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Vinayavekhin N, Kongchai W, Piapukiew J, Chavasiri W. Aspergillus niger upregulated glycerolipid metabolism and ethanol utilization pathway under ethanol stress. Microbiologyopen 2019; 9:e00948. [PMID: 31646764 PMCID: PMC6957411 DOI: 10.1002/mbo3.948] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 09/24/2019] [Accepted: 09/27/2019] [Indexed: 11/26/2022] Open
Abstract
The knowledge of how Aspergillus niger responds to ethanol can lead to the design of strains with enhanced ethanol tolerance to be utilized in numerous industrial bioprocesses. However, the current understanding about the response mechanisms of A. niger toward ethanol stress remains quite limited. Here, we first applied a cell growth assay to test the ethanol tolerance of A. niger strain ES4, which was isolated from the wall near a chimney of an ethanol tank of a petroleum company, and found that it was capable of growing in 5% (v/v) ethanol to 30% of the ethanol‐free control level. Subsequently, the metabolic responses of this strain toward ethanol were investigated using untargeted metabolomics, which revealed the elevated levels of triacylglycerol (TAG) in the extracellular components, and of diacylglycerol, TAG, and hydroxy‐TAG in the intracellular components. Lastly, stable isotope labeling mass spectrometry with ethanol‐d6 showed altered isotopic patterns of molecular ions of lipids in the ethanol‐d6 samples, compared with the nonlabeled ethanol controls, suggesting the ability of A. niger ES4 to utilize ethanol as a carbon source. Together, the studies revealed the upregulation of glycerolipid metabolism and ethanol utilization pathway as novel response mechanisms of A. niger ES4 toward ethanol stress, thereby underlining the utility of untargeted metabolomics and the overall approaches as tools for elucidating new biological insights.
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Affiliation(s)
- Nawaporn Vinayavekhin
- Center of Excellence in Natural Products Chemistry, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand.,Biocatalyst and Environmental Biotechnology Research Unit, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Wimonsiri Kongchai
- Center of Excellence in Natural Products Chemistry, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Jittra Piapukiew
- Biocatalyst and Environmental Biotechnology Research Unit, Faculty of Science, Chulalongkorn University, Bangkok, Thailand.,Department of Botany, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Warinthorn Chavasiri
- Center of Excellence in Natural Products Chemistry, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
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Ajit A, Sulaiman AZ, Chisti Y. Production of bioethanol by Zymomonas mobilis in high-gravity extractive fermentations. FOOD AND BIOPRODUCTS PROCESSING 2017. [DOI: 10.1016/j.fbp.2016.12.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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3
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Cope JL, Hammett AJM, Kolomiets EA, Forrest AK, Golub KW, Hollister EB, DeWitt TJ, Gentry TJ, Holtzapple MT, Wilkinson HH. Evaluating the performance of carboxylate platform fermentations across diverse inocula originating as sediments from extreme environments. BIORESOURCE TECHNOLOGY 2014; 155:388-394. [PMID: 24502857 DOI: 10.1016/j.biortech.2013.12.105] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2013] [Revised: 12/22/2013] [Accepted: 12/24/2013] [Indexed: 06/03/2023]
Abstract
To test the hypothesis that microbial communities from saline and thermal sediment environments are pre-adapted to exhibit superior fermentation performances, 501 saline and thermal samples were collected from a wide geographic range. Each sediment sample was screened as inoculum in a 30-day batch fermentation. Using multivariate statistics, the capacity of each community was assessed to determine its ability to degrade a cellulosic substrate and produce carboxylic acids in the context of the inoculum sediment chemistry. Conductance of soils was positively associated with production of particular acids, but negatively associated with conversion efficiency. In situ sediment temperature and conversion efficiency were consistently positively related. Because inoculum characteristics influence carboxylate platform productivity, optimization of the inoculum is an important and realistic goal.
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Affiliation(s)
- Julia L Cope
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843-2132, USA; Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX 77030-2617, USA
| | - Amy Jo M Hammett
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843-2132, USA
| | - Elena A Kolomiets
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843-2132, USA
| | - Andrea K Forrest
- Department of Chemical Engineering, Texas A&M University, College Station, TX 77843-3122, USA
| | - Kristina W Golub
- Department of Chemical Engineering, Texas A&M University, College Station, TX 77843-3122, USA
| | - Emily B Hollister
- Department of Soil and Crop Sciences, Texas A&M University, College Station, TX 77843-2474, USA; Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX 77030-2617, USA
| | - Thomas J DeWitt
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843-2132, USA
| | - Terry J Gentry
- Department of Soil and Crop Sciences, Texas A&M University, College Station, TX 77843-2474, USA
| | - Mark T Holtzapple
- Department of Chemical Engineering, Texas A&M University, College Station, TX 77843-3122, USA
| | - Heather H Wilkinson
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843-2132, USA.
