101
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Shan Y, Lai Y, Yan A. Metabolic reprogramming under microaerobic and anaerobic conditions in bacteria. Subcell Biochem 2012; 64:159-179. [PMID: 23080250 DOI: 10.1007/978-94-007-5055-5_8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Oxygen has a great impact on the metabolism and physiology of microorganisms. It serves as the most efficient terminal electron acceptor to drive the energy conservation process of cellular respiration and is required in many biosynthetic reactions. Bacteria encounter oxygen fluctuation and limitation during their growth in both natural ecological niches and in laboratory vessels. In response to oxygen limitation, facultative bacteria undergo substantial metabolic reprogramming to switch from the aerobic respiration to either anaerobic respiration, fermentation, or photosynthesis. Two key factors determine the metabolic pathways bacteria adopt under oxygen deprived microaerobic and anaerobic conditions: maximal energy conservation and redox homeostasis. In this chapter, we first describe how the fulfillment of these two key factors governs the metabolic reprogramming of facultative bacteria and how the process is tightly controlled by several global regulatory factors: FNR, ArcBA, as well as NarL and NarP. We then utilizes fermentation of glycerol, a large surplus byproduct of biodiesel industry, as an example to illustrate how environment, process, and strain based approaches can be exploited to manipulate and engineer the anaerobic metabolic pathways so that desirable fermentation products can be achieved with optimal yield.
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Affiliation(s)
- Yue Shan
- School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
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102
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Zeng AP, Sabra W. Microbial production of diols as platform chemicals: Recent progresses. Curr Opin Biotechnol 2011; 22:749-57. [DOI: 10.1016/j.copbio.2011.05.005] [Citation(s) in RCA: 217] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Revised: 05/11/2011] [Accepted: 05/16/2011] [Indexed: 11/24/2022]
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103
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Posada JA, Cardona CA, Gonzalez R. Analysis of the Production Process of Optically Pure d-Lactic Acid from Raw Glycerol Using Engineered Escherichia coli Strains. Appl Biochem Biotechnol 2011; 166:680-99. [DOI: 10.1007/s12010-011-9458-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2011] [Accepted: 11/09/2011] [Indexed: 11/28/2022]
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104
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Trchounian K, Pinske C, Sawers RG, Trchounian A. Dependence on the F0F1-ATP synthase for the activities of the hydrogen-oxidizing hydrogenases 1 and 2 during glucose and glycerol fermentation at high and low pH in Escherichia coli. J Bioenerg Biomembr 2011; 43:645-50. [DOI: 10.1007/s10863-011-9397-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2011] [Accepted: 10/20/2011] [Indexed: 11/24/2022]
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105
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Cintolesi A, Clomburg JM, Rigou V, Zygourakis K, Gonzalez R. Quantitative analysis of the fermentative metabolism of glycerol in Escherichia coli. Biotechnol Bioeng 2011; 109:187-98. [DOI: 10.1002/bit.23309] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Revised: 08/09/2011] [Accepted: 08/12/2011] [Indexed: 11/11/2022]
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106
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Oh BR, Seo JW, Heo SY, Hong WK, Luo LH, Joe MH, Park DH, Kim CH. Efficient production of ethanol from crude glycerol by a Klebsiella pneumoniae mutant strain. BIORESOURCE TECHNOLOGY 2011; 102:3918-22. [PMID: 21186120 DOI: 10.1016/j.biortech.2010.12.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Revised: 11/29/2010] [Accepted: 12/01/2010] [Indexed: 05/04/2023]
Abstract
A mutant strain of Klebsiella pneumoniae, termed GEM167, was obtained by γ irradiation, in which glycerol metabolism was dramatically affected on exposure to γ rays. Levels of metabolites of the glycerol reductive pathway, 1,3-propanediol (1,3-PD) and 3-hydroxypropionic acid (3-HP), were decreased in the GEM167 strain compared to a control strain, whereas the levels of metabolites derived from the oxidative pathway, 2,3-butanediol (2,3-BD), ethanol, lactate, and succinate, were increased. Notably, ethanol production from glycerol was greatly enhanced upon fermentation by the mutant strain, to a maximum production level of 21.5 g/l, with a productivity of 0.93 g/l/h. Ethanol production level was further improved to 25.0 g/l upon overexpression of Zymomonas mobilis pdc and adhII genes encoding pyruvate decarboxylase (Pdc) and aldehyde dehydrogenase (Adh), respectively in the mutant strain GEM167.
