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Nishitani A, Hiramatsu K, Kadooka C, Hiroshima K, Sawada K, Okutsu K, Yoshizaki Y, Takamine K, Goto M, Tamaki H, Futagami T. Overexpression of the DHA1 family, ChlH and ChlK, leads to enhanced dicarboxylic acids production in koji fungi, Aspergillus luchuensis mut. kawachii and Aspergillus oryzae. J Biosci Bioeng 2024; 137:281-289. [PMID: 38331655 DOI: 10.1016/j.jbiosc.2024.01.010] [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: 09/26/2023] [Revised: 01/09/2024] [Accepted: 01/14/2024] [Indexed: 02/10/2024]
Abstract
The white koji fungus Aspergillus luchuensis mut. kawachii secretes substantial amounts of citric acid through the expression of the citric acid exporter CexA, a member of the DHA1 family. In this study, we aimed to characterize 11 CexA homologs (Chl proteins) encoded in the genome of A. luchuensis mut. kawachii to identify novel transporters useful for organic acid production. We constructed overexpression strains of chl genes using a cexA disruptant of the A. luchuensis mut. kawachii as the host strain, which prevented excessive secretion of citric acid into the culture supernatant. Subsequently, we evaluated the effects of overexpression of chl on producing organic acids by analyzing the culture supernatant. All overexpression strains did not exhibit significant citric acid accumulation in the culture supernatant, indicating that Chl proteins are not responsible for citric acid export. Furthermore, the ChlH overexpression strain displayed an accumulation of 2-oxoglutaric and fumaric acids in the culture supernatant, while the ChlK overexpression strain exhibited the accumulation of 2-oxoglutaric, malic and succinic acids. Notably, the ChlH and ChlK overexpression led to a substantial increase in the production of 2-oxoglutaric acid, reaching approximately 25 mM and 50 mM, respectively. Furthermore, ChlH and ChlK overexpression also significantly increased the secretory production of dicarboxylic acids, including 2-oxoglutaric acid, in the yellow koji fungus, Aspergillus oryzae. Our study demonstrates that overexpression of DHA1 family gene results in enhanced secretion of organic acids in koji fungi of the genus Aspergillus.
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Affiliation(s)
- Atsushi Nishitani
- United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0065, Japan; Center for Advanced Science Research and Promotion, Kagoshima University, Kagoshima 890-0065, Japan
| | - Kentaro Hiramatsu
- Graduate School of Agriculture, Forestry and Fisheries, Kagoshima University, Kagoshima 890-0065, Japan
| | - Chihiro Kadooka
- Department of Biotechnology and Life Sciences, Faculty of Biotechnology and Life Sciences, Sojo University, Kumamoto 860-0082, Japan
| | - Kyoka Hiroshima
- Graduate School of Agriculture, Forestry and Fisheries, Kagoshima University, Kagoshima 890-0065, Japan
| | | | - Kayu Okutsu
- Graduate School of Agriculture, Forestry and Fisheries, Kagoshima University, Kagoshima 890-0065, Japan; Education and Research Center for Fermentation Studies, Faculty of Agriculture, Kagoshima University, Kagoshima 890-0065, Japan
| | - Yumiko Yoshizaki
- United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0065, Japan; Graduate School of Agriculture, Forestry and Fisheries, Kagoshima University, Kagoshima 890-0065, Japan; Education and Research Center for Fermentation Studies, Faculty of Agriculture, Kagoshima University, Kagoshima 890-0065, Japan
| | - Kazunori Takamine
- United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0065, Japan; Graduate School of Agriculture, Forestry and Fisheries, Kagoshima University, Kagoshima 890-0065, Japan; Education and Research Center for Fermentation Studies, Faculty of Agriculture, Kagoshima University, Kagoshima 890-0065, Japan
| | - Masatoshi Goto
- United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0065, Japan; Department of Applied Biochemistry and Food Science, Faculty of Agriculture, Saga University, Saga 840-8502, Japan
| | - Hisanori Tamaki
- United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0065, Japan; Graduate School of Agriculture, Forestry and Fisheries, Kagoshima University, Kagoshima 890-0065, Japan; Education and Research Center for Fermentation Studies, Faculty of Agriculture, Kagoshima University, Kagoshima 890-0065, Japan
| | - Taiki Futagami
- United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0065, Japan; Graduate School of Agriculture, Forestry and Fisheries, Kagoshima University, Kagoshima 890-0065, Japan; Education and Research Center for Fermentation Studies, Faculty of Agriculture, Kagoshima University, Kagoshima 890-0065, Japan.
