMCID: PMC7674653 DOI: 10.3389/fbioe.2020.598392] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 10/20/2020] [Indexed: 11/19/2022] Open
Abstract
N-Butanol, a valuable solvent and potential fuel extender, can be produced via acetone-butanol-ethanol (ABE) fermentation. One of the main drawbacks of ABE fermentation is the high toxicity of butanol to producing cells, leading to cell membrane disruption, low culture viability and, consequently, low produced concentrations of butanol. The goal of this study was to obtain mutant strains of Clostridium beijerinckii NRRL B-598 with improved butanol tolerance using random chemical mutagenesis, describe changes in their phenotypes compared to the wild-type strain and reveal changes in the genome that explain improved tolerance or other phenotypic changes. Nine mutant strains with stable improved features were obtained by three different approaches and, for two of them, ethidium bromide (EB), a known substrate of efflux pumps, was used for either selection or as a mutagenic agent. It is the first utilization of this approach for the development of butanol-tolerant mutants of solventogenic clostridia, for which generally there is a lack of knowledge about butanol efflux or efflux mechanisms and their regulation. Mutant strains exhibited increase in butanol tolerance from 36% up to 127% and the greatest improvement was achieved for the strains for which EB was used as a mutagenic agent. Additionally, increased tolerance to other substrates of efflux pumps, EB and ethanol, was observed in all mutants and higher antibiotic tolerance in some of the strains. The complete genomes of mutant strains were sequenced and revealed that improved butanol tolerance can be attributed to mutations in genes encoding typical stress responses (chemotaxis, autolysis or changes in cell membrane structure), but, also, to mutations in genes X276_07980 and X276_24400, encoding efflux pump regulators. The latter observation confirms the importance of efflux in butanol stress response of the strain and offers new targets for rational strain engineering.
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Affiliation(s)
- Maryna Vasylkivska
- Department of Biotechnology, University of Chemistry and Technology, Prague, Prague, Czechia
| | - Barbora Branska
- Department of Biotechnology, University of Chemistry and Technology, Prague, Prague, Czechia
| | - Karel Sedlar
- Department of Biomedical Engineering, Faculty of Electrical Engineering and Communication, Brno University of Technology, Brno, Czechia
| | - Katerina Jureckova
- Department of Biomedical Engineering, Faculty of Electrical Engineering and Communication, Brno University of Technology, Brno, Czechia
| | - Ivo Provaznik
- Department of Biomedical Engineering, Faculty of Electrical Engineering and Communication, Brno University of Technology, Brno, Czechia
| | - Petra Patakova
- Department of Biotechnology, University of Chemistry and Technology, Prague, Prague, Czechia
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14
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How to outwit nature: Omics insight into butanol tolerance. Biotechnol Adv 2020; 46:107658. [PMID: 33220435 DOI: 10.1016/j.biotechadv.2020.107658] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 11/10/2020] [Accepted: 11/13/2020] [Indexed: 12/16/2022]
Abstract
The energy crisis, depletion of oil reserves, and global climate changes are pressing problems of developed societies. One possibility to counteract that is microbial production of butanol, a promising new fuel and alternative to many petrochemical reagents. However, the high butanol toxicity to all known microbial species is the main obstacle to its industrial implementation. The present state of the art review aims to expound the recent advances in modern omics approaches to resolving this insurmountable to date problem of low butanol tolerance. Genomics, transcriptomics, and proteomics show that butanol tolerance is a complex phenomenon affecting multiple genes and their expression. Efflux pumps, stress and multidrug response, membrane transport, and redox-related genes are indicated as being most important during butanol challenge, in addition to fine-tuning of global regulators of transcription (Spo0A, GntR), which may further improve tolerance. Lipidomics shows that the alterations in membrane composition (saturated lipids and plasmalogen increase) are very much species-specific and butanol-related. Glycomics discloses the pleiotropic effect of CcpA, the role of alternative sugar transport, and the production of exopolysaccharides as alternative routes to overcoming butanol stress. Unfortunately, the strain that simultaneously syntheses and tolerates butanol in concentrations that allow its commercialization has not yet been discovered or produced. Omics insight will allow the purposeful increase of butanol tolerance in natural and engineered producers and the effective heterologous expression of synthetic butanol pathways in strains hereditary butanol-resistant up to 3.2 - 4.9% (w/v). Future breakthrough can be achieved by a detailed study of the membrane proteome, of which 21% are proteins with unknown functions.
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15
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Chen Y, Yang Y, Ji X, Zhao R, Li G, Gu Y, Shi A, Jiang W, Zhang Q. The SCIFF-Derived Ranthipeptides Participate in Quorum Sensing in Solventogenic Clostridia. Biotechnol J 2020; 15:e2000136. [PMID: 32713052 DOI: 10.1002/biot.202000136] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 06/25/2020] [Indexed: 12/29/2022]
Abstract
Ranthipeptides, defined as radical non-α thioether-containing peptides, are a newly emerging class of natural products belonging to the ribosomally synthesized and post-translationally modified peptide (RiPP) superfamily. Ranthipeptides are shown to be widespread in the bacterial kingdom, whereas heretofore their biological functions remain completely elusive. In this work, putative ranthipeptides are investigated from two solventogenic clostridia, Clostridium beijerinckii and Clostridium ljungdahlii, which are derived from the so-called six Cys in forty-five residues (SCIFF) family of precursor peptides. A series of analysis show that these two ranthipeptides participate in quorum sensing and controlling cellular metabolism. These results highlight the diverse biological functions of the ever-increasing family of RiPP natural products and showcase the potential to engineer industrially interesting organisms by manipulating their RiPP biosynthetic pathways.
