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Ma X, Li S, Tong X, Liu K. An overview on the current status and future prospects in Aspergillus cellulase production. Environ Res 2024; 244:117866. [PMID: 38061590 DOI: 10.1016/j.envres.2023.117866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 12/01/2023] [Accepted: 12/02/2023] [Indexed: 12/17/2023]
Abstract
Cellulase is a new research point besides glucoamylase, amylase, and protease in the enzyme industry. Cellulase can decompose lignocellulosic biomass into small-molecule sugars, which facilitates microbial utilization; thus, it has a vast market potential in the field of feed, food, energy, and chemistry. The Aspergillus was the first strain used in cellulase preparation because of its safety and non-toxicity, strong growth ability, and high enzyme yield. This review provides the latest research and advances on preparing cellulase from Aspergillus. The metabolic mechanisms of cellulase secretion by Aspergillus, the selection of fermentation substrates, the comparison of the fermentation modes, and the effect of fermentation conditions have been discussed in this review. Also, the subsequent separation and purification techniques of Aspergillus cellulase, including salting out, organic solvent precipitation, ultrafiltration, and chromatography, have been declared. Further, bottlenecks in Aspergillus cellulase preparation and corresponding feasible approaches, such as genetic engineering, mixed culture, and cellulase immobilization, have also been proposed in this review. This paper provides theoretical support for the efficient production and application of Aspergillus cellulase.
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Affiliation(s)
- Xiaoyu Ma
- China Institute of Geo-Environment Monitoring, China Geological Survey, Beijing 100081, China
| | - Shengpin Li
- China Institute of Geo-Environment Monitoring, China Geological Survey, Beijing 100081, China
| | - Xiaoxia Tong
- China Institute of Geo-Environment Monitoring, China Geological Survey, Beijing 100081, China
| | - Kun Liu
- China Institute of Geo-Environment Monitoring, China Geological Survey, Beijing 100081, China.
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Zhao Z, Gu S, Liu D, Liu D, Chen B, Li J, Tian C. The putative methyltransferase LaeA regulates mycelium growth and cellulase production in Myceliophthora thermophila. Biotechnol Biofuels Bioprod 2023; 16:58. [PMID: 37013645 PMCID: PMC10071736 DOI: 10.1186/s13068-023-02313-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 03/28/2023] [Indexed: 04/05/2023]
Abstract
BACKGROUND Filamentous fungi with the ability to use complex carbon sources has been developed as platforms for biochemicals production. Myceliophthora thermophila has been developed as the cell factory to produce lignocellulolytic enzymes and plant biomass-based biofuels and biochemicals in biorefinery. However, low fungal growth rate and cellulose utilization efficiency are significant barriers to the satisfactory yield and productivity of target products, which needs our further exploration and improvement. RESULTS In this study, we comprehensively explored the roles of the putative methyltransferase LaeA in regulating mycelium growth, sugar consumption, and cellulases expression. Deletion of laeA in thermophile fungus Myceliophthora thermophila enhanced mycelium growth and glucose consumption significantly. Further exploration of LaeA regulatory network indicated that multiple growth regulatory factors (GRF) Cre-1, Grf-1, Grf-2, and Grf-3, which act as negative repressors of carbon metabolism, were regulated by LaeA in this fungus. We also determined that phosphoenolpyruvate carboxykinase (PCK) is the core node of the metabolic network related to fungal vegetative growth, of which enhancement partially contributed to the elevated sugar consumption and fungal growth of mutant ΔlaeA. Noteworthily, LaeA participated in regulating the expression of cellulase genes and their transcription regulator. ΔlaeA exhibited 30.6% and 5.5% increases in the peak values of extracellular protein and endo-glucanase activity, respectively, as compared to the WT strain. Furthermore, the global histone methylation assays indicated that LaeA is associated with modulating H3K9 methylation levels. The normal function of LaeA on regulating fungal physiology is dependent on methyltransferase activity. CONCLUSIONS The research presented in this study clarified the function and elucidated the regulatory network of LaeA in the regulation of fungal growth and cellulase production, which will significantly deepen our understanding about the regulation mechanism of LaeA in filamentous fungi and provides the new strategy for improvement the fermentation properties of industrial fungal strain by metabolic engineering.
