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Liu J, Zhu J, Zhang Q, Lv R, Liu H. Establishing a one-step marker-free CRISPR/Cas9 system for industrial Aspergillus niger using counter-selectable marker Ang-ace2. Biotechnol Lett 2023; 45:1477-1485. [PMID: 37805953 DOI: 10.1007/s10529-023-03434-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 07/24/2023] [Accepted: 09/06/2023] [Indexed: 10/10/2023]
Abstract
OBJECTIVES To develop a one-step, marker-free CRISPR/Cas9 system for highly efficient genome editing in industrial Aspergillus niger, with a short genetic operation cycle. RESULTS Firstly, evaluation of different promoters for sgRNA expression revealed tRNAGly15 as the most efficient, achieving a remarkable 100% gene editing efficiency. Furthermore, a counter-selectable marker, Ang-ace2, was identified for A. niger. Subsequently, a CRISPR/Cas9 plasmid was developed, utilizing a truncated AMA1 element and the Ang-ace2 conditional expression cassette driven by a Tet-on promoter. In the presence of doxycycline, the plasmid demonstrated a 33% loss efficiency in the progeny of A. niger spores after a single generation, resulting in a shortened genetic operation cycle of 16 days for CRISPR/Cas9. CONCLUSIONS The one-step marker-free CRISPR/Cas9 system was successfully developed in industrial A. niger, allowing for efficient gene editing while simultaneously reducing the editing time.
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Affiliation(s)
- Jiao Liu
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, China
- Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, Tianjin University of Science & Technology, Tianjin, 300457, China
| | - Jie Zhu
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, China
| | - Qian Zhang
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, China
| | - Ruitong Lv
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, China
| | - Hao Liu
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, China.
- Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, Tianjin University of Science & Technology, Tianjin, 300457, China.
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, People's Republic of China.
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Sun M, Lu T, Chen P, Wang X, Yang H, Zhou R, Zheng W, Zhao Y. The sensor histidine kinase (SLN1) and acetyl-CoA carboxylase (ACC1) coordinately regulate the response of Neurospora crassa to the springtail Sinella curviseta (Collembola: Entomobryidae) attack. Appl Environ Microbiol 2023; 89:e0101823. [PMID: 37855634 PMCID: PMC10686092 DOI: 10.1128/aem.01018-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Accepted: 08/12/2023] [Indexed: 10/20/2023] Open
Abstract
IMPORTANCE Understanding the regulatory pathways by which fungi respond to environmental signals through interlinked genes provides insights into the interactions between fungi and insects. The coordinated optimization of the regulatory networks is necessary for fungi to adapt to their habitats. We demonstrated that the synergistic regulation of sensor histidine kinase (SLN1) and acetyl-CoA carboxylase (ACC1) plays a critical role in regulating the fungal response to Sinella curviseta stress. Furthermore, we found that the enhanced production of trehalose, carotenoids, and 5-MTHF plays crucial role in the resistance to the fungivore. Our results provide insights into the understanding of the adaptation of N. crassa to environmental stimuli.
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Affiliation(s)
- Mengni Sun
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
| | - Ting Lu
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
| | - Pengxu Chen
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
| | - Xiaomeng Wang
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
| | - Hanbing Yang
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
| | - Rong Zhou
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
| | - Weifa Zheng
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
| | - Yanxia Zhao
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
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Jovanovic Gasovic S, Dietrich D, Gläser L, Cao P, Kohlstedt M, Wittmann C. Multi-omics view of recombinant Yarrowia lipolytica: Enhanced ketogenic amino acid catabolism increases polyketide-synthase-driven docosahexaenoic production to high selectivity at the gram scale. Metab Eng 2023; 80:45-65. [PMID: 37683719 DOI: 10.1016/j.ymben.2023.09.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 09/04/2023] [Accepted: 09/04/2023] [Indexed: 09/10/2023]
Abstract
DHA is a marine PUFA of commercial value, given its multiple health benefits. The worldwide emerging shortage in DHA supply has increased interest in microbial cell factories that can provide the compound de novo. In this regard, the present work aimed to improve DHA production in the oleaginous yeast strain Y. lipolytica Af4, which synthetized the PUFA via a heterologous myxobacterial polyketide synthase (PKS)-like gene cluster. As starting point, we used transcriptomics, metabolomics, and 13C-based metabolic pathway profiling to study the cellular dynamics of Y. lipolytica Af4. The shift from the growth to the stationary DHA-production phase was associated with fundamental changes in carbon core metabolism, including a strong upregulation of the PUFA gene cluster, as well as an increase in citrate and fatty acid degradation. At the same time, the intracellular levels of the two DHA precursors acetyl-CoA and malonyl-CoA dropped by up to 98% into the picomolar range. Interestingly, the degradation pathways for the ketogenic amino acids l-lysine, l-leucine, and l-isoleucine were transcriptionally activated, presumably to provide extra acetyl-CoA. Supplementation with small amounts of these amino acids at the beginning of the DHA production phase beneficially increased the intracellular CoA-ester pools and boosted the DHA titer by almost 40%. Isotopic 13C-tracer studies revealed that the supplements were efficiently directed toward intracellular CoA-esters and DHA. Hereby, l-lysine was found to be most efficient, as it enabled long-term activation, due to storage within the vacuole and continuous breakdown. The novel strategy enabled DHA production in Y. lipolytica at the gram scale for the first time. DHA was produced at a high selectivity (27% of total fatty acids) and free of the structurally similar PUFA DPA, which facilitates purification for high-value medical applications that require API-grade DHA. The assembled multi-omics picture of the central metabolism of Y. lipolytica provides valuable insights into this important yeast. Beyond our work, the enhanced catabolism of ketogenic amino acids seems promising for the overproduction of other compounds in Y. lipolytica, whose synthesis is limited by the availability of CoA ester precursors.
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Affiliation(s)
| | - Demian Dietrich
- Institute of Systems Biotechnology, Saarland University, Germany
| | - Lars Gläser
- Institute of Systems Biotechnology, Saarland University, Germany
| | - Peng Cao
- Institute of Systems Biotechnology, Saarland University, Germany
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4
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Zhou S, Ding N, Han R, Deng Y. Metabolic engineering and fermentation optimization strategies for producing organic acids of the tricarboxylic acid cycle by microbial cell factories. BIORESOURCE TECHNOLOGY 2023; 379:128986. [PMID: 37001700 DOI: 10.1016/j.biortech.2023.128986] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 03/26/2023] [Accepted: 03/27/2023] [Indexed: 05/03/2023]
Abstract
The organic acids of the tricarboxylic acid (TCA) pathway are important platform compounds and are widely used in many areas. The high-productivity strains and high-efficient and low-cost fermentation are required to satisfy a huge market size. The high metabolic flux of the TCA pathway endows microorganisms potential to produce high titers of these organic acids. Coupled with metabolic engineering and fermentation optimization, the titer of the organic acids has been significantly improved in recent years. Herein, we discuss and compare the recent advances in synthetic pathway engineering, cofactor engineering, transporter engineering, and fermentation optimization strategies to maximize the biosynthesis of organic acids. Such engineering strategies were mainly based on the TCA pathway and glyoxylate pathway. Furthermore, organic-acid-secretion enhancement and renewable-substrate-based fermentation are often performed to assist the biosynthesis of organic acids. Further strategies are also discussed to construct high-productivity and acid-resistant strains for industrial large-scale production.