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Affiliation(s)
- Yunliang Chen
- School of Agricultural Equipment Engineering, Jiangsu University, Zhenjiang, 212013, China.,Department of Chemistry, Fudan University, Shanghai, 200433, China
| | - Yunpeng Yang
- Chinese Academy of Sciences (CAS) Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai Institute of Plant Physiology and Ecology, Shanghai, 200032, China.,Institute of Neuroscience, Chinese Academy of Sciences (CAS) Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, CAS, Shanghai Institutes for Biological Sciences, Shanghai, 200031, China
| | - Xinjian Ji
- Department of Chemistry, Fudan University, Shanghai, 200433, China
| | - Ran Zhao
- Chinese Academy of Sciences (CAS) Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai Institute of Plant Physiology and Ecology, Shanghai, 200032, China
| | - Guoquan Li
- School of Agricultural Equipment Engineering, Jiangsu University, Zhenjiang, 212013, China
| | - Yang Gu
- Chinese Academy of Sciences (CAS) Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai Institute of Plant Physiology and Ecology, Shanghai, 200032, China
| | - Aiping Shi
- School of Agricultural Equipment Engineering, Jiangsu University, Zhenjiang, 212013, China
| | - Weihong Jiang
- Chinese Academy of Sciences (CAS) Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai Institute of Plant Physiology and Ecology, Shanghai, 200032, China
| | - Qi Zhang
- Department of Chemistry, Fudan University, Shanghai, 200433, China
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16
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The Small RNA sr8384 Is a Crucial Regulator of Cell Growth in Solventogenic Clostridia. Appl Environ Microbiol 2020; 86:AEM.00665-20. [PMID: 32358006 DOI: 10.1128/aem.00665-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 04/27/2020] [Indexed: 01/08/2023] Open
Abstract
Small RNAs (sRNAs) are crucial regulatory molecules in organisms and are well-known not only for their roles in the control of diverse crucial biological processes but also for their value in regulation rewiring. However, to date, in Gram-positive anaerobic solventogenic clostridia (a group of important industrial bacteria with exceptional substrate and product diversity), sRNAs remain minimally explored, and thus there is a lack of detailed understanding regarding these important molecules and their use as targets for genetic improvement. Here, we performed large-scale phenotypic screens of a transposon-mediated mutant library of Clostridium acetobutylicum, a typical solventogenic clostridial species, and discovered a novel sRNA (sr8384) that functions as a crucial regulator of cell growth. Comparative transcriptomic data combined with genetic and biochemical analyses revealed that sr8384 acts as a pleiotropic regulator and controls multiple targets that are associated with crucial biological processes through direct or indirect interactions. Notably, the in vivo expression level of sr8384 determined the cell growth rate, thereby affecting the solvent titer and productivity. These findings indicate the importance of the sr8384-mediated regulatory network in C. acetobutylicum Furthermore, a homolog of sr8384 was discovered and proven to be functional in another important Clostridium species, C. beijerinckii, suggesting the potential broad role of this sRNA in clostridia. Our work showcases a previously unknown potent and complex role of sRNAs in clostridia, providing new opportunities for understanding and engineering these anaerobes.IMPORTANCE The uses of sRNAs as new resources for functional studies and strain modifications are promising strategies in microorganisms. However, these crucial regulatory molecules have hardly been explored in industrially important solventogenic clostridia. Here, we identified sr8384 as a novel determinant sRNA controlling the cell growth of solventogenic Clostridium acetobutylicum Based on a detailed functional analysis, we further reveal the pleiotropic function of sr8384 and its multiple direct and indirect crucial targets, which represents a valuable source for understanding and optimizing this anaerobe. Of note, manipulation of this sRNA achieves improved cell growth and solvent synthesis. Our findings provide a new perspective for future studies on regulatory sRNAs in clostridia.
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17
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Role of efflux in enhancing butanol tolerance of bacteria. J Biotechnol 2020; 320:17-27. [PMID: 32553531 DOI: 10.1016/j.jbiotec.2020.06.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 06/02/2020] [Accepted: 06/12/2020] [Indexed: 12/11/2022]
Abstract
N-butanol, a valued solvent and potential fuel extender, could possibly be produced by fermentation using either native producers, i.e. solventogenic Clostridia, or engineered platform organisms such as Escherichia coli or Pseudomonas species, if the main process obstacle, a low final butanol concentration, could be overcome. A low final concentration of butanol is the result of its high toxicity to production cells. Nevertheless, bacteria have developed several mechanisms to cope with this toxicity and one of them is active butanol efflux. This review presents information about a few well characterized butanol efflux pumps from Gram-negative bacteria (P. putida and E. coli) and summarizes knowledge about putative butanol efflux systems in Gram-positive bacteria.
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18
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Effects of Spo0A on Clostridium acetobutylicum with an emphasis on biofilm formation. World J Microbiol Biotechnol 2020; 36:80. [PMID: 32444896 DOI: 10.1007/s11274-020-02859-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 05/18/2020] [Indexed: 02/08/2023]
Abstract
Clostridium acetobutylicum is a well-known strain for biofuel production. In previous work, it was found that this strain formed biofilm readily during fermentation processes. Biofilm formation could protect cells and enhance productivities under environmental stresses in our previous work. To explore the molecular mechanism of biofilm formation, Spo0A of C. acetobutylicum was selected to investigate its influences on biofilm formation and other physiological performances. When spo0A gene was disrupted, the spo0A mutant could hardly form biofilm. The aggregation and adhesion abilities of the spo0A mutant as well as its swarming motility were dramatically reduced compared to those of wild type strain. Sporulation was also negatively influenced by spo0A disruption, and solvent production was almost undetectable in the spo0A mutant fermentation. Furthermore, proteomic differences between wild type strain and the spo0A mutant were consistent with physiological performances. This is the first study confirming a genetic clue to C. acetobutylicum biofilm and will be valuable for biofilm optimization through genetic engineering in the future.
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19
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Yang Y, Lang N, Zhang L, Wu H, Jiang W, Gu Y. A novel regulatory pathway consisting of a two-component system and an ABC-type transporter contributes to butanol tolerance in Clostridium acetobutylicum. Appl Microbiol Biotechnol 2020; 104:5011-5023. [DOI: 10.1007/s00253-020-10555-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 02/23/2020] [Accepted: 03/16/2020] [Indexed: 11/28/2022]
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20
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Ferrous-Iron-Activated Transcriptional Factor AdhR Regulates Redox Homeostasis in Clostridium beijerinckii. Appl Environ Microbiol 2020; 86:AEM.02782-19. [PMID: 32005735 DOI: 10.1128/aem.02782-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 01/27/2020] [Indexed: 11/20/2022] Open
Abstract
The AdhR regulatory protein is an activator of σ54-dependent transcription of adhA1 and adhA2 genes, which are required for alcohol synthesis in Clostridium beijerinckii Here, we identified the signal perceived by AdhR and determined the regulatory mechanism of AdhR activity. By assaying the activity of AdhR in N-terminally truncated forms, a negative control mechanism of AdhR activity was identified in which the central AAA+ domain is subject to repression by the N-terminal GAF and PAS domains. Binding of Fe2+ to the GAF domain was found to relieve intramolecular repression and stimulate the ATPase activity of AdhR, allowing the AdhR to activate transcription. This control mechanism enables AdhR to regulate transcription of adhA1 and adhA2 in response to cellular redox status. The mutants deficient in AdhR or σ54 showed large shifts in intracellular redox state indicated by the NADH/NAD+ ratio under conditions of increased electron availability or oxidative stress. We demonstrated that the Fe2+-activated transcriptional regulator AdhR and σ54 control alcohol synthesis to maintain redox homeostasis in clostridial cells. Expression of N-terminally truncated forms of AdhR resulted in improved solvent production by C. beijerinckii IMPORTANCE Solventogenic clostridia are anaerobic bacteria that can produce butanol, ethanol, and acetone, which can be used as biofuels or building block chemicals. Here, we show that AdhR, a σ54-dependent transcriptional activator, senses the intracellular redox status and controls alcohol synthesis in Clostridium beijerinckii AdhR provides a new example of a GAF domain coordinating a mononuclear non-heme iron to sense and transduce the redox signal. Our study reveals a previously unrecognized functional role of σ54 in control of cellular redox balance and provides new insights into redox signaling and regulation in clostridia. Our results reveal AdhR as a novel engineering target for improving solvent production by C. beijerinckii and other solventogenic clostridia.