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Affiliation(s)
- Zhen Zhao
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Shuying Gu
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Defei Liu
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
| | - Dandan Liu
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
| | - Bingchen Chen
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
| | - Jingen Li
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China.
| | - Chaoguang Tian
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China.
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Wang X, Jarmusch SA, Frisvad JC, Larsen TO. Current status of secondary metabolite pathways linked to their related biosynthetic gene clusters in Aspergillus section Nigri. Nat Prod Rep 2023; 40:237-274. [PMID: 35587705 DOI: 10.1039/d1np00074h] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Covering: up to the end of 2021Aspergilli are biosynthetically 'talented' micro-organisms and therefore the natural products community has continually been interested in the wealth of biosynthetic gene clusters (BGCs) encoding numerous secondary metabolites related to these fungi. With the rapid increase in sequenced fungal genomes combined with the continuous development of bioinformatics tools such as antiSMASH, linking new structures to unknown BGCs has become much easier when taking retro-biosynthetic considerations into account. On the other hand, in most cases it is not as straightforward to prove proposed biosynthetic pathways due to the lack of implemented genetic tools in a given fungal species. As a result, very few secondary metabolite biosynthetic pathways have been characterized even amongst some of the most well studied Aspergillus spp., section Nigri (black aspergilli). This review will cover all known biosynthetic compound families and their structural diversity known from black aspergilli. We have logically divided this into sub-sections describing major biosynthetic classes (polyketides, non-ribosomal peptides, terpenoids, meroterpenoids and hybrid biosynthesis). Importantly, we will focus the review on metabolites which have been firmly linked to their corresponding BGCs.
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Affiliation(s)
- Xinhui Wang
- DTU Bioengineering, Technical University of Denmark, DK-2800, Kgs. Lyngby, Denmark.
| | - Scott A Jarmusch
- DTU Bioengineering, Technical University of Denmark, DK-2800, Kgs. Lyngby, Denmark.
| | - Jens C Frisvad
- DTU Bioengineering, Technical University of Denmark, DK-2800, Kgs. Lyngby, Denmark.
| | - Thomas O Larsen
- DTU Bioengineering, Technical University of Denmark, DK-2800, Kgs. Lyngby, Denmark.
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Pomraning KR, Dai Z, Munoz N, Kim Y, Gao Y, Deng S, Lemmon T, Swita MS, Zucker JD, Kim J, Mondo SJ, Panisko E, Burnet MC, Webb-robertson BM, Hofstad B, Baker SE, Burnum-johnson KE, Magnuson JK. Itaconic acid production is regulated by LaeA in Aspergillus pseudoterreus. Metab Eng Commun 2022; 15:e00203. [PMID: 36065328 PMCID: PMC9440423 DOI: 10.1016/j.mec.2022.e00203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 07/08/2022] [Accepted: 08/15/2022] [Indexed: 11/22/2022] Open
Abstract
The global regulator LaeA controls secondary metabolism in diverse Aspergillus species. Here we explored its role in regulation of itaconic acid production in Aspergillus pseudoterreus. To understand its role in regulating metabolism, we deleted and overexpressed laeA, and assessed the transcriptome, proteome, and secreted metabolome prior to and during initiation of phosphate limitation induced itaconic acid production. We found that secondary metabolite clusters, including the itaconic acid biosynthetic gene cluster, are regulated by laeA and that laeA is required for high yield production of itaconic acid. Overexpression of LaeA improves itaconic acid yield at the expense of biomass by increasing the expression of key biosynthetic pathway enzymes and attenuating the expression of genes involved in phosphate acquisition and scavenging. Increased yield was observed in optimized conditions as well as conditions containing excess nutrients that may be present in inexpensive sugar containing feedstocks such as excess phosphate or complex nutrient sources. This suggests that global regulators of metabolism may be useful targets for engineering metabolic flux that is robust to environmental heterogeneity. The Itaconic acid biosynthetic gene cluster is regulated by laeA. LaeA is required for production of itaconic acid. Overexpression of laeA attenuates genes involved in phosphate acquisition. Global regulator engineering increases robustness of itaconic acid production.