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Nishitani A, Hiramatsu K, Kadooka C, Mori K, Okutsu K, Yoshizaki Y, Takamine K, Tashiro K, Goto M, Tamaki H, Futagami T. Expression of heterochromatin protein 1 affects citric acid production in Aspergillus luchuensis mut. kawachii. J Biosci Bioeng 2023; 136:443-451. [PMID: 37775438 DOI: 10.1016/j.jbiosc.2023.09.004] [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: 06/11/2023] [Revised: 08/17/2023] [Accepted: 09/07/2023] [Indexed: 10/01/2023]
Abstract
A putative methyltransferase, LaeA, controls citric acid production through epigenetic regulation of the citrate exporter gene, cexA, in the white koji fungus Aspergillus luchuensis mut. kawachii. In this study, we investigated the role of another epigenetic regulator, heterochromatin protein 1, HepA, in citric acid production. The ΔhepA strain exhibited reduced citric acid production in liquid culture, although to a lesser extent compared to the ΔlaeA strain. In addition, the ΔlaeA ΔhepA strain showed citric acid production similar to the ΔlaeA strain, indicating that HepA plays a role in citric acid production, albeit with a less-significant regulatory effect than LaeA. RNA-seq analysis revealed that the transcriptomic profiles of the ΔhepA and ΔlaeA strains were similar, and the expression level of cexA was reduced in both strains. These findings suggest that the genes regulated by HepA are similar to those regulated by LaeA in A. luchuensis mut. kawachii. However, the reductions in citric acid production and cexA expression observed in the disruptants were mitigated in rice koji, a solid-state culture. Thus, the mechanism by which citric acid production is regulated differs between liquid and solid cultivation. Further investigation is thus needed to understand the regulatory mechanism in koji.
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Affiliation(s)
- Atsushi Nishitani
- United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0065, Japan; Center for Advanced Science Research and Promotion, Kagoshima University, Kagoshima 890-0065, Japan
| | - Kentaro Hiramatsu
- Graduate School of Agriculture, Forestry and Fisheries, Kagoshima University, Kagoshima 890-0065, Japan
| | - Chihiro Kadooka
- Department of Biotechnology and Life Sciences, Faculty of Biotechnology and Life Sciences, Sojo University, Kumamoto 860-0082, Japan
| | - Kazuki Mori
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Fukuoka 819-0395, Japan
| | - Kayu Okutsu
- Graduate School of Agriculture, Forestry and Fisheries, Kagoshima University, Kagoshima 890-0065, Japan; Education and Research Center for Fermentation Studies, Faculty of Agriculture, Kagoshima University, Kagoshima 890-0065, Japan
| | - Yumiko Yoshizaki
- United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0065, Japan; Graduate School of Agriculture, Forestry and Fisheries, Kagoshima University, Kagoshima 890-0065, Japan; Education and Research Center for Fermentation Studies, Faculty of Agriculture, Kagoshima University, Kagoshima 890-0065, Japan
| | - Kazunori Takamine
- United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0065, Japan; Graduate School of Agriculture, Forestry and Fisheries, Kagoshima University, Kagoshima 890-0065, Japan; Education and Research Center for Fermentation Studies, Faculty of Agriculture, Kagoshima University, Kagoshima 890-0065, Japan
| | - Kosuke Tashiro
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Fukuoka 819-0395, Japan
| | - Masatoshi Goto
- United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0065, Japan; Department of Applied Biochemistry and Food Science, Faculty of Agriculture, Saga University, Saga 840-8502, Japan
| | - Hisanori Tamaki
- United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0065, Japan; Graduate School of Agriculture, Forestry and Fisheries, Kagoshima University, Kagoshima 890-0065, Japan; Education and Research Center for Fermentation Studies, Faculty of Agriculture, Kagoshima University, Kagoshima 890-0065, Japan
| | - Taiki Futagami
- United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0065, Japan; Graduate School of Agriculture, Forestry and Fisheries, Kagoshima University, Kagoshima 890-0065, Japan; Education and Research Center for Fermentation Studies, Faculty of Agriculture, Kagoshima University, Kagoshima 890-0065, Japan.
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3
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Deng S, Kim J, Pomraning KR, Gao Y, Evans JE, Hofstad BA, Dai Z, Webb-Robertson BJ, Powell SM, Novikova IV, Munoz N, Kim YM, Swita M, Robles AL, Lemmon T, Duong RD, Nicora C, Burnum-Johnson KE, Magnuson J. Identification of a specific exporter that enables high production of aconitic acid in Aspergillus pseudoterreus. Metab Eng 2023; 80:163-172. [PMID: 37778408 DOI: 10.1016/j.ymben.2023.09.011] [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: 01/31/2023] [Revised: 07/25/2023] [Accepted: 09/18/2023] [Indexed: 10/03/2023]
Abstract
Aconitic acid is an unsaturated tricarboxylic acid that is attractive for its potential use in manufacturing biodegradable and biocompatible polymers, plasticizers, and surfactants. Previously Aspergillus pseudoterreus was engineered as a platform to produce aconitic acid by deleting the cadA (cis-aconitic acid decarboxylase) gene in the itaconic acid biosynthetic pathway. In this study, the aconitic acid transporter gene (aexA) was identified using comparative global discovery proteomics analysis between the wild-type and cadA deletion strains. The protein AexA belongs to the Major Facilitator Superfamily (MFS). Deletion of aexA almost abolished aconitic acid secretion, while its overexpression led to a significant increase in aconitic acid production. Transportation of aconitic acid across the plasma membrane is a key limiting step in its production. In vitro, proteoliposome transport assay further validated AexA's function and substrate specificity. This research provides new approaches to efficiently pinpoint and characterize exporters of fungal organic acids and accelerate metabolic engineering to improve secretion capability and lower the cost of bioproduction.