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21
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Guo J, Chia GW, Berezhnoy NV, Cazenave-Gassiot A, Kjelleberg S, Hinks J, Mu Y, Seviour T. Bacterial lipopolysaccharide core structures mediate effects of butanol ingress. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183150. [DOI: 10.1016/j.bbamem.2019.183150] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 11/07/2019] [Accepted: 12/06/2019] [Indexed: 12/13/2022]
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22
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Yang B, Nie X, Gu Y, Jiang W, Yang C. Control of solvent production by sigma-54 factor and the transcriptional activator AdhR in Clostridium beijerinckii. Microb Biotechnol 2019; 13:328-338. [PMID: 31691520 PMCID: PMC7017808 DOI: 10.1111/1751-7915.13505] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Revised: 10/09/2019] [Accepted: 10/09/2019] [Indexed: 11/30/2022] Open
Abstract
Clostridia are obligate anaerobic bacteria that can produce solvents such as acetone, butanol and ethanol. Alcohol dehydrogenases (ADHs) play a key role in solvent production; however, their regulatory mechanisms remain largely unknown. In this study, we characterized the regulatory mechanisms of two ADH-encoding genes in C. beijerinckii. SigL (sigma factor σ54 ) was found to be required for transcription of adhA1 and adhA2 genes. Moreover, a novel transcriptional activator AdhR was identified, which binds to the σ54 promoter and activates σ54 -dependent transcription of adhA1 and adhA2. Clostridia beijerinckii mutants deficient in SigL or AdhR showed severely impaired butanol and ethanol production as well as altered acetone and butyrate synthesis. Overexpression of SigL resulted in significantly improved solvent production by C. beijerinckii when butyrate was added to cultures. Our results reveal SigL as a novel engineering target for improving solvent production by C. beijerinckii and other solvent-producing clostridia. Moreover, this study gains an insight into regulation of alcohol metabolism in diverse clostridia.
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Affiliation(s)
- Bin Yang
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Xiaoqun Nie
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Yang Gu
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Weihong Jiang
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Chen Yang
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
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23
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Guo J, Ho JCS, Chin H, Mark AE, Zhou C, Kjelleberg S, Liedberg B, Parikh AN, Cho NJ, Hinks J, Mu Y, Seviour T. Response of microbial membranes to butanol: interdigitation vs. disorder. Phys Chem Chem Phys 2019; 21:11903-11915. [PMID: 31125035 DOI: 10.1039/c9cp01469a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Biobutanol production by fermentation is potentially a sustainable alternative to butanol production from fossil fuels. However, the toxicity of butanol to fermentative bacteria, resulting largely from cell membrane fluidization, limits production titers and is a major factor limiting the uptake of the technology. Here, studies were undertaken, in vitro and in silico, on the butanol effects on a representative bacterial (i.e. Escherichia coli) inner cell membrane. A critical butanol : lipid ratio for stability of 2 : 1 was observed, computationally, consistent with complete interdigitation. However, at this ratio the bilayer was ∼20% thicker than for full interdigitation. Furthermore, butanol intercalation induced acyl chain bending and increased disorder, measured as a 27% lateral diffusivity increase experimentally in a supported lipid bilayer. There was also a monophasic Tm reduction in butanol-treated large unilamellar vesicles. Both behaviours are inconsistent with an interdigitated gel. Butanol thus causes only partial interdigitation at physiological temperatures, due to butanol accumulating at the phospholipid headgroups. Acyl tail disordering (i.e. splaying and bending) fills the subsequent voids. Finally, butanol short-circuits the bilayer and creates a coupled system where interdigitated and splayed phospholipids coexist. These findings will inform the design of strategies targeting bilayer stability for increasing biobutanol production titers.
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Affiliation(s)
- Jingjing Guo
- Singapore Centre for Environmental Sciences Engineering (SCELSE), Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore.
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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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Liposomes as models for membrane integrity. Biochem Soc Trans 2019; 47:919-932. [PMID: 31085615 DOI: 10.1042/bst20190123] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 04/18/2019] [Accepted: 04/23/2019] [Indexed: 12/23/2022]
Abstract
Biological membranes form the boundaries to cells. They are integral to cellular function, retaining the valuable components inside and preventing access of unwanted molecules. Many different classes of molecules demonstrate disruptive properties to the plasma membrane. These include alcohols, detergents and antimicrobial agents. Understanding this disruption and the mechanisms by which it can be mitigated is vital for improved therapeutics as well as enhanced industrial processes where the compounds produced can be toxic to the membrane. This mini-review describes the most common molecules that disrupt cell membranes along with a range of in vitro liposome-based techniques that can be used to monitor and delineate these disruptive processes.
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Liao Z, Suo Y, Xue C, Fu H, Wang J. Improving the fermentation performance of Clostridium acetobutylicum ATCC 824 by strengthening the VB1 biosynthesis pathway. Appl Microbiol Biotechnol 2018; 102:8107-8119. [DOI: 10.1007/s00253-018-9208-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 06/20/2018] [Accepted: 06/27/2018] [Indexed: 11/24/2022]
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Improvement of butanol production by the development and co-culture of C. acetobutylicum TSH1 and B. cereus TSH2. Appl Microbiol Biotechnol 2018; 102:6753-6763. [DOI: 10.1007/s00253-018-9151-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 05/17/2018] [Accepted: 05/29/2018] [Indexed: 01/07/2023]
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Patakova P, Kolek J, Sedlar K, Koscova P, Branska B, Kupkova K, Paulova L, Provaznik I. Comparative analysis of high butanol tolerance and production in clostridia. Biotechnol Adv 2018; 36:721-738. [DOI: 10.1016/j.biotechadv.2017.12.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 12/05/2017] [Accepted: 12/12/2017] [Indexed: 12/24/2022]
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Liu D, Yang Z, Wang P, Niu H, Zhuang W, Chen Y, Wu J, Zhu C, Ying H, Ouyang P. Towards acetone-uncoupled biofuels production in solventogenic Clostridium through reducing power conservation. Metab Eng 2018; 47:102-112. [DOI: 10.1016/j.ymben.2018.03.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 03/11/2018] [Accepted: 03/11/2018] [Indexed: 12/22/2022]
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Kushwaha D, Srivastava N, Mishra I, Upadhyay SN, Mishra PK. Recent trends in biobutanol production. REV CHEM ENG 2018. [DOI: 10.1515/revce-2017-0041] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Abstract
Finite availability of conventional fossil carbonaceous fuels coupled with increasing pollution due to their overexploitation has necessitated the quest for renewable fuels. Consequently, biomass-derived fuels are gaining importance due to their economic viability and environment-friendly nature. Among various liquid biofuels, biobutanol is being considered as a suitable and sustainable alternative to gasoline. This paper reviews the present state of the preprocessing of the feedstock, biobutanol production through fermentation and separation processes. Low butanol yield and its toxicity are the major bottlenecks. The use of metabolic engineering and integrated fermentation and product recovery techniques has the potential to overcome these challenges. The application of different nanocatalysts to overcome the existing challenges in the biobutanol field is gaining much interest. For the sustainable production of biobutanol, algae, a third-generation feedstock has also been evaluated.
