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Kajla S, Kumari R, Nagi GK. Microbial CO2 fixation and biotechnology in reducing industrial CO2 emissions. Arch Microbiol 2022; 204:149. [DOI: 10.1007/s00203-021-02677-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 10/20/2021] [Accepted: 10/21/2021] [Indexed: 11/30/2022]
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2
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Screening of Acetyl Donors and the Robust Enzymatic Synthesis of Acetyl-CoA by 10-Deacetylbaccatin III-10-β-O-acetyltransferase. Catalysts 2021. [DOI: 10.3390/catal11101240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Acetyl-CoA is the precursor of many bio-manufacturing products and is also the hub of the cellular metabolism of energy and substances. However, acetyl-CoA is not a bulk commodity and its application is hindered due to its high cost and low yield. In this study, we screened acetyl donor candidates and utilized 10-deacetylbaccatin III-10-β-O-acetyltransferase (DBAT) in the synthesis of acetyl-CoA with CoASH as the acetyl acceptor. Among the tested candidates, acetylsalicylic acid methyl ester was identified to be the best acetyl donor, followed by acetyl-trans-resveratrol, acetylsalicylic acid ethyl ester, acetylsalicylsalicylic acid, and 4-acetoxyacetanilide. The enzymatic reaction conditions were optimized and the maximum yield of acetyl-CoA reached 14.82 mg/mL, which is the highest yield among all reported approaches to date. Meanwhile, 4.22 mg/mL of the by-product salicylic acid methyl ester, which is another industrial material, was produced. Additionally, a preliminary purification process for acetyl-CoA was established, in which 40 mg acetyl-CoA (HPLC purity > 98%) was acquired from the finished 20 mL reaction system (feeding 46 mg CoASH and 34 mg ASME) with a recovery rate of 86%. Our study lays the foundation for the large-scale production of acetyl-CoA by an enzymatic approach and will promote its application in different fields.
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Ling F, Tang X, Zhang H, Chen YQ, Zhao J, Chen H, Chen W. Role of the mitochondrial citrate-oxoglutarate carrier in lipid accumulation in the oleaginous fungus Mortierella alpina. Biotechnol Lett 2021; 43:1455-1466. [PMID: 33907945 DOI: 10.1007/s10529-021-03133-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 04/10/2021] [Indexed: 11/25/2022]
Abstract
OBJECTIVES The transport of citrate from the mitochondria to the cytoplasm is essential during lipid accumulation. This study aimed to explore the role of mitochondrial citrate-oxoglutarate carrier in lipid accumulation in the oleaginous fungus Mortierella alpina. RESULTS Homologous MaYHM (the gene encoding the mitochondrial citrate-oxoglutarate carrier) was overexpressed in M. alpina. The fatty acid content of MaYHM-overexpressing recombinant strains was increased by up to 30% compared with the control. Moreover, the intracellular α-ketoglutarate level in recombinant strains was increased by 2.2 fold, together with a 23-35% decrease in NAD+-isocitrate dehydrogenase activity compared with the control. The overexpression of MaYHM altered the metabolic flux in the glutamate dehydrogenase shunt and 4-aminobutyric acid shunt during metabolic reprogramming, supplying more carbon to synthesize fatty acids. CONCLUSIONS Overexpression of MaYHM resulted in more efflux of citrate from mitochondria to the cytoplasm and enhanced lipid accumulation. These findings provide new perspectives for the improvement of industrial lipid production in M. alpina.
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Affiliation(s)
- Fengzhu Ling
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- School of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
| | - Xin Tang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China.
- School of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China.