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Pandey J, Khan F, Mahajan V, Pant M, Jain RK, Pandey G. Evidence for vital role of endo-β-N-acetylglucosaminidase in the resistance of Arthrobacter protophormiae RKJ100 towards elevated concentrations of o-nitrobenzoate. Extremophiles 2014; 18:491-500. [PMID: 24562786 DOI: 10.1007/s00792-014-0632-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 01/25/2014] [Indexed: 10/25/2022]
Abstract
Arthrobacter protophormiae RKJ100 was previously characterized for its ability to tolerate extremely high concentrations of o-nitrobenzoate (ONB), a toxic xenobiotic environmental pollutant. The physiological responses of strain RKJ100 to ≥30 mM ONB indicated towards a resistance mechanism manifested via alteration of cell morphology and cell wall structure. In this study, we aim to characterize gene(s) involved in the resistance of strain RKJ100 towards extreme concentrations (i.e. 150 mM) of ONB. Transposon mutagenesis was carried out to generate a mutant library of strain RKJ100, which was then screened for ONB-sensitive mutants. A sensitive mutant was defined and selected as one that could not tolerate ≥30 mM ONB. Molecular and biochemical characterization of this mutant showed that the disruption of endo-β-N-acetylglucosaminidase (ENGase) gene caused the sensitivity. ENGase is an important enzyme for oligosaccharide processing and cell wall recycling in bacteria, fungi, plants and animals. Previous reports have already indicated several possible roles of this enzyme in cellular homeostasis. Results presented here provide the first evidence for its involvement in bacterial resistance towards extreme concentrations of a toxic xenobiotic compound and also suggest that strain RKJ100 employs ENGase as an important component in osmotic shock response for resisting extreme concentrations of ONB.
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Affiliation(s)
- Janmejay Pandey
- Institute of Microbial Technology, Sector 39-A, Chandigarh, 160036, India,
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Tang X, Feng H, Zhang J, Chen WN. Comparative proteomics analysis of engineered Saccharomyces cerevisiae with enhanced biofuel precursor production. PLoS One 2013; 8:e84661. [PMID: 24376832 PMCID: PMC3871657 DOI: 10.1371/journal.pone.0084661] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 11/15/2013] [Indexed: 11/18/2022] Open
Abstract
The yeast Saccharomyces cerevisiae was metabolically modified for enhanced biofuel precursor production by knocking out genes encoding mitochondrial isocitrate dehydrogenase and over-expression of a heterologous ATP-citrate lyase. A comparative iTRAQ-coupled 2D LC-MS/MS analysis was performed to obtain a global overview of ubiquitous protein expression changes in S. cerevisiae engineered strains. More than 300 proteins were identified. Among these proteins, 37 were found differentially expressed in engineered strains and they were classified into specific categories based on their enzyme functions. Most of the proteins involved in glycolytic and pyruvate branch-point pathways were found to be up-regulated and the proteins involved in respiration and glyoxylate pathway were however found to be down-regulated in engineered strains. Moreover, the metabolic modification of S. cerevisiae cells resulted in a number of up-regulated proteins involved in stress response and differentially expressed proteins involved in amino acid metabolism and protein biosynthesis pathways. These LC-MS/MS based proteomics analysis results not only offered extensive information in identifying potential protein-protein interactions, signal pathways and ubiquitous cellular changes elicited by the engineered pathways, but also provided a meaningful biological information platform serving further modification of yeast cells for enhanced biofuel production.