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Affiliation(s)
- Shuang Deng
- DOE Agile Biofoundry, Emeryville, CA, 94608, USA; Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
| | - Joonhoon Kim
- DOE Agile Biofoundry, Emeryville, CA, 94608, USA; Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
| | - Kyle R Pomraning
- DOE Agile Biofoundry, Emeryville, CA, 94608, USA; Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
| | - Yuqian Gao
- DOE Agile Biofoundry, Emeryville, CA, 94608, USA; Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
| | - James E Evans
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
| | - Beth A Hofstad
- DOE Agile Biofoundry, Emeryville, CA, 94608, USA; Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
| | - Ziyu Dai
- DOE Agile Biofoundry, Emeryville, CA, 94608, USA; Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
| | - Bobbie-Jo Webb-Robertson
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
| | - Samantha M Powell
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
| | - Irina V Novikova
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
| | - Nathalie Munoz
- DOE Agile Biofoundry, Emeryville, CA, 94608, USA; Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
| | - Young-Mo Kim
- DOE Agile Biofoundry, Emeryville, CA, 94608, USA; Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
| | - Marie Swita
- Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
| | - Ana L Robles
- DOE Agile Biofoundry, Emeryville, CA, 94608, USA; Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
| | - Teresa Lemmon
- Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
| | - Rylan D Duong
- Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
| | - Carrie Nicora
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
| | - Kristin E Burnum-Johnson
- DOE Agile Biofoundry, Emeryville, CA, 94608, USA; Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
| | - Jon Magnuson
- DOE Agile Biofoundry, Emeryville, CA, 94608, USA; Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
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Alves J, Sousa-Silva M, Soares P, Sauer M, Casal M, Soares-Silva I. Structural characterization of the Aspergillus niger citrate transporter CexA uncovers the role of key residues S75, R192 and Q196. Comput Struct Biotechnol J 2023; 21:2884-2898. [PMID: 37216016 PMCID: PMC10196274 DOI: 10.1016/j.csbj.2023.04.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 04/25/2023] [Accepted: 04/25/2023] [Indexed: 05/24/2023] Open
Abstract
The Aspergillus niger CexA transporter belongs to the DHA1 (Drug-H+ antiporter) family. CexA homologs are exclusively found in eukaryotic genomes, and CexA is the sole citrate exporter to have been functionally characterized in this family so far. In the present work, we expressed CexA in Saccharomyces cerevisiae, demonstrating its ability to bind isocitric acid, and import citrate at pH 5.5 with low affinity. Citrate uptake was independent of the proton motive force and compatible with a facilitated diffusion mechanism. To unravel the structural features of this transporter, we then targeted 21 CexA residues for site-directed mutagenesis. Residues were identified by a combination of amino acid residue conservation among the DHA1 family, 3D structure prediction, and substrate molecular docking analysis. S. cerevisiae cells expressing this library of CexA mutant alleles were evaluated for their capacity to grow on carboxylic acid-containing media and transport of radiolabeled citrate. We also determined protein subcellular localization by GFP tagging, with seven amino acid substitutions affecting CexA protein expression at the plasma membrane. The substitutions P200A, Y307A, S315A, and R461A displayed loss-of-function phenotypes. The majority of the substitutions affected citrate binding and translocation. The S75 residue had no impact on citrate export but affected its import, as the substitution for alanine increased the affinity of the transporter for citrate. Conversely, expression of CexA mutant alleles in the Yarrowia lipolytica cex1Δ strain revealed the involvement of R192 and Q196 residues in citrate export. Globally, we uncovered a set of relevant amino acid residues involved in CexA expression, export capacity and import affinity.
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Affiliation(s)
- J. Alves
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
- Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - M. Sousa-Silva
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
- Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - P. Soares
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
- Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - M. Sauer
- University of Natural Resources and Life Sciences, Vienna, Department of Biotechnology, Institute of Microbiology and Microbial Biotechnology, Muthgasse 18, 1190 Vienna, Austria
- Austrian Centre of Industrial Biotechnology (ACIB GmbH), Muthgasse 11, 1190 Vienna, Austria
| | - M. Casal
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
- Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - I. Soares-Silva
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
- Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
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Laothanachareon T, Asin-Garcia E, Volkers RJM, Tamayo-Ramos JA, Martins Dos Santos VAP, Schaap PJ. Identification of Aspergillus niger Aquaporins Involved in Hydrogen Peroxide Signaling. J Fungi (Basel) 2023; 9:jof9040499. [PMID: 37108953 PMCID: PMC10144872 DOI: 10.3390/jof9040499] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 04/13/2023] [Accepted: 04/18/2023] [Indexed: 04/29/2023] Open
Abstract
Aspergillus niger is a robust microbial cell factory for organic acid production. However, the regulation of many industrially important pathways is still poorly understood. The regulation of the glucose oxidase (Gox) expression system, involved in the biosynthesis of gluconic acid, has recently been uncovered. The results of that study show hydrogen peroxide, a by-product of the extracellular conversion of glucose to gluconate, has a pivotal role as a signaling molecule in the induction of this system. In this study, the facilitated diffusion of hydrogen peroxide via aquaporin water channels (AQPs) was studied. AQPs are transmembrane proteins of the major intrinsic proteins (MIPs) superfamily. In addition to water and glycerol, they may also transport small solutes such as hydrogen peroxide. The genome sequence of A. niger N402 was screened for putative AQPs. Seven AQPs were found and could be classified into three main groups. One protein (AQPA) belonged to orthodox AQP, three (AQPB, AQPD, and AQPE) were grouped in aquaglyceroporins (AQGP), two (AQPC and AQPF) were in X-intrinsic proteins (XIPs), and the other (AQPG) could not be classified. Their ability to facilitate diffusion of hydrogen peroxide was identified using yeast phenotypic growth assays and by studying AQP gene knock-outs in A. niger. The X-intrinsic protein AQPF appears to play roles in facilitating hydrogen peroxide transport across the cellular membrane in both Saccharomyces cerevisiae and A. niger experiments.