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Affiliation(s)
- Deepika Kushwaha
- Department of Chemical Engineering and Technology, Indian Institute of Technology (BHU) , Varanasi 221005 , India
| | - Neha Srivastava
- Department of Chemical Engineering and Technology, Indian Institute of Technology (BHU) , Varanasi 221005 , India
| | - Ishita Mishra
- Green Brick Eco Solutions, Okha Industrial Area , New Delhi 110020 , India
| | - Siddh Nath Upadhyay
- Department of Chemical Engineering and Technology, Indian Institute of Technology (BHU) , Varanasi 221005 , India
| | - Pradeep Kumar Mishra
- Department of Chemical Engineering and Technology, Indian Institute of Technology (BHU) , Varanasi 221005 , India
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A Novel Dual- cre Motif Enables Two-Way Autoregulation of CcpA in Clostridium acetobutylicum. Appl Environ Microbiol 2018; 84:AEM.00114-18. [PMID: 29427432 DOI: 10.1128/aem.00114-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 01/26/2018] [Indexed: 11/20/2022] Open
Abstract
The master regulator CcpA (catabolite control protein A) manages a large and complex regulatory network that is essential for cellular physiology and metabolism in Gram-positive bacteria. Although CcpA can affect the expression of target genes by binding to a cis-acting catabolite-responsive element (cre), whether and how the expression of CcpA is regulated remain poorly explored. Here, we report a novel dual-cre motif that is employed by the CcpA in Clostridium acetobutylicum, a typical solventogenic Clostridium species, for autoregulation. Two cre sites are involved in CcpA autoregulation, and they reside in the promoter and coding regions of CcpA. In this dual-cre motif, creP, in the promoter region, positively regulates ccpA transcription, whereas creORF, in the coding region, negatively regulates this transcription, thus enabling two-way autoregulation of CcpA. Although CcpA bound creP more strongly than creORFin vitro, the in vivo assay showed that creORF-based repression dominates CcpA autoregulation during the entire fermentation. Finally, a synonymous mutation of creORF was made within the coding region, achieving an increased intracellular CcpA expression and improved cellular performance. This study provides new insights into the regulatory role of CcpA in C. acetobutylicum and, moreover, contributes a new engineering strategy for this industrial strain.IMPORTANCE CcpA is known to be a key transcription factor in Gram-positive bacteria. However, it is still unclear whether and how the intracellular CcpA level is regulated, which may be essential for maintaining normal cell physiology and metabolism. We discovered here that CcpA employs a dual-cre motif to autoregulate, enabling dynamic control of its own expression level during the entire fermentation process. This finding answers the questions above and fills a void in our understanding of the regulatory network of CcpA. Interference in CcpA autoregulation leads to improved cellular performance, providing a new useful strategy in genetic engineering of C. acetobutylicum Since CcpA is widespread in Gram-positive bacteria, including pathogens, this dual-cre-based CcpA autoregulation would be valuable for increasing our understanding of CcpA-based global regulation in bacteria.
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Ramió-Pujol S, Ganigué R, Bañeras L, Colprim J. Effect of ethanol and butanol on autotrophic growth of model homoacetogens. FEMS Microbiol Lett 2018; 365:4956523. [DOI: 10.1093/femsle/fny084] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 03/28/2018] [Indexed: 01/13/2023] Open
Affiliation(s)
- Sara Ramió-Pujol
- Group of Molecular Microbial Ecology, Institute of Aquatic Ecology (IEA), University of Girona, Ma Aurèlia Capmany, 40, E-17003 Girona, Catalonia, Spain
- LEQUIA, Institute of the Environment, University of Girona, Ma Aurèlia Capmany, 69, E-17003 Girona, Catalonia, Spain
| | - Ramon Ganigué
- Center for Microbiology Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - Lluís Bañeras
- Group of Molecular Microbial Ecology, Institute of Aquatic Ecology (IEA), University of Girona, Ma Aurèlia Capmany, 40, E-17003 Girona, Catalonia, Spain
| | - Jesús Colprim
- LEQUIA, Institute of the Environment, University of Girona, Ma Aurèlia Capmany, 69, E-17003 Girona, Catalonia, Spain
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Zhang J, Zong W, Hong W, Zhang ZT, Wang Y. Exploiting endogenous CRISPR-Cas system for multiplex genome editing in Clostridium tyrobutyricum and engineer the strain for high-level butanol production. Metab Eng 2018. [PMID: 29530750 DOI: 10.1016/j.ymben.2018.03.007] [Citation(s) in RCA: 124] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Although CRISPR-Cas9/Cpf1 have been employed as powerful genome engineering tools, heterologous CRISPR-Cas9/Cpf1 are often difficult to introduce into bacteria and archaea due to their severe toxicity. Since most prokaryotes harbor native CRISPR-Cas systems, genome engineering can be achieved by harnessing these endogenous immune systems. Here, we report the exploitation of Type I-B CRISPR-Cas of Clostridium tyrobutyricum for genome engineering. In silico CRISPR array analysis and plasmid interference assay revealed that TCA or TCG at the 5'-end of the protospacer was the functional protospacer adjacent motif (PAM) for CRISPR targeting. With a lactose inducible promoter for CRISPR array expression, we significantly decreased the toxicity of CRISPR-Cas and enhanced the transformation efficiency, and successfully deleted spo0A with an editing efficiency of 100%. We further evaluated effects of the spacer length on genome editing efficiency. Interestingly, spacers ≤ 20 nt led to unsuccessful transformation consistently, likely due to severe off-target effects; while a spacer of 30-38 nt is most appropriate to ensure successful transformation and high genome editing efficiency. Moreover, multiplex genome editing for the deletion of spo0A and pyrF was achieved in a single transformation, with an editing efficiency of up to 100%. Finally, with the integration of the alcohol dehydrogenase gene (adhE1 or adhE2) to replace cat1 (the key gene responsible for butyrate production and previously could not be deleted), two mutants were created for n-butanol production, with the butanol titer reached historically record high of 26.2 g/L in a batch fermentation. Altogether, our results demonstrated the easy programmability and high efficiency of endogenous CRISPR-Cas. The developed protocol herein has a broader applicability to other prokaryotes containing endogenous CRISPR-Cas systems. C. tyrobutyricum could be employed as an excellent platform to be engineered for biofuel and biochemical production using the CRISPR-Cas based genome engineering toolkit.