| | - Hao Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- School of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
- National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
- Wuxi Translational Medicine Research Center and Jiangsu Translational Medicine Research Institute Wuxi Branch, Wuxi, Jiangsu, 214122, People's Republic of China
| | - Yong Q Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- School of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
- National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
- Wuxi Translational Medicine Research Center and Jiangsu Translational Medicine Research Institute Wuxi Branch, Wuxi, Jiangsu, 214122, People's Republic of China
| | - Jianxin Zhao
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- School of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
| | - Haiqin Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- School of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
| | - Wei Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- School of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
- National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
- Beijing Innovation Centre of Food Nutrition and Human Health, Beijing Technology and Business University (BTBU), Beijing, 100048, People's Republic of China
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Pham N, Reijnders M, Suarez-Diez M, Nijsse B, Springer J, Eggink G, Schaap PJ. Genome-scale metabolic modeling underscores the potential of Cutaneotrichosporon oleaginosus ATCC 20509 as a cell factory for biofuel production. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:2. [PMID: 33407779 PMCID: PMC7788717 DOI: 10.1186/s13068-020-01838-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 11/23/2020] [Indexed: 05/03/2023]
Abstract
BACKGROUND Cutaneotrichosporon oleaginosus ATCC 20509 is a fast-growing oleaginous basidiomycete yeast that is able to grow in a wide range of low-cost carbon sources including crude glycerol, a byproduct of biodiesel production. When glycerol is used as a carbon source, this yeast can accumulate more than 50% lipids (w/w) with high concentrations of mono-unsaturated fatty acids. RESULTS To increase our understanding of this yeast and to provide a knowledge base for further industrial use, a FAIR re-annotated genome was used to build a genome-scale, constraint-based metabolic model containing 1553 reactions involving 1373 metabolites in 11 compartments. A new description of the biomass synthesis reaction was introduced to account for massive lipid accumulation in conditions with high carbon-to-nitrogen (C/N) ratio in the media. This condition-specific biomass objective function is shown to better predict conditions with high lipid accumulation using glucose, fructose, sucrose, xylose, and glycerol as sole carbon source. CONCLUSION Contributing to the economic viability of biodiesel as renewable fuel, C. oleaginosus ATCC 20509 can effectively convert crude glycerol waste streams in lipids as a potential bioenergy source. Performance simulations are essential to identify optimal production conditions and to develop and fine tune a cost-effective production process. Our model suggests ATP-citrate lyase as a possible target to further improve lipid production.
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Affiliation(s)
- Nhung Pham
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Wageningen, the Netherlands
| | - Maarten Reijnders
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Wageningen, the Netherlands
- Department of Ecology and Evolution, University of Lausanne, Swiss Institute of Bioinformatics, 1015, Lausanne, Switzerland
| | - Maria Suarez-Diez
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Wageningen, the Netherlands
| | - Bart Nijsse
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Wageningen, the Netherlands
| | - Jan Springer
- Food and Biobased Research and AlgaePARC, Wageningen University and Research, Wageningen, the Netherlands
| | - Gerrit Eggink
- Food and Biobased Research and AlgaePARC, Wageningen University and Research, Wageningen, the Netherlands
- Bioprocess Engineering and AlgaePARC, Wageningen University and Research, Wageningen, the Netherlands
| | - Peter J Schaap
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Wageningen, the Netherlands.
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Hossain AH, van Gerven R, Overkamp KM, Lübeck PS, Taşpınar H, Türker M, Punt PJ. Metabolic engineering with ATP-citrate lyase and nitrogen source supplementation improves itaconic acid production in Aspergillus niger. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:233. [PMID: 31583019 PMCID: PMC6767652 DOI: 10.1186/s13068-019-1577-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Accepted: 09/21/2019] [Indexed: 05/28/2023]
Abstract
BACKGROUND Bio-based production of organic acids promises to be an attractive alternative for the chemicals industry to substitute petrochemicals as building-block chemicals. In recent years, itaconic acid (IA, methylenesuccinic acid) has been established as a sustainable building-block chemical for the manufacture of various products such as synthetic resins, coatings, and biofuels. The natural IA producer Aspergillus terreus is currently used for industrial IA production; however, the filamentous fungus Aspergillus niger has been suggested to be a more suitable host for this purpose. In our previous report, we communicated the overexpression of a putative cytosolic citrate synthase citB in an A. niger strain carrying the full IA biosynthesis gene cluster from A. terreus, which resulted in the highest final titer reported for A. niger (26.2 g/L IA). In this research, we have attempted to improve this pathway by increasing the cytosolic acetyl-CoA pool. Additionally, we have also performed fermentation optimization by varying the nitrogen source and concentration. RESULTS To increase the cytosolic acetyl-CoA pool, we have overexpressed genes acl1 and acl2 that together encode for ATP-citrate lyase (ACL). Metabolic engineering of ACL resulted in improved IA production through an apparent increase in glycolytic flux. Strains that overexpress acl12 show an increased yield, titer and productivity in comparison with parental strain CitB#99. Furthermore, IA fermentation conditions were improved by nitrogen supplementation, which resulted in alkalization of the medium and thereby reducing IA-induced weak-acid stress. In turn, the alkalizing effect of nitrogen supplementation enabled an elongated idiophase and allowed final titers up to 42.7 g/L to be reached at a productivity of 0.18 g/L/h and yield of 0.26 g/g in 10-L bioreactors. CONCLUSION Ultimately, this study shows that metabolic engineering of ACL in our rewired IA biosynthesis pathway leads to improved IA production in A. niger due to an increase in glycolytic flux. Furthermore, IA fermentation conditions were improved by nitrogen supplementation that alleviates IA induced weak-acid stress and extends the idiophase.
