1
|
A bi-enzymatic cascade to yield pyruvate as co-substrate for l-tyrosine production. Appl Microbiol Biotechnol 2020; 104:10005-10018. [DOI: 10.1007/s00253-020-10975-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 10/07/2020] [Accepted: 10/25/2020] [Indexed: 11/25/2022]
|
2
|
Med15B Regulates Acid Stress Response and Tolerance in Candida glabrata by Altering Membrane Lipid Composition. Appl Environ Microbiol 2017; 83:AEM.01128-17. [PMID: 28710262 DOI: 10.1128/aem.01128-17] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 07/04/2017] [Indexed: 12/16/2022] Open
Abstract
Candida glabrata is a promising producer of organic acids. To elucidate the physiological function of the Mediator tail subunit Med15B in the response to low-pH stress, we constructed a deletion strain, C. glabratamed15BΔ, and an overexpression strain, C. glabrata HTUΔ/CgMED15B Deletion of MED15B caused biomass production, glucose consumption rate, and cell viability to decrease by 28.3%, 31.7%, and 26.5%, respectively, compared with those of the parent (HTUΔ) strain at pH 2.0. Expression of lipid metabolism-related genes was significantly downregulated in the med15BΔ strain, whereas key genes of ergosterol biosynthesis showed abnormal upregulation. This caused the proportion of C18:1 fatty acids, the ratio of unsaturated to saturated fatty acids (UFA/SFA), and the total phospholipid content to decrease by 11.6%, 27.4%, and 37.6%, respectively. Cells failed to synthesize fecosterol and ergosterol, leading to the accumulation and a 60.3-fold increase in the concentration of zymosterol. Additionally, cells showed reductions of 69.2%, 11.6%, and 21.8% in membrane integrity, fluidity, and H+-ATPase activity, respectively. In contrast, overexpression of Med15B increased the C18:1 levels, total phospholipids, ergosterol content, and UFA/SFA by 18.6%, 143.5%, 94.5%, and 18.7%, respectively. Membrane integrity, fluidity, and H+-ATPase activity also increased by 30.2%, 6.9%, and 51.8%, respectively. Furthermore, in the absence of pH buffering, dry weight of cells and pyruvate concentrations were 29.3% and 61.2% higher, respectively, than those of the parent strain. These results indicated that in C. glabrata, Med15B regulates tolerance toward low pH via transcriptional regulation of acid stress response genes and alteration in lipid composition.IMPORTANCE This study explored the role of the Mediator tail subunit Med15B in the metabolism of Candida glabrata under acidic conditions. Overexpression of MED15B enhanced yeast tolerance to low pH and improved biomass production, cell viability, and pyruvate yield. Membrane lipid composition data indicated that Med15B might play a critical role in membrane integrity, fluidity, and H+-ATPase activity homeostasis at low pH. Thus, controlling membrane composition may serve to increase C. glabrata productivity at low pH.
Collapse
|
3
|
CgMED3 Changes Membrane Sterol Composition To Help Candida glabrata Tolerate Low-pH Stress. Appl Environ Microbiol 2017; 83:AEM.00972-17. [PMID: 28667115 DOI: 10.1128/aem.00972-17] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 06/23/2017] [Indexed: 12/11/2022] Open
Abstract
Candida glabrata is a promising microorganism for organic acid production. The present study aimed to investigate the role of C. glabrata Mediator complex subunit 3 (CgMed3p) in protecting C. glabrata under low-pH conditions. To this end, genes CgMED3A and CgMED3B were deleted, resulting in the double-deletion Cgmed3ABΔ strain. The final biomass and cell viability levels of Cgmed3ABΔ decreased by 64.5% and 35.8%, respectively, compared to the wild-type strain results at pH 2.0. In addition, lack of CgMed3ABp resulted in selective repression of a subset of genes in the lipid biosynthesis and metabolism pathways. Furthermore, C18:1, lanosterol, zymosterol, fecosterol, and ergosterol were 13.2%, 80.4%, 40.4%, 78.1%, and 70.4% less abundant, respectively, in the Cgmed3ABΔ strain. In contrast, the concentration of squalene increased by about 44.6-fold. As a result, membrane integrity, rigidity, and H+-ATPase activity in the Cgmed3ABΔ strain were reduced by 62.7%, 13.0%, and 50.3%, respectively. In contrast, overexpression of CgMED3AB increased the levels of C18:0, C18:1, and ergosterol by 113.2%, 5.9%, and 26.4%, respectively. Moreover, compared to the wild-type results, dry cell weight and pyruvate production increased, irrespective of pH buffering. These results suggest that CgMED3AB regulates membrane composition, which in turn enables cells to tolerate low-pH stress. We propose that regulation of CgMed3ABp may provide a novel strategy for enhancing low-pH tolerance and increasing organic acid production by C. glabrataIMPORTANCE The objective of this study was to investigate the role of Candida glabrata Mediator complex subunit 3 (CgMed3ABp) and its regulation of gene expression at low pH in C. glabrata We found that CgMed3ABp was critical for cellular survival and pyruvate production during low-pH stress. Measures of the levels of plasma membrane fatty acids and sterol composition indicated that CgMed3ABp could play an important role in regulating homeostasis in C. glabrata We propose that controlling membrane lipid composition may enhance the robustness of C. glabrata for the production of organic acids.