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Affiliation(s)
- Jie Zhang
- Department of Biosystems Engineering, Auburn University, Auburn, AL 36849, USA
| | - Wenming Zong
- Department of Biosystems Engineering, Auburn University, Auburn, AL 36849, USA; School of Engineering, Anhui Agricultural University, Hefei 230036, China
| | - Wei Hong
- Department of Biosystems Engineering, Auburn University, Auburn, AL 36849, USA; Key Laboratory of Endemic and Ethnic Diseases (Guizhou Medical University), Ministry of Education, Guiyang 550000, China
| | - Zhong-Tian Zhang
- Department of Biosystems Engineering, Auburn University, Auburn, AL 36849, USA
| | - Yi Wang
- Department of Biosystems Engineering, Auburn University, Auburn, AL 36849, USA; Center for Bioenergy and Bioproducts, Auburn University, Auburn, AL 36849, USA.
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The industrial anaerobe Clostridium acetobutylicum uses polyketides to regulate cellular differentiation. Nat Commun 2017; 8:1514. [PMID: 29138399 PMCID: PMC5686105 DOI: 10.1038/s41467-017-01809-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 10/17/2017] [Indexed: 11/24/2022] Open
Abstract
Polyketides are an important class of bioactive small molecules valued not only for their diverse therapeutic applications, but also for their role in controlling interesting biological phenotypes in their producing organisms. While numerous polyketides are known to be derived from aerobic organisms, only a single family of polyketides has been identified from anaerobic organisms. Here we uncover a family of polyketides native to the anaerobic bacterium Clostridium acetobutylicum, an organism well-known for its historical use as an industrial producer of the organic solvents acetone, butanol, and ethanol. Through mutational analysis and chemical complementation assays, we demonstrate that these polyketides act as chemical triggers of sporulation and granulose accumulation in this strain. This study represents a significant addition to the body of work demonstrating the existence and importance of polyketides in anaerobes, and showcases a strategy of manipulating the secondary metabolism of an organism to improve traits relevant for industrial applications. Polyketides are secondary metabolites mainly found in aerobic organisms with wide applications in medicine and agriculture. Here, the authors uncover new polyketides native to the anaerobic bacterium Clostridium acetobutylicum and show their role in triggering sporulation and granulose accumulation.
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35
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Li D, Zhang K, Chen L, Ding M, Zhao M, Chen S. Selection of Schizochytrium limacinum mutants based on butanol tolerance. ELECTRON J BIOTECHN 2017. [DOI: 10.1016/j.ejbt.2017.08.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
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Popovic J, Ye X, Haluska A, Finneran KT. Ferric iron and extracellular electron shuttling increase xylose utilization and butanol production during fermentation with multiple solventogenic bacteria. Appl Microbiol Biotechnol 2017; 101:8053-8061. [PMID: 28963627 DOI: 10.1007/s00253-017-8533-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 09/05/2017] [Accepted: 09/13/2017] [Indexed: 01/18/2023]
Abstract
Xylose is the second most abundant sugar derived from lignocellulose; it is considered less desirable than glucose for fermentation, and strategies that specifically increase xylose utilization in wild-type cells are goals for biofuel production. Xylose consumption, butanol production, and hydrogen production increased in both Clostridium beijerinckii and a novel solventogenic bacterium (strain DC-1) when anthraquinone-2,6,-disulfonate (AQDS) or riboflavin were used as redox mediators to transfer electrons to poorly crystalline Fe(OH)3 as an extracellular electron sink. Strain DC-1 was most closely related to Rhizobiales bacterium Mfc52 based on 95% 16S rRNA gene sequence similarity, which demonstrates that this response is not limited to a single genus of xylose-fermenting bacteria. Xylose utilization and butanol production were negligible in control incubations containing cells plus 3% (w/v) xylose alone during a 10-day batch fermentation, for both strains tested (n-butanol titers of 0.05 g L-1). Micromolar concentrations of AQDS and riboflavin were added as electron shuttling compounds with poorly crystalline Fe(OH)3 as an insoluble electron acceptor, and respective n-butanol titers increased to 6.35 and 7.46 g L-1. Increases in xylose consumption for the iron treatments were relatively high, from less than 0.49 g L-1 (xylose alone, no iron or electron shuttling molecules) to 25.98 and 29.15 g L-1 for the AQDS and riboflavin treatments, respectively. Hydrogen production was also 3.68 times greater for the AQDS treatment and 5.27 greater for the riboflavin treatment relative to controls. Strain DC-1 data were similar, again indicating that the effects are not specific to the genus Clostridium.
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Affiliation(s)
- Jovan Popovic
- BioTechnology Institute, University of Minnesota, 1479 Gortner Ave, Falcon Heights, MN, 55108, USA
| | - Xiaofeng Ye
- Novozymes North America, Franklinton, NC, 27525, USA
| | - Anne Haluska
- Civil and Environmental Engineering, University of Illinois, Urbana, IL, 61801, USA
| | - Kevin T Finneran
- Department of Environmental Engineering and Earth Sciences, Clemson University, 105 Collings St., Clemson, SC, USA.
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Jiménez-Bonilla P, Wang Y. In situ biobutanol recovery from clostridial fermentations: a critical review. Crit Rev Biotechnol 2017; 38:469-482. [PMID: 28920460 DOI: 10.1080/07388551.2017.1376308] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Butanol is a precursor of many industrial chemicals, and a fuel that is more energetic, safer and easier to handle than ethanol. Fermentative biobutanol can be produced using renewable carbon sources such as agro-industrial residues and lignocellulosic biomass. Solventogenic clostridia are known as the most preeminent biobutanol producers. However, until now, solvent production through the fermentative routes is still not economically competitive compared to the petrochemical approaches, because the butanol is toxic to their own producer bacteria, and thus, the production capability is limited by the butanol tolerance of producing cells. In order to relieve butanol toxicity to the cells and improve the butanol production, many recovery strategies (either in situ or downstream of the fermentation) have been attempted by many researchers and varied success has been achieved. In this article, we summarize in situ recovery techniques that have been applied to butanol production through Clostridium fermentation, including liquid-liquid extraction, perstraction, reactive extraction, adsorption, pervaporation, vacuum fermentation, flash fermentation and gas stripping. We offer a prospective and an opinion about the past, present and the future of these techniques, such as the application of advanced membrane technology and use of recent extractants, including polymer solutions and ionic liquids, as well as the application of these techniques to assist the in situ synthesis of butanol derivatives.