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Affiliation(s)
- Shenghu Zhou
- National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
| | - Nana Ding
- College of Food and Health, Zhejiang A&F University, Hangzhou 311300, China
| | - Runhua Han
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, United States
| | - Yu Deng
- National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China.
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5
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Liu J, Zhang S, Li W, Wang G, Xie Z, Cao W, Gao W, Liu H. Engineering a Phosphoketolase Pathway to Supplement Cytosolic Acetyl-CoA in Aspergillus niger Enables a Significant Increase in Citric Acid Production. J Fungi (Basel) 2023; 9:jof9050504. [PMID: 37233215 DOI: 10.3390/jof9050504] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 04/19/2023] [Accepted: 04/19/2023] [Indexed: 05/27/2023] Open
Abstract
Citric acid is widely used in the food, chemical and pharmaceutical industries. Aspergillus niger is the workhorse used for citric acid production in industry. A canonical citrate biosynthesis that occurred in mitochondria was well established; however, some research suggested that the cytosolic citrate biosynthesis pathway may play a role in this chemical production. Here, the roles of cytosolic phosphoketolase (PK), acetate kinase (ACK) and acetyl-CoA synthetase (ACS) in citrate biosynthesis were investigated by gene deletion and complementation in A. niger. The results indicated that PK, ACK and ACS were important for cytosolic acetyl-CoA accumulation and had significant effects on citric acid biosynthesis. Subsequently, the functions of variant PKs and phosphotransacetylase (PTA) were evaluated, and their efficiencies were determined. Finally, an efficient PK-PTA pathway was reconstructed in A. niger S469 with Ca-PK from Clostridium acetobutylicum and Ts-PTA from Thermoanaerobacterium saccharolyticum. The resultant strain showed an increase of 96.4% and 88% in the citrate titer and yield, respectively, compared with the parent strain in the bioreactor fermentation. These findings indicate that the cytosolic citrate biosynthesis pathway is important for citric acid biosynthesis, and increasing the cytosolic acetyl-CoA level can significantly enhance citric acid production.
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Affiliation(s)
- Jiao Liu
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin 300457, China
- Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, Tianjin University of Science & Technology, Tianjin 300457, China
| | - Shanshan Zhang
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin 300457, China
| | - Wenhao Li
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin 300457, China
| | - Guanyi Wang
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin 300457, China
| | - Zhoujie Xie
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin 300457, China
- Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, Tianjin University of Science & Technology, Tianjin 300457, China
| | - Wei Cao
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin 300457, China
- Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, Tianjin University of Science & Technology, Tianjin 300457, China
| | - Weixia Gao
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin 300457, China
- Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, Tianjin University of Science & Technology, Tianjin 300457, China
| | - Hao Liu
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin 300457, China
- Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, Tianjin University of Science & Technology, Tianjin 300457, China
- National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China
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Recent advances and perspectives on production of value-added organic acids through metabolic engineering. Biotechnol Adv 2023; 62:108076. [PMID: 36509246 DOI: 10.1016/j.biotechadv.2022.108076] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 12/06/2022] [Accepted: 12/06/2022] [Indexed: 12/13/2022]
Abstract
Organic acids are important consumable materials with a wide range of applications in the food, biopolymer and chemical industries. The global consumer organic acids market is estimated to increase to $36.86 billion by 2026. Conventionally, organic acids are produced from the chemical catalysis process with petrochemicals as raw materials, which posts severe environmental concerns and conflicts with our sustainable development goals. Most of the commonly used organic acids can be produced from various organisms. As a state-of-the-art technology, large-scale fermentative production of important organic acids with genetically-modified microbes has become an alternative to the chemical route to meet the market demand. Despite the fact that bio-based organic acid production from renewable cheap feedstock provides a viable solution, low productivity has impeded their industrial-scale application. With our deeper understanding of strain genetics, physiology and the availability of strain engineering tools, new technologies including synthetic biology, various metabolic engineering strategies, omics-based system biology tools, and high throughput screening methods are gradually established to bridge our knowledge gap. And they were further applied to modify the cellular reaction networks of potential microbial hosts and improve the strain performance, which facilitated the commercialization of consumable organic acids. Here we present the recent advances of metabolic engineering strategies to improve the production of important organic acids including fumaric acid, citric acid, itaconic acid, adipic acid, muconic acid, and we also discuss the current challenges and future perspectives on how we can develop a cost-efficient, green and sustainable process to produce these important chemicals from low-cost feedstocks.
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7
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Jiang C, Wang H, Liu M, Wang L, Yang R, Wang P, Lu Z, Zhou Y, Zheng Z, Zhao G. Identification of chitin synthase activator in Aspergillus niger and its application in citric acid fermentation. Appl Microbiol Biotechnol 2022; 106:6993-7011. [PMID: 36149454 DOI: 10.1007/s00253-022-12174-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 08/30/2022] [Accepted: 09/01/2022] [Indexed: 11/02/2022]
Abstract
The biosynthesis of citric acid (CA) using Aspergillus niger as a carrier is influenced by mycelium morphology, which is determined by the expression level of morphology-related genes. As a key component of the fungal cell wall, chitin content has an important effect on morphogenesis, and to investigate the effects of this on fermentation performance, we used RNA interference to knockdown chitin synthase C (CHSC) and chitin synthase activator (CHS3) to obtain the single-gene mutant strains A. niger chs3 and chsC and the double mutant A. niger chs3C. We found that the CA fermentation performance of the two single mutants was significantly better than that of the double mutant. The mutant A. niger chs3-4 exhibited CA production potential compared to that of the parent strain in scale-up fermentation; we determined certain characteristics of CA high-yielding strain fermentation pellets. In addition, when chsC alone was silenced, there was very little change in chs3 mRNA levels, whereas those of chsC were significantly reduced when only chs3 was silenced. As this may be because of a synergistic effect between chsC and chs3, and we speculated that the latent activation target of CHS3 is CHSC, our results confirmed this hypothesis. This study is the first application of a separation and combination silence strategy of chitin synthase and chitin synthase activator in the morphology of A. niger CA fermentation. Furthermore, it provides new insights into the method for the morphological study of A. niger fermentation and the interaction of homologous genes. KEY POINTS: • The function of chitin synthase C (chsC) and chitin synthase activator (chs3) is tightly interrelated. • Mycelial morphology was optimized by knockdown of CHS3, resulting in the overproduction of citric acid. • The separation and combination silence strategies are promising tools for the interaction of homologous housekeeping genes.