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Zhang G, Yan P, Leng D, Shang L, Zhang C, Wu Z, Wang Z. Functional Roles of LaeA-like Genes in Fungal Growth, Cellulase Activity, and Secondary Metabolism in Pleurotus ostreatus. J Fungi (Basel) 2022; 8:902. [PMID: 36135627 PMCID: PMC9502681 DOI: 10.3390/jof8090902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 08/18/2022] [Accepted: 08/23/2022] [Indexed: 11/16/2022] Open
Abstract
The global regulator LaeA plays crucial roles in morphological development and secondary metabolite biosynthesis in filamentous fungi. However, the functions of LaeA in basidiomycetes are less reported. The basidiomycete Pleurotus ostreatus is a well-known fungus used both in medicine and as food that produces polysaccharides and cellulolytic enzymes. In this study, we characterized three LaeA homologs (PoLaeA1, PoLaeA2, and PoLaeA3) in P. ostreatus. PoLaeA1 showed different expression patterns than PoLaeA2 and PoLaeA3 during different developmental stages. Silencing PoLaeA1 decreased the intracellular polysaccharide (IPS) content by approximately 28–30% and reduced intracellular ROS levels compared with those of the WT strain. However, silencing PoLaeA2 and PoLaeA3 decreased cellulase activity by 31–34% and 35–40%, respectively, and reduced the cytosolic Ca2+ content, compared with those of the WT strain. Further analysis showed that PoLaeA1 regulated IPS biosynthesis through intracellular ROS levels, whereas PoLaeA2 and PoLaeA3 regulated cellulase activity through intracellular Ca2+ signaling. Our results provide new insights into the regulation of polysaccharide biosynthesis and cellulase production in filamentous fungi.
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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: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Batista RD, Melo FG, do Amaral Santos CCA, de Paula-Elias FC, Perna RF, Xavier MCA, Villalba Morales SA, de Almeida AF. Optimization of β-Fructofuranosidase Production from Agrowaste by Aspergillus carbonarius and Its Application in the Production of Inverted Sugar. Food Technol Biotechnol 2021; 59:306-313. [PMID: 34759762 PMCID: PMC8542183 DOI: 10.17113/ftb.59.03.21.6934] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Accepted: 07/14/2021] [Indexed: 11/12/2022] Open
Abstract
Research background Microbial β-fructofuranosidases are widely employed in food industry to produce inverted sugar or fructooligosaccharides. In this study, a newly isolated Aspergillus carbonarius PC-4 strain was used to optimize the β-fructofuranosidase production in a cost-effective process and the sucrose hydrolysis was evaluated to produce inverted sugars. Experimental approach Optimization of nutritional components of culture medium was carried out using simplex lattice mixture design for 72 and 120 h at 28 °C. One-factor-at-a-time methodology was used to optimize the physicochemical parameters. Crude enzyme was used for sucrose hydrolysis at different concentrations. Results and conclusions The optimized conditions of enzyme production were achieved from cultivations containing pineapple crown waste (1.3%, m/V) and yeast extract (0.3%, m/V) after 72 h with an enzyme activity of 9.4 U/mL, obtaining R2=91.85%, R2 adjusted=85.06%, highest F-value (13.52) and low p-value (0.003). One-factor-at-a-time used for optimizing the physicochemical conditions showed optimum temperature (20 °C), pH (5.5), agitation (180 rpm) and time course (72 h) with a 3-fold increase of enzyme production. The invertase-induced sucrose hydrolysis showed the maximum yield (3.45 mmol of reducing sugars) using 10% of initial sucrose concentration. Higher sucrose concentrations caused the inhibition of invertase activity, possibly due to the saturation of substrate or formation of sucrose aggregates, making it difficult for the enzyme to access sucrose molecules within the created clusters. Therefore, a cost-effective method was developed for the invertase production using agroindustrial waste and the produced enzyme can be used efficiently for inverted sugar production at high sucrose concentration. Novelty and scientific contribution This study presents an efficient utilization of pineapple crown waste to produce invertase by a newly isolated Aspergillus carbonarius PC-4 strain. This enzyme exhibited a good potential for inverted sugar production at high initial sucrose concentration, which is interesting for industrial applications.
