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ATP citrate lyase mediated cytosolic acetyl-CoA biosynthesis increases mevalonate production in Saccharomyces cerevisiae. Microb Cell Fact 2016; 15:48. [PMID: 26939608 PMCID: PMC4778282 DOI: 10.1186/s12934-016-0447-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 02/23/2016] [Indexed: 12/05/2022] Open
Abstract
Background With increasing concern about the environmental impact of a petroleum based economy, focus has shifted towards greener production strategies including metabolic engineering of microbes for the conversion of plant-based feedstocks to second generation biofuels and industrial chemicals. Saccharomyces cerevisiae is an attractive host for this purpose as it has been extensively engineered for production of various fuels and chemicals. Many of the target molecules are derived from the central metabolite and molecular building block, acetyl-CoA. To date, it has been difficult to engineer S. cerevisiae to continuously convert sugars present in biomass-based feedstocks to acetyl-CoA derived products due to intrinsic physiological constraints—in respiring cells, the precursor pyruvate is directed away from the endogenous cytosolic acetyl-CoA biosynthesis pathway towards the mitochondria, and in fermenting cells pyruvate is directed towards the byproduct ethanol. In this study we incorporated an alternative mode of acetyl-CoA biosynthesis mediated by ATP citrate lyase (ACL) that may obviate such constraints. Results We characterized the activity of several heterologously expressed ACLs in crude cell lysates, and found that ACL from Aspergillus nidulans demonstrated the highest activity. We employed a push/pull strategy to shunt citrate towards ACL by deletion of the mitochondrial NAD+-dependent isocitrate dehydrogenase (IDH1) and engineering higher flux through the upper mevalonate pathway. We demonstrated that combining the two modifications increases accumulation of mevalonate pathway intermediates, and that both modifications are required to substantially increase production. Finally, we incorporated a block strategy by replacing the native ERG12 (mevalonate kinase) promoter with the copper-repressible CTR3 promoter to maximize accumulation of the commercially important molecule mevalonate. Conclusion By combining the push/pull/block strategies, we significantly improved mevalonate production. We anticipate that this strategy can be used to improve the efficiency with which industrial strains of S. cerevisiae convert feedstocks to acetyl-CoA derived fuels and chemicals. Electronic supplementary material The online version of this article (doi:10.1186/s12934-016-0447-1) contains supplementary material, which is available to authorized users.
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Hossain GS, Shin HD, Li J, Wang M, Du G, Liu L, Chen J. Integrating error-prone PCR and DNA shuffling as an effective molecular evolution strategy for the production of α-ketoglutaric acid byl-amino acid deaminase. RSC Adv 2016. [DOI: 10.1039/c6ra02940j] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
l-Amino acid deaminases (LAADs; EC 1.4.3.2) belong to a family of amino acid dehydrogenases that catalyze the formation of α-keto acids froml-amino acids.
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Affiliation(s)
- Gazi Sakir Hossain
- School of Food Science and Technology
- Jiangnan University
- Wuxi 214122
- China
- Key Laboratory of Carbohydrate Chemistry and Biotechnology
| | - Hyun-dong Shin
- School of Chemical and Biomolecular Engineering
- Georgia Institute of Technology
- Atlanta
- USA
| | - Jianghua Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology
- Ministry of Education
- Jiangnan University
- Wuxi 214122
- China
| | - Miao Wang
- School of Food Science and Technology
- Jiangnan University
- Wuxi 214122
- China
| | - Guocheng Du
- Key Laboratory of Carbohydrate Chemistry and Biotechnology
- Ministry of Education
- Jiangnan University
- Wuxi 214122
- China
| | - Long Liu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology
- Ministry of Education
- Jiangnan University
- Wuxi 214122
- China
| | - Jian Chen
- Key Laboratory of Carbohydrate Chemistry and Biotechnology
- Ministry of Education
- Jiangnan University
- Wuxi 214122
- China
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Becker J, Gießelmann G, Hoffmann SL, Wittmann C. Corynebacterium glutamicum for Sustainable Bioproduction: From Metabolic Physiology to Systems Metabolic Engineering. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2016; 162:217-263. [DOI: 10.1007/10_2016_21] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Top value platform chemicals: bio-based production of organic acids. Curr Opin Biotechnol 2015; 36:168-75. [DOI: 10.1016/j.copbio.2015.08.022] [Citation(s) in RCA: 193] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 08/11/2015] [Accepted: 08/18/2015] [Indexed: 11/19/2022]
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Identification of the phd gene cluster responsible for phenylpropanoid utilization in Corynebacterium glutamicum. Appl Microbiol Biotechnol 2015; 100:1871-1881. [DOI: 10.1007/s00253-015-7165-1] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 11/07/2015] [Indexed: 10/22/2022]
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Doroshenko VG, Livshits VA, Airich LG, Shmagina IS, Savrasova EA, Ovsienko MV, Mashko SV. Metabolic engineering of Escherichia coli for the production of phenylalanine and related compounds. APPL BIOCHEM MICRO+ 2015. [DOI: 10.1134/s0003683815070017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Diversity of hydrolases from hydrothermal vent sediments of the Levante Bay, Vulcano Island (Aeolian archipelago) identified by activity-based metagenomics and biochemical characterization of new esterases and an arabinopyranosidase. Appl Microbiol Biotechnol 2015; 99:10031-46. [PMID: 26266751 PMCID: PMC4643112 DOI: 10.1007/s00253-015-6873-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 06/12/2015] [Accepted: 07/20/2015] [Indexed: 11/18/2022]
Abstract