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Affiliation(s)
- Chunxu Jiang
- Hefei Institutes of Physical Science, Comprehensive Laboratory Building, Chinese Academy of Sciences, 350 Shushanhu Road, P.O. Box 1138, Hefei Anhui, 230031, People's Republic of China.,University of Science and Technology of China, Hefei, Anhui, People's Republic of China
| | - Han Wang
- Hefei Institutes of Physical Science, Comprehensive Laboratory Building, Chinese Academy of Sciences, 350 Shushanhu Road, P.O. Box 1138, Hefei Anhui, 230031, People's Republic of China.
| | - Menghan Liu
- COFCO Biotechnology Co, Ltd. No. 1, Zhongliang Avenue, Bengbu Anhui, 233010, People's Republic of China
| | - Li Wang
- Hefei Institutes of Physical Science, Comprehensive Laboratory Building, Chinese Academy of Sciences, 350 Shushanhu Road, P.O. Box 1138, Hefei Anhui, 230031, People's Republic of China
| | - Ruwen Yang
- COFCO Biotechnology Co, Ltd. No. 1, Zhongliang Avenue, Bengbu Anhui, 233010, People's Republic of China
| | - Peng Wang
- Hefei Institutes of Physical Science, Comprehensive Laboratory Building, Chinese Academy of Sciences, 350 Shushanhu Road, P.O. Box 1138, Hefei Anhui, 230031, People's Republic of China
| | - Zongmei Lu
- COFCO Biotechnology Co, Ltd. No. 1, Zhongliang Avenue, Bengbu Anhui, 233010, People's Republic of China
| | - Yong Zhou
- COFCO Biotechnology Co, Ltd. No. 1, Zhongliang Avenue, Bengbu Anhui, 233010, People's Republic of China.
| | - Zhiming Zheng
- Hefei Institutes of Physical Science, Comprehensive Laboratory Building, Chinese Academy of Sciences, 350 Shushanhu Road, P.O. Box 1138, Hefei Anhui, 230031, People's Republic of China.
| | - Genhai Zhao
- Hefei Institutes of Physical Science, Comprehensive Laboratory Building, Chinese Academy of Sciences, 350 Shushanhu Road, P.O. Box 1138, Hefei Anhui, 230031, People's Republic of China.
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Cao W, Zhang L, Wu L, Zhang M, Liu J, Xie Z, Liu H. Identification and genetic characterization of mitochondrial citrate transporters in Aspergillus niger. Front Microbiol 2022; 13:1009491. [PMID: 36177470 PMCID: PMC9512666 DOI: 10.3389/fmicb.2022.1009491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 08/22/2022] [Indexed: 11/13/2022] Open
Abstract
Aspergillus niger is a major cell factory for citric acid production, and the process of citrate export from mitochondria to cytoplasm is predicted to be one of rate-limiting steps in citric acid accumulation. Currently, the mitochondrial citrate transporters (Ctps) in A. niger are not fully characterized. Here, six putative Ctp encoding genes (ctpA to ctpF) were identified based on their homology with a mitochondrial citrate transporter ScCtp1 from Saccharomyces cerevisiae. Disruption of individual ctpA to ctpF caused varying degrees of decline in citric acid accumulation at different fermentation stages, whereas a mutant strain S1696 with disruption of all six ctps showed complete loss of citiric acid production. S1696 also exhibited delayed growth, reduced conidia formation, and decreased pigmentogenesis. Exogenous addition of citrate partially restored the conidia formation and pigmentogenesis in S1696 mutant. Reintroduction of individual ctps (ctpA to ctpF) into S1696 at the amyA locus showed that ctpA, ctpB, and ctpD restored the citric acid titers to 88.5, 93.8, and 94.6% of the parent strain, respectively. Additionally, the formation of conidia and pigment production was partially restored after reintroduction of ctpA, ctpB, or ctpD. Overexpression of respective ctpA, ctpB, and ctpD in the parent strain resulted in increases in citric acid accumulation by 32.8, 19.3, and 24.2%, respectively. These results demonstrate that CtpA, CtpB, and CtpD play important roles in citric acid transport across the mitochondrial membrane and function in a redundant manner. Enhancement of citric acid transport process can serve as a target for boosting citric acid accumulation in A. niger.
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Affiliation(s)
- Wei Cao
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
- Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, Tianjin University of Science and Technology, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
| | - Licheng Zhang
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Liu Wu
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Mingyi Zhang
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Jiao Liu
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
- Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, Tianjin University of Science and Technology, Tianjin, China
| | - Zhoujie Xie
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
- Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, Tianjin University of Science and Technology, Tianjin, China
| | - Hao Liu
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
- Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, Tianjin University of Science and Technology, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
- *Correspondence: Hao Liu,
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Futagami T. The white koji fungus Aspergillus luchuensis mut. kawachii. Biosci Biotechnol Biochem 2022; 86:574-584. [PMID: 35238900 DOI: 10.1093/bbb/zbac033] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 02/24/2022] [Indexed: 11/13/2022]
Abstract
The white koji fungus, Aspergillus luchuensis mut. kawachii, is used in the production of shochu, a traditional Japanese distilled spirit. White koji fungus plays an important role in the shochu production process by supplying amylolytic enzymes such as α-amylase and glucoamylase. These enzymes convert starch contained in primary ingredients such as rice, barley, buckwheat, and sweet potato into glucose, which is subsequently utilized by the yeast Saccharomyces cerevisiae to produce ethanol. White koji fungus also secretes large amounts of citric acid, which lowers the pH of the shochu mash, thereby preventing the growth of undesired microbes and enabling stable production of shochu in relatively warm regions of Japan. This review describes the historical background, research tools, and recent advances in studies of the mechanism of citric acid production by white koji fungus.
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Affiliation(s)
- Taiki Futagami
- Education and Research Center for Fermentation Studies, Faculty of Agriculture, Kagoshima University, Kagoshima, Japan.,United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima, Japan
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10
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Behera BC, Mishra R, Mohapatra S. Microbial citric acid: Production, properties, application, and future perspectives. FOOD FRONTIERS 2021. [DOI: 10.1002/fft2.66] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Bikash Chandra Behera
- School of Biological Sciences National Institute of Science Education and Research Bhubaneswar India
| | | | - Sonali Mohapatra
- Department of Biotechnology College of Engineering & Technology Bhubaneswar India
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11
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Abstract
Microbial citric acid has high economic importance and widely used in beverage, food, detergents, cosmetics and pharmaceutical industries. The filamentous fungus Aspergillus niger is a work horse and important cell factory in industry for the production of citric acid. Although in-depth literatures and reviews have been published to explain the biochemistry, biotechnology and genetic engineering study of citric acid production by Aspergillus niger separately but the present review compiled, all the aspects with upto date brief summary of the subject describing microorganisms, substrates and their pre-treatment, screening, fermentation techniques, metabolic engineering, biochemistry, product recovery and numerous biotechnological application of citric acid for simple understanding of microbial citric acid production. The availability of genome sequence of this organism has facilitated numerous studies in gene function, gene regulation, primary and secondary metabolism. An attempt has been also made to address the molecular mechanisms and application of recent advanced techniques such as CRISPR/Cas9 systems in enhancement of citric acid production.