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Affiliation(s)
- Abeer H. Hossain
- Dutch DNA Biotech B.V., Padualaan 8, 3584 CH Utrecht, The Netherlands
- Molecular Biology and Microbial Food Safety, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Roy van Gerven
- Dutch DNA Biotech B.V., Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Karin M. Overkamp
- Dutch DNA Biotech B.V., Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Peter S. Lübeck
- Section for Sustainable Biotechnology, Department of Chemistry and Bioscience, Aalborg University, A.C. Meyers Vaenge 15, 2450 Copenhagen SV, Denmark
| | - Hatice Taşpınar
- Pakmaya, Kosekoy Mah. Ankara Cad. No:277, 41310 Kartepe, Kocaeli Turkey
| | - Mustafa Türker
- Pakmaya, Kosekoy Mah. Ankara Cad. No:277, 41310 Kartepe, Kocaeli Turkey
| | - Peter J. Punt
- Dutch DNA Biotech B.V., Padualaan 8, 3584 CH Utrecht, The Netherlands
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Zhang H, Zhang L, Chen H, Chen YQ, Chen W, Song Y, Ratledge C. Enhanced lipid accumulation in the yeast Yarrowia lipolytica by over-expression of ATP:citrate lyase from Mus musculus. J Biotechnol 2015; 192 Pt A:78-84. [PMID: 25450640 DOI: 10.1016/j.jbiotec.2014.10.004] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 09/15/2014] [Accepted: 10/01/2014] [Indexed: 12/18/2022]
Abstract
Yarrowia lipolytica can accumulate large amounts of storage lipids and has considerable potential for the production of polyunsaturated fatty acids and other lipids for biofuels. When the nitrogen source is exhausted in the medium, the key intermediate, citrate, is converted to acetyl-CoA by ATP:citrate lyase (ACL) for lipid accumulation. However, in this yeast most of the citrate is also secreted into the culture medium. To increase the endogenous substrate (acetyl-CoA) level for lipid biosynthesis, the acl gene from Mus musculus was over-expressed in Y. lipolytica with mono-copy integration vector pINA1312sp and multi-copy integration vector pINA1292sp. This increased the lipid content from 7.3% to between 11% and 23% (w/w) of the cell dry weight. Cell growth was only slightly affected. Multi-copy integration transformants had higher lipid contents than mono-copy integration transformants; the lipid content of the transformants was consistent with the copy number of acl gene integrated. Over-expression of ACL had no significant effect on fatty acid profile of the yeast. These results suggested that ACL is an important acetyl-CoA producer and plays a vital role in lipid accumulation in oleaginous yeast Y. lipolytica.
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Chen H, He X, Geng H, Liu H. Physiological characterization of ATP-citrate lyase in Aspergillus niger. J Ind Microbiol Biotechnol 2014; 41:721-31. [PMID: 24566752 DOI: 10.1007/s10295-014-1418-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 02/10/2014] [Indexed: 10/25/2022]
Abstract
Acetyl-CoA, an important molecule in cellular metabolism, is generated in multiple subcellular compartments and mainly used for energy production, biosynthesis of a diverse set of molecules, and protein acetylation. In eukaryotes, cytosolic acetyl-CoA is derived mainly from the conversion of citrate and CoA by ATP-citrate lyase. Here, we describe the targeted deletions of acl1 and acl2, two tandem divergently transcribed genes encoding subunits of ATP-citrate lyase in Aspergillus niger. We show that loss of acl1 or/and acl2 results in a significant decrease of acetyl-CoA and citric acid levels in these mutants, concomitant with diminished vegetative growth, decreased pigmentation, reduced asexual conidiogenesis, and delayed conidial germination. Exogenous addition of acetate repaired the defects of acl-deficient strains in growth and conidial germination but not pigmentation and conidiogenesis. We demonstrate that both Acl1 and Acl2 subunits are required to form a functional ATP-citrate lyase in A. niger. First, deletion of acl1 or/and acl2 resulted in similar defects in growth and development. Second, enzyme activity assays revealed that loss of either acl1 or acl2 gene resulted in loss of ATP-citrate lyase activity. Third, in vitro enzyme assays using bacterially expressed 6His-tagged Acl protein revealed that only the complex of Acl1 and Acl2 showed ATP-citrate lyase activity, no enzyme activities were detected with the individual protein. Fourth, EGFP-Acl1 and mCherry-Acl2 proteins were co-localized in the cytosol. Thus, acl1 and acl2 coordinately modulate the cytoplasmic acetyl-CoA levels to regulate growth, development, and citric acid synthesis in A. niger.