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Affiliation(s)
- Baek-Rock Oh
- Microbe-based Fusion Technology Research Center, Jeonbuk Branch Institute, KRIBB, Jeongeup, Jeonbuk 580-185, South Korea
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107
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Choi WJ, Hartono MR, Chan WH, Yeo SS. Ethanol production from biodiesel-derived crude glycerol by newly isolated Kluyvera cryocrescens. Appl Microbiol Biotechnol 2011; 89:1255-64. [PMID: 21212944 DOI: 10.1007/s00253-010-3076-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 12/14/2010] [Accepted: 12/14/2010] [Indexed: 10/18/2022]
Abstract
The rapidly expanding market for biodiesel has increased the supply and reduced the cost of glycerol, making it an attractive sustainable feed stock for the fuel and chemical industry. Glycerol-based biorefinery is the microbial fermentation of crude glycerol to produce fuels and chemicals. A major challenge is to obtain microbes tolerant to inhibitors such as salts and organic solvents present in crude glycerol. Microbial screening was attempted to isolate novel strain capable of growing on crude glycerol as a sole carbon source. The newly isolated bacteria, identified as nonpathogenic Kluyvera cryocrescens S26 could convert biodiesel-derived crude glycerol to ethanol with high yield and productivity. The supplementation of nutrients such as yeast extract resulted in distinguished enhancement in cell growth as well as ethanol productivity under anaerobic condition. When glycerol fermentation is performed under microaerobic condition, there is also a remarkable improvement in cell growth, ethanol productivity and yield, compared with those under strict anaerobic condition. In batch fermentation under microaerobic condition, K. cryocrescens S26 produced 27 g/l of ethanol from crude glycerol with high molar yield of 80% and productivity of 0.61 g/l/h.
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Affiliation(s)
- Won Jae Choi
- Institute of Chemical and Engineering Sciences, Agency for Science, Technology and Research (A STAR), 1 Pesek Road, Jurong Island, Singapore.
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108
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Clomburg JM, Gonzalez R. Metabolic engineering of Escherichia coli for the production of 1,2-propanediol from glycerol. Biotechnol Bioeng 2010; 108:867-79. [DOI: 10.1002/bit.22993] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Revised: 10/11/2010] [Accepted: 10/15/2010] [Indexed: 11/07/2022]
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109
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Liu H, Kang J, Qi Q, Chen G. Production of lactate in Escherichia coli by redox regulation genetically and physiologically. Appl Biochem Biotechnol 2010; 164:162-9. [PMID: 21069474 DOI: 10.1007/s12010-010-9123-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Accepted: 10/27/2010] [Indexed: 10/18/2022]
Abstract
Escherichia coli grows fermentatively in glucose-containing medium under anaerobic condition with formation of a mixture of organic acids (lactate, acetate, formate, and succinate) and ethanol to accommodate reducing equivalents generated during glycolysis. In this paper, we tried to improve the lactate accumulation in E. coli by redox regulation genetically and physiologically. Our results indicated that genetic regulation of the host by reducing the reductive by-product may improve the lactate production. In addition, lactate accumulation was also improved under reduced and anaerobic cultivation conditions. Engineered E. coli SDU4 was able to accumulate lactate under strictly anaerobic conditions to 100 g/L with a yield of 1.97 mol/mol glucose.