Collapse
|
4
|
Xu N, Ye C, Chen X, Liu J, Liu L. Genome-scale metabolic modelling common cofactors metabolism in microorganisms. J Biotechnol 2017; 251:1-13. [PMID: 28385592 DOI: 10.1016/j.jbiotec.2017.04.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Revised: 04/02/2017] [Accepted: 04/03/2017] [Indexed: 12/20/2022]
Abstract
The common cofactors ATP/ADP, NAD(P)(H), and acetyl-CoA/CoA are indispensable participants in biochemical reactions in industrial microbes. To systematically explore the effects of these cofactors on cell growth and metabolic phenotypes, the first genome-scale cofactor metabolic model, icmNX6434, including 6434 genes, 1782 metabolites, and 6877 reactions, was constructed from 14 genome-scale metabolic models of 14 industrial strains. The origin, consumption, and interactions of these common cofactors in microbial cells were elucidated by the icmNX6434 model, and they played important roles in cell growth. The essential cofactor modules contained 2480 genes and 2948 reactions; therefore, improving cofactor biosynthesis, directing these cofactors into essential metabolic pathways, as well as avoiding cofactor utilization during byproduct biosynthesis and futile cycles, are three ways to increase cell growth. The effects of these common cofactors on the distribution and rate of the carbon flux in four universal modes, as well as an optimized metabolic flux, could be obtained by manipulating cofactor availability and balance. Significant changes in the ATP, NAD(H), NADP(H), or acetyl-CoA concentrations triggered relevant metabolic responses to acidic, oxidative, heat, and osmotic stress. Globally, the model icmNX6434 provides a comprehensive platform to elucidate the physiological effects of these cofactors on cell growth, metabolic flux, and industrial robustness. Moreover, the results of this study are a further example of using a consensus genome-scale metabolic model to increase our understanding of key biological processes.
Collapse
Affiliation(s)
- Nan Xu
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; College of Bioscience and Biotechnology, Yangzhou University, Yangzhou, Jiangsu 225009, China; The Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi 214122, China
| | - Chao Ye
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; The Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi 214122, China
| | - Xiulai Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; The Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi 214122, China
| | - Jia Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; The Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi 214122, China
| | - Liming Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; The Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi 214122, China.
| |
Collapse
|
5
|
|
6
|
Chen X, Song W, Gao C, Qin W, Luo Q, Liu J, Liu L. Fumarate Production by Torulopsis glabrata: Engineering Heterologous Fumarase Expression and Improving Acid Tolerance. PLoS One 2016; 11:e0164141. [PMID: 27711153 PMCID: PMC5053504 DOI: 10.1371/journal.pone.0164141] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 09/20/2016] [Indexed: 01/12/2023] Open
Abstract
Fumarate is a well-known biomass building block compound. However, the poor catalytic efficiency of fumarase is one of the major factors preventing its widespread production. To address this issue, we selected residues 159HPND162 of fumarase from Rhizopus oryzae as targets for site-directed mutagenesis based on molecular docking analysis. Twelve mutants were generated and characterized in detail. Kinetic studies showed that the Km values of the P160A, P160T, P160H, N161E, and D162W mutants were decreased, whereas Km values of H159Y, H159V, H159S, N161R, N161F, D162K, and D162M mutants were increased. In addition, all mutants displayed decreased catalytic efficiency except for the P160A mutant, whose kcat/Km was increased by 33.2%. Moreover, by overexpressing the P160A mutant, the engineered strain T.G-PMS-P160A was able to produce 5.2 g/L fumarate. To further enhance fumarate production, the acid tolerance of T.G-PMS-P160A was improved by deleting ade12, a component of the purine nucleotide cycle, and the resulting strain T.G(△ade12)-PMS-P160A produced 9.2 g/L fumarate. The strategy generated in this study opens up new avenues for pathway optimization and efficient production of natural products.