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Affiliation(s)
- Ryhára Dias Batista
- Graduate Program in Food Science and Technology, Federal University of Tocantins, 109 Norte Av. NS-15, ALCNO-14, Plano Diretor Norte, CEP: 77001-090, Palmas, Tocantins, Brazil
| | - Fernanda Guimarães Melo
- Graduate Program in Food Science and Technology, Federal University of Tocantins, 109 Norte Av. NS-15, ALCNO-14, Plano Diretor Norte, CEP: 77001-090, Palmas, Tocantins, Brazil
| | - Claudia Cristina Auler do Amaral Santos
- Graduate Program in Food Science and Technology, Federal University of Tocantins, 109 Norte Av. NS-15, ALCNO-14, Plano Diretor Norte, CEP: 77001-090, Palmas, Tocantins, Brazil
| | - Fabrício Coutinho de Paula-Elias
- Graduate Program in Food Science and Technology, Federal University of Tocantins, 109 Norte Av. NS-15, ALCNO-14, Plano Diretor Norte, CEP: 77001-090, Palmas, Tocantins, Brazil
| | - Rafael Firmani Perna
- Federal University of Alfenas (UNIFAL-MG), Institute of Science and Technology, José Aurélio Vilela Road 11999, Km 533, Zip Code 37715-400, Poços de Caldas, MG, Brazil
| | - Michelle Cunha Abreu Xavier
- Federal University of Tocantins (UFT), Department of Bioprocess Engineering and Biotechnology, Badejos Street 69-72, Jardim Cervilha, Zip Code 77404-970, Gurupi, TO, Brazil
| | - Sergio Andres Villalba Morales
- Federal University of Alfenas (UNIFAL-MG), Institute of Science and Technology, José Aurélio Vilela Road 11999, Km 533, Zip Code 37715-400, Poços de Caldas, MG, Brazil
| | - Alex Fernando de Almeida
- Graduate Program in Food Science and Technology, Federal University of Tocantins, 109 Norte Av. NS-15, ALCNO-14, Plano Diretor Norte, CEP: 77001-090, Palmas, Tocantins, Brazil
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Burgstaller W. Overflow Metabolism in Penicillium ochrochloron and Causation in Organisms. Front Fungal Biol 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Wang B, Li X, Tabudravu J, Wang S, Deng H, Pan L. The chemical profile of activated secondary metabolites by overexpressing LaeA in Aspergillus niger. Microbiol Res 2021; 248:126735. [PMID: 33706119 DOI: 10.1016/j.micres.2021.126735] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Revised: 02/04/2021] [Accepted: 02/20/2021] [Indexed: 11/19/2022]
Abstract
Although the mechanisms of regulating secondary metabolism by LaeA remains unclear, the synthesis of many secondary metabolites (SMs) in Aspergilli could be activated by LaeA mutation. In our previous sutdy, RNA-seq data has showed that the transcriptional level of many SM backbone genes could be upregulated by overexpressing LaeA. Herein, we analyzed the chemical profile of activated secondary metabolites in the variant of A. niger FGSC A1279 by overexpressing LaeA (OElaeA). 14 compounds were activated in A. niger FGSC A1279 OElaeA variant in the WATM medium. Chemical workup of organic extracts of the culture broth from the A. niger OElaeA mutant identified three pure compounds, flaviolin, orlandin and kotanin. The structures of these compounds were confirmed by HR-ESIMS, 1D/2D NMR, and computer assisted structure elucidation (CASE). Based on homologous alignment and comparison of literatures, the biosynthetic gene cluster (fla) of flaviolin was identified. The in vivo function of the backbone gene, flaA, encoding a multidomain non-reducing polyketide synthase (SAT-KS-AT-PT-ACP), was verified via gene knockout and chemical analysis. Finally, a biosynthetic model for fungal flaviolin was proposed.