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Affiliation(s)
- Thanaporn Laothanachareon
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, 6708 WE Wageningen, The Netherlands
- Enzyme Technology Laboratory, Biorefinery and Bioproduct Technology Research Group, National Center for Genetic Engineering and Biotechnology, 113 Thailand Science Park, Khlong Luang, Pathumthani 12120, Thailand
| | - Enrique Asin-Garcia
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, 6708 WE Wageningen, The Netherlands
- Biomanufacturing and Digital Twins, Wageningen University & Research, 6708 PB Wageningen, The Netherlands
| | - Rita J M Volkers
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, 6708 WE Wageningen, The Netherlands
| | - Juan Antonio Tamayo-Ramos
- ITENE Research Center, Industrial Biotechnology Area, C/Albert Einstein 1, 46980 Paterna, Valencia, Spain
| | | | - Peter J Schaap
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, 6708 WE Wageningen, The Netherlands
- UNLOCK Large Scale Infrastructure for Microbial Communities, Wageningen University & Research, Delft University of Technology, 6708 WE Wageningen, The Netherlands
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Díaz-Muñoz C, Verce M, De Vuyst L, Weckx S. Phylogenomics of a Saccharomyces cerevisiae cocoa strain reveals adaptation to a West African fermented food population. iScience 2022; 25:105309. [PMID: 36304120 PMCID: PMC9593892 DOI: 10.1016/j.isci.2022.105309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 07/22/2022] [Accepted: 10/03/2022] [Indexed: 11/27/2022] Open
Abstract
Various yeast strains have been proposed as candidate starter cultures for cocoa fermentation, especially strains of Saccharomyces cerevisiae. In the current study, the genome of the cocoa strain S. cerevisiae IMDO 050523 was unraveled based on a combination of long- and short-read sequencing. It consisted of 16 nuclear chromosomes and a mitochondrial chromosome, which were organized in 20 contigs, with only two small gaps. A phylogenomic analysis of this genome together with another 105 S cerevisiae genomes, among which 20 from cocoa strains showed a geographical distribution of the latter, including S. cerevisiae IMDO 050523. Its genome clustered together with that of a West African fermented food population, indicating a wider adaptation to West African food niches than cocoa. Furthermore, S. cerevisiae IMDO 050523 contained genetic signatures involved in sucrose hydrolysis, pectin degradation, osmotolerance, and conserved amino acid changes in key ester-producing enzymes that could point toward specific niche adaptations.
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Affiliation(s)
- Cristian Díaz-Muñoz
- Research Group of Industrial Microbiology and Food Biotechnology, Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Marko Verce
- Research Group of Industrial Microbiology and Food Biotechnology, Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Luc De Vuyst
- Research Group of Industrial Microbiology and Food Biotechnology, Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Stefan Weckx
- Research Group of Industrial Microbiology and Food Biotechnology, Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium,Corresponding author
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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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Zou Y, Li X, Xin X, Xu H, Mo L, Yu Y, Zhao G. Comparative transcriptomics to reveal the mechanism of enhanced catalytic activities of Aspergillus niger whole-cells cultured with different inducers in hydrolysis of citrus flavonoids. Food Res Int 2022; 156:111344. [DOI: 10.1016/j.foodres.2022.111344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 04/11/2022] [Accepted: 05/03/2022] [Indexed: 11/28/2022]
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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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Sousa-Silva M, Soares P, Alves J, Vieira D, Casal M, Soares-Silva I. Uncovering Novel Plasma Membrane Carboxylate Transporters in the Yeast Cyberlindnera jadinii. J Fungi (Basel) 2022; 8:51. [PMID: 35049991 PMCID: PMC8779868 DOI: 10.3390/jof8010051] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 12/31/2021] [Accepted: 01/02/2022] [Indexed: 12/22/2022] Open
Abstract
The yeast Cyberlindnera jadinii has great potential in the biotechnology industry due to its ability to produce a variety of compounds of interest, including carboxylic acids. In this work, we identified genes encoding carboxylate transporters from this yeast species. The functional characterization of sixteen plasma membrane carboxylate transporters belonging to the AceTr, SHS, TDT, MCT, SSS, and DASS families was performed by heterologous expression in Saccharomyces cerevisiae. The newly identified C. jadinii transporters present specificity for mono-, di-, and tricarboxylates. The transporters CjAto5, CjJen6, CjSlc5, and CjSlc13-1 display the broadest substrate specificity; CjAto2 accepts mono- and dicarboxylates; and CjAto1,3,4, CjJen1-5, CjSlc16, and CjSlc13-2 are specific for monocarboxylic acids. A detailed characterization of these transporters, including phylogenetic reconstruction, 3D structure prediction, and molecular docking analysis is presented here. The properties presented by these transporters make them interesting targets to be explored as organic acid exporters in microbial cell factories.