Collapse
Affiliation(s)
- Xiulai Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
- Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi, China
| | - Wei Song
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
- Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi, China
| | - Cong Gao
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
- Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi, China
| | - Wen Qin
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
- Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi, China
| | - Qiuling Luo
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
- Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi, China
| | - Jia Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
- Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi, China
| | - Liming Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
- Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi, China
| |
Collapse
|
7
|
Chen X, Xu G, Xu N, Zou W, Zhu P, Liu L, Chen J. Metabolic engineering of Torulopsis glabrata for malate production. Metab Eng 2013; 19:10-6. [DOI: 10.1016/j.ymben.2013.05.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2012] [Revised: 05/12/2013] [Accepted: 05/15/2013] [Indexed: 01/15/2023]
|
8
|
Bignucolo A, Appanna VP, Thomas SC, Auger C, Han S, Omri A, Appanna VD. Hydrogen peroxide stress provokes a metabolic reprogramming in Pseudomonas fluorescens: enhanced production of pyruvate. J Biotechnol 2013; 167:309-15. [PMID: 23871654 DOI: 10.1016/j.jbiotec.2013.07.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 06/28/2013] [Accepted: 07/02/2013] [Indexed: 10/26/2022]
Abstract
Pseudomonas fluorescens invoked a metabolic reconfiguration that resulted in enhanced production of pyruvate under the challenge of hydrogen peroxide (H₂O₂). Although this stress led to a sharp reduction in the activities of numerous tricarboxylic acid (TCA) cycle enzymes, there was a marked increase in the activities of catalase and various NADPH-generating enzymes to counter the oxidative burden. The upregulation of phosphoenolpyruvate synthase (PEPS) and pyruvate kinase (PK) coupled with the reduction of pyruvate dehydrogenase (PDH) in the H₂O₂-challenged cells appear to be important contributors to the elevated levels of pyruvate found in these bacteria. Increased pyruvate synthesis was evident in the presence of a variety of carbon sources including d-glucose. Intact cells rapidly consumed d-glucose with the concomitant formation of this monocarboxylic acid. At least a 12-fold increase in pyruvate production within 1h was observed in the stressed cells. These findings may be exploited in the development of technologies aimed at the conversion of carbohydrates into pyruvate.
Collapse
Affiliation(s)
- Adam Bignucolo
- Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario P3E 2C6, Canada
| | | | | | | | | | | | | |
Collapse
|
9
|
Liu Z, Wang X, Qi Q, Hua Q. Quantification and analysis of metabolic characteristics of aerobic succinate-producing Escherichia coli under different aeration conditions. Process Biochem 2012. [DOI: 10.1016/j.procbio.2012.01.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
|
10
|
van Bloois E, Dudek HM, Duetz WA, Fraaije MW. A stepwise approach for the reproducible optimization of PAMO expression in Escherichia coli for whole-cell biocatalysis. BMC Biotechnol 2012; 12:31. [PMID: 22720747 PMCID: PMC3404926 DOI: 10.1186/1472-6750-12-31] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 06/21/2012] [Indexed: 11/22/2022] Open
Abstract
Background Baeyer-Villiger monooxygenases (BVMOs) represent a group of enzymes of considerable biotechnological relevance as illustrated by their growing use as biocatalyst in a variety of synthetic applications. However, due to their increased use the reproducible expression of BVMOs and other biotechnologically relevant enzymes has become a pressing matter while knowledge about the factors governing their reproducible expression is scattered. Results Here, we have used phenylacetone monooxygenase (PAMO) from Thermobifida fusca, a prototype Type I BVMO, as a model enzyme to develop a stepwise strategy to optimize the biotransformation performance of recombinant E. coli expressing PAMO in 96-well microtiter plates in a reproducible fashion. Using this system, the best expression conditions of PAMO were investigated first, including different host strains, temperature as well as time and induction period for PAMO expression. This optimized system was used next to improve biotransformation conditions, the PAMO-catalyzed conversion of phenylacetone, by evaluating the best electron donor, substrate concentration, and the temperature and length of biotransformation. Combining all optimized parameters resulted in a more than four-fold enhancement of the biocatalytic performance and, importantly, this was highly reproducible as indicated by the relative standard deviation of 1% for non-washed cells and 3% for washed cells. Furthermore, the optimized procedure was successfully adapted for activity-based mutant screening. Conclusions Our optimized procedure, which provides a comprehensive overview of the key factors influencing the reproducible expression and performance of a biocatalyst, is expected to form a rational basis for the optimization of miniaturized biotransformations and for the design of novel activity-based screening procedures suitable for BVMOs and other NAD(P)H-dependent enzymes as well.