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Affiliation(s)
- Bin Wang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou, 510006, China; Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou, 510006, China
| | - Xuejie Li
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou, 510006, China; Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou, 510006, China
| | - Jioji Tabudravu
- Marine Biodiscovery Centre, Department of Chemistry, University of Aberdeen, Meston Walk, Aberdeen, AB24 3UE, Scotland, UK; School of Forensic and Applied Sciences, Faculty of Science & Technology, University of Central Lancashire, Preston, Lancashire, PR1 2HE, UK
| | - Shan Wang
- Marine Biodiscovery Centre, Department of Chemistry, University of Aberdeen, Meston Walk, Aberdeen, AB24 3UE, Scotland, UK
| | - Hai Deng
- Marine Biodiscovery Centre, Department of Chemistry, University of Aberdeen, Meston Walk, Aberdeen, AB24 3UE, Scotland, UK.
| | - Li Pan
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou, 510006, China; Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou, 510006, China.
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11
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Ding Z, Wang X, Kong FD, Huang HM, Zhao YN, Liu M, Wang ZP, Han J. Overexpression of Global Regulator Talae1 Leads to the Discovery of New Antifungal Polyketides From Endophytic Fungus Trichoderma afroharzianum. Front Microbiol 2020; 11:622785. [PMID: 33424824 PMCID: PMC7785522 DOI: 10.3389/fmicb.2020.622785] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 12/04/2020] [Indexed: 12/12/2022] Open
Abstract
Transcription regulation caused by global regulators exerts important effects on fungal secondary metabolism. By overexpression of the global regulator Talae1 in a Ficus elastica-associated fungus Trichoderma afroharzianum, two structurally new polyketides (1 and 2) that were newly produced in the transformant were isolated and identified. Their structures, including the absolute configurations, were elucidated through a combination of high resolution mass spectrometer (HRMS), NMR, and electronic circular dichroism (ECD) calculations. The growth inhibitory activities of compounds 1 and 2 were evaluated against four bacteria and six plant-pathogenic fungi. Compound 1 showed the highest antifungal activity against Botrytis cinerea and Fusarium oxysporum f. sp. nicotianae with MIC of 8 μg/ml. To the best of our knowledge, this is the first study to report on the application of the global regulator in T. afroharzianum to activate the biosynthesis of bioactive secondary metabolites.
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Affiliation(s)
- Zhuang Ding
- Institute of BioPharmaceutical Research, Liaocheng University, Liaocheng, China
| | - Xiao Wang
- Institute of BioPharmaceutical Research, Liaocheng University, Liaocheng, China
| | - Fan-Dong Kong
- Hainan Key Laboratory for Research and Development of Natural Product From Li Folk Medicine, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agriculture Sciences, Haikou, China
| | - Hui-Ming Huang
- School of Life Sciences, Liaocheng University, Liaocheng, China
| | - Yan-Na Zhao
- Institute of BioPharmaceutical Research, Liaocheng University, Liaocheng, China
| | - Min Liu
- Institute of BioPharmaceutical Research, Liaocheng University, Liaocheng, China
| | - Zheng-Ping Wang
- Institute of BioPharmaceutical Research, Liaocheng University, Liaocheng, China
| | - Jun Han
- Institute of BioPharmaceutical Research, Liaocheng University, Liaocheng, China
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Kadooka C, Nakamura E, Mori K, Okutsu K, Yoshizaki Y, Takamine K, Goto M, Tamaki H, Futagami T. LaeA Controls Citric Acid Production through Regulation of the Citrate Exporter-Encoding cexA Gene in Aspergillus luchuensis mut. kawachii. Appl Environ Microbiol 2020; 86:e01950-19. [PMID: 31862728 DOI: 10.1128/AEM.01950-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [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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Yang L, Linde T, Hossain AH, Lübeck M, Punt PJ, Lübeck PS. Disruption of a putative mitochondrial oxaloacetate