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Affiliation(s)
- Xiaoling Tang
- School of Chemical and Biomedical Engineering, College of Engineering, Nanyang Technological University, Singapore, Singapore
| | - Huixing Feng
- School of Chemical and Biomedical Engineering, College of Engineering, Nanyang Technological University, Singapore, Singapore
| | - Jianhua Zhang
- School of Chemical and Biomedical Engineering, College of Engineering, Nanyang Technological University, Singapore, Singapore
| | - Wei Ning Chen
- School of Chemical and Biomedical Engineering, College of Engineering, Nanyang Technological University, Singapore, Singapore
- * E-mail:
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Lin L, Xu J. Dissecting and engineering metabolic and regulatory networks of thermophilic bacteria for biofuel production. Biotechnol Adv 2013; 31:827-37. [DOI: 10.1016/j.biotechadv.2013.03.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 03/06/2013] [Accepted: 03/10/2013] [Indexed: 01/08/2023]
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Lin L, Ji Y, Tu Q, Huang R, Teng L, Zeng X, Song H, Wang K, Zhou Q, Li Y, Cui Q, He Z, Zhou J, Xu J. Microevolution from shock to adaptation revealed strategies improving ethanol tolerance and production in Thermoanaerobacter. BIOTECHNOLOGY FOR BIOFUELS 2013; 6:103. [PMID: 23875846 PMCID: PMC3751872 DOI: 10.1186/1754-6834-6-103] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 07/17/2013] [Indexed: 05/08/2023]
Abstract
INTRODUCTION The molecular links between shock-response and adaptation remain poorly understood, particularly for extremophiles. This has hindered rational engineering of solvent tolerance and correlated traits (e.g., productivity) in extremophiles. To untangle such molecular links, here we established a model that tracked the microevolution from shock to adaptation in thermophilic bacteria. METHOD Temporal dynamics of genomes and transcriptomes was tracked for Thermoanaerobacter sp. X514 which under increasing exogenous ethanol evolved from ethanol-sensitive wild-type (Strain X) to tolerance of 2%- (XI) and eventually 6%-ethanol (XII). Based on the reconstructed transcriptional network underlying stress tolerance, genetic engineering was employed to improve ethanol tolerance and production in Thermoanaerobacter. RESULTS The spontaneous genome mutation rate (μg) of Thermoanaerobacter sp. X514, calculated at 0.045, suggested a higher mutation rate in thermophile than previously thought. Transcriptomic comparison revealed that shock-response and adaptation were distinct in nature, whereas the transcriptomes of XII resembled those of the extendedly shocked X. To respond to ethanol shock, X employed fructose-specific phosphotransferase system (PTS), Arginine Deiminase (ADI) pathway, alcohol dehydrogenase (Adh) and a distinct mechanism of V-type ATPase. As an adaptation to exogenous ethanol, XI mobilized resistance-nodulation-cell division (RND) efflux system and Adh, whereas XII, which produced higher ethanol than XI, employed ECF-type ϭ24, an alcohol catabolism operon and phase-specific heat-shock proteins (Hsps), modulated hexose/pentose-transport operon structure and reinforced membrane rigidity. Exploiting these findings, we further showed that ethanol productivity and tolerance can be improved simultaneously by overexpressing adh or ϭ24 in X. CONCLUSION Our work revealed thermophilic-bacteria specific features of adaptive evolution and demonstrated a rational strategy to engineer co-evolving industrial traits. As improvements of shock-response, stress tolerance and productivity have been crucial aims in industrial applications employing thermophiles, our findings should be valuable not just to the production of ethanol but also to a wide variety of biofuels and biochemicals.
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Affiliation(s)
- Lu Lin
- BioEnergy Genome Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, P. R. China
| | - Yuetong Ji
- BioEnergy Genome Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, P. R. China
| | - Qichao Tu
- Institute for Environmental Genomics, and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA
| | - Ranran Huang
- BioEnergy Genome Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, P. R. China
| | - Lin Teng
- BioEnergy Genome Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, P. R. China
| | - Xiaowei Zeng
- BioEnergy Genome Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, P. R. China
| | - Houhui Song
- BioEnergy Genome Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, P. R. China
| | - Kun Wang
- BioEnergy Genome Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, P. R. China
| | - Qian Zhou
- BioEnergy Genome Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, P. R. China
| | - Yifei Li
- BioEnergy Genome Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, P. R. China
| | - Qiu Cui
- BioEnergy Genome Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, P. R. China
| | - Zhili He
- Institute for Environmental Genomics, and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA
| | - Jizhong Zhou
- Institute for Environmental Genomics, and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA
| | - Jian Xu
- BioEnergy Genome Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, P. R. China
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Over-expression of stress protein-encoding genes helps Clostridium acetobutylicum to rapidly adapt to butanol stress. Biotechnol Lett 2012; 34:1643-9. [PMID: 22618238 DOI: 10.1007/s10529-012-0951-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 05/05/2012] [Indexed: 10/28/2022]
Abstract
The toxicity of n-butanol in microbial fermentations limits its formation. The stress response of Clostridium acetobutylicum involves various stress proteins and therefore, over-expression of genes encoding stress proteins constitutes an option to improve solvent tolerance. Over-expression of groESL, grpE and htpG, significantly improved butanol tolerance of C. acetobutylicum. Whereas the wild type and vector control strain did not survive 2 % (v/v) butanol for 2 h, the recombinant strains showed 45 % (groESL), 25 % (grpE) and 56 % (htpG), respectively, of the initial c.f.u. after 2 h of butanol exposure. As previously, over-expression of groESL led to higher butanol production rates, but the novel strains over-expressing grpE or htpG produced only 51 and 68 %, respectively, of the wild type butanol concentrations after 72 h clearly differentiating butanol tolerance and production. Not only butanol tolerance but also the adaptation to butanol in successive stress experiments was significantly facilitated by increased levels of GroESL, GrpE and HtpG. Re-transformation and sequence analyses of the plasmids confirmed that not the plasmids, but the host cells evolved to a more robust phenotype.