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Affiliation(s)
- Maria Sousa-Silva
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; (M.S.-S.); (P.S.); (J.A.); (D.V.); (M.C.)
- Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, 4710-057 Braga, Portugal
| | - Pedro Soares
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; (M.S.-S.); (P.S.); (J.A.); (D.V.); (M.C.)
- Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, 4710-057 Braga, Portugal
| | - João Alves
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; (M.S.-S.); (P.S.); (J.A.); (D.V.); (M.C.)
- Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, 4710-057 Braga, Portugal
| | - Daniel Vieira
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; (M.S.-S.); (P.S.); (J.A.); (D.V.); (M.C.)
- Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, 4710-057 Braga, Portugal
| | - Margarida Casal
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; (M.S.-S.); (P.S.); (J.A.); (D.V.); (M.C.)
- Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, 4710-057 Braga, Portugal
| | - Isabel Soares-Silva
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; (M.S.-S.); (P.S.); (J.A.); (D.V.); (M.C.)
- Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, 4710-057 Braga, Portugal
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11
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Farkas B, Vojtková H, Bujdoš M, Kolenčík M, Šebesta M, Matulová M, Duborská E, Danko M, Kim H, Kučová K, Kisová Z, Matúš P, Urík M. Fungal Mobilization of Selenium in the Presence of Hausmannite and Ferric Oxyhydroxides. J Fungi (Basel) 2021; 7:jof7100810. [PMID: 34682232 PMCID: PMC8539610 DOI: 10.3390/jof7100810] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/22/2021] [Accepted: 09/24/2021] [Indexed: 01/06/2023] Open
Abstract
Bioleaching of mineral phases plays a crucial role in the mobility and availability of various elements, including selenium. Therefore, the leachability of selenium associated with the surfaces of ferric and manganese oxides and oxyhydroxides, the prevailing components of natural geochemical barriers, has been studied in the presence of filamentous fungus. Both geoactive phases were exposed to selenate and subsequently to growing fungus Aspergillus niger for three weeks. This common soil fungus has shown exceptional ability to alter the distribution and mobility of selenium in the presence of both solid phases. The fungus initiated the extensive bioextraction of selenium from the surfaces of amorphous ferric oxyhydroxides, while the hausmannite (Mn3O4) was highly susceptible to biodeterioration in the presence of selenium. This resulted in specific outcomes regarding the selenium, iron, and manganese uptake by fungus and residual selenium concentrations in mineral phases as well. The adverse effects of bioleaching on fungal growth are also discussed.
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Affiliation(s)
- Bence Farkas
- Institute of Laboratory Research on Geomaterials, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská Dolina, Ilkovičova 6, 842 15 Bratislava, Slovakia; (B.F.); (M.B.); (M.Š.); (M.M.); (E.D.); (P.M.)
| | - Hana Vojtková
- Department of Environmental Engineering, Faculty of Mining and Geology, VŠB–Technical University of Ostrava, 17. Listopadu 15/2172, 708 00 Ostrava, Czech Republic; (H.V.); (K.K.)
| | - Marek Bujdoš
- Institute of Laboratory Research on Geomaterials, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská Dolina, Ilkovičova 6, 842 15 Bratislava, Slovakia; (B.F.); (M.B.); (M.Š.); (M.M.); (E.D.); (P.M.)
| | - Marek Kolenčík
- Institute of Agronomic Sciences, Faculty of Agrobiology and Food Resources, Slovak University of Agriculture in Nitra, Tr. A. Hlinku 2, 949 76 Nitra, Slovakia;
| | - Martin Šebesta
- Institute of Laboratory Research on Geomaterials, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská Dolina, Ilkovičova 6, 842 15 Bratislava, Slovakia; (B.F.); (M.B.); (M.Š.); (M.M.); (E.D.); (P.M.)
| | - Michaela Matulová
- Institute of Laboratory Research on Geomaterials, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská Dolina, Ilkovičova 6, 842 15 Bratislava, Slovakia; (B.F.); (M.B.); (M.Š.); (M.M.); (E.D.); (P.M.)
| | - Eva Duborská
- Institute of Laboratory Research on Geomaterials, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská Dolina, Ilkovičova 6, 842 15 Bratislava, Slovakia; (B.F.); (M.B.); (M.Š.); (M.M.); (E.D.); (P.M.)