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Affiliation(s)
- Pablo Jiménez-Bonilla
- a Department of Biosystems Engineering , Auburn University , Auburn , AL , USA.,b Laboratory of Natural Products and Biological Assays (LAPRONEB), Chemistry Department , National University (UNA) , Heredia , Costa Rica
| | - Yi Wang
- a Department of Biosystems Engineering , Auburn University , Auburn , AL , USA.,c Center for Bioenergy and Bioproducts , Auburn University , Auburn , AL , USA
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Shen S, Gu Y, Chai C, Jiang W, Zhuang Y, Wang Y. Enhanced alcohol titre and ratio in carbon monoxide-rich off-gas fermentation of Clostridium carboxidivorans through combination of trace metals optimization with variable-temperature cultivation. BIORESOURCE TECHNOLOGY 2017; 239:236-243. [PMID: 28521234 DOI: 10.1016/j.biortech.2017.04.099] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 04/23/2017] [Accepted: 04/24/2017] [Indexed: 06/07/2023]
Abstract
Bioconversion of C1 gases to produce chemicals has good application prospects. Here, the combination of trace metals optimization using a statistical method with variable-temperature cultivation was used to enhance alcohol synthesis during CO-rich off-gas fermentation by Clostridium carboxidivorans P7. Based on ATCC medium 1754, the optimum concentration of the trace metals was found to be 5-fold Ni2+, Co2+, SeO42+, and WO42+; 3.48-fold Cu2+; 0.55-fold MoO42+; 0.5-fold Zn2+ and (NH4)2SO4·FeSO4·6H2O; and additional 44.32μM FeCl3·6H2O. The production of alcohol and organic acid changed to 4.40g/L and 0.50g/L from 2.16g/L and 2.37g/L, respectively, yielding an increase of alcohol-to-product ratio from 47.7% to 89.8%. By fermenting with the optimized medium and timed control of the incubation temperature (37°C [0-24h]-25°C [24-144h]), the alcohol titre further increased to 6.97g/L with 1.67g/L butanol and 1.33g/L hexanol, exceeding those previously reported for strain P7.
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Affiliation(s)
- Shaohuang Shen
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, 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
| | - 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
| | - 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
| | - Yingping Zhuang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Yonghong Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China.
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Adenine Addition Restores Cell Viability and Butanol Production in Clostridium saccharoperbutylacetonicum N1-4 (ATCC 13564) Cultivated at 37°C. Appl Environ Microbiol 2017; 83:AEM.02960-16. [PMID: 28130303 DOI: 10.1128/aem.02960-16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 01/20/2017] [Indexed: 12/11/2022] Open
Abstract
We have developed butanol-producing consolidated bioprocessing from cellulosic substrates through coculture of cellulolytic clostridia and butanol-producing Clostridium saccharoperbutylacetonicum strain N1-4. However, the butanol fermentation by strain N1-4 (which has an optimal growth temperature of 30°C) is sensitive to the higher cultivation temperature of 37°C; the nature of this deleterious effect remains unclear. Comparison of the intracellular metabolites of strain N1-4 cultivated at 30°C and 37°C revealed decreased levels of multiple primary metabolites (notably including nucleic acids and cofactors) during growth at the higher temperature. Supplementation of the culture medium with 250 mg/liter adenine enhanced both cell growth (with the optical density at 600 nm increasing from 4.3 to 10.2) and butanol production (increasing from 3.9 g/liter to 9.6 g/liter) at 37°C, compared to those obtained without adenine supplementation, such that the supplemented 37°C culture exhibited growth and butanol production approaching those observed at 30°C in the absence of adenine supplementation. These improved properties were based on the maintenance of cell viability. We further showed that adenine supplementation enhanced cell viability during growth at 37°C by maintaining ATP levels and inhibiting spore formation. This work represents the first demonstration (to our knowledge) of the importance of adenine-related metabolism for clostridial butanol production, suggesting a new means of enhancing target pathways based on metabolite levels.IMPORTANCE Metabolomic analysis revealed decreased levels of multiple primary metabolites during growth at 37°C, compared to 30°C, in C. saccharoperbutylacetonicum strain N1-4. We found that adenine supplementation restored the cell growth and butanol production of strain N1-4 at 37°C. The effects of adenine supplementation reflected the maintenance of cell viability originating from the maintenance of ATP levels and the inhibition of spore formation. Thus, our metabolomic analysis identified the depleted metabolites that were required to maintain cell viability. Our strategy, which is expected to be applicable to a wide range of organisms, permits the identification of the limiting metabolic pathway, which can serve as a new target for molecular breeding. The other novel finding of this work is that adenine supplementation inhibits clostridial spore formation. The mechanism linking spore formation and metabolomic status in butanol-producing clostridia is expected to be the focus of further research.
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A Flexible Binding Site Architecture Provides New Insights into CcpA Global Regulation in Gram-Positive Bacteria. mBio 2017; 8:mBio.02004-16. [PMID: 28119470 PMCID: PMC5263246 DOI: 10.1128/mbio.02004-16] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Catabolite control protein A (CcpA) is the master regulator in Gram-positive bacteria that mediates carbon catabolite repression (CCR) and carbon catabolite activation (CCA), two fundamental regulatory mechanisms that enable competitive advantages in carbon catabolism. It is generally regarded that CcpA exerts its regulatory role by binding to a typical 14- to 16-nucleotide (nt) consensus site that is called a catabolite response element (cre) within the target regions. However, here we report a previously unknown noncanonical flexible architecture of the CcpA-binding site in solventogenic clostridia, providing new mechanistic insights into catabolite regulation. This novel CcpA-binding site, named crevar, has a unique architecture that consists of two inverted repeats and an intervening spacer, all of which are variable in nucleotide composition and length, except for a 6-bp core palindromic sequence (TGTAAA/TTTACA). It was found that the length of the intervening spacer of crevar can affect CcpA binding affinity, and moreover, the core palindromic sequence of crevar is the key structure for regulation. Such a variable architecture of crevar shows potential importance for CcpA’s diverse and fine regulation. A total of 103 potential crevar sites were discovered in solventogenic Clostridium acetobutylicum, of which 42 sites were picked out for electrophoretic mobility shift assays (EMSAs), and 30 sites were confirmed to be bound by CcpA. These 30 crevar sites are associated with 27 genes involved in many important pathways. Also of significance, the crevar sites are found to be widespread and function in a great number of taxonomically different Gram-positive bacteria, including pathogens, suggesting their global role in Gram-positive bacteria. In Gram-positive bacteria, the global regulator CcpA controls a large number of important physiological and metabolic processes. Although a typical consensus CcpA-binding site, cre, has been identified, it remains poorly explored for the diversity of CcpA-mediated catabolite regulation. Here, we discovered a novel flexible CcpA-binding site architecture (crevar) that is highly variable in both length and base composition but follows certain principles, providing new insights into how CcpA can differentially recognize a variety of target genes to form a complicated regulatory network. A comprehensive search further revealed the wide distribution of crevar sites in Gram-positive bacteria, indicating it may have a universal function. This finding is the first to characterize such a highly flexible transcription factor-binding site architecture, which would be valuable for deeper understanding of CcpA-mediated global catabolite regulation in bacteria.