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Affiliation(s)
- Huimin Liu
- State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, People's Republic of China
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110
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Enabling unbalanced fermentations by using engineered electrode-interfaced bacteria. mBio 2010; 1. [PMID: 21060736 PMCID: PMC2975363 DOI: 10.1128/mbio.00190-10] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Accepted: 10/05/2010] [Indexed: 11/29/2022] Open
Abstract
Cellular metabolism is a series of tightly linked oxidations and reductions that must be balanced. Recycling of intracellular electron carriers during fermentation often requires substrate conversion to undesired products, while respiration demands constant addition of electron acceptors. The use of electrode-based electron acceptors to balance biotransformations may overcome these constraints. To test this hypothesis, the metal-reducing bacterium Shewanella oneidensis was engineered to stoichiometrically convert glycerol into ethanol, a biotransformation that will not occur unless two electrons are removed via an external reaction, such as electrode reduction. Multiple modules were combined into a single plasmid to alter S. oneidensis metabolism: a glycerol module, consisting of glpF, glpK, glpD, and tpiA from Escherichia coli, and an ethanol module containing pdc and adh from Zymomonas mobilis. A further increase in product yields was accomplished through knockout of pta, encoding phosphate acetyltransferase, shifting flux toward ethanol and away from acetate production. In this first-generation demonstration, conversion of glycerol to ethanol required the presence of an electrode to balance the reaction, and electrode-linked rates were on par with volumetric conversion rates observed in engineered E. coli. Linking microbial biocatalysis to current production can eliminate redox constraints by shifting other unbalanced reactions to yield pure products and serve as a new platform for next-generation bioproduction strategies. All reactions catalyzed by whole cells or enzymes must achieve redox balance. In rare cases, conversion can be achieved via perfectly balanced fermentations, allowing all electron equivalents to be recovered in a single product. In most biotransformations, organisms must produce a mixture of acids, gasses, and/or alcohols, and no amount of enzyme or strain engineering can overcome this fundamental requirement. Stoichiometric conversion of glycerol, a waste product from biodiesel transesterification, into ethanol and CO2 with no side products represents such an impossible fermentation, due to the more reduced state of glycerol than of ethanol and CO2. The unbalanced conversion of glycerol to ethanol has been viewed as having only two solutions: fermenting glycerol to ethanol and potentially useful coproducts or “burning off” excess electrons via careful introduction of oxygen. Here, we use the glycerol-to-ethanol example to demonstrate a third strategy, using bacteria directly interfaced to electrodes.
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111
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Characterization of hydrogen production by engineered Escherichia coli strains using rich defined media. BIOTECHNOL BIOPROC E 2010. [DOI: 10.1007/s12257-009-3139-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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112
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Blankschien MD, Clomburg JM, Gonzalez R. Metabolic engineering of Escherichia coli for the production of succinate from glycerol. Metab Eng 2010; 12:409-19. [DOI: 10.1016/j.ymben.2010.06.002] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Revised: 06/09/2010] [Accepted: 06/14/2010] [Indexed: 12/18/2022]
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113
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Mazumdar S, Clomburg JM, Gonzalez R. Escherichia coli strains engineered for homofermentative production of D-lactic acid from glycerol. Appl Environ Microbiol 2010; 76:4327-36. [PMID: 20472739 PMCID: PMC2897450 DOI: 10.1128/aem.00664-10] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Accepted: 05/03/2010] [Indexed: 11/20/2022] Open
Abstract
Given its availability and low price, glycerol has become an ideal feedstock for the production of fuels and chemicals. We recently reported the pathways mediating the metabolism of glycerol in Escherichia coli under anaerobic and microaerobic conditions. In this work, we engineer E. coli for the efficient conversion of glycerol to d-lactic acid (d-lactate), a negligible product of glycerol metabolism in wild-type strains. A homofermentative route for d-lactate production was engineered by overexpressing pathways involved in the conversion of glycerol to this product and blocking those leading to the synthesis of competing by-products. The former included the overexpression of the enzymes involved in the conversion of glycerol to glycolytic intermediates (GlpK-GlpD and GldA-DHAK pathways) and the synthesis of d-lactate from pyruvate (d-lactate dehydrogenase). On the other hand, the synthesis of succinate, acetate, and ethanol was minimized through two strategies: (i) inactivation of pyruvate-formate lyase (DeltapflB) and fumarate reductase (DeltafrdA) (strain LA01) and (ii) inactivation of fumarate reductase (DeltafrdA), phosphate acetyltransferase (Deltapta), and alcohol/acetaldehyde dehydrogenase (DeltaadhE) (strain LA02). A mutation that blocked the aerobic d-lactate dehydrogenase (Deltadld) also was introduced in both LA01 and LA02 to prevent the utilization of d-lactate. The most efficient strain (LA02Deltadld, with GlpK-GlpD overexpressed) produced 32 g/liter of d-lactate from 40 g/liter of glycerol at a yield of 85% of the theoretical maximum and with a chiral purity higher than 99.9%. This strain exhibited maximum volumetric and specific productivities for d-lactate production of 1.5 g/liter/h and 1.25 g/g cell mass/h, respectively. The engineered homolactic route generates 1 to 2 mol of ATP per mol of d-lactate and is redox balanced, thus representing a viable metabolic pathway.