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Affiliation(s)
- Bikash Chandra Behera
- School of Biological sciences, National Institute of Science Education and Research, Bhubaneswar, Odisha, India
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12
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Cao W, Yan L, Li M, Liu X, Xu Y, Xie Z, Liu H. Identification and engineering a C4-dicarboxylate transporter for improvement of malic acid production in Aspergillus niger. Appl Microbiol Biotechnol 2020; 104:9773-9783. [DOI: 10.1007/s00253-020-10932-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 08/12/2020] [Accepted: 09/23/2020] [Indexed: 12/13/2022]
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13
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Zhou X, Zhang Y, Shen Y, Zhang X, Zan Z, Xia M, Luo J, Wang M. Efficient repeated batch production of androstenedione using untreated cane molasses by Mycobacterium neoaurum driven by ATP futile cycle. BIORESOURCE TECHNOLOGY 2020; 309:123307. [PMID: 32315913 DOI: 10.1016/j.biortech.2020.123307] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 03/31/2020] [Accepted: 04/01/2020] [Indexed: 06/11/2023]
Abstract
The biotransformation of phytosterol to androstenedione (AD) by mycobacteria is a unique process accompanied by energy-producing. However, high intracellular ATP content can severely inhibit the efficient production of AD. In this study, a novel citrate-based ATP futile cycle (AFC) and pyruvate-based AFC were constructed for the first time. Application of AFCs reduced intracellular ATP and propionyl-CoA levels and increased NAD+/NADH ratios and cell viability. The forced consumption of ATP promotes the transcription of critical genes in propionyl-CoA metabolism. The synergistic effect of enhanced propionyl-CoA metabolism and AFC increased AD conversion yield from 60.6% to 97.3%. The AD productivity was further improved by repeated batch fermentation using untreated cane molasses. The maximum productivity was 181% higher than that of the original strain. Therefore, the strategy of combining AFC and repeated batch fermentation is a valuable tool for the efficient and low-cost production of AD and other steroidal pharmaceutical precursors.
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Affiliation(s)
- Xiuling Zhou
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin 300457, China
| | - Yang Zhang
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin 300457, China; College of Life Science, Liaocheng University, Liaocheng, Shandong 252059, China.
| | - Yanbing Shen
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin 300457, China
| | - Xiao Zhang
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin 300457, China
| | - Zehui Zan
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin 300457, China
| | - Menglei Xia
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin 300457, China
| | - Jianmei Luo
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin 300457, China
| | - Min Wang
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin 300457, China.
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Palys S, Pham TTM, Tsang A. Biosynthesis of Alkylcitric Acids in Aspergillus niger Involves Both Co-localized and Unlinked Genes. Front Microbiol 2020; 11:1378. [PMID: 32695080 PMCID: PMC7338620 DOI: 10.3389/fmicb.2020.01378] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 05/28/2020] [Indexed: 01/08/2023] Open
Abstract
Filamentous fungi are an abundant source of bioactive secondary metabolites (SMs). In many cases, the biosynthetic processes of SMs are not well understood. This work focuses on a group of SMs, the alkylcitric acids, each of which contains a saturated alkyl "tail," and a citrate-derived "head." We initially identified their biosynthetic gene cluster and the transcriptional regulator (akcR) involved in the biosynthesis of alkylcitrates in the filamentous fungus Aspergillus niger by examining the functional annotation of SM gene clusters predicted from genomic data. We overexpressed the transcription regulator gene akcR and obtained from one liter of culture filtrate 8.5 grams of extract, which are represented by seven alkylcitric acids as determined by NMR. Hexylaconitic acid A comprised 94.1% of the total production, and four of the seven identified alkylcitrates have not been reported previously. Analysis of orthologous alkylcitrate gene clusters in the Aspergilli revealed that in A. oryzae and A. flavus an in-cluster gene displays sequence similarity to cis-aconitate decarboxylase, the orthologue of which in A. niger, NRRL3_00504, is located on a different chromosome. Overexpression of the A. niger NRRL3_00504 and akcR genes together shifted the profile of alkylcitrates production from primarily hexylaconitic acids to mainly hexylitaconic acids, suggesting that NRRL3_00504 encodes an enzyme with hexyl aconitate decarboxylase activity. We also detected two additional, previously unreported, alkylcitric acids in the double overexpression strain. This study shows that phylogenomic analysis together with experimental manipulations can be used to reconstruct a more complete biosynthetic pathway in generating a broader spectrum of alkylcitric compounds. The approach adopted here has the potential of elucidating the complexity of other SM biosynthetic pathways in fungi.
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Affiliation(s)
| | | | - Adrian Tsang
- Centre for Structural and Functional Genomics, Concordia University, Montreal, QC, Canada
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Xu Y, Zhou Y, Cao W, Liu H. Improved Production of Malic Acid in Aspergillus niger by Abolishing Citric Acid Accumulation and Enhancing Glycolytic Flux. ACS Synth Biol 2020; 9:1418-1425. [PMID: 32379964 DOI: 10.1021/acssynbio.0c00096] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Microbial fermentation was widely explored to produce malic acid. Previously, Aspergillus niger has been successfully engineered, and a high titer of malic acid was achieved with strain S575, but it also produced a high level of byproduct citric acid. Here, the capability of A. niger in malic acid biosynthesis was further improved by eliminating the accumulation of citric acid and enhancing glycolytic flux. Characterization of variant mutants suggested that disruption of cexA, a gene encoding citric acid transporter located on cell membrane, abolished citric acid accumulation. However, cexA-deficient strain S895 showed significantly decreased malic acid production. Further analysis of S895 indicated that the transcription level of genes involved in glucose transportation and glycolytic pathway was significantly reduced, and the corresponding enzyme activity was also lower than those of S575. Individual overexpression of genes encoding glucose transporter MstC and key enzymes (hexokinase HxkA, 6-phosphofructo-2-kinase PfkA, and pyruvate kinase PkiA) involved in irreversible reactions of glycolic pathway increased malic acid production. Accordingly, genes of mstC, hxkA, pfkA, and pkiA were overexpressed altogether in S895, and the resultant strain S1149 was constructed. The titer of malic acid in fed-batch fermentation with S1149 reached 201.13 g/L. Compared with S575, the byproduct of citric acid was completely abolished in S1149, and the ratio of malic acid/glucose was increased from 1.27 to 1.64 mol/mol, the highest yield reported so far, and the fermentation period was shortened from 9 to 8 days. Thus, a strain with great industrial application potential was developed by engineering nine genes in A. niger, and a pilot fermentation technology was exploited.