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ARTP mutation and genome shuffling of ABE fermentation symbiotic system for improvement of butanol production. Appl Microbiol Biotechnol 2017; 101:2189-2199. [DOI: 10.1007/s00253-017-8093-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 12/20/2016] [Accepted: 12/23/2016] [Indexed: 12/20/2022]
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42
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Zhang J, Taylor S, Wang Y. Effects of end products on fermentation profiles in Clostridium carboxidivorans P7 for syngas fermentation. BIORESOURCE TECHNOLOGY 2016; 218:1055-63. [PMID: 27459682 DOI: 10.1016/j.biortech.2016.07.071] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 07/18/2016] [Accepted: 07/19/2016] [Indexed: 05/28/2023]
Abstract
Clostridium carboxidivorans P7 is a strict anaerobic bacterium capable of converting syngas to biofuels. However, its fermentation profiles is poorly understood. Here, various end-products, including acetic acid, butyric acid, hexanoic acid, ethanol and butanol were supplemented to evaluate their effects on fermentation profiles in C. carboxidivorans at two temperatures. At 37°C, fatty acids addition likely led to more corresponding alcohols production. At 25°C, C2 and C4 fatty acids supplementation resulted in more corresponding higher fatty acids, while supplemented hexanoic acid increased yields of C2 and C4 fatty acids and hexanol. Supplementation of ethanol or butanol caused increased production of C2 and C4 acids at both temperatures; however, long-chain alcohols were still more likely produced at lower temperature. In conclusion, fermentation profiles of C. carboxidivorans can be changed in respond to pre-added end-products and carbon flow may be redirected to desired products by controlling culture conditions.
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Affiliation(s)
- Jie Zhang
- Department of Biosystems Engineering, Auburn University, Auburn, AL 36849, USA
| | - Steven Taylor
- Department of Biosystems Engineering, Auburn University, Auburn, AL 36849, USA; Center for Bioenergy and Bioproducts, Auburn University, Auburn, AL 36849, USA
| | - Yi Wang
- Department of Biosystems Engineering, Auburn University, Auburn, AL 36849, USA; Center for Bioenergy and Bioproducts, Auburn University, Auburn, AL 36849, USA.
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43
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Johnson TJ, Gibbons JL, Gu L, Zhou R, Gibbons WR. Molecular genetic improvements of cyanobacteria to enhance the industrial potential of the microbe: A review. Biotechnol Prog 2016; 32:1357-1371. [DOI: 10.1002/btpr.2358] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Revised: 08/30/2016] [Indexed: 12/17/2022]
Affiliation(s)
- Tylor J. Johnson
- Dept. of Biology and MicrobiologySouth Dakota State UniversityBrookings SD57007
- Dept. of MicrobiologyThe University of TennesseeKnoxville TN37996
| | - Jaimie L. Gibbons
- Dept. of Biology and MicrobiologySouth Dakota State UniversityBrookings SD57007
| | - Liping Gu
- Dept. of Biology and MicrobiologySouth Dakota State UniversityBrookings SD57007
| | - Ruanbao Zhou
- Dept. of Biology and MicrobiologySouth Dakota State UniversityBrookings SD57007
| | - William R. Gibbons
- Dept. of Biology and MicrobiologySouth Dakota State UniversityBrookings SD57007
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44
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Wang YF, Tian J, Ji ZH, Song MY, Li H. Intracellular metabolic changes of Clostridium acetobutylicum and promotion to butanol tolerance during biobutanol fermentation. Int J Biochem Cell Biol 2016; 78:297-306. [DOI: 10.1016/j.biocel.2016.07.031] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Revised: 07/22/2016] [Accepted: 07/27/2016] [Indexed: 12/16/2022]
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Shen X, Liu D, Liu J, Wang Y, Xu J, Yang Z, Guo T, Niu H, Ying H. Enhanced production of butanol and acetoin by heterologous expression of an acetolactate decarboxylase in Clostridium acetobutylicum. BIORESOURCE TECHNOLOGY 2016; 216:601-606. [PMID: 27285575 DOI: 10.1016/j.biortech.2016.05.121] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 05/28/2016] [Accepted: 05/30/2016] [Indexed: 06/06/2023]
Abstract
Butanol is an important industrial chemical and an attractive transportation fuel. However, the deficiency of reducing equivalents NAD(P)H in butanol fermentation results in a large quantity of oxidation products, which is a major problem limiting the atom economy and economic viability of bio-butanol processes. Here, we integrated the butanol fermentation process with a NADH-generating, acetoin biosynthesis process to improve the butanol production. By overexpressing the α-acetolactate decarboxylase gene alsD from Bacillus subtilis in Clostridium acetobutylicum, acetoin yield was significantly increased at the cost of acetone. After optimization of fermentation conditions, butanol (12.9g/L), acetoin (6.5g/L), and ethanol (1.9g/L) were generated by the recombinant strain, with acetone no more than 1.8g/L. Thus, both mass yield and product value were greatly improved. This study demonstrates that reducing power compensation is effective to improve the atom economy of butanol fermentation, and provides a novel approach to improve the economic viability of bio-butanol production.
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Affiliation(s)
- Xiaoning Shen
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30, Puzhu South Road, Nanjing 211816, China
| | - Dong Liu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30, Puzhu South Road, Nanjing 211816, China.
| | - Jun Liu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30, Puzhu South Road, Nanjing 211816, China
| | - Yanyan Wang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30, Puzhu South Road, Nanjing 211816, China
| | - Jiahui Xu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30, Puzhu South Road, Nanjing 211816, China
| | - Zhengjiao Yang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30, Puzhu South Road, Nanjing 211816, China
| | - Ting Guo
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30, Puzhu South Road, Nanjing 211816, China
| | - Huanqing Niu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30, Puzhu South Road, Nanjing 211816, China
| | - Hanjie Ying
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30, Puzhu South Road, Nanjing 211816, China.
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46
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Johnson TJ, Halfmann C, Zahler JD, Zhou R, Gibbons WR. Increasing the tolerance of filamentous cyanobacteria to next-generation biofuels via directed evolution. ALGAL RES 2016. [DOI: 10.1016/j.algal.2016.06.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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47
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Pomaranski E, Tiquia-Arashiro SM. Butanol tolerance of carboxydotrophic bacteria isolated from manure composts. ENVIRONMENTAL TECHNOLOGY 2016; 37:1970-1982. [PMID: 26809187 DOI: 10.1080/09593330.2015.1137360] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Carboxydotrophic bacteria (carboxydotrophs) have the ability to uptake carbon monoxide (CO) and synthesize butanol. The aims of this study were to determine the butanol tolerance and biological production of butanol carboxydotrophic strains. In this study, 11 carboxydotrophic strains were exposed to increasing n-butanol concentrations (1-3% vol/vol) to determine their effect on growth. Butanol production by the strains was quantified and the identity of the strains was elucidated using 16S rRNA sequencing. The carboxydotrophic strains possessed inherent tolerance to butanol and tolerated up to 3% n-butanol. Among the 11 strains, T1-16, M2-32 and M3-28 were the most tolerant to butanol. The 16S rRNA gene sequence of these strains was similar (99% nucleotide similarity) to the butanol-tolerant strains Bacillus licheniformis YP1A, Pediococcus acidilacti IMUA20068 and Enterococcus faecium IMAU60169, respectively. The carboxydotrophic strains screened in this study have two distinct features: (1) high tolerance to butanol and (2) natural production of low concentration of butanol from CO, which distinguish them from other screened butanol-tolerant strains. The butanol tolerance of these carboxydotrophic strains makes them ideal for genetic studies, particularly the molecular mechanisms that enable them to survive such hostile environmental conditions and the identification of genes that confer tolerance to butanol.