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Affiliation(s)
- Suman Mazumdar
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas, Department of Bioengineering, Rice University, Houston, Texas
| | - James M. Clomburg
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas, Department of Bioengineering, Rice University, Houston, Texas
| | - Ramon Gonzalez
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas, Department of Bioengineering, Rice University, Houston, Texas
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114
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Debottlenecking the 1,3-propanediol pathway by metabolic engineering. Biotechnol Adv 2010; 28:519-30. [DOI: 10.1016/j.biotechadv.2010.03.003] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Revised: 03/20/2010] [Accepted: 03/25/2010] [Indexed: 11/20/2022]
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115
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Hong WK, Kim CH, Heo SY, Luo LH, Oh BR, Seo JW. Enhanced production of ethanol from glycerol by engineered Hansenula polymorpha expressing pyruvate decarboxylase and aldehyde dehydrogenase genes from Zymomonas mobilis. Biotechnol Lett 2010; 32:1077-82. [PMID: 20354759 DOI: 10.1007/s10529-010-0259-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Accepted: 03/23/2010] [Indexed: 11/25/2022]
Abstract
To improve production of ethanol from glycerol, the methylotrophic yeast Hansenula polymorpha was engineered to express the pdc and adhB genes encoding pyruvate decarboxylase and aldehyde dehydrogenase II from Zymomonas mobilis, respectively, under the control of the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) promoter. The ethanol yield was 3.3-fold higher (2.74 g l(-1)) in the engineered yeast compared with the parent strain (0.83 g l(-1)). Further engineering to stimulate glycerol utilization in the recombinant strain via expression of dhaD and dhaKLM genes from Klebsiella pneumoniae encoding glycerol dehydrogenase and dehydroxyacetone kinase, respectively, resulted in a 3.7-fold increase (3.1 g l(-1)) in ethanol yield.
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Affiliation(s)
- Won-Kyung Hong
- Microbe-based Fusion Technology Research Center, Jeonbuk Branch Institute, KRIBB, Jeongeup, Jeonbuk 580-185, South Korea
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116
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Fermentation of glycerol to succinate by metabolically engineered strains of Escherichia coli. Appl Environ Microbiol 2010; 76:2397-401. [PMID: 20154114 DOI: 10.1128/aem.02902-09] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The fermentative metabolism of Escherichia coli was reengineered to efficiently convert glycerol to succinate under anaerobic conditions without the use of foreign genes. Formate and ethanol were the dominant fermentation products from glycerol in wild-type Escherichia coli ATCC 8739, followed by succinate and acetate. Inactivation of pyruvate formate-lyase (pflB) in the wild-type strain eliminated the production of formate and ethanol and reduced the production of acetate. However, this deletion slowed growth and decreased cell yields due to either insufficient energy production or insufficient levels of electron acceptors. Reversing the direction of the gluconeogenic phosphoenolpyruvate carboxykinase reaction offered an approach to solve both problems, conserving energy as an additional ATP and increasing the pool of electron acceptors (fumarate and malate). Recruiting this enzyme through a promoter mutation (pck*) to increase expression also increased the rate of growth, cell yield, and succinate production. Presumably, the high NADH/NAD(+) ratio served to establish the direction of carbon flow. Additional mutations were also beneficial. Glycerol dehydrogenase and the phosphotransferase-dependent dihydroxyacetone kinase are regarded as the primary route for glycerol metabolism under anaerobic conditions. However, this is not true for succinate production by engineered strains. Deletion of the ptsI gene or any other gene essential for the phosphotranferase system was found to increase succinate yield. Deletion of pflB in this background provided a further increase in the succinate yield. Together, these three core mutations (pck*, ptsI, and pflB) effectively redirected carbon flow from glycerol to succinate at 80% of the maximum theoretical yield during anaerobic fermentation in mineral salts medium.