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Taylor MP, Mulako I, Tuffin M, Cowan D. Understanding physiological responses to pre-treatment inhibitors in ethanologenic fermentations. Biotechnol J 2012; 7:1169-81. [PMID: 22331581 DOI: 10.1002/biot.201100335] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 12/15/2011] [Accepted: 01/17/2012] [Indexed: 11/10/2022]
Abstract
Alcohol-based liquid fuels feature significantly in the political and social agendas of many countries, seeking energy sustainability. It is certain that ethanol will be the entry point for many sustainable processes. Conventional ethanol production using maize- and sugarcane-based carbohydrates with Saccharomyces cerevisiae is well established, while lignocellulose-based processes are receiving growing interest despite posing greater technical and scientific challenges. A significant challenge that arises from the chemical hydrolysis of lignocellulose is the generation of toxic compounds in parallel with the release of sugars. These compounds, collectively termed pre-treatment inhibitors, impair metabolic functionality and growth. Their removal, pre-fermentation or their abatement, via milder hydrolysis, are currently uneconomic options. It is widely acknowledged that a more cost effective strategy is to develop resistant process strains. Here we describe and classify common inhibitors and describe in detail the reported physiological responses that occur in second-generation strains, which include engineered yeast and mesophilic and thermophilic prokaryotes. It is suggested that a thorough understanding of tolerance to common pre-treatment inhibitors should be a major focus in ongoing strain engineering. This review is a useful resource for future metabolic engineering strategies.
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Affiliation(s)
- Mark P Taylor
- TMO Renewables Ltd., The Surrey Research Park, Guildford, UK
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10
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Improving Biomass Sugar Utilization by Engineered Saccharomyces cerevisiae. MICROBIOLOGY MONOGRAPHS 2012. [DOI: 10.1007/978-3-642-21467-7_6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Jang YS, Park JM, Choi S, Choi YJ, Seung DY, Cho JH, Lee SY. Engineering of microorganisms for the production of biofuels and perspectives based on systems metabolic engineering approaches. Biotechnol Adv 2011; 30:989-1000. [PMID: 21889585 DOI: 10.1016/j.biotechadv.2011.08.015] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2011] [Revised: 08/06/2011] [Accepted: 08/17/2011] [Indexed: 12/30/2022]
Abstract
The increasing oil price and environmental concerns caused by the use of fossil fuel have renewed our interest in utilizing biomass as a sustainable resource for the production of biofuel. It is however essential to develop high performance microbes that are capable of producing biofuels with very high efficiency in order to compete with the fossil fuel. Recently, the strategies for developing microbial strains by systems metabolic engineering, which can be considered as metabolic engineering integrated with systems biology and synthetic biology, have been developed. Systems metabolic engineering allows successful development of microbes that are capable of producing several different biofuels including bioethanol, biobutanol, alkane, and biodiesel, and even hydrogen. In this review, the approaches employed to develop efficient biofuel producers by metabolic engineering and systems metabolic engineering approaches are reviewed with relevant example cases. It is expected that systems metabolic engineering will be employed as an essential strategy for the development of microbial strains for industrial applications.