A metagenomic fosmid expression library established from environmental DNA (eDNA) from the shallow hot vent sediment sample collected from the Levante Bay, Vulcano Island (Aeolian archipelago) was established in Escherichia coli. Using activity-based screening assays, we have assessed 9600 fosmid clones corresponding to approximately 350 Mbp of the cloned eDNA, for the lipases/esterases/lactamases, haloalkane and haloacid dehalogenases, and glycoside hydrolases. Thirty-four positive fosmid clones were selected from the total of 120 positive hits and sequenced to yield ca. 1360 kbp of high-quality assemblies. Fosmid inserts were attributed to the members of ten bacterial phyla, including Proteobacteria, Bacteroidetes, Acidobateria, Firmicutes, Verrucomicrobia, Chloroflexi, Spirochaetes, Thermotogae, Armatimonadetes, and Planctomycetes. Of ca. 200 proteins with high biotechnological potential identified therein, we have characterized in detail three distinct α/β-hydrolases (LIPESV12_9, LIPESV12_24, LIPESV12_26) and one new α-arabinopyranosidase (GLV12_5). All LIPESV12 enzymes revealed distinct substrate specificities tested against 43 structurally diverse esters and 4 p-nitrophenol carboxyl esters. Of 16 different glycosides tested, the GLV12_5 hydrolysed only p-nitrophenol-α-(l)-arabinopyranose with a high specific activity of about 2.7 kU/mg protein. Most of the α/β-hydrolases were thermophilic and revealed a high tolerance to, and high activities in the presence of, numerous heavy metal ions. Among them, the LIPESV12_24 was the best temperature-adapted, retaining its activity after 40 min of incubation at 90 °C. Furthermore, enzymes were active in organic solvents (e.g., >30 % methanol). Both LIPESV12_24 and LIPESV12_26 had the GXSXG pentapeptides and the catalytic triads Ser-Asp-His typical to the representatives of carboxylesterases of EC 3.1.1.1.
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Ramzi AB, Hyeon JE, Kim SW, Park C, Han SO. 5-Aminolevulinic acid production in engineered Corynebacterium glutamicum via C5 biosynthesis pathway. Enzyme Microb Technol 2015; 81:1-7. [PMID: 26453466 DOI: 10.1016/j.enzmictec.2015.07.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 07/03/2015] [Accepted: 07/22/2015] [Indexed: 12/20/2022]
Abstract
ALA (5-aminolevulinic acid) is an important intermediate in the synthesis of tetrapyrroles and the use of ALA has been gradually increasing in many fields, including medicine and agriculture. In this study, improved biological production of ALA in Corynebacterium glutamicum was achieved by overexpressing glutamate-initiated C5 pathway. For this purpose, copies of the glutamyl t-RNA reductase HemA from several bacteria were mutated by site-directed mutagenesis of which a HemA version from Salmonella typhimurium exhibited the highest ALA production. Cultivation of the HemA-expressing strain produced approximately 204 mg/L of ALA, while co-expression with HemL (glutamate-1-semialdehyde aminotransferase) increased ALA concentration to 457 mg/L, representing 11.6- and 25.9-fold increases over the control strain (17 mg/L of ALA). Further effects of metabolic perturbation were investigated, leading to penicillin addition that further improves ALA production to 584 mg/L. In an optimized flask fermentation, engineered C. glutamicum strains expressing the HemA and hemAL operon produced up to 1.1 and 2.2g/L ALA, respectively, under glutamate-producing conditions. The final yields represent 10.7- and 22.0-fold increases over the control strain (0.1g/L of ALA). From these findings, ALA biosynthesis from glucose was successfully demonstrated and this study is the first to report ALA overproduction in C. glutamicum via metabolic engineering.
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Affiliation(s)
- Ahmad Bazli Ramzi
- Department of Biotechnology, Korea University, Seoul 136-701, Republic of Korea
| | - Jeong Eun Hyeon
- Department of Biotechnology, Korea University, Seoul 136-701, Republic of Korea
| | - Seung Wook Kim
- Department of Chemical and Biological Engineering, Korea University, Seoul 136-701, Republic of Korea
| | - Chulhwan Park
- Department of Chemical Engineering, Kwangwoon University, Seoul 139-701, Republic of Korea
| | - Sung Ok Han
- Department of Biotechnology, Korea University, Seoul 136-701, Republic of Korea.
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Impact of an energy-conserving strategy on succinate production under weak acidic and anaerobic conditions in Enterobacter aerogenes. Microb Cell Fact 2015; 14:80. [PMID: 26063229 PMCID: PMC4464251 DOI: 10.1186/s12934-015-0269-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 05/25/2015] [Indexed: 11/10/2022] Open
Abstract
Background Succinate is an important C4 building block chemical, and its production via fermentative processes in bacteria has many practical applications in the biotechnology field. One of the major goals of optimizing the bacterium-based succinate production process is to lower the culture pH from the current neutral conditions, as this would reduce total production costs. In our previous studies, we selected Enterobacter aerogenes, a rapid glucose assimilator at pH 5.0, in order to construct a metabolically engineered strain that could produce succinate under weakly acidic conditions. This engineered strain produced succinate from glucose with a 72.7% (g/g) yield at pH 5.7, with a volumetric productivity of 0.23 g/L/h. Although this demonstrates proof-of-concept that bacterium-based succinate fermentation can be improved under weakly acidic conditions, several parameters still required further optimization. Results In this study, we genetically modified an E. aerogenes strain previously developed in our laboratory in order to increase the production of ATP during succinate synthesis, as we inferred that this would positively impact succinate biosynthesis. This led to the development of the ES08ΔptsG strain, which contains the following modifications: chromosomally expressed Actinobacillus succinogenes phosphoenolpyruvate carboxykinase, enhanced fumarate reductase, inactivated pyruvate formate lyase, pyruvate oxidase, and glucose-phosphotransferase permease (enzyme IIBCGlc). This strain produced 55.4 g/L succinate from glucose, with 1.8 g/L acetate as the major byproduct at pH 5.7 and anaerobic conditions. The succinate yield and volumetric productivity of this strain were 86.8% and 0.92 g/L/h, respectively. Conclusions Focusing on increasing net ATP production during succinate synthesis leads to increased succinate yield and volumetric productivity in E. aerogenes. We propose that the metabolically engineered E. aerogenes ES08ΔptsG strain, which effectively produces succinate under weakly acidic and anaerobic conditions, has potential utility for economical succinate production.