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117
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Biofuel production in Escherichia coli: the role of metabolic engineering and synthetic biology. Appl Microbiol Biotechnol 2010; 86:419-34. [DOI: 10.1007/s00253-010-2446-1] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2009] [Revised: 01/07/2010] [Accepted: 01/09/2010] [Indexed: 01/06/2023]
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118
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Nikel PI, Ramirez MC, Pettinari MJ, Méndez BS, Galvagno MA. Ethanol synthesis from glycerol by Escherichia coli redox mutants expressing adhE from Leuconostoc mesenteroides. J Appl Microbiol 2010; 109:492-504. [PMID: 20149000 DOI: 10.1111/j.1365-2672.2010.04668.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIMS Analysis of the physiology and metabolism of Escherichia coli arcA and creC mutants expressing a bifunctional alcohol-acetaldehyde dehydrogenase from Leuconostoc mesenteroides growing on glycerol under oxygen-restricted conditions. The effect of an ldhA mutation and different growth medium modifications was also assessed. METHODS AND RESULTS Expression of adhE in E. coli CT1061 [arcA creC(Con)] resulted in a 1.4-fold enhancement in ethanol synthesis. Significant amounts of lactate were produced during micro-oxic cultures and strain CT1061LE, in which fermentative lactate dehydrogenase was deleted, produced up to 6.5 +/- 0.3 g l(-1) ethanol in 48 h. Escherichia coli CT1061LE derivatives resistant to >25 g l(-1) ethanol were obtained by metabolic evolution. Pyruvate and acetaldehyde addition significantly increased both biomass and ethanol concentrations, probably by overcoming acetyl-coenzyme A (CoA) shortage. Yeast extract also promoted growth and ethanol synthesis, and this positive effect was mainly attributable to its vitamin content. Two-stage bioreactor cultures were conducted in a minimal medium containing 100 microg l(-1) calcium d-pantothenate to evaluate oxic acetyl-CoA synthesis followed by a switch into fermentative conditions. Ethanol reached 15.4 +/- 0.9 g l(-1) with a volumetric productivity of 0.34 +/- 0.02 g l(-1) h(-1). CONCLUSIONS Escherichia coli responded to adhE over-expression by funnelling carbon and reducing equivalents into a highly reduced metabolite, ethanol. Acetyl-CoA played a key role in micro-oxic ethanol synthesis and growth. SIGNIFICANCE AND IMPACT OF THE STUDY Insight into the micro-oxic metabolism of E. coli growing on glycerol is essential for the development of efficient industrial processes for reduced biochemicals production from this substrate, with special relevance to biofuels synthesis.