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Affiliation(s)
- Hong Chen
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, China
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Saini R, Kapoor R, Kumar R, Siddiqi TO, Kumar A. CO2 utilizing microbes — A comprehensive review. Biotechnol Adv 2011; 29:949-60. [PMID: 21856405 DOI: 10.1016/j.biotechadv.2011.08.009] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2010] [Revised: 08/04/2011] [Accepted: 08/05/2011] [Indexed: 11/30/2022]
Affiliation(s)
- Rashmi Saini
- Department of Botany, North Campus, University of Delhi, New Delhi-110007, India
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9
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ATP-citrate lyase is required for production of cytosolic acetyl coenzyme A and development in Aspergillus nidulans. EUKARYOTIC CELL 2010; 9:1039-48. [PMID: 20495057 DOI: 10.1128/ec.00080-10] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Acetyl coenzyme A (CoA) is a central metabolite in carbon and energy metabolism and in the biosynthesis of cellular molecules. A source of cytoplasmic acetyl-CoA is essential for the production of fatty acids and sterols and for protein acetylation, including histone acetylation in the nucleus. In Saccharomyces cerevisiae and Candida albicans acetyl-CoA is produced from acetate by cytoplasmic acetyl-CoA synthetase, while in plants and animals acetyl-CoA is derived from citrate via ATP-citrate lyase. In the filamentous ascomycete Aspergillus nidulans, tandem divergently transcribed genes (aclA and aclB) encode the subunits of ATP-citrate lyase, and we have deleted these genes. Growth is greatly diminished on carbon sources that do not result in cytoplasmic acetyl-CoA, such as glucose and proline, while growth is not affected on carbon sources that result in the production of cytoplasmic acetyl-CoA, such as acetate and ethanol. Addition of acetate restores growth on glucose or proline, and this is dependent on facA, which encodes cytoplasmic acetyl-CoA synthetase, but not on the regulatory gene facB. Transcription of aclA and aclB is repressed by growth on acetate or ethanol. Loss of ATP-citrate lyase results in severe developmental effects, with the production of asexual spores (conidia) being greatly reduced and a complete absence of sexual development. This is in contrast to Sordaria macrospora, in which fruiting body formation is initiated but maturation is defective in an ATP-citrate lyase mutant. Addition of acetate does not repair these defects, indicating a specific requirement for high levels of cytoplasmic acetyl-CoA during differentiation. Complementation in heterokaryons between aclA and aclB deletions for all phenotypes indicates that the tandem gene arrangement is not essential.
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Beopoulos A, Cescut J, Haddouche R, Uribelarrea JL, Molina-Jouve C, Nicaud JM. Yarrowia lipolytica as a model for bio-oil production. Prog Lipid Res 2009; 48:375-87. [PMID: 19720081 DOI: 10.1016/j.plipres.2009.08.005] [Citation(s) in RCA: 425] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 08/18/2009] [Accepted: 08/20/2009] [Indexed: 01/13/2023]
Abstract
The yeast Yarrowialipolytica has developed very efficient mechanisms for breaking down and using hydrophobic substrates. It is considered an oleaginous yeast, based on its ability to accumulate large amounts of lipids. Completion of the sequencing of the Y.lipolytica genome and the existence of suitable tools for genetic manipulation have made it possible to use the metabolic function of this species for biotechnological applications. In this review, we describe the coordinated pathways of lipid metabolism, storage and mobilization in this yeast, focusing in particular on the roles and regulation of the various enzymes and organelles involved in these processes. The physiological responses of Y.lipolytica to hydrophobic substrates include surface-mediated and direct interfacial transport processes, the production of biosurfactants, hydrophobization of the cytoplasmic membrane and the formation of protrusions. We also discuss culture conditions, including the mode of culture control and the culture medium, as these conditions can be modified to enhance the accumulation of lipids with a specific composition and to identify links between various biological processes occurring in the cells of this yeast. Examples are presented demonstrating the potential use of Y.lipolytica in fatty-acid bioconversion, substrate valorization and single-cell oil production. Finally, this review also discusses recent progress in our understanding of the metabolic fate of hydrophobic compounds within the cell: their terminal oxidation, further degradation or accumulation in the form of intracellular lipid bodies.