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Gunnarsson IB, Kuglarz M, Karakashev D, Angelidaki I. Thermochemical pretreatments for enhancing succinic acid production from industrial hemp (Cannabis sativa L.). BIORESOURCE TECHNOLOGY 2015; 182:58-66. [PMID: 25682224 DOI: 10.1016/j.biortech.2015.01.126] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 01/26/2015] [Accepted: 01/28/2015] [Indexed: 05/03/2023]
Abstract
The aim of this study was to develop an efficient thermochemical method for treatment of industrial hemp biomass, in order to increase its bioconversion to succinic acid. Industrial hemp was subjected to various thermochemical pretreatments using 0-3% H2SO4, NaOH or H2O2 at 121-180°C prior to enzymatic hydrolysis. The influence of the different pretreatments on hydrolysis and succinic acid production by Actinobacillus succinogenes 130Z was investigated in batch mode, using anaerobic bottles and bioreactors. Enzymatic hydrolysis and fermentation of hemp material pretreated with 3% H2O2 resulted in the highest overall sugar yield (73.5%), maximum succinic acid titer (21.9 g L(-1)), as well as the highest succinic acid yield (83%). Results obtained clearly demonstrated the impact of different pretreatments on the bioconversion efficiency of industrial hemp into succinic acid.
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Affiliation(s)
- Ingólfur B Gunnarsson
- Department of Environmental Engineering, Technical University of Denmark, Building 115, DK-2800 Lyngby, Denmark
| | - Mariusz Kuglarz
- Faculty of Materials and Environmental Sciences, University of Bielsko-Biala, Willowa 2, Bielsko-Biala, Poland
| | - Dimitar Karakashev
- Department of Environmental Engineering, Technical University of Denmark, Building 115, DK-2800 Lyngby, Denmark
| | - Irini Angelidaki
- Department of Environmental Engineering, Technical University of Denmark, Building 115, DK-2800 Lyngby, Denmark.
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Simultaneous saccharification and fermentation of cellulose in ionic liquid for efficient production of α-ketoglutaric acid by Yarrowia lipolytica. Appl Microbiol Biotechnol 2015; 99:4237-44. [PMID: 25783627 DOI: 10.1007/s00253-015-6521-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 03/01/2015] [Accepted: 03/02/2015] [Indexed: 01/06/2023]
Abstract
Ionic liquids (ILs) are benign solvents that are highly effective for biomass pretreatment. However, their applications for scale-up biorefinery are limited due to multiple expensive IL recovery and separation steps that are required. To overcome this limitation, it is very critical to develop a compatible enzymatic and microbial biocatalyst system to carry the simultaneous saccharification and fermentation in IL environments (SSF-IL). While enzymatic biocatalysts have been demonstrated to be compatible with various IL environments, it is challenging to develop microbial biocatalysts that can thrive and perform efficient biotransformation under the same conditions (pH and temperature). In this study, we harnessed the robust metabolism of Yarrowia lipolytica as a microbial platform highly compatible with the IL environments such as 1-ethyl-3-methylimidazolium acetate ([EMIM][OAc]). We optimized the enzymatic and microbial biocatalyst system using commercial cellulases and demonstrated the capability of Y. lipolytica to convert cellulose into high-value organics such as α-ketoglutaric acid (KGA) in the SSF-IL process at relatively low temperature 28 °C and high pH 6.3. We showed that SSF-IL not only enhanced the enzymatic saccharification but also produced KGA up to 92% of the maximum theoretical yield.
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Eggeling L, Bott M. A giant market and a powerful metabolism: L-lysine provided by Corynebacterium glutamicum. Appl Microbiol Biotechnol 2015; 99:3387-94. [PMID: 25761623 DOI: 10.1007/s00253-015-6508-2] [Citation(s) in RCA: 150] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 02/23/2015] [Accepted: 02/23/2015] [Indexed: 11/30/2022]
Abstract
L-lysine is made in an exceptional large quantity of currently 2,200,000 tons/year and belongs therefore to one of the leading biotechnological products. Production is done almost exclusively with mutants of Corynebacterium glutamicum. The increasing L-lysine market forces companies to improve the production process fostering also a deeper understanding of the microbial physiology of C. glutamicum. Current major challenges are the identification of ancillary mutations not intuitively related with product increase. This review gives insights on how cellular characteristics enable to push the carbon flux in metabolism towards its theoretical maximum, and this example may also serve as a guide to achieve and increase the formation of other products of interest in microbial biotechnology.