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Affiliation(s)
- P I Nikel
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín, Buenos Aires, Argentina., Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Autonoma de Buenos Aires, Argentina
| | - M C Ramirez
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín, Buenos Aires, Argentina
| | - M J Pettinari
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Autonoma de Buenos Aires, Argentina
| | - B S Méndez
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Autonoma de Buenos Aires, Argentina
| | - M A Galvagno
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín, Buenos Aires, Argentina., Departamento de Ingeniería Química, Facultad de Ingeniería, Universidad de Buenos Aires, Ciudad Autonoma de Buenos Aires, Argentina
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119
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An evolved Escherichia coli strain for producing hydrogen and ethanol from glycerol. Biochem Biophys Res Commun 2010; 391:1033-8. [DOI: 10.1016/j.bbrc.2009.12.013] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Accepted: 12/03/2009] [Indexed: 11/22/2022]
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120
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Gonzalez R, Campbell P, Wong M. Production of ethanol from thin stillage by metabolically engineered Escherichia coli. Biotechnol Lett 2009; 32:405-11. [DOI: 10.1007/s10529-009-0159-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Revised: 10/14/2009] [Accepted: 10/19/2009] [Indexed: 11/28/2022]
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121
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Gupta A, Murarka A, Campbell P, Gonzalez R. Anaerobic fermentation of glycerol in Paenibacillus macerans: metabolic pathways and environmental determinants. Appl Environ Microbiol 2009; 75:5871-83. [PMID: 19617389 PMCID: PMC2747847 DOI: 10.1128/aem.01246-09] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2009] [Accepted: 07/13/2009] [Indexed: 11/20/2022] Open
Abstract
Paenibacillus macerans is one of the species with the broadest metabolic capabilities in the genus Paenibacillus, able to ferment hexoses, deoxyhexoses, pentoses, cellulose, and hemicellulose. However, little is known about glycerol metabolism in this organism, and some studies have reported that glycerol is not fermented. Despite these reports, we found that several P. macerans strains are capable of anaerobic fermentation of glycerol. One of these strains, P. macerans N234A, grew fermentatively on glycerol at a maximum specific growth rate of 0.40 h(-1) and was chosen for further characterization. The use of [U-13C]glycerol and further analysis of extracellular metabolites and proteinogenic amino acids via nuclear magnetic resonance (NMR) spectroscopy allowed identification of ethanol, formate, acetate, succinate, and 1,2-propanediol (1,2-PDO) as fermentation products and demonstrated that glycerol is incorporated into cellular components. A medium formulation with low concentrations of potassium and phosphate, cultivation at acidic pH, and the use of a CO2-enriched atmosphere stimulated glycerol fermentation and are proposed to be environmental determinants of this process. The pathways involved in glycerol utilization and synthesis of fermentation products were identified using NMR spectroscopy in combination with enzyme assays. Based on these studies, the synthesis of ethanol and 1,2-PDO is proposed to be a metabolic determinant of glycerol fermentation in P. macerans N234A. Conversion of glycerol to ethanol fulfills energy requirements by generating one molecule of ATP per molecule of ethanol synthesized. Conversion of glycerol to 1,2-PDO results in the consumption of reducing equivalents, thus facilitating redox balance. Given the availability, low price, and high degree of reduction of glycerol, the high metabolic rates exhibited by P. macerans N234A are of paramount importance for the production of fuels and chemicals.
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Affiliation(s)
- Ashutosh Gupta
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, MS-362, Houston, TX 77005, USA
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122
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Scholten E, Renz T, Thomas J. Continuous cultivation approach for fermentative succinic acid production from crude glycerol by Basfia succiniciproducens DD1. Biotechnol Lett 2009; 31:1947-51. [DOI: 10.1007/s10529-009-0104-4] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Revised: 07/27/2009] [Accepted: 07/30/2009] [Indexed: 11/30/2022]
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123
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Durnin G, Clomburg J, Yeates Z, Alvarez PJ, Zygourakis K, Campbell P, Gonzalez R. Understanding and harnessing the microaerobic metabolism of glycerol inEscherichia coli. Biotechnol Bioeng 2009; 103:148-61. [DOI: 10.1002/bit.22246] [Citation(s) in RCA: 148] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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124
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Shams Yazdani S, Gonzalez R. Engineering Escherichia coli for the efficient conversion of glycerol to ethanol and co-products. Metab Eng 2008; 10:340-51. [DOI: 10.1016/j.ymben.2008.08.005] [Citation(s) in RCA: 177] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2008] [Accepted: 08/13/2008] [Indexed: 10/21/2022]
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