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Affiliation(s)
- Athanasios Beopoulos
- Microbiology and Molecular Genetic Laboratory, CNRS UMR2585, INRA UMR1238, AgroParisTech, INRA centre de Versailles-Grignon BP 01, F-78850 Thiverval-Grignon, France
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Didek-brumec M, Gaberc-porekar V, Alačević M. Relationship between theClavicepsLife Cycle and Productivity of Ergot Alkaloids. Crit Rev Biotechnol 2008. [DOI: 10.3109/07388559609147423] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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12
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Kanao T, Fukui T, Atomi H, Imanaka T. ATP-citrate lyase from the green sulfur bacteriumChlorobium limicolais a heteromeric enzyme composed of two distinct gene products. ACTA ACUST UNITED AC 2003. [DOI: 10.1046/j.1432-1327.2001.02034.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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13
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Ratledge C, Wynn JP. The biochemistry and molecular biology of lipid accumulation in oleaginous microorganisms. ADVANCES IN APPLIED MICROBIOLOGY 2003; 51:1-51. [PMID: 12236054 DOI: 10.1016/s0065-2164(02)51000-5] [Citation(s) in RCA: 534] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Colin Ratledge
- Lipid Research Centre, Department of Biological Sciences, University of Hull, HU6 7RX, United Kingdom
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14
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Kanao T, Fukui T, Atomi H, Imanaka T. Kinetic and biochemical analyses on the reaction mechanism of a bacterial ATP-citrate lyase. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:3409-16. [PMID: 12135479 DOI: 10.1046/j.1432-1033.2002.03016.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The prokaryotic ATP-citrate lyase is considered to be a key enzyme of the carbon dioxide-fixing reductive tricarboxylic acid (RTCA) cycle. Kinetic examination of the ATP-citrate lyase from the green sulfur bacterium Chlorobium limicola (Cl-ACL), an alpha(4)beta(4) heteromeric enzyme, revealed that the enzyme displayed typical Michaelis-Menten kinetics toward ATP with an apparent K(m) value of 0.21 +/- 0.04 mm. However, strong negative cooperativity was observed with respect to citrate binding, with a Hill coefficient (n(H)) of 0.45. Although the dissociation constant of the first citrate molecule was 0.057 +/- 0.008 mm, binding of the first citrate molecule to the enzyme drastically decreased the affinity of the enzyme for the second molecule by a factor of 23. ADP was a competitive inhibitor of ATP with a K(i) value of 0.037 +/- 0.006 mm. Together with previous findings that the enzyme catalyzed the reaction only in the direction of citrate cleavage, these kinetic features indicated that Cl-ACL can regulate both the direction and carbon flux of the RTCA cycle in C. limicola. Furthermore, in order to gain insight on the reaction mechanism, we performed biochemical analyses of Cl-ACL. His273 of the alpha subunit was indicated to be the phosphorylated residue in the catalytic center, as both catalytic activity and phosphorylation of the enzyme by ATP were abolished in an H273A mutant enzyme. We found that phosphorylation of the subunit was reversible. Nucleotide preference for activity was in good accordance with the preference for phosphorylation of the enzyme. Although residues interacting with nucleotides in the succinyl-CoA synthetase from Escherichia coli were conserved in AclB, AclA alone could be phoshorylated with the same nucleotide specificity observed in the holoenzyme. However, AclB was necessary for enzyme activity and contributed to enhance phosphorylation and stabilization of AclA.
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Affiliation(s)
- Tadayoshi Kanao
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Japan
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15
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Adams IP, Dack S, Dickinson FM, Ratledge C. The distinctiveness of ATP:citrate lyase from Aspergillus nidulans. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1597:36-41. [PMID: 12009400 DOI: 10.1016/s0167-4838(02)00276-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
ATP:citrate lyase (ACL), an important enzyme in lipid synthesis, has been purified from Aspergillus nidulans to a specific activity of 19.6 micromol min(-1) mg(-1), almost twice that of any other purified ACL and shown to be distinct from any previously purified ACL. The enzyme is a 371+/-31 kDa hexamer of 3 alpha, 3 beta proteins, unlike the 4 alpha tetramer found in rats or yeasts. The molecular weights of the alpha and beta protein subunits were determined by SDS-PAGE to be 70 and 55 kDa. ACL in A. nidulans (unlike Aspergillus niger) appears to be regulated by the carbon source present in the media. In crude extracts, it was found at high activity (88 micromol min(-1) mg protein(-1)) in glucose-grown cells but only at low activity (10 micromol min(-1) mg protein(-1)) in acetate-grown cells.