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Affiliation(s)
- Lothar Eggeling
- IBG-1: Biotechnology, Institute of Bio- and Geosciences, Forschungszentrum Jülich, 52458, Jülich, Germany,
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63
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Sun J, Alper HS. Metabolic engineering of strains: from industrial-scale to lab-scale chemical production. ACTA ACUST UNITED AC 2015; 42:423-36. [DOI: 10.1007/s10295-014-1539-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Accepted: 11/06/2014] [Indexed: 12/11/2022]
Abstract
Abstract
A plethora of successful metabolic engineering case studies have been published over the past several decades. Here, we highlight a collection of microbially produced chemicals using a historical framework, starting with titers ranging from industrial scale (more than 50 g/L), to medium-scale (5–50 g/L), and lab-scale (0–5 g/L). Although engineered Escherichia coli and Saccharomyces cerevisiae emerge as prominent hosts in the literature as a result of well-developed genetic engineering tools, several novel native-producing strains are gaining attention. This review catalogs the current progress of metabolic engineering towards production of compounds such as acids, alcohols, amino acids, natural organic compounds, and others.
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Affiliation(s)
- Jie Sun
- grid.89336.37 0000000419369924 McKetta Department of Chemical Engineering The University of Texas at Austin 200 E Dean Keeton St. Stop C0400 78712 Austin TX USA
| | - Hal S Alper
- grid.89336.37 0000000419369924 McKetta Department of Chemical Engineering The University of Texas at Austin 200 E Dean Keeton St. Stop C0400 78712 Austin TX USA
- grid.89336.37 0000000419369924 Institute for Cellular and Molecular Biology The University of Texas at Austin 2500 Speedway Avenue 78712 Austin TX USA
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Becker J, Wittmann C. Advanced Biotechnology: Metabolically Engineered Cells for the Bio-Based Production of Chemicals and Fuels, Materials, and Health-Care Products. Angew Chem Int Ed Engl 2015; 54:3328-50. [DOI: 10.1002/anie.201409033] [Citation(s) in RCA: 223] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Indexed: 12/16/2022]
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Biotechnologie von Morgen: metabolisch optimierte Zellen für die bio-basierte Produktion von Chemikalien und Treibstoffen, Materialien und Gesundheitsprodukten. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201409033] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Naerdal I, Pfeifenschneider J, Brautaset T, Wendisch VF. Methanol-based cadaverine production by genetically engineered Bacillus methanolicus strains. Microb Biotechnol 2015; 8:342-50. [PMID: 25644214 PMCID: PMC4353347 DOI: 10.1111/1751-7915.12257] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 11/29/2014] [Accepted: 12/01/2014] [Indexed: 01/05/2023] Open
Abstract
Methanol is regarded as an attractive substrate for biotechnological production of value-added bulk products, such as amino acids and polyamines. In the present study, the methylotrophic and thermophilic bacterium Bacillus methanolicus was engineered into a microbial cell factory for the production of the platform chemical 1,5-diaminopentane (cadaverine) from methanol. This was achieved by the heterologous expression of the Escherichia coli genes cadA and ldcC encoding two different lysine decarboxylase enzymes, and by increasing the overall L-lysine production levels in this host. Both CadA and LdcC were functional in B. methanolicus cultivated at 50°C and expression of cadA resulted in cadaverine production levels up to 500 mg l−1 during shake flask conditions. A volume-corrected concentration of 11.3 g l−1 of cadaverine was obtained by high-cell density fed-batch methanol fermentation. Our results demonstrated that efficient conversion of L-lysine into cadaverine presumably has severe effects on feedback regulation of the L-lysine biosynthetic pathway in B. methanolicus. By also investigating the cadaverine tolerance level, B. methanolicus proved to be an exciting alternative host and comparable to the well-known bacterial hosts E. coli and Corynebacterium glutamicum. This study represents the first demonstration of microbial production of cadaverine from methanol.
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Affiliation(s)
- Ingemar Naerdal
- Sector for Biotechnology and Nanomedicine, Department of Molecular Biology, SINTEF Materials and Chemistry, Trondheim, Norway
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Isolation and screening of thermophilic bacilli from compost for electrotransformation and fermentation: characterization of Bacillus smithii ET 138 as a new biocatalyst. Appl Environ Microbiol 2015; 81:1874-83. [PMID: 25556192 DOI: 10.1128/aem.03640-14] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Thermophilic bacteria are regarded as attractive production organisms for cost-efficient conversion of renewable resources to green chemicals, but their genetic accessibility is a major bottleneck in developing them into versatile platform organisms. In this study, we aimed to isolate thermophilic, facultatively anaerobic bacilli that are genetically accessible and have potential as platform organisms. From compost, we isolated 267 strains that produced acids from C5 and C6 sugars at temperatures of 55°C or 65°C. Subsequently, 44 strains that showed the highest production of acids were screened for genetic accessibility by electroporation. Two Geobacillus thermodenitrificans isolates and one Bacillus smithii isolate were found to be transformable with plasmid pNW33n. Of these, B. smithii ET 138 was the best-performing strain in laboratory-scale fermentations and was capable of producing organic acids from glucose as well as from xylose. It is an acidotolerant strain able to produce organic acids until a lower limit of approximately pH 4.5. As genetic accessibility of B. smithii had not been described previously, six other B. smithii strains from the DSMZ culture collection were tested for electroporation efficiencies, and we found the type strain DSM 4216(T) and strain DSM 460 to be transformable. The transformation protocol for B. smithii isolate ET 138 was optimized to obtain approximately 5 × 10(3) colonies per μg plasmid pNW33n. Genetic accessibility combined with robust acid production capacities on C5 and C6 sugars at a relatively broad pH range make B. smithii ET 138 an attractive biocatalyst for the production of lactic acid and potentially other green chemicals.