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Affiliation(s)
- Yongxue Xu
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, 300457 Tianjin, China
| | - Yutao Zhou
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, 300457 Tianjin, China
| | - Wei Cao
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, 300457 Tianjin, China
- Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, Tianjin University of Science & Technology, 300457 Tianjin, China
| | - Hao Liu
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, 300457 Tianjin, China
- Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, Tianjin University of Science & Technology, 300457 Tianjin, China
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Jezierska S, Claus S, Van Bogaert INA. Identification and importance of mitochondrial citrate carriers and ATP citrate lyase for glycolipid production in Starmerella bombicola. Appl Microbiol Biotechnol 2020; 104:6235-6248. [PMID: 32474798 DOI: 10.1007/s00253-020-10702-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 05/19/2020] [Accepted: 05/24/2020] [Indexed: 09/16/2023]
Abstract
Starmerella bombicola is a non-conventional yeast commercially used as a microbial cell factory for sophorolipid production. Sophorolipids are glycolipid biosurfactants composed of a glucose disaccharide sophorose and a fatty acid. In de novo sophorolipid synthesis, the fatty acid moiety is derived from the fatty acid synthesis (FAS) complex; therefore, the yeast's lipid metabolism plays a crucial role in sophorolipid biosynthesis. As a fatty acid precursor, citric acid is a key primary metabolite that connects carbohydrate and lipid metabolism, and in S. bombicola, it also has a regulatory effect on sophorolipid composition and productivity. We aimed to identify the mitochondrial transporters involved in citrate shuttling and the ATP citrate lyase (Acl), the enzyme that converts citric acid into acetyl-CoA. Subsequently, we studied their role in the citric acid shuttle and glycolipid synthesis and the potential of citrate metabolism as a genetic manipulation target for increased glycolipid synthesis. Bioinformatics analyses predicted 32 mitochondrial carriers of which two were identified as citrate transporters, named SbCtp1 and SbYhm2. Deletion of these mitochondrial carriers led to a lesser sophorolipid yield and a shift in the lactonic/acidic sophorolipid ratio. However, only the knockout of SbYhm2 caused a decrease of citric and an increase of malic acid extracellular concentrations. Additionally, deletion of SbAcl1 had a negative effect on S. bombicola's specific growth rate and sophorolipid synthesis and contributed to extra- and intracellular citric acid accumulation. Unexpectedly, SbAcl1 overexpression also decreased glycolipid production.Key Points• Starmerella bombicola is an industrially relevant microbial cell factory for biosurfactant production.• There are 32 predicted mitochondrial carriers in S. bombicola.• Citrate mitochondrial carriers SbYhm2 and SbCtp1 are essential for glycolipid synthesis in S. bombicola.• Deletion of SbAcl1 negatively affects growth and sophorolipid production in S. bombicola. Graphical abstract.
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Affiliation(s)
- Sylwia Jezierska
- Centre for Synthetic Biology, Department of Biotechnology, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Silke Claus
- Centre for Synthetic Biology, Department of Biotechnology, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Inge N A Van Bogaert
- Centre for Synthetic Biology, Department of Biotechnology, Ghent University, Coupure Links 653, 9000, Ghent, Belgium.
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Papizadeh M, Rohani M, Hosseini SN, Shojaosadati SA, Nahrevanian H, Talebi M, Pourshafie MR. Screening for efficient nitrogen sources for overproduction of the biomass of the functionally probiotic L. plantarum strain RPR42 in a cane molasses-based medium. AMB Express 2020; 10:53. [PMID: 32185601 PMCID: PMC7078425 DOI: 10.1186/s13568-020-00976-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 02/26/2020] [Indexed: 11/10/2022] Open
Abstract
Nitrogen source has a vital role for the efficient growth of lactobacilli. The effects of cheese whey, corn steep liquor, and wheat germ extract on the growth of L. plantarum strain RPR42 in cane molasses-based media was evaluated using various approaches of design of experiments. Our results showed that such protein-rich agricultural by-products significantly increase the biomass production of the strain RPR42 in cane molasses-based media. The most affecting nitrogenous material was cheese whey followed by CSL and the minor effect was reported for wheat germ extract as revealed in factorial and Box–Behnken design experiments. The replacement of costly beef extract and yeast extract with a defined mixtures of the above nitrogenous agricultural by-products in cane molasses-based medium led to production of up to 12.64 g/L/24 h of dry biomass of strain RPR42. A detectable cell density of strain RPR42 (~ 9.81 × 109 CFU/mL 24 h) which was observed in such an economic medium showed that the large-scale production of the strain RPR42 tend to be feasible at significantly low costs.
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Han X, Zhao Z, Wen Y, Chen Z. Enhancement of docosahexaenoic acid production by overexpression of ATP-citrate lyase and acetyl-CoA carboxylase in Schizochytrium sp. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:131. [PMID: 32699554 PMCID: PMC7372839 DOI: 10.1186/s13068-020-01767-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 07/11/2020] [Indexed: 05/18/2023]
Abstract
BACKGROUND Docosahexaenoic acid (DHA) is an important omega-3 long-chain polyunsaturated fatty acid that has a variety of physiological functions for infant development and human health. Although metabolic engineering was previously demonstrated to be a highly efficient way to rapidly increase lipid production, metabolic engineering has seldom been previously used to increase DHA accumulation in Schizochytrium spp. RESULTS Here, a sensitive β-galactosidase reporter system was established to screen for strong promoters in Schizochytrium sp. Four constitutive promoters (EF-1α p , TEF-1 p , ccg1 p , and ubiquitin p ) and one methanol-induced AOX1 promoter were characterized by the reporter system with the promoter activity ccg1 p > TEF-1 p > AOX1 p (induced) > EF-1α p > ubiquitin p . With the strong constitutive promoter ccg1 p , Schizochytrium ATP-citrate lyase (ACL) and acetyl-CoA carboxylase (ACC) were overexpressed in Schizochytrium sp. ATCC 20888. The cells were cultivated at 28 °C and 250 rpm for 120 h with glucose as the carbon source. Shake-flask fermentation results showed that the overexpression strains exhibited growth curves and biomass similar to those of the wild-type strain. The lipid contents of the wild-type strain and of the OACL, OACC, and OACL-ACC strains were 53.8, 68.8, 69.8, and 73.0%, respectively, and the lipid yields of the overexpression strains were increased by 21.9, 30.5, and 38.3%, respectively. DHA yields of the wild-type strain and of the corresponding overexpression strains were 4.3, 5.3, 6.1, and 6.4 g/L, i.e., DHA yields of the overexpression strains were increased by 23.3, 41.9, and 48.8%, respectively. CONCLUSIONS Acetyl-CoA and malonyl-CoA are precursors for fatty acid synthesis. ACL catalyzes the conversion of citrate in the cytoplasm into acetyl-CoA, and ACC catalyzes the synthesis of malonyl-CoA from acetyl-CoA. The results demonstrate that overexpression of ACL and ACC enhances lipid accumulation and DHA production in Schizochytrium sp.