Collapse
Affiliation(s)
- Edwin van Bloois
- Laboratory of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, The Netherlands
| | | | | | | |
Collapse
|
11
|
|
12
|
Gordon JL, Byrne KP, Wolfe KH. Additions, losses, and rearrangements on the evolutionary route from a reconstructed ancestor to the modern Saccharomyces cerevisiae genome. PLoS Genet 2009; 5:e1000485. [PMID: 19436716 PMCID: PMC2675101 DOI: 10.1371/journal.pgen.1000485] [Citation(s) in RCA: 183] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Accepted: 04/20/2009] [Indexed: 11/26/2022] Open
Abstract
Comparative genomics can be used to infer the history of genomic rearrangements that occurred during the evolution of a species. We used the principle of parsimony, applied to aligned synteny blocks from 11 yeast species, to infer the gene content and gene order that existed in the genome of an extinct ancestral yeast about 100 Mya, immediately before it underwent whole-genome duplication (WGD). The reconstructed ancestral genome contains 4,703 ordered loci on eight chromosomes. The reconstruction is complete except for the subtelomeric regions. We then inferred the series of rearrangement steps that led from this ancestor to the current Saccharomyces cerevisiae genome; relative to the ancestral genome we observe 73 inversions, 66 reciprocal translocations, and five translocations involving telomeres. Some fragile chromosomal sites were reused as evolutionary breakpoints multiple times. We identified 124 genes that have been gained by S. cerevisiae in the time since the WGD, including one that is derived from a hAT family transposon, and 88 ancestral loci at which S. cerevisiae did not retain either of the gene copies that were formed by WGD. Sites of gene gain and evolutionary breakpoints both tend to be associated with tRNA genes and, to a lesser extent, with origins of replication. Many of the gained genes in S. cerevisiae have functions associated with ethanol production, growth in hypoxic environments, or the uptake of alternative nutrient sources.
Collapse
Affiliation(s)
- Jonathan L. Gordon
- Smurfit Institute of Genetics, Trinity College, Dublin, Ireland
- Department of Plant Systems Biology, VIB, Ghent, Belgium
| | - Kevin P. Byrne
- Smurfit Institute of Genetics, Trinity College, Dublin, Ireland
| | | |
Collapse
|
13
|
Biwer AP, Zuber PT, Zelic B, Gerharz T, Bellmann KJ, Heinzle E. Modeling and Analysis of a New Process for Pyruvate Production. Ind Eng Chem Res 2005. [DOI: 10.1021/ie0491138] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Arno P. Biwer
- Institute of Biochemical Engineering, Saarland University, 66123 Saarbruecken, Germany, Lehrstuhl für Allgemeine Betriebswirtschaftslehre und Produktionswirtschaft, University of Mainz, 55099 Mainz, Germany, Faculty of Chemical Engineering and Technology, Univerisity of Zagreb, 10000 Zagreb, Croatia, and Institute of Biotechnology, Research Center Juelich GmbH, Leo-Brand Strasse, 52425 Juelich, Germany
| | - Pascal T. Zuber
- Institute of Biochemical Engineering, Saarland University, 66123 Saarbruecken, Germany, Lehrstuhl für Allgemeine Betriebswirtschaftslehre und Produktionswirtschaft, University of Mainz, 55099 Mainz, Germany, Faculty of Chemical Engineering and Technology, Univerisity of Zagreb, 10000 Zagreb, Croatia, and Institute of Biotechnology, Research Center Juelich GmbH, Leo-Brand Strasse, 52425 Juelich, Germany
| | - Bruno Zelic