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Effects of eliminating pyruvate node pathways and of coexpression of heterogeneous carboxylation enzymes on succinate production by Enterobacter aerogenes. Appl Environ Microbiol 2014; 81:929-37. [PMID: 25416770 DOI: 10.1128/aem.03213-14] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lowering the pH in bacterium-based succinate fermentation is considered a feasible approach to reduce total production costs. Newly isolated Enterobacter aerogenes strain AJ110637, a rapid carbon source assimilator under weakly acidic (pH 5.0) conditions, was selected as a platform for succinate production. Our previous work showed that the ΔadhE/PCK strain, developed from AJ110637 with inactivated ethanol dehydrogenase and introduced Actinobacillus succinogenes phosphoenolpyruvate carboxykinase (PCK), generated succinate as a major product of anaerobic mixed-acid fermentation from glucose under weakly acidic conditions (pH <6.2). To further improve the production of succinate by the ΔadhE/PCK strain, metabolically engineered strains were designed based on the elimination of pathways that produced undesirable products and the introduction of two carboxylation pathways from phosphoenolpyruvate and pyruvate to oxaloacetate. The highest production of succinate was observed with strain ES04/PCK+PYC, which had inactivated ethanol, lactate, acetate, and 2,3-butanediol pathways and coexpressed PCK and Corynebacterium glutamicum pyruvate carboxylase (PYC). This strain produced succinate from glucose with over 70% yield (gram per gram) without any measurable formation of ethanol, lactate, or 2,3-butanediol under weakly acidic conditions. The impact of lowering the pH from 7.0 to 5.5 on succinate production in this strain was evaluated under pH-controlled batch culture conditions and showed that the lower pH decreased the succinate titer but increased its yield. These findings can be applied to identify additional engineering targets to increase succinate production.
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69
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de Lorenzo V. Chassis organism fromCorynebacterium glutamicum: The way towards biotechnological domestication of Corynebacteria. Biotechnol J 2014; 10:244-5. [DOI: 10.1002/biot.201400493] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Kind S, Neubauer S, Becker J, Yamamoto M, Völkert M, Abendroth GV, Zelder O, Wittmann C. From zero to hero – Production of bio-based nylon from renewable resources using engineered Corynebacterium glutamicum. Metab Eng 2014; 25:113-23. [DOI: 10.1016/j.ymben.2014.05.007] [Citation(s) in RCA: 203] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 04/03/2014] [Accepted: 05/05/2014] [Indexed: 01/06/2023]
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Kosciow K, Zahid N, Schweiger P, Deppenmeier U. Production of a periplasmic trehalase in Gluconobacter oxydans and growth on trehalose. J Biotechnol 2014; 189:27-35. [PMID: 25179874 DOI: 10.1016/j.jbiotec.2014.08.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 08/19/2014] [Accepted: 08/21/2014] [Indexed: 11/19/2022]
Abstract
Gluconobacter strains are specialized in the incomplete oxidation of monosaccharides. In contrast, growth and product formation from disaccharides is either very low or impossible. A pathway that allows growth on trehalose was rationally designed to broaden the substrate range of Gluconobacter oxydans. Expression vectors containing different signal sequences and the gene encoding alkaline phosphatase, phoA, from Escherichia coli were constructed. The signal peptide that exhibited the strongest periplasmic PhoA activity was used to generate a G. oxydans strain able to utilize the model disaccharide trehalose as a carbon and energy source by expressing the periplasmic trehalase TreA from E. coli. The strain had a doubling time of 3.7h and reached a final optical density of 1.7 when trehalose was used as a growth substrate. In comparison, the wild-type harboring the empty vector and the strain expressing treA without a signal sequence grew slowly to a final OD of only 0.15. The trehalose concentration in treA expressing cultures decreased continuously during the exponential growth phase indicating that the substrate was hydrolyzed to glucose by TreA. In contrast to the wild-type growing on glucose, the treA expression strain mainly formed acetate and 5-ketogluconate as end products rather than gluconate.
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Affiliation(s)
- K Kosciow
- Institute of Microbiology and Biotechnology, University of Bonn, 168 Meckenheimer Allee, 53115 Bonn, Germany
| | - N Zahid
- Institute of Microbiology and Biotechnology, University of Bonn, 168 Meckenheimer Allee, 53115 Bonn, Germany
| | - P Schweiger
- Missouri State University, Biology Department, 901 S. National Avenue, Springfield, MO 65897, United States
| | - U Deppenmeier
- Institute of Microbiology and Biotechnology, University of Bonn, 168 Meckenheimer Allee, 53115 Bonn, Germany.
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72
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Teo WS, Chang MW. Bacterial XylRs and synthetic promoters function as genetically encoded xylose biosensors in Saccharomyces cerevisiae. Biotechnol J 2014; 10:315-22. [PMID: 24975936 DOI: 10.1002/biot.201400159] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 05/21/2014] [Accepted: 06/25/2014] [Indexed: 12/22/2022]
Abstract
Lignocellulosic biomass is a sustainable and abundant starting material for biofuel production. However, lignocellulosic hydrolysates contain not only glucose, but also other sugars including xylose which cannot be metabolized by the industrial workhorse Saccharomyces cerevisiae. Hence, engineering of xylose assimilating S. cerevisiae has been much studied, including strain optimization strategies. In this work, we constructed genetically encoded xylose biosensors that can control protein expression upon detection of xylose sugars. These were constructed with the constitutive expression of heterologous XylR repressors, which function as protein sensors, and cloning of synthetic promoters with XylR operator sites. Three XylR variants and the corresponding synthetic promoters were used: XylR from Tetragenococcus halophile, Clostridium difficile, and Lactobacillus pentosus. To optimize the biosensor, two promoters with different strengths were used to express the XylR proteins. The ability of XylR to repress yEGFP expression from the synthetic promoters was demonstrated. Furthermore, xylose sugars added exogenously to the cells were shown to regulate gene expression. We envision that the xylose biosensors can be used as a tool to engineer and optimize yeast that efficiently utilizes xylose as carbon source for growth and biofuel production.