| | - Martin Danko
- Polymer Institute, Slovak Academy of Sciences, Dúbravská Cesta 9, 845 41 Bratislava, Slovakia;
| | - Hyunjung Kim
- Department of Mineral Resources and Energy Engineering, Jeonbuk National University, Jeonju 54896, Jeonbuk, Korea;
- Department of Environment and Energy, Jeonbuk National University, Jeonju 54896, Jeonbuk, Korea
| | - Kateřina Kučová
- Department of Environmental Engineering, Faculty of Mining and Geology, VŠB–Technical University of Ostrava, 17. Listopadu 15/2172, 708 00 Ostrava, Czech Republic; (H.V.); (K.K.)
| | - Zuzana Kisová
- Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská Cesta 21, 845 51 Bratislava, Slovakia;
| | - Peter Matúš
- Institute of Laboratory Research on Geomaterials, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská Dolina, Ilkovičova 6, 842 15 Bratislava, Slovakia; (B.F.); (M.B.); (M.Š.); (M.M.); (E.D.); (P.M.)
| | - Martin Urík
- Institute of Laboratory Research on Geomaterials, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská Dolina, Ilkovičova 6, 842 15 Bratislava, Slovakia; (B.F.); (M.B.); (M.Š.); (M.M.); (E.D.); (P.M.)
- Correspondence:
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12
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Soares-Silva I, Ribas D, Sousa-Silva M, Azevedo-Silva J, Rendulić T, Casal M. Membrane transporters in the bioproduction of organic acids: state of the art and future perspectives for industrial applications. FEMS Microbiol Lett 2021; 367:5873408. [PMID: 32681640 PMCID: PMC7419537 DOI: 10.1093/femsle/fnaa118] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 07/17/2020] [Indexed: 12/16/2022] Open
Abstract
Organic acids such as monocarboxylic acids, dicarboxylic acids or even more complex molecules such as sugar acids, have displayed great applicability in the industry as these compounds are used as platform chemicals for polymer, food, agricultural and pharmaceutical sectors. Chemical synthesis of these compounds from petroleum derivatives is currently their major source of production. However, increasing environmental concerns have prompted the production of organic acids by microorganisms. The current trend is the exploitation of industrial biowastes to sustain microbial cell growth and valorize biomass conversion into organic acids. One of the major bottlenecks for the efficient and cost-effective bioproduction is the export of organic acids through the microbial plasma membrane. Membrane transporter proteins are crucial elements for the optimization of substrate import and final product export. Several transporters have been expressed in organic acid-producing species, resulting in increased final product titers in the extracellular medium and higher productivity levels. In this review, the state of the art of plasma membrane transport of organic acids is presented, along with the implications for industrial biotechnology.
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Affiliation(s)
- I Soares-Silva
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal.,Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
| | - D Ribas
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal.,Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
| | - M Sousa-Silva
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal.,Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
| | - J Azevedo-Silva
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal.,Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
| | - T Rendulić
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal.,Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
| | - M Casal
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal.,Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
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13
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Hayashi K, Kajiwara Y, Futagami T, Goto M, Takashita H. Making Traditional Japanese Distilled Liquor, Shochu and Awamori, and the Contribution of White and Black Koji Fungi. J Fungi (Basel) 2021; 7:517. [PMID: 34203379 PMCID: PMC8306306 DOI: 10.3390/jof7070517] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 06/16/2021] [Accepted: 06/25/2021] [Indexed: 11/30/2022] Open
Abstract
The traditional Japanese single distilled liquor, which uses koji and yeast with designated ingredients, is called "honkaku shochu." It is made using local agricultural products and has several types, including barley shochu, sweet potato shochu, rice shochu, and buckwheat shochu. In the case of honkaku shochu, black koji fungus (Aspergillus luchuensis) or white koji fungus (Aspergillus luchuensis mut. kawachii) is used to (1) saccharify the starch contained in the ingredients, (2) produce citric acid to prevent microbial spoilage, and (3) give the liquor its unique flavor. In order to make delicious shochu, when cultivating koji fungus during the shochu production process, we use a unique temperature control method to ensure that these three important elements, which greatly affect the taste of the produced liquor, are balanced without any excess or deficiency. This review describes in detail the production method of honkaku shochu, a distilled spirit unique to Japan and whose market is expected to expand worldwide, with special attention paid to the koji fungi cultivation step. Furthermore, we describe the history of the koji fungi used today in the production of shochu, and we provide a thorough explanation of the characteristics of each koji fungi. We also report the latest research progress on this topic.
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Affiliation(s)
- Kei Hayashi
- Sanwa Research Institute, Sanwa Shurui Co., Ltd., Usa 879-0495, Japan; (Y.K.); (H.T.)
| | - Yasuhiro Kajiwara
- Sanwa Research Institute, Sanwa Shurui Co., Ltd., Usa 879-0495, Japan; (Y.K.); (H.T.)
| | - Taiki Futagami
- Education and Research Center for Fermentation Studies, Faculty of Agriculture, Kagoshima University, Kagoshima 890-0065, Japan;
- United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0065, Japan;
| | - Masatoshi Goto
- United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0065, Japan;
- Department of Applied Biochemistry and Food Science, Faculty of Agriculture, Saga University, Saga 840-8502, Japan
| | - Hideharu Takashita
- Sanwa Research Institute, Sanwa Shurui Co., Ltd., Usa 879-0495, Japan; (Y.K.); (H.T.)