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Affiliation(s)
- Xiao Han
- State Key Laboratory of Agrobiotechnology and Key Laboratory of Soil Microbiology, Ministry of Agriculture, College of Biological Sciences, China Agricultural University, Beijing, 100193 China
| | - Zhunan Zhao
- State Key Laboratory of Agrobiotechnology and Key Laboratory of Soil Microbiology, Ministry of Agriculture, College of Biological Sciences, China Agricultural University, Beijing, 100193 China
| | - Ying Wen
- State Key Laboratory of Agrobiotechnology and Key Laboratory of Soil Microbiology, Ministry of Agriculture, College of Biological Sciences, China Agricultural University, Beijing, 100193 China
| | - Zhi Chen
- State Key Laboratory of Agrobiotechnology and Key Laboratory of Soil Microbiology, Ministry of Agriculture, College of Biological Sciences, China Agricultural University, Beijing, 100193 China
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19
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Development of a Cre-loxP-based genetic system in Aspergillus niger ATCC1015 and its application to construction of efficient organic acid-producing cell factories. Appl Microbiol Biotechnol 2019; 103:8105-8114. [DOI: 10.1007/s00253-019-10054-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 07/08/2019] [Accepted: 07/26/2019] [Indexed: 02/06/2023]
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20
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High-level production of Monascus pigments in Monascus ruber CICC41233 through ATP-citrate lyase overexpression. Biochem Eng J 2019. [DOI: 10.1016/j.bej.2019.03.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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21
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Mitochondrial Citrate Transporters CtpA and YhmA Are Required for Extracellular Citric Acid Accumulation and Contribute to Cytosolic Acetyl Coenzyme A Generation in Aspergillus luchuensis mut. kawachii. Appl Environ Microbiol 2019; 85:AEM.03136-18. [PMID: 30737343 DOI: 10.1128/aem.03136-18] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 01/27/2019] [Indexed: 11/20/2022] Open
Abstract
Aspergillus luchuensis mut. kawachii (A. kawachii) produces a large amount of citric acid during the process of fermenting shochu, a traditional Japanese distilled spirit. In this study, we characterized A. kawachii CtpA and YhmA, which are homologous to the yeast Saccharomyces cerevisiae mitochondrial citrate transporters Ctp1 and Yhm2, respectively. CtpA and YhmA were purified from A. kawachii and reconstituted into liposomes. The proteoliposomes exhibited only counterexchange transport activity; CtpA transported citrate using countersubstrates, especially cis-aconitate and malate, whereas YhmA transported citrate using a wider variety of countersubstrates, including citrate, 2-oxoglutarate, malate, cis-aconitate, and succinate. Disruption of ctpA and yhmA caused deficient hyphal growth and conidium formation with reduced mycelial weight-normalized citrate production. Because we could not obtain a ΔctpA ΔyhmA strain, we constructed an S-tagged ctpA (ctpA-S) conditional expression strain in the ΔyhmA background using the Tet-On promoter system. Knockdown of ctpA-S in ΔyhmA resulted in a severe growth defect on minimal medium with significantly reduced acetyl coenzyme A (acetyl-CoA) and lysine levels, indicating that double disruption of ctpA and yhmA leads to synthetic lethality; however, we subsequently found that the severe growth defect was relieved by addition of acetate or lysine, which could remedy the acetyl-CoA level. Our results indicate that CtpA and YhmA are mitochondrial citrate transporters involved in citric acid production and that transport of citrate from mitochondria to the cytosol plays an important role in acetyl-CoA biogenesis in A. kawachii IMPORTANCE Citrate transport is believed to play a significant role in citrate production by filamentous fungi; however, details of the process remain unclear. This study characterized two citrate transporters from Aspergillus luchuensis mut. kawachii Biochemical and gene disruption analyses showed that CtpA and YhmA are mitochondrial citrate transporters required for normal hyphal growth, conidium formation, cytosolic acetyl-CoA synthesis, and citric acid production. The characteristics of fungal citrate transporters elucidated in this study will help expand our understanding of the citrate production mechanism and facilitate the development and optimization of industrial organic acid fermentation processes.
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Karaffa L, Kubicek CP. Citric acid and itaconic acid accumulation: variations of the same story? Appl Microbiol Biotechnol 2019; 103:2889-2902. [PMID: 30758523 PMCID: PMC6447509 DOI: 10.1007/s00253-018-09607-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 12/28/2018] [Accepted: 12/28/2018] [Indexed: 01/15/2023]
Abstract
Citric acid production by Aspergillus niger and itaconic acid production by Aspergillus terreus are two major examples of technical scale fungal fermentations based on metabolic overflow of primary metabolism. Both organic acids are formed by the same metabolic pathway, but whereas citric acid is the end product in A. niger, A. terreus performs two additional enzymatic steps leading to itaconic acid. Despite of this high similarity, the optimization of the production process and the mechanism and regulation of overflow of these two acids has mostly been investigated independently, thereby ignoring respective knowledge from the other. In this review, we will highlight where the similarities and the real differences of these two processes occur, which involves various aspects of medium composition, metabolic regulation and compartmentation, transcriptional regulation, and gene evolution. These comparative data may facilitate further investigations of citric acid and itaconic acid accumulation and may contribute to improvements in their industrial production.
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Affiliation(s)
- Levente Karaffa
- Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, Debrecen, H-4032, Hungary.
| | - Christian P Kubicek
- Institute of Chemical, Environmental & Bioscience Engineering, TU Wien, Getreidemarkt 9, 1060, Vienna, Austria.,, 1100, Vienna, Austria
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23
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Tong Z, Zheng X, Tong Y, Shi YC, Sun J. Systems metabolic engineering for citric acid production by Aspergillus niger in the post-genomic era. Microb Cell Fact 2019; 18:28. [PMID: 30717739 PMCID: PMC6362574 DOI: 10.1186/s12934-019-1064-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 01/16/2019] [Indexed: 11/11/2022] Open
Abstract
Citric acid is the world’s largest consumed organic acid and is widely used in beverage, food and pharmaceutical industries. Aspergillus niger is the main industrial workhorse for citric acid production. Since the release of the genome sequence, extensive multi-omic data are being rapidly obtained, which greatly boost our understanding of the citric acid accumulation mechanism in A. niger to a molecular and system level. Most recently, the rapid development of CRISPR/Cas9 system facilitates highly efficient genome-scale genetic perturbation in A. niger. In this review, we summarize the impact of systems biology on the citric acid molecular regulatory mechanisms, the advances in metabolic engineering strategies for enhancing citric acid production and discuss the development and application of CRISPR/Cas9 systems for genome editing in A. niger. We believe that future systems metabolic engineering efforts will redesign and engineer A. niger as a highly optimized cell factory for industrial citric acid production.