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Affiliation(s)
- Wei Suong Teo
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Synthetic Biology Research Consortium, National University of Singapore, Singapore
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73
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Mazzoli R, Bosco F, Mizrahi I, Bayer EA, Pessione E. Towards lactic acid bacteria-based biorefineries. Biotechnol Adv 2014; 32:1216-1236. [PMID: 25087936 DOI: 10.1016/j.biotechadv.2014.07.005] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 07/14/2014] [Accepted: 07/16/2014] [Indexed: 10/25/2022]
Abstract
Lactic acid bacteria (LAB) have long been used in industrial applications mainly as starters for food fermentation or as biocontrol agents or as probiotics. However, LAB possess several characteristics that render them among the most promising candidates for use in future biorefineries in converting plant-derived biomass-either from dedicated crops or from municipal/industrial solid wastes-into biofuels and high value-added products. Lactic acid, their main fermentation product, is an attractive building block extensively used by the chemical industry, owing to the potential for production of polylactides as biodegradable and biocompatible plastic alternative to polymers derived from petrochemicals. LA is but one of many high-value compounds which can be produced by LAB fermentation, which also include biofuels such as ethanol and butanol, biodegradable plastic polymers, exopolysaccharides, antimicrobial agents, health-promoting substances and nutraceuticals. Furthermore, several LAB strains have ascertained probiotic properties, and their biomass can be considered a high-value product. The present contribution aims to provide an extensive overview of the main industrial applications of LAB and future perspectives concerning their utilization in biorefineries. Strategies will be described in detail for developing LAB strains with broader substrate metabolic capacity for fermentation of cheaper biomass.
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Affiliation(s)
- Roberto Mazzoli
- Laboratory of Biochemistry: Proteomics and Metabolic Engineering of Prokaryotes, Department of Life Sciences and Systems Biology, University of Torino, Via Accademia Albertina 13, 10123 Torino, Italy.
| | - Francesca Bosco
- Department of Applied Science and Technology (DISAT), Politecnico of Torino, Corso Duca degli Abruzzi, 24, 10129 Torino, Italy.
| | - Itzhak Mizrahi
- Institute of Animal Science, ARO, Volcani Research Center, P.O. Box 6Â, Bet Dagan 50-250, Israel.
| | - Edward A Bayer
- Department of Biological Chemistry, the Weizmann Institute of Science, Rehovot 76100 Israel.
| | - Enrica Pessione
- Laboratory of Biochemistry: Proteomics and Metabolic Engineering of Prokaryotes, Department of Life Sciences and Systems Biology, University of Torino, Via Accademia Albertina 13, 10123 Torino, Italy.
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74
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Krylov AA, Kolontaevsky EE, Mashko SV. Oligonucleotide recombination in corynebacteria without the expression of exogenous recombinases. J Microbiol Methods 2014; 105:109-15. [PMID: 25087479 DOI: 10.1016/j.mimet.2014.07.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 07/21/2014] [Accepted: 07/23/2014] [Indexed: 11/24/2022]
Abstract
Brevibacterium lactofermentum and Corynebacterium glutamicum are important biotechnology species of the genus Corynebacterium. The single-strand DNA annealing protein (SSAP)-independent oligonucleotide-mediated recombination procedure was successfully applied to the commonly used wild-type strains B. lactofermentum AJ1511 and C. glutamicum ATCC13032. When the rpsL gene was used as a target, the optimized protocol yielded up to (1.4±0.3)×10(3) and (6.7±1.3)×10(3) streptomycin-resistant colonies per 10(8) viable cells for the corresponding strains. We tested the influence of several parameters that are known to enhance the efficiency of oligonucleotide-mediated recombination in other bacterial species. Among them, increasing the concentration of oligonucleotides and targeting the lagging strand of the chromosome have proven to have positive effects on both of the tested species. No difference in the efficiency of recombination was observed between the oligonucleotides phosphorothiorated at the 5' ends and the unmodified oligonucleotides or between the oligonucleotides with four mutated nucleotides and those with one mutated nucleotide. The described approach demonstrates that during the adaptation of the recombineering technique, testing SSAP-independent oligonucleotide-mediated recombination could be a good starting point. Such testing could decrease the probability of an incorrect interpretation of the effect of exogenous protein factors (such as SSAP and/or corresponding exonucleases) due to non-optimal experimental conditions. In addition, SSAP-independent recombination itself could be useful in combination with suitable selection/enrichment methods.
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Affiliation(s)
- Alexander A Krylov
- Ajinomoto-Genetika Research Institute, 1-st Dorozhny proezd 1, Moscow 117545, Russia.