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14
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The Role of Metal Ions in Fungal Organic Acid Accumulation. Microorganisms 2021; 9:microorganisms9061267. [PMID: 34200938 PMCID: PMC8230503 DOI: 10.3390/microorganisms9061267] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 06/08/2021] [Accepted: 06/09/2021] [Indexed: 11/22/2022] Open
Abstract
Organic acid accumulation is probably the best-known example of primary metabolic overflow. Both bacteria and fungi are capable of producing various organic acids in large amounts under certain conditions, but in terms of productivity-and consequently, of commercial importance-fungal platforms are unparalleled. For high product yield, chemical composition of the growth medium is crucial in providing the necessary conditions, of which the concentrations of four of the first-row transition metal elements, manganese (Mn2+), iron (Fe2+), copper (Cu2+) and zinc (Zn2+) stand out. In this paper we critically review the biological roles of these ions, the possible biochemical and physiological consequences of their influence on the accumulation of the most important mono-, di- and tricarboxylic as well as sugar acids by fungi, and the metal ion-related aspects of submerged organic acid fermentations, including the necessary instrumental analytics. Since producing conditions are associated with a cell physiology that differs strongly to what is observed under “standard” growth conditions, here we consider papers and patents only in which organic acid accumulation levels achieved at least 60% of the theoretical maximum yield, and the actual trace metal ion concentrations were verified.
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15
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Laothanachareon T, Bruinsma L, Nijsse B, Schonewille T, Suarez-Diez M, Tamayo-Ramos JA, Martins dos Santos VAP, Schaap PJ. Global Transcriptional Response of Aspergillus niger to Blocked Active Citrate Export through Deletion of the Exporter Gene. J Fungi (Basel) 2021; 7:jof7060409. [PMID: 34071072 PMCID: PMC8224569 DOI: 10.3390/jof7060409] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 05/21/2021] [Accepted: 05/21/2021] [Indexed: 11/16/2022] Open
Abstract
Aspergillus niger is the major industrial citrate producer worldwide. Export as well as uptake of citric acid are believed to occur by active, proton-dependent, symport systems. Both are major bottlenecks for industrial citrate production. Therefore, we assessed the consequences of deleting the citT gene encoding the A. niger citrate exporter, effectively blocking active citrate export. We followed the consumption of glucose and citrate as carbon sources, monitored the secretion of organic acids and carried out a thorough transcriptome pathway enrichment analysis. Under controlled cultivation conditions that normally promote citrate secretion, the knock-out strain secreted negligible amounts of citrate. Blocking active citrate export in this way led to a reduced glucose uptake and a reduced expression of high-affinity glucose transporter genes, mstG and mstH. The glyoxylate shunt was strongly activated and an increased expression of the OAH gene was observed, resulting in a more than two-fold higher concentration of oxalate in the medium. Deletion of citT did not affect citrate uptake suggesting that citrate export and citrate uptake are uncoupled from the system.
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Affiliation(s)
- Thanaporn Laothanachareon
- Laboratory of Systems and Synthetic Biology, Department of Agrotechnology and Food Sciences, Wageningen University & Research, 6708 WE Wageningen, The Netherlands; (L.B.); (B.N.); (T.S.); (M.S.-D.); (P.J.S.)
- Enzyme Technology Laboratory, Biorefinery and Bioproduct Research Group, National Center for Genetic Engineering and Biotechnology, 113 Thailand Science Park, Khlong Luang, Pathumthani 12120, Thailand
- Correspondence: (T.L.); (V.A.P.M.d.S.)
| | - Lyon Bruinsma
- Laboratory of Systems and Synthetic Biology, Department of Agrotechnology and Food Sciences, Wageningen University & Research, 6708 WE Wageningen, The Netherlands; (L.B.); (B.N.); (T.S.); (M.S.-D.); (P.J.S.)
| | - Bart Nijsse
- Laboratory of Systems and Synthetic Biology, Department of Agrotechnology and Food Sciences, Wageningen University & Research, 6708 WE Wageningen, The Netherlands; (L.B.); (B.N.); (T.S.); (M.S.-D.); (P.J.S.)
| | - Tom Schonewille
- Laboratory of Systems and Synthetic Biology, Department of Agrotechnology and Food Sciences, Wageningen University & Research, 6708 WE Wageningen, The Netherlands; (L.B.); (B.N.); (T.S.); (M.S.-D.); (P.J.S.)
| | - Maria Suarez-Diez
- Laboratory of Systems and Synthetic Biology, Department of Agrotechnology and Food Sciences, Wageningen University & Research, 6708 WE Wageningen, The Netherlands; (L.B.); (B.N.); (T.S.); (M.S.-D.); (P.J.S.)
| | - Juan Antonio Tamayo-Ramos
- International Research Center in Critical Raw Materials-ICCRAM, University of Burgos, 09001 Burgos, Spain;
| | - Vitor A. P. Martins dos Santos
- Laboratory of Systems and Synthetic Biology, Department of Agrotechnology and Food Sciences, Wageningen University & Research, 6708 WE Wageningen, The Netherlands; (L.B.); (B.N.); (T.S.); (M.S.-D.); (P.J.S.)