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Affiliation(s)
- Eric Pomaranski
- a Department of Natural Sciences , The University of Michigan , Dearborn , MI , USA
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48
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Changes in the membrane fatty acid composition in Anoxybacillus flavithermus subsp. yunnanensis E13 T as response to solvent stress. Arch Microbiol 2016; 199:1-8. [PMID: 27387529 DOI: 10.1007/s00203-016-1266-9] [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: 01/18/2016] [Revised: 06/28/2016] [Accepted: 07/01/2016] [Indexed: 10/21/2022]
Abstract
Anoxybacillus flavithermus subsp. yunnanensis is currently the first species of strictly thermophilic bacteria that is able to tolerate a broad range of solvents. Unlike most of solvent-tolerant mesophilic bacteria, the bacterium does not synthesize unsaturated fatty acids. Our results revealed that in growing cells of A. flavithermus subsp. yunnanensis E13T, ethanol and toluene resulted in an increase in straight-chain fatty acids, mainly C16:0, leading to a more rigid membrane. Moreover, the increase in straight-chain fatty acids caused by ethanol was much higher than that of toluene. High temperature had little effect on the fatty acid composition by itself, whereas the combined conditions of high temperature and ethanol caused the dramatic increase in straight-chain fatty acids (mainly C16:0), that was balanced by decreasing branched fatty acids. The increase was also temperature dependent. The proportion of C16:0 further increased above 60 °C. No similar evidence was found in four other species of Anoxybacillus. The results suggested that A. flavithermus subsp. yunnanesis seems to develop a different response to solvents compared to its mesophilic counterparts, which consist of an increase in the saturated straight/branched ratio.
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49
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Li Q, Chen J, Minton NP, Zhang Y, Wen Z, Liu J, Yang H, Zeng Z, Ren X, Yang J, Gu Y, Jiang W, Jiang Y, Yang S. CRISPR-based genome editing and expression control systems in Clostridium acetobutylicum and Clostridium beijerinckii. Biotechnol J 2016; 11:961-72. [PMID: 27213844 DOI: 10.1002/biot.201600053] [Citation(s) in RCA: 124] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 05/11/2016] [Accepted: 05/13/2016] [Indexed: 11/05/2022]
Abstract
Solventogenic clostridia are important industrial microorganisms that produce various chemicals and fuels. Effective genetic tools would facilitate physiological studies aimed both at improving our understanding of metabolism and optimizing solvent productivity through metabolic engineering. Here we have developed an all-in-one, CRISPR-based genome editing plasmid, pNICKclos, that can be used to achieve successive rounds of gene editing in Clostridium acetobutylicum ATCC 824 and Clostridium beijerinckii NCIMB 8052 with efficiencies varying from 6.7% to 100% and 18.8% to 100%, respectively. The plasmid specifies the requisite target-specific guide RNA, the gene encoding the Streptococcus pyogenes Cas9 nickase and the genome editing template encompassing the gene-specific homology arms. It can be used to create single target mutants within three days, with a further two days required for the curing of the pNICKclos plasmid ready for a second round of mutagenesis. A S. pyogenes dCas9-mediated gene regulation control system, pdCASclos, was also developed and used in a CRISPRi strategy to successfully repress the expression of spo0A in C. acetobutylicum and C. beijerinckii. The combined application of the established high efficiency CRISPR-Cas9 based genome editing and regulation control systems will greatly accelerate future progress in the understanding and manipulation of metabolism in solventogenic clostridia.
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Affiliation(s)
- Qi Li
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- Graduate University of the Chinese Academy of Sciences, Beijing, China
| | - Jun Chen
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Nigel P Minton
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Ying Zhang
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Zhiqiang Wen
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Jinle Liu
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- Graduate University of the Chinese Academy of Sciences, Beijing, China
| | - Haifeng Yang
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- Graduate University of the Chinese Academy of Sciences, Beijing, China
| | - Zhe Zeng
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- Graduate University of the Chinese Academy of Sciences, Beijing, China
| | - Xiaodan Ren
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- Graduate University of the Chinese Academy of Sciences, Beijing, China
| | - Junjie Yang
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Yang Gu
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Weihong Jiang
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Yu Jiang
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- Shanghai Research and Development Center of Industrial Biotechnology, Shanghai, China
| | - Sheng Yang
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.
- Shanghai Research and Development Center of Industrial Biotechnology, Shanghai, China.
- Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing, China.
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50
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Xue Q, Yang Y, Chen J, Chen L, Yang S, Jiang W, Gu Y. Roles of three AbrBs in regulating two-phase Clostridium acetobutylicum fermentation. Appl Microbiol Biotechnol 2016; 100:9081-9089. [PMID: 27276910 DOI: 10.1007/s00253-016-7638-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 05/14/2016] [Indexed: 12/11/2022]
Abstract
Clostridium acetobutylicum is an important industrial microorganism for n-butanol bioproduction, and its transcription factor AbrB0310 regulates various important cellular processes. However, the roles of two abrB homologues, abrB1941 and abrB3647, have not been determined because they appear inactive during transcription. Here, we performed a detailed investigation into the function of abrB1941 and abrB3647 in C. acetobutylicum. Interestingly, we observed that AbrB3647 exerts an important influence on biphasic fermentation that opposes the influence of AbrB0310, while AbrB1941 might not be essential. When abrB3647 was disrupted using the Targetron system, a greatly improved cellular growth occurred. The following analysis shows that all three AbrBs participated in metabolically regulating acidogenesis, solventogenesis, and a two-phase transition in C. acetobutylicum, but the AbrB0310 and AbrB3647 functions were the most important. Moreover, the target genes subject to AbrB0310 and AbrB3647 regulation closely overlap. Based on these results, we will better understand the roles of the three AbrBs in regulating solventogenic clostridia cell physiology.
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Affiliation(s)
- Qiong Xue
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Yunpeng Yang
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai, 200032, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jun Chen
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai, 200032, China
| | - Lei Chen
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Sheng Yang
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, 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, 300 Fenglin Road, 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, 300 Fenglin Road, Shanghai, 200032, China. .,Shanghai Collaborative Innovation Center for Biomanufacturing Technology, 130 Meilong Road, Shanghai, 200237, China.
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