| | - Egor E Kolontaevsky
- Ajinomoto-Genetika Research Institute, 1-st Dorozhny proezd 1, Moscow 117545, Russia
| | - Sergey V Mashko
- Ajinomoto-Genetika Research Institute, 1-st Dorozhny proezd 1, Moscow 117545, Russia
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75
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Matano C, Uhde A, Youn JW, Maeda T, Clermont L, Marin K, Krämer R, Wendisch VF, Seibold GM. Engineering of Corynebacterium glutamicum for growth and L-lysine and lycopene production from N-acetyl-glucosamine. Appl Microbiol Biotechnol 2014; 98:5633-43. [PMID: 24668244 DOI: 10.1007/s00253-014-5676-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 03/05/2014] [Accepted: 03/06/2014] [Indexed: 11/27/2022]
Abstract
Sustainable supply of feedstock has become a key issue in process development in microbial biotechnology. The workhorse of industrial amino acid production Corynebacterium glutamicum has been engineered towards utilization of alternative carbon sources. Utilization of the chitin-derived aminosugar N-acetyl-glucosamine (GlcNAc) for both cultivation and production with C. glutamicum has hitherto not been investigated. Albeit this organism harbors the enzymes N-acetylglucosamine-6-phosphatedeacetylase and glucosamine-6P deaminase of GlcNAc metabolism (encoded by nagA and nagB, respectively) growth of C. glutamicum with GlcNAc as substrate was not observed. This was attributed to the lack of a functional system for GlcNAc uptake. Of the 17 type strains of the genus Corynebacterium tested here for their ability to grow with GlcNAc, only Corynebacterium glycinophilum DSM45794 was able to utilize this substrate. Complementation studies with a GlcNAc-uptake deficient Escherichia coli strain revealed that C. glycinophilum possesses a nagE-encoded EII permease for GlcNAc uptake. Heterologous expression of the C. glycinophilum nagE in C. glutamicum indeed enabled uptake of GlcNAc. For efficient GlcNac utilization in C. glutamicum, improved expression of nagE with concurrent overexpression of the endogenous nagA and nagB genes was found to be necessary. Based on this strategy, C. glutamicum strains for the efficient production of the amino acid L-lysine as well as the carotenoid lycopene from GlcNAc as sole substrate were constructed.
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Affiliation(s)
- Christian Matano
- Faculty of Biology and CeBiTec, Bielefeld University, 33501, Bielefeld, Germany
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76
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Zhuang ZY, Li SY. Rubisco-based engineered Escherichia coli for in situ carbon dioxide recycling. BIORESOURCE TECHNOLOGY 2013; 150:79-88. [PMID: 24152790 DOI: 10.1016/j.biortech.2013.09.116] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 09/21/2013] [Accepted: 09/25/2013] [Indexed: 05/16/2023]
Abstract
In this study, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and phosphoribulokinase (PrkA) were overexpressed individually and in combination in Escherichia coli under different fermentation conditions. While wild-type E. coli produced 0.731 mol of CO2 per consumption of one mole of arabinose, engineered E. coli JB, containing both heterologous Rubisco and PrkA, produced only 0.621 mol of CO2 per consumption of one mole of arabinose. This represents a 15% reduction in CO2 emission and achieves 38% of theoretical CO2 reduction. The CO2 fixation rate of Rubisco-based engineered E. coli JB is 67 mg-CO2·mole-arabinose(-1) L(-1) h(-1), which is comparable to the performance of microalgae and cyanobacteria. It has been found that overexpressing Rubisco dramatically elevates the bacteria growth and sugar consumptions in the presence of oxygen and L-arabinose. It has been also found that overexpressing PrkA could demolish the balance of ATP regeneration, yet can be recovered simply by controlling the pH at 7.0±0.1.
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Affiliation(s)
- Zong-Yu Zhuang
- Department of Chemical Engineering, National Chung Hsing University, Taichung 402, Taiwan
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77
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Claypool JT, Raman DR. Development and validation of a technoeconomic analysis tool for early-stage evaluation of bio-based chemical production processes. BIORESOURCE TECHNOLOGY 2013; 150:486-495. [PMID: 24041977 DOI: 10.1016/j.biortech.2013.08.094] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 08/13/2013] [Accepted: 08/14/2013] [Indexed: 06/02/2023]
Abstract
By using cost correlations and standard scale-factors, a spreadsheet-based early-stage cost estimation tool was developed. Named BioPET (Biorenewables Process Evaluation Tool), this tool allows users to specify up to seven primary unit operations--fermentation, separation, three catalytic stages, and purification--along with key parameters for each. BioPET then computes an estimated minimum selling price for the pathway. Model validation was conducted by selecting three molecules (ethanol, succinic acid, and adipic acid), and comparing BioPET's results to literature values and to results from a commercial process design tool. BioPET produced virtually identical prices to the process design tool, although the costs were not identically distributed amongst the categories. BioPET produced estimates that were within 40% of other literature values at low feedstock costs, and within 5% at high feedstock costs.
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Affiliation(s)
- Joshua T Claypool
- Agricultural and Biosystems Engineering Department, 3222 NSRIC, Iowa State University, Ames, IA 50010-3310, United States
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78
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Becker J, Schäfer R, Kohlstedt M, Harder BJ, Borchert NS, Stöveken N, Bremer E, Wittmann C. Systems metabolic engineering of Corynebacterium glutamicum for production of the chemical chaperone ectoine. Microb Cell Fact 2013; 12:110. [PMID: 24228689 PMCID: PMC4225761 DOI: 10.1186/1475-2859-12-110] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 11/05/2013] [Indexed: 11/14/2022] Open
Abstract
Background The stabilizing and function-preserving effects of ectoines have attracted considerable biotechnological interest up to industrial scale processes for their production. These rely on the release of ectoines from high-salinity-cultivated microbial producer cells upon an osmotic down-shock in rather complex processor configurations. There is growing interest in uncoupling the production of ectoines from the typical conditions required for their synthesis, and instead design strains that naturally release ectoines into the medium without the need for osmotic changes, since the use of high-salinity media in the fermentation process imposes notable constraints on the costs, design, and durability of fermenter systems. Results Here, we used a Corynebacterium glutamicum strain as a cellular chassis to establish a microbial cell factory for the biotechnological production of ectoines. The implementation of a mutant aspartokinase enzyme ensured efficient supply of L-aspartate-beta-semialdehyde, the precursor for ectoine biosynthesis. We further engineered the genome of the basic C. glutamicum strain by integrating a codon-optimized synthetic ectABCD gene cluster under expressional control of the strong and constitutive C. glutamicum tuf promoter. The resulting recombinant strain produced ectoine and excreted it into the medium; however, lysine was still found as a by-product. Subsequent inactivation of the L-lysine exporter prevented the undesired excretion of lysine while ectoine was still exported. Using the streamlined cell factory, a fed-batch process was established that allowed the production of ectoine with an overall productivity of 6.7 g L-1 day-1 under growth conditions that did not rely on the use of high-salinity media. Conclusions The present study describes the construction of a stable microbial cell factory for recombinant production of ectoine. We successfully applied metabolic engineering strategies to optimize its synthetic production in the industrial workhorse C. glutamicum and thereby paved the way for further improvements in ectoine yield and biotechnological process optimization.