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Affiliation(s)
- Ian P Adams
- Department of Biological Sciences, University of Hull, Hull HU6 7RX, UK.
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Alvarez-Vasquez F, González-Alcón C, Torres NV. Metabolism of citric acid production by Aspergillus niger: model definition, steady-state analysis and constrained optimization of citric acid production rate. Biotechnol Bioeng 2000; 70:82-108. [PMID: 10940866 DOI: 10.1002/1097-0290(20001005)70:1<82::aid-bit10>3.0.co;2-v] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
In an attempt to provide a rational basis for the optimization of citric acid production by A. niger, we developed a mathematical model of the metabolism of this filamentous fungus when in conditions of citric acid accumulation. The present model is based in a previous one, but extended with the inclusion of new metabolic processes and updated with currently available kinetic data. Among the different alternatives to represent the system behavior we have chosen the S-system representation within power-law formalism. This type of representation allows us to verify not only the ability of the model to exhibit a stable steady state of the integrated system but also the robustness and quality of the representation. The model analysis is shown to be self-consistent, with a stable steady state, and in good agreement with experimental evidence. Moreover, the model representation is sufficiently robust, as indicated by sensitivity and steady-state and dynamic analyses. From the steady-state results we concluded that the range of accuracy of the S-system representation is wide enough to model realistic deviations from the nominal steady state. The dynamic analysis indicated a reasonable response time, which provided further indication that the model is adequate. The extensive assessment of the reliability and quality of the model put us in a position to address questions of optimization of the system with respect to increased citrate production. We carried out the constrained optimization of A. niger metabolism with the goal of predicting an enzyme activity profile yielding the maximum rate of citrate production, while, at the same time, keeping all enzyme activities within predetermined, physiologically acceptable ranges. The optimization is based on a method described and tested elsewhere that utilizes the fact that the S-system representation of a metabolic system becomes linear at steady state, which allows application of linear programming techniques. Our results show that: (i) while the present profile of enzyme activities in A. niger at idiophase steady state yields high rates of citric acid production, it still leaves room for changes and suggests possible optimization of the activity profile to over five times the basal rate synthesis; (ii) when the total enzyme concentration is allowed to double its basal value, the citric acid production rate can be increased by more than 12-fold, and even larger values can be attained if the total enzyme concentration is allowed to increase even more (up to 50-fold when the total enzyme concentration may rise up to 10-fold the basal value); and (iii) the systematic search of the best combination of subsets of enzymes shows that, under all conditions assayed, a minimum of 13 enzymes need be modified if significant increases in citric acid are to be obtained. This implies that improvements by single enzyme modulation are unlikely, which is in agreement with the findings of some investigators in this and other fields.