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Affiliation(s)
- Zhenyu Tong
- Department of Grain Science and Industry, Kansas State University, Manhattan, KS, 66506, USA
| | - Xiaomei Zheng
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China.,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China
| | - Yi Tong
- COFCO Biochemical (Anhui) Co. Ltd, Bengbu, 233000, People's Republic of China
| | - Yong-Cheng Shi
- Department of Grain Science and Industry, Kansas State University, Manhattan, KS, 66506, USA
| | - Jibin Sun
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China. .,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China.
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Long C, Liu M, Zhang D, Xie S, Yuan W, Gui N, Cui J, Zeng B. Highly efficient improvement of Monascus pigment production by accelerating starch hydrolysis in Monascus ruber CICC41233. 3 Biotech 2018; 8:329. [PMID: 30073114 DOI: 10.1007/s13205-018-1359-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 07/16/2018] [Indexed: 12/21/2022] Open
Abstract
To investigate the relationship between starch hydrolysis and Monascus pigments (MPs) production, the α-amylase gene (AOamyA) from Aspergillus oryzae was heterologously expressed in Monascus ruber CICC41233, and we obtained a positive transformant named Monascus ruber Amy9. In M. ruber Amy9, the α-amylase activities were 6.65- and 4.26-fold higher at 72 h and 144 h, respectively, than those in the parent strain with the glucose as solo carbon medium. Surprisingly, in the MPs fermentation medium with rice powder as solo material, M. ruber Amy9 completely degraded starch at 48 h, while 43.93 and 7.29 mg/mL starch remained at 48 and 144 h, respectively, in the parent strain. Monascus ruber Amy9 accelerated starch hydrolysis, which enhanced biomass and also increased total MPs by 132% after 144 h. Compared with M. ruber CICC41233, the relative gene expression levels, as determined by a quantitative real-time polymerase chain reaction analysis, of acl2 encoding ATP-citrate lyase subunit 2, pks encoding polyketide synthase, and fasB encoding the fatty acid synthase beta subunit increased by 33.14, 145.18, and 32.15%, respectively, after 144 h in M. ruber Amy9. The up-regulated expression of these key genes in MPs synthesis contributed to the large increase in MPs production. This interesting work provided us with a new idea and a new target for the study of the MPs production.
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Li KT, Peng WF, Xia W, Huang L, Cheng X. Metabolic differences of industrial acarbose-producing Actinoplanes sp. A56 under various osmolality levels. World J Microbiol Biotechnol 2015; 32:3. [PMID: 26712618 DOI: 10.1007/s11274-015-1976-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 10/14/2015] [Indexed: 11/26/2022]
Abstract
Many investigations have revealed that a certain concentration of osmolality was indispensable for efficient acarbose production, but little information was available on the response mechanism of acarbose-producing strains to osmotic stress. By using the gas chromatography-mass spectrometry (GC-MS) analysis coupled with the enzyme activity determination of central carbon metabolism, the present work investigated the metabolic characteristics of industrial acarbose-producing Actinoplanes sp. A56 under various osmolality levels. Relatively high osmolality (450-500 mOsm/kg) appeared to favor efficient acarbose production by Actinoplanes sp. A56, although it inhibited cell growth. Further GC-MS analysis showed that fatty acids were the uppermost differential intracellular metabolites under various osmolality levels, and the relatively high osmolality resulted in increases in levels of fatty acids.
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Affiliation(s)
- Kun-tai Li
- Nanchang Key Laboratory of Applied Fermentation Technology, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Wei-fu Peng
- Nanchang Key Laboratory of Applied Fermentation Technology, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Wei Xia
- Nanchang Key Laboratory of Applied Fermentation Technology, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Lin Huang
- Nanchang Key Laboratory of Applied Fermentation Technology, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Xin Cheng
- Nanchang Key Laboratory of Applied Fermentation Technology, Jiangxi Agricultural University, Nanchang, 330045, China.
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Dulermo T, Lazar Z, Dulermo R, Rakicka M, Haddouche R, Nicaud JM. Analysis of ATP-citrate lyase and malic enzyme mutants of Yarrowia lipolytica points out the importance of mannitol metabolism in fatty acid synthesis. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:1107-17. [PMID: 25959598 DOI: 10.1016/j.bbalip.2015.04.007] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 04/27/2015] [Accepted: 04/29/2015] [Indexed: 12/20/2022]
Abstract
The role of the two key enzymes of fatty acid (FA) synthesis, ATP-citrate lyase (Acl) and malic enzyme (Mae), was analyzed in the oleaginous yeast Yarrowia lipolytica. In most oleaginous yeasts, Acl and Mae are proposed to provide, respectively, acetyl-CoA and NADPH for FA synthesis. Acl was mainly studied at the biochemical level but no strain depleted for this enzyme was analyzed in oleaginous microorganisms. On the other hand the role of Mae in FA synthesis in Y. lipolytica remains unclear since it was proposed to be a mitochondrial NAD(H)-dependent enzyme and not a cytosolic NADP(H)-dependent enzyme. In this study, we analyzed for the first time strains inactivated for corresponding genes. Inactivation of ACL1 decreases FA synthesis by 60 to 80%, confirming its essential role in FA synthesis in Y. lipolytica. Conversely, inactivation of MAE1 has no effects on FA synthesis, except in a FA overaccumulating strain where it improves FA synthesis by 35%. This result definitively excludes Mae as a major key enzyme for FA synthesis in Y. lipolytica. During the analysis of both mutants, we observed a negative correlation between FA and mannitol level. As mannitol and FA pathways may compete for carbon storage, we inactivated YlSDR, encoding a mannitol dehydrogenase converting fructose and NADPH into mannitol and NADP+. The FA content of the resulting mutant was improved by 60% during growth on fructose, demonstrating that mannitol metabolism may modulate FA synthesis in Y. lipolytica.
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Affiliation(s)
- Thierry Dulermo
- INRA, UMR1319 Micalis, F-78350 Jouy-en-Josas, France; AgroParisTech, UMR Micalis, Jouy-en-Josas, France
| | - Zbigniew Lazar
- INRA, UMR1319 Micalis, F-78350 Jouy-en-Josas, France; AgroParisTech, UMR Micalis, Jouy-en-Josas, France; Department of Biotechnology and Food Microbiology, Wroclaw University of Environmental and Life Sciences, Chełmońskiego 37/41, 51-630 Wroclaw, Poland
| | - Rémi Dulermo
- INRA, UMR1319 Micalis, F-78350 Jouy-en-Josas, France; AgroParisTech, UMR Micalis, Jouy-en-Josas, France
| | - Magdalena Rakicka
- INRA, UMR1319 Micalis, F-78350 Jouy-en-Josas, France; AgroParisTech, UMR Micalis, Jouy-en-Josas, France; Department of Biotechnology and Food Microbiology, Wroclaw University of Environmental and Life Sciences, Chełmońskiego 37/41, 51-630 Wroclaw, Poland
| | - Ramedane Haddouche
- INRA, UMR1319 Micalis, F-78350 Jouy-en-Josas, France; AgroParisTech, UMR Micalis, Jouy-en-Josas, France
| | - Jean-Marc Nicaud
- INRA, UMR1319 Micalis, F-78350 Jouy-en-Josas, France; AgroParisTech, UMR Micalis, Jouy-en-Josas, France.