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Affiliation(s)
- Judith Becker
- Institute of Biochemical Engineering, Technische Universität Braunschweig, Braunschweig, Germany.
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79
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Ikeda N, Miyamoto M, Adachi N, Nakano M, Tanaka T, Kondo A. Direct cadaverine production from cellobiose using β-glucosidase displaying Escherichia coli. AMB Express 2013; 3:67. [PMID: 24206923 PMCID: PMC3827850 DOI: 10.1186/2191-0855-3-67] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 10/31/2013] [Indexed: 11/30/2022] Open
Abstract
In this study, we demonstrate the one-step production of cadaverine (1,5-diaminopentane) from cellobiose using an Escherichia coli strain displaying β-glucosidase (BGL) on its cell surface. L-lysine decarboxylase (CadA) derived from E. coli and BGL from Thermobifida fusca YX (Tfu0937) fused to the anchor protein Blc from E. coli were co-expressed using E. coli as a host. The expression of CadA was confirmed by Western blotting and BGL activity on the cell surface was evaluated using pNPG as a substrate. Growth on cellobiose as the sole carbon source was also achieved. The OD600 value of the BGL and CadA co-expressing strain was 8.0 after 48 h cultivation, which is higher than that obtained by growth on glucose (5.4 after 48 h cultivation). The engineered strain produced cadaverine from cellobiose more effectively than from glucose: 6.1 mM after 48 h from 28 g/L of consumed cellobiose, vs. 3.3 mM from 20 g/L of consumed glucose.
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80
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Eram MS, Ma K. Decarboxylation of pyruvate to acetaldehyde for ethanol production by hyperthermophiles. Biomolecules 2013; 3:578-96. [PMID: 24970182 PMCID: PMC4030962 DOI: 10.3390/biom3030578] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 08/02/2013] [Accepted: 08/15/2013] [Indexed: 11/16/2022] Open
Abstract
Pyruvate decarboxylase (PDC encoded by pdc) is a thiamine pyrophosphate (TPP)-containing enzyme responsible for the conversion of pyruvate to acetaldehyde in many mesophilic organisms. However, no pdc/PDC homolog has yet been found in fully sequenced genomes and proteomes of hyper/thermophiles. The only PDC activity reported in hyperthermophiles was a bifunctional, TPP- and CoA-dependent pyruvate ferredoxin oxidoreductase (POR)/PDC enzyme from the hyperthermophilic archaeon Pyrococcus furiosus. Another enzyme known to be involved in catalysis of acetaldehyde production from pyruvate is CoA-acetylating acetaldehyde dehydrogenase (AcDH encoded by mhpF and adhE). Pyruvate is oxidized into acetyl-CoA by either POR or pyruvate formate lyase (PFL), and AcDH catalyzes the reduction of acetyl-CoA to acetaldehyde in mesophilic organisms. AcDH is present in some mesophilic (such as clostridia) and thermophilic bacteria (e.g., Geobacillus and Thermoanaerobacter). However, no AcDH gene or protein homologs could be found in the released genomes and proteomes of hyperthermophiles. Moreover, no such activity was detectable from the cell-free extracts of different hyperthermophiles under different assay conditions. In conclusion, no commonly-known PDCs was found in hyperthermophiles. Instead of the commonly-known PDC, it appears that at least one multifunctional enzyme is responsible for catalyzing the non-oxidative decarboxylation of pyruvate to acetaldehyde in hyperthermophiles.
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Affiliation(s)
- Mohammad S Eram
- Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
| | - Kesen Ma
- Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
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81
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Aggelopoulos T, Katsieris K, Bekatorou A, Pandey A, Banat IM, Koutinas AA. Solid state fermentation of food waste mixtures for single cell protein, aroma volatiles and fat production. Food Chem 2013; 145:710-6. [PMID: 24128535 DOI: 10.1016/j.foodchem.2013.07.105] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 07/13/2013] [Accepted: 07/20/2013] [Indexed: 02/01/2023]
Abstract
Growth of selected microorganisms of industrial interest (Saccharomyces cerevisiae, Kluyveromyces marxianus and kefir) by solid state fermentation (SSF) of various food industry waste mixtures was studied. The fermented products were analysed for protein, and nutrient minerals content, as well as for aroma volatile compounds by GC/MS. The substrate fermented by K. marxianus contained the highest sum of fat and protein concentration (59.2% w/w dm) and therefore it could be considered for utilisation of its fat content and for livestock feed enrichment. Regarding volatiles, the formation of high amounts of ε-pinene was observed only in the SSF product of kefir at a yield estimated to be 4 kg/tn of SSF product. A preliminary design of a biorefinery-type process flow sheet and its economic analysis, indicated potential production of products (enriched livestock feed, fat and ε-pinene) of significant added value.
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Affiliation(s)
- Theodoros Aggelopoulos
- Food Biotechnology Group, Department of Chemistry, University of Patras, Patras 26500, Greece
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