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Affiliation(s)
- F Alvarez-Vasquez
- Grupo Tecnología Bioquímica y Control Metabólico, Departamento de Bioquímica y Biología Molecular, Facultad de Biología, Universidad de La Laguna, 38206 La Laguna, Tenerife, Islas Canarias, España
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Nowrousian M, Masloff S, Pöggeler S, Kück U. Cell differentiation during sexual development of the fungus Sordaria macrospora requires ATP citrate lyase activity. Mol Cell Biol 1999; 19:450-60. [PMID: 9858569 PMCID: PMC83903 DOI: 10.1128/mcb.19.1.450] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
During sexual development, mycelial cells from most filamentous fungi differentiate into typical fruiting bodies. Here, we describe the isolation and characterization of the Sordaria macrospora developmental mutant per5, which exhibits a sterile phenotype with defects in fruiting body maturation. Cytological investigations revealed that the mutant strain forms only ascus precursors without any mature spores. Using an indexed cosmid library, we were able to complement the mutant to fertility by DNA-mediated transformation. A single cosmid clone, carrying a 3.5-kb region able to complement the mutant phenotype, has been identified. Sequencing of the 3.5-kb region revealed an open reading frame of 2.1 kb interrupted by a 66-bp intron. The predicted polypeptide (674 amino acids) shows significant homology to eukaryotic ATP citrate lyases (ACLs), with 62 to 65% amino acid identity, and the gene was named acl1. The molecular mass of the S. macrospora ACL1 polypeptide is 73 kDa, as was verified by Western blot analysis with a hemagglutinin (HA) epitope-tagged ACL1 polypeptide. Immunological in situ detection of the HA-tagged polypeptide demonstrated that ACL is located within the cytosol. Sequencing of the mutant acl1 gene revealed a 1-nucleotide transition within the coding region, resulting in an amino acid substitution within the predicted polypeptide. Further evidence that ACL1 is essential for fruiting body maturation comes from experiments in which truncated and mutated versions of the acl1 gene were used for transformation. None of these copies was able to reconstitute the fertile phenotype in transformed per5 recipient strains. ACLs are usually involved in the formation of cytosolic acetyl coenzyme A (acetyl-CoA), which is used for the biosynthesis of fatty acids and sterols. Protein extracts from the mutant strain showed a drastic reduction in enzymatic activity compared to values obtained from the wild-type strain. Investigation of the time course of ACL expression suggests that ACL is specifically induced at the beginning of the sexual cycle and produces acetyl-CoA, which most probably is a prerequisite for fruiting body formation during later stages of sexual development. We discuss the contribution of ACL activity to the life cycle of S. macrospora.
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Affiliation(s)
- M Nowrousian
- Lehrstuhl für Allgemeine Botanik, Ruhr-Universität Bochum, D-44780 Bochum, Germany
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Jernejc K, Legisa M. Purification and properties of carnitine acetyltransferase from citric acid producing Aspergillus niger. Appl Biochem Biotechnol 1996; 60:151-8. [PMID: 8856942 DOI: 10.1007/bf02788069] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Carnitine acetyltransferase was purified from the citric acid producing A. niger mycelium with a protein band showing a relative molecular weight of 77,000 and a pH optimum of 7.3. The K(m) values for the purified enzyme for acetyl-CoA and for carnitine were 0.1 mM and 1 mM, respectively. Carnitine acetyltransferase was located both in the mitochondria and in the cytosol. Both mitochondrial and cytosolic enzyme were purified using ammonium sulfate precipitation, Mono Q and Superose 12 separation. Regarding the localization, except for maximum velocity, there were no differences observed in substrate specificity and inhibition. Inhibition of the enzyme with micromolar concentrations of Cu2+ could contribute to a greater citric acid biosynthesis. Carnitine acetyltransferase can be considered as an enzyme necessary for the transport of acetyl groups through mitochondrial membrane in both directions.
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Affiliation(s)
- K Jernejc
- National Institute of Chemistry, Ljubljana, Slovenia
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19
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Henriksen CM, Christensen LH, Nielsen J, Villadsen J. Growth energetics and metabolic fluxes in continuous cultures of Penicillium chrysogenum. J Biotechnol 1996; 45:149-64. [PMID: 9147448 DOI: 10.1016/0168-1656(95)00164-6] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Continuous cultures of the penicillin producing fungus Penicillium chrysogenum have been analyzed with respect to the macromolecular composition of the mycelium. All cultivations were carried out using a chemically defined medium with glucose as the growth limiting component. Biomass was harvested at steady state and analyzed for proteins, lipids, RNA, DNA, and carbohydrates. Carbohydrates present in the cell wall, i.e., glucans and chitin, and carbohydrates serving as storage materials, i.e., glycogen, were measured. It was observed that the levels of DNA and lipids are relative constant, whereas the proteins and stable RNA levels increase with the specific growth rate and the total amount of carbohydrates decreases with the specific growth rate. Glycogen is only present in small amounts, decreasing with the specific growth rate. As an average the measured macromolecules account for 77 +/- 2% (w/w) of the biomass. On the basis of estimations of the metabolic costs for biosynthesis and polymerization of the different macromolecules the total ATP and NADPH requirements for cell biosynthesis from glucose and inorganic salts, i.e., YxATP,growth and YxNADPH, have been quantified. The biosynthesis of 1 g biomass was calculated to require 39.9 mmol of ATP and 7.5 mmol of NADPH when cytosolic acetyl-CoA is formed from citrate by citrate lyase and oxaloacetate is recycled back into the TCA cycle. Other pathways of acetyl-CoA biosynthesis have been considered. The calculations show that the different biosynthetic routes for generating cytosolic acetyl-CoA have a significant influence on the theoretical value of ATP and NADPH requirements for cell biosynthesis. Combining a detailed stoichiometric model for growth and product formation of P. chrysogenum with experimental data on the macromolecular composition of P. chrysogenum and precise measurements of substrate uptake and product formation the intracellular flux distribution was calculated for different cultivation conditions.