- Institute of Biochemical Engineering, Saarland University, 66123 Saarbruecken, Germany, Lehrstuhl für Allgemeine Betriebswirtschaftslehre und Produktionswirtschaft, University of Mainz, 55099 Mainz, Germany, Faculty of Chemical Engineering and Technology, Univerisity of Zagreb, 10000 Zagreb, Croatia, and Institute of Biotechnology, Research Center Juelich GmbH, Leo-Brand Strasse, 52425 Juelich, Germany
| | - Tanja Gerharz
- Institute of Biochemical Engineering, Saarland University, 66123 Saarbruecken, Germany, Lehrstuhl für Allgemeine Betriebswirtschaftslehre und Produktionswirtschaft, University of Mainz, 55099 Mainz, Germany, Faculty of Chemical Engineering and Technology, Univerisity of Zagreb, 10000 Zagreb, Croatia, and Institute of Biotechnology, Research Center Juelich GmbH, Leo-Brand Strasse, 52425 Juelich, Germany
| | - Klaus J. Bellmann
- Institute of Biochemical Engineering, Saarland University, 66123 Saarbruecken, Germany, Lehrstuhl für Allgemeine Betriebswirtschaftslehre und Produktionswirtschaft, University of Mainz, 55099 Mainz, Germany, Faculty of Chemical Engineering and Technology, Univerisity of Zagreb, 10000 Zagreb, Croatia, and Institute of Biotechnology, Research Center Juelich GmbH, Leo-Brand Strasse, 52425 Juelich, Germany
| | - Elmar Heinzle
- Institute of Biochemical Engineering, Saarland University, 66123 Saarbruecken, Germany, Lehrstuhl für Allgemeine Betriebswirtschaftslehre und Produktionswirtschaft, University of Mainz, 55099 Mainz, Germany, Faculty of Chemical Engineering and Technology, Univerisity of Zagreb, 10000 Zagreb, Croatia, and Institute of Biotechnology, Research Center Juelich GmbH, Leo-Brand Strasse, 52425 Juelich, Germany
| |
Collapse
|
14
|
Liu LM, Li Y, Li HZ, Chen J. Manipulating the pyruvate dehydrogenase bypass of a multi-vitamin auxotrophic yeast Torulopsis glabrata enhanced pyruvate production. Lett Appl Microbiol 2004; 39:199-206. [PMID: 15242462 DOI: 10.1111/j.1472-765x.2004.01563.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS To investigate the relationship between the activity of pyruvate dehydrogenase (PDH) bypass and the production of pyruvate of a multi-vitamin auxotrophic yeast Torulopsis glabrata. METHODS AND RESULTS Torulopsis glabrata CCTCC M202019, a multi-vitamin auxotrophic yeast that requires acetate for complete growth on glucose minimum medium, was selected after nitrosoguanidine mutagenesis of the parent strain T. glabrata WSH-IP303 screened in previous study [Li et al. (2001) Appl. Microbiol. Biotechnol. 55, 680-685]. Strain CCTCC M202019 produced 21% higher pyruvate than the parent strain and was genetically stable in flask cultures. The activities of the pyruvate metabolism-related enzymes in parent and mutant strains were measured. Compared with the parent strain, the activity of pyruvate decarboxylase (PDC) of the mutant strain CCTCC M202019 decreased by roughly 40%, while the activity of acetyl-CoA synthetase (ACS) of the mutant increased by 103.5 or 57.4%, respectively, in the presence or absence of acetate. Pyruvate production by the mutant strain CCTCC M202019 reached 68.7 g l(-1) at 62 h (yield on glucose of 0.651 g g(-1)) in a 7-l jar fermentor. CONCLUSIONS The increased pyruvate yield in T. glabrata CCTCC M202019 was due to a balanced manipulation of the PDH bypass, where the shortage of cytoplasmic acetyl-CoA caused by the decreased activity of PDC was properly compensated by the increased activity of ACS. SIGNIFICANCE AND IMPACT OF THE STUDY Manipulating the PDH bypass may provide an alternative approach to enhance the production of glycolysis-related metabolites.