- LifeGlimmer GmbH, 12163 Berlin, Germany
- Correspondence: (T.L.); (V.A.P.M.d.S.)
| | - Peter J. Schaap
- Laboratory of Systems and Synthetic Biology, Department of Agrotechnology and Food Sciences, Wageningen University & Research, 6708 WE Wageningen, The Netherlands; (L.B.); (B.N.); (T.S.); (M.S.-D.); (P.J.S.)
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16
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Burgstaller W. Overflow Metabolism in Penicillium ochrochloron and Causation in Organisms. FRONTIERS IN FUNGAL BIOLOGY 2021; 2:682062. [PMID: 37744154 PMCID: PMC10512369 DOI: 10.3389/ffunb.2021.682062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 04/13/2021] [Indexed: 09/26/2023]
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17
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Odoni DI, Vazquez-Vilar M, van Gaal MP, Schonewille T, Martins Dos Santos VAP, Tamayo-Ramos JA, Suarez-Diez M, Schaap PJ. Aspergillus niger citrate exporter revealed by comparison of two alternative citrate producing conditions. FEMS Microbiol Lett 2020; 366:5437674. [PMID: 31062025 PMCID: PMC6502548 DOI: 10.1093/femsle/fnz071] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 04/05/2019] [Indexed: 02/02/2023] Open
Abstract
Currently, there is no consensus regarding the mechanism underlying Aspergillus niger citrate biosynthesis and secretion. We hypothesise that depending on the experimental setup, extracellular citrate accumulation can have fundamentally different underlying transcriptomic landscapes. We show that varying the amount and type of supplement of an arginine auxotrophic A. niger strain results in transcriptional down-regulation of citrate metabolising enzymes in the condition in which more citrate is accumulated extracellularly. This contrasts with the transcriptional adaptations when increased citrate production is triggered by iron limitation. By combining gene expression data obtained from these two very distinct experimental setups with hidden Markov models and transporter homology approaches, we were able to compile a shortlist of the most likely citrate transporter candidates. Two candidates (An17g01710 and An09g06720m.01) were heterologously expressed in the yeast Saccharomyces cerevisiae, and one of the resultant mutants showed the ability to secrete citrate. Our findings provide steps in untangling the complex interplay of different mechanisms underlying A. niger citrate accumulation, and we demonstrate how a comparative transcriptomics approach complemented with further bioinformatics analyses can be used to pinpoint a fungal citrate exporter.
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Affiliation(s)
- Dorett I Odoni
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Marta Vazquez-Vilar
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Merlijn P van Gaal
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Tom Schonewille
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Vitor A P Martins Dos Santos
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Juan Antonio Tamayo-Ramos
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.,International Research Center in Critical Raw Materials-ICCRAM, Advanced Materials, Nuclear Technology and Applied Bio/Nanotechnology, University of Burgos, Plaza Misael Bañuelos s/n, 09001 Burgos, Spain
| | - Maria Suarez-Diez
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Peter J Schaap
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
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18
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LaeA Controls Citric Acid Production through Regulation of the Citrate Exporter-Encoding cexA Gene in Aspergillus luchuensis mut. kawachii. Appl Environ Microbiol 2020; 86:AEM.01950-19. [PMID: 31862728 DOI: 10.1128/aem.01950-19] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Accepted: 12/17/2019] [Indexed: 11/20/2022] Open
Abstract
The putative methyltransferase LaeA is a global regulator of metabolic and development processes in filamentous fungi. We characterized the homologous laeA genes of the white koji fungus Aspergillus luchuensis mut. kawachii (A. kawachii) to determine their role in citric acid hyperproduction. The ΔlaeA strain exhibited a significant reduction in citric acid production. Cap analysis gene expression (CAGE) revealed that laeA is required for the expression of a putative citrate exporter-encoding cexA gene, which is critical for citric acid production. Deficient citric acid production by a ΔlaeA strain was rescued by the overexpression of cexA to a level comparable with that of a cexA-overexpressing ΔcexA strain. In addition, chromatin immunoprecipitation coupled with quantitative PCR (ChIP-qPCR) analysis indicated that LaeA regulates the expression of cexA via methylation levels of the histones H3K4 and H3K9. These results indicate that LaeA is involved in citric acid production through epigenetic regulation of cexA in A. kawachii IMPORTANCE A. kawachii has been traditionally used for production of the distilled spirit shochu in Japan. Citric acid produced by A. kawachii plays an important role in preventing microbial contamination during the shochu fermentation process. This study characterized homologous laeA genes; using CAGE, complementation tests, and ChIP-qPCR, it was found that laeA is required for citric acid production through the regulation of cexA in A. kawachii The epigenetic regulation of citric acid production elucidated in this study will be useful for controlling the fermentation processes of shochu.
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