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Affiliation(s)
- C M Henriksen
- Center for Process Biotechnology, Technical University of Denmark, Lyngby
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Kontopidis G, Mattey M, Kristiansen B. Citrate transport during the citric acid fermentation by Aspergillus niger. Biotechnol Lett 1995. [DOI: 10.1007/bf00143110] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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21
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Midgley M. Carnitine acetyltransferase is absent from acuJ mutants of Aspergillus nidulans. FEMS Microbiol Lett 1993. [DOI: 10.1111/j.1574-6968.1993.tb06064.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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22
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ATP: citrate lyase and carnitine acetyltransferase activity in a citric-acid-producing Aspergillus niger strain. Appl Microbiol Biotechnol 1991. [DOI: 10.1007/bf00164705] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Ishii M, Igarashi Y, Kodama T. Purification and characterization of ATP:citrate lyase from Hydrogenobacter thermophilus TK-6. J Bacteriol 1989; 171:1788-92. [PMID: 2703459 PMCID: PMC209823 DOI: 10.1128/jb.171.4.1788-1792.1989] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
ATP:citrate lyase [ATP citrate (pro-3S)-lyase; EC 4.1.3.8] was purified and characterized from the cells of Hydrogenobacter thermophilus, an aerobic, thermophilic, hydrogen-oxidizing bacterium which fixes carbon dioxide by a reductive carboxylic acid cycle. The enzyme was quite stable, even in the absence of sulfhydryl reagents. Optimum pH for reaction was 6.7 to 6.9, and optimum temperature was around 80 degrees C. The molecular weight of native enzyme was estimated to be 260,000 by gel filtration analysis, and that of a subunit was estimated to be 43,000 by sodium dodecyl sulfate-polyacrylamide gel analysis. Km values for reaction components were as follows: citrate, 6.25 mM; ATP, 650 microM; coenzyme A, 40.8 microM; and Mg2+, 8 mM. The enzyme showed citrate synthase activity in the presence of Mg2+, but the reaction rate was very low (less than 1/200 of the lyase activity).
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Affiliation(s)
- M Ishii
- Department of Agricultural Chemistry, University of Tokyo, Japan
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Purohit HJ, Ratledge C. Mitochondrial location of pyruvate carboxylase inAspergillus niger. FEMS Microbiol Lett 1988. [DOI: 10.1111/j.1574-6968.1988.tb13920.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Kubicek CP, Schreferl-Kunar G, Wöhrer W, Röhr M. Evidence for a cytoplasmic pathway of oxalate biosynthesis in Aspergillus niger. Appl Environ Microbiol 1988; 54:633-7. [PMID: 3132096 PMCID: PMC202517 DOI: 10.1128/aem.54.3.633-637.1988] [Citation(s) in RCA: 124] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Oxalate accumulation of up to 8 g/liter was induced in Aspergillus niger by shifting the pH from 6 to 8. This required the presence of Pi and a nitrogen source and was inhibited by the protein synthesis inhibitor cycloheximide. Exogenously added 14CO2 was not incorporated into oxalate, but was incorporated into acetate and malate, thus indicating the biosynthesis of oxalate by hydrolytic cleavage of oxaloacetate. Inhibition of mitochondrial citrate metabolism by fluorocitrate did not significantly decrease the oxalate yield. The putative enzyme that was responsible for this was oxaloacetate hydrolase (EC 3.7.1.1), which was induced de novo during the pH shift. Subcellular fractionation of oxalic acid-forming mycelia of A. niger showed that this enzyme is located in the cytoplasm of A. niger. The results are consistent with a cytoplasmic pathway of oxalate formation which does not involve the tricarboxylic acid cycle.
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Affiliation(s)
- C P Kubicek
- Abteilung für Mikrobielle Biochemie, TU Wien, Vienna, Austria
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Acetate oxidation to CO2 via a citric acid cycle involving an ATP-citrate lyase: a mechanism for the synthesis of ATP via substrate level phosphorylation in Desulfobacter postgatei growing on acetate and sulfate. Arch Microbiol 1987. [DOI: 10.1007/bf00414812] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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