Collapse
Affiliation(s)
- L-M Liu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, and School of Biotechnology, Southern Yangtze University, Wuxi, China
| | | | | | | |
Collapse
|
15
|
Hua Q, Yang C, Baba T, Mori H, Shimizu K. Responses of the central metabolism in Escherichia coli to phosphoglucose isomerase and glucose-6-phosphate dehydrogenase knockouts. J Bacteriol 2004; 185:7053-67. [PMID: 14645264 PMCID: PMC296241 DOI: 10.1128/jb.185.24.7053-7067.2003] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The responses of Escherichia coli central carbon metabolism to knockout mutations in phosphoglucose isomerase and glucose-6-phosphate (G6P) dehydrogenase genes were investigated by using glucose- and ammonia-limited chemostats. The metabolic network structures and intracellular carbon fluxes in the wild type and in the knockout mutants were characterized by using the complementary methods of flux ratio analysis and metabolic flux analysis based on [U-(13)C]glucose labeling and two-dimensional nuclear magnetic resonance (NMR) spectroscopy of cellular amino acids, glycerol, and glucose. Disruption of phosphoglucose isomerase resulted in use of the pentose phosphate pathway as the primary route of glucose catabolism, while flux rerouting via the Embden-Meyerhof-Parnas pathway and the nonoxidative branch of the pentose phosphate pathway compensated for the G6P dehydrogenase deficiency. Furthermore, additional, unexpected flux responses to the knockout mutations were observed. Most prominently, the glyoxylate shunt was found to be active in phosphoglucose isomerase-deficient E. coli. The Entner-Doudoroff pathway also contributed to a minor fraction of the glucose catabolism in this mutant strain. Moreover, although knockout of G6P dehydrogenase had no significant influence on the central metabolism under glucose-limited conditions, this mutation resulted in extensive overflow metabolism and extremely low tricarboxylic acid cycle fluxes under ammonia limitation conditions.
Collapse
Affiliation(s)
- Qiang Hua
- Institute for Advanced Biosciences, Keio University, Tsuruoka 997-0017, Japan.
| | | | | | | | | |
Collapse
|
16
|
Yang C, Hua Q, Baba T, Mori H, Shimizu K. Analysis of Escherichia coli anaplerotic metabolism and its regulation mechanisms from the metabolic responses to altered dilution rates and phosphoenolpyruvate carboxykinase knockout. Biotechnol Bioeng 2003; 84:129-44. [PMID: 12966569 DOI: 10.1002/bit.10692] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The gluconeogenic phosphoenolpyruvate (PEP) carboxykinase is active in Escherichia coli during its growth on glucose. The present study investigated the influence of growth rates and PEP carboxykinase knockout on the anaplerotic fluxes in E. coli. The intracellular fluxes were determined using the complementary methods of flux ratio analysis and metabolic flux analysis based on [U-(13)C(6)]glucose labeling experiments and 2D nuclear magnetic resonance (NMR) spectroscopy of cellular amino acids and glycerol. Significant activity of PEP carboxykinase was identified in wild-type E. coli, and the ATP dissipation for the futile cycling via this reaction accounted for up to 8.2% of the total energy flux. Flux analysis of pck deletion mutant revealed that abolishment of PEP carboxykinase activity resulted in a remarkably reduced flux through the anaplerotic PEP carboxylase and the activation of the glyoxylate shunt, with 23% of isocitrate found being channeled in the glyoxylate shunt. The changes in intracellular metabolite concentrations and specific enzyme activities associated with different growth rates and pck deletion, were also determined. Combining the measurement data of in vivo fluxes, metabolite concentrations and enzyme activities, the in vivo regulations of PEP carboxykinase flux, PEP carboxylation, and glyoxylate shunt in E. coli are discussed.
Collapse
Affiliation(s)
- Chen Yang
- Metabolome Unit, Institute for Advanced Biosciences, Keio University, Tsuruoka 997-0017, Japan
| | | | | | | | | |
Collapse
|
17
|
Characterization of xanthan gum biosynthesis in a centrifugal, packed-bed reactor using metabolic flux analysis. Process Biochem 2003. [DOI: 10.1016/s0032-9592(03)00054-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
18
|
Shimizu H. Metabolic engineering — Integrating methodologies of molecular breeding and bioprocess systems engineering. J Biosci Bioeng 2002. [DOI: 10.1016/s1389-1723(02)80196-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
19
|
A review on metabolic pathway analysis with emphasis on isotope labeling approach. BIOTECHNOL BIOPROC E 2002. [DOI: 10.1007/bf02932832] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
20
|
Current Awareness. Yeast 2001. [DOI: 10.1002/yea.686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
|