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Affiliation(s)
- Yu-Sin Jang
- Metabolic and Biomolecular Engineering National Research Laboratory, Department of Chemical and Biomolecular Engineering (BK21 Program), BioProcess Engineering Research Center, Center for Systems and Synthetic Biotechnology, Institute for the BioCentury, KAIST, Daejeon, Republic of Korea
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Achievements and perspectives to overcome the poor solvent resistance in acetone and butanol-producing microorganisms. Appl Microbiol Biotechnol 2009; 85:1697-712. [DOI: 10.1007/s00253-009-2390-0] [Citation(s) in RCA: 225] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2009] [Revised: 11/27/2009] [Accepted: 11/28/2009] [Indexed: 11/26/2022]
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Nikodinovic-Runic J, Flanagan M, Hume AR, Cagney G, O'Connor KE. Analysis of the Pseudomonas putida CA-3 proteome during growth on styrene under nitrogen-limiting and non-limiting conditions. Microbiology (Reading) 2009; 155:3348-3361. [DOI: 10.1099/mic.0.031153-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Pseudomonas putida CA-3 is a styrene-degrading bacterium capable of accumulating medium-chain-length polyhydroxyalkanoate (mclPHA) when exposed to limiting concentrations of a nitrogen source in the growth medium. Using shotgun proteomics we analysed global proteome expression in P. putida CA-3 supplied with styrene as the sole carbon and energy source under N-limiting (condition permissive for mclPHA synthesis) and non-limiting (condition non-permissive for mclPHA accumulation) growth conditions in order to provide insight into the molecular response of P. putida CA-3 to limitation of nitrogen when grown on styrene. A total of 1761 proteins were identified with high confidence and the detected proteins could be assigned to functional groups including styrene degradation, energy, nucleotide metabolism, protein synthesis, transport, stress response and motility. Proteins involved in the upper and lower styrene degradation pathway were expressed throughout the 48 h growth period under both nitrogen limitation and excess. Proteins involved in polyhydroxyalkanoate (PHA) biosynthesis, nitrogen assimilation and amino acid transport, and outer membrane proteins were upregulated under nitrogen limitation. PHA accumulation and biosynthesis were only expressed under nitrogen limitation. Nitrogen assimilation proteins were detected on average at twofold higher amounts under nitrogen limitation. Expression of the branched-chain amino acid ABC transporter was up to 16-fold higher under nitrogen-limiting conditions. Branched chain amino acid uptake by nitrogen-limited cultures was also higher than that by non-limited cultures. Outer membrane lipoproteins were expressed at twofold higher levels under nitrogen limitation. This was confirmed by Western blotting (immunochemical detection) of cells grown under nitrogen limitation. Our study provides the first global description of protein expression changes during growth of any organism on styrene and accumulating mclPHA (nitrogen-limited growth).
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Affiliation(s)
- Jasmina Nikodinovic-Runic
- School of Biomolecular and Biomedical Science, Centre for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
| | - Michelle Flanagan
- Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Aisling R. Hume
- School of Biomolecular and Biomedical Science, Centre for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
| | - Gerard Cagney
- Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Kevin E. O'Connor
- School of Biomolecular and Biomedical Science, Centre for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
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Liang Y, Feng Z, Yesuf J, Blackburn JW. Optimization of Growth Medium and Enzyme Assay Conditions for Crude Cellulases Produced by a Novel Thermophilic and Cellulolytic Bacterium, Anoxybacillus sp. 527. Appl Biochem Biotechnol 2009; 160:1841-52. [DOI: 10.1007/s12010-009-8677-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2009] [Accepted: 05/18/2009] [Indexed: 11/29/2022]
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Taylor MP, Eley KL, Martin S, Tuffin MI, Burton SG, Cowan DA. Thermophilic ethanologenesis: future prospects for second-generation bioethanol production. Trends Biotechnol 2009; 27:398-405. [PMID: 19481826 DOI: 10.1016/j.tibtech.2009.03.006] [Citation(s) in RCA: 140] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2009] [Revised: 03/18/2009] [Accepted: 03/26/2009] [Indexed: 10/20/2022]
Abstract
Strategies for improving fermentative ethanol production have focused almost exclusively on the development of processes based on the utilization of the carbohydrate fraction of lignocellulosic material. These so-called 'second-generation' technologies require metabolically engineered production strains that possess a high degree of catabolic versatility and are homoethanologenic. It has been suggested that the production of ethanol at higher temperatures would facilitate process design, and as a result the engineered progeny of Geobacillus thermoglucosidasius, Thermoanerobacterium saccharolyticum and Thermoanerobacter mathranii now form the platform technology of several new biotechnology companies. This review highlights the milestones in the development of these production strains, with particular focus on the development of reliable methods for cell competency, gene deletion or upregulation.
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Biotech paper watch. Biotechnol J 2009. [DOI: 10.1002/biot.200990007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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