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Show PL, Oladele KO, Siew QY, Aziz Zakry FA, Lan JCW, Ling TC. Overview of citric acid production fromAspergillus niger. FRONTIERS IN LIFE SCIENCE 2015. [DOI: 10.1080/21553769.2015.1033653] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Sheridan KJ, Dolan SK, Doyle S. Endogenous cross-talk of fungal metabolites. Front Microbiol 2015; 5:732. [PMID: 25601857 PMCID: PMC4283610 DOI: 10.3389/fmicb.2014.00732] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 12/04/2014] [Indexed: 12/21/2022] Open
Abstract
Non-ribosomal peptide (NRP) synthesis in fungi requires a ready supply of proteogenic and non-proteogenic amino acids which are subsequently incorporated into the nascent NRP via a thiotemplate mechanism catalyzed by NRP synthetases. Substrate amino acids can be modified prior to or during incorporation into the NRP, or following incorporation into an early stage amino acid-containing biosynthetic intermediate. These post-incorporation modifications involve a range of additional enzymatic activities including but not exclusively, monooxygenases, methyltransferases, epimerases, oxidoreductases, and glutathione S-transferases which are essential to effect biosynthesis of the final NRP. Likewise, polyketide biosynthesis is directly by polyketide synthase megaenzymes and cluster-encoded ancillary decorating enzymes. Additionally, a suite of additional primary metabolites, for example: coenzyme A (CoA), acetyl CoA, S-adenosylmethionine, glutathione (GSH), NADPH, malonyl CoA, and molecular oxygen, amongst others are required for NRP and polyketide synthesis (PKS). Clearly these processes must involve exquisite orchestration to facilitate the simultaneous biosynthesis of different types of NRPs, polyketides, and related metabolites requiring identical or similar biosynthetic precursors or co-factors. Moreover, the near identical structures of many natural products within a given family (e.g., ergot alkaloids), along with localization to similar regions within fungi (e.g., conidia) suggests that cross-talk may exist, in terms of biosynthesis and functionality. Finally, we speculate if certain biosynthetic steps involved in NRP and PKS play a role in cellular protection or environmental adaptation, and wonder if these enzymatic reactions are of equivalent importance to the actual biosynthesis of the final metabolite.
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Affiliation(s)
| | - Stephen K Dolan
- Department of Biology, Maynooth University Maynooth, Ireland
| | - Sean Doyle
- Department of Biology, Maynooth University Maynooth, Ireland
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Michielse CB, Studt L, Janevska S, Sieber CMK, Arndt B, Espino JJ, Humpf HU, Güldener U, Tudzynski B. The global regulator FfSge1 is required for expression of secondary metabolite gene clusters but not for pathogenicity in Fusarium fujikuroi. Environ Microbiol 2014; 17:2690-708. [PMID: 25115968 DOI: 10.1111/1462-2920.12592] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 08/04/2014] [Accepted: 08/05/2014] [Indexed: 12/11/2022]
Abstract
The plant pathogenic fungus Fusarium fujikuroi is the causal agent of bakanae disease on rice due to its ability to produce gibberellins. Besides these phytohormones, F. fujikuroi is able to produce several other secondary metabolites (SMs). Although much progress has been made in the field of secondary metabolism, the transcriptional regulation of SM biosynthesis is complex and still incompletely understood. Environmental conditions, global as well as pathway-specific regulators and chromatin remodelling have been shown to play major roles. Here, the role of FfSge1, a homologue of the morphological switch regulators Wor1 and Ryp1 in Candida albicans and Histoplasma capsulatum, respectively, is explored with emphasis on secondary metabolism. FfSge1 is not required for formation of conidia and pathogenicity but is involved in vegetative growth. Transcriptome analysis of the mutant Δffsge1 compared with the wild type, as well as comparative chemical analysis between the wild type, Δffsge1 and OE:FfSGE1, revealed that FfSge1 functions as a global activator of secondary metabolism in F. fujikuroi. Double mutants of FfSGE1 and other SM regulatory genes brought insights into the hierarchical regulation of secondary metabolism. In addition, FfSge1 is also required for expression of a yet uncharacterized SM gene cluster containing a non-canonical non-ribosomal peptide synthetase.
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Affiliation(s)
- Caroline B Michielse
- Institute of Biology and Biotechnology of Plants, Westfälische Wilhelms-University, Schlossplatz 8, Münster, 48143, Germany
| | - Lena Studt
- Institute of Biology and Biotechnology of Plants, Westfälische Wilhelms-University, Schlossplatz 8, Münster, 48143, Germany
| | - Slavica Janevska
- Institute of Biology and Biotechnology of Plants, Westfälische Wilhelms-University, Schlossplatz 8, Münster, 48143, Germany
| | - Christian M K Sieber
- Institute of Bioinformatics and Systems Biology, Helmholtz Zentrum München, Germany Research Center for Environmental Health (GmbH), Ingolstädter Landstr. 1, Neuherberg, 85764, Germany
| | - Birgit Arndt
- NRW Graduate School of Chemistry, Westfälische Wilhelms-University, Wilhelm-Klemm-Strasse 10, Münster, 48149, Germany.,Institute of Food Chemistry, Westfälische Wilhelms-University, Corrensstr. 45, Münster, 48149, Germany
| | - Jose Juan Espino
- Institute of Biology and Biotechnology of Plants, Westfälische Wilhelms-University, Schlossplatz 8, Münster, 48143, Germany
| | - Hans-Ulrich Humpf
- NRW Graduate School of Chemistry, Westfälische Wilhelms-University, Wilhelm-Klemm-Strasse 10, Münster, 48149, Germany.,Institute of Food Chemistry, Westfälische Wilhelms-University, Corrensstr. 45, Münster, 48149, Germany
| | - Ulrich Güldener
- Institute of Bioinformatics and Systems Biology, Helmholtz Zentrum München, Germany Research Center for Environmental Health (GmbH), Ingolstädter Landstr. 1, Neuherberg, 85764, Germany
| | - Bettina Tudzynski
- Institute of Biology and Biotechnology of Plants, Westfälische Wilhelms-University, Schlossplatz 8, Münster, 48143, Germany
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