shuttle protein in Aspergillus carbonarius results in secretion of malic acid at the expense of citric acid production. BMC Biotechnol 2019; 19:72. [PMID: 31684928 PMCID: PMC6829807 DOI: 10.1186/s12896-019-0572-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 10/16/2019] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND In filamentous fungi, transport of organic acids across the mitochondrial membrane is facilitated by active transport via shuttle proteins. These transporters may transfer different organic acids across the membrane while taking others the opposite direction. In Aspergillus niger, accumulation of malate in the cytosol can trigger production of citric acid via the exchange of malate and citrate across the mitochondrial membrane. Several mitochondrial organic acid transporters were recently studied in A. niger showing their effects on organic acid production. RESULTS In this work, we studied another citric acid producing fungus, Aspergillus carbonarius, and identified by genome-mining a putative mitochondrial transporter MtpA, which was not previously studied, that might be involved in production of citric acid. This gene named mtpA encoding a putative oxaloacetate transport protein was expressed constitutively in A. carbonarius based on transcription analysis. To study its role in organic acid production, we disrupted the gene and analyzed its effects on production of citric acid and other organic acids, such as malic acid. In total, 6 transformants with gene mtpA disrupted were obtained and they showed secretion of malic acid at the expense of citric acid production. CONCLUSION A putative oxaloacetate transporter gene which is potentially involved in organic acid production by A. carbonarius was identified and further investigated on its effects on production of citric acid and malic acid. The mtpA knockout strains obtained produced less citric acid and more malic acid than the wild type, in agreement with our original hypothesis. More extensive studies should be conducted in order to further reveal the mechanism of organic acid transport as mediated by the MtpA transporter.
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Affiliation(s)
- Lei Yang
- Department of Chemistry and Bioscience, Section for Sustainable Biotechnology, Aalborg University, A.C. Meyers Vaenge 15, DK-2450, Copenhagen, SV, Denmark
| | - Tore Linde
- Department of Chemistry and Bioscience, Section for Sustainable Biotechnology, Aalborg University, A.C. Meyers Vaenge 15, DK-2450, Copenhagen, SV, Denmark.,Present address: AGC Biologics, Vandtaarnsvej 83B, DK-2860, Soeborg, Copenhagen, Denmark
| | - Abeer H Hossain
- Dutch DNA Biotech BV, Padualaan 8, 3584CH, Utrecht, The Netherlands
| | - Mette Lübeck
- Department of Chemistry and Bioscience, Section for Sustainable Biotechnology, Aalborg University, A.C. Meyers Vaenge 15, DK-2450, Copenhagen, SV, Denmark
| | - Peter J Punt
- Dutch DNA Biotech BV, Padualaan 8, 3584CH, Utrecht, The Netherlands
| | - Peter S Lübeck
- Department of Chemistry and Bioscience, Section for Sustainable Biotechnology, Aalborg University, A.C. Meyers Vaenge 15, DK-2450, Copenhagen, SV, Denmark.
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Yu J, Han H, Zhang X, Ma C, Sun C, Che Q, Gu Q, Zhu T, Zhang G, Li D. Discovery of Two New Sorbicillinoids by Overexpression of the Global Regulator LaeA in a Marine-Derived Fungus Penicillium dipodomyis YJ-11. Mar Drugs 2019; 17:md17080446. [PMID: 31357680 PMCID: PMC6723206 DOI: 10.3390/md17080446] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 07/18/2019] [Accepted: 07/26/2019] [Indexed: 01/14/2023] Open
Abstract
Overexpression of the global regulator LaeA in a marine-derived fungal strain of Penicillium dipodomyis YJ-11 induced obvious morphological changes and metabolic variations. Further chemical investigation of the mutant strain afforded a series of sorbicillinoids including two new ones named 10,11-dihydrobislongiquinolide (1) and 10,11,16,17-tetrahydrobislongiquinolide (2), as well as four known analogues, bislongiquinolide (3), 16,17-dihydrobislongiquinolide (4), sohirnone A (5), and 2′,3′-dihydrosorbicillin (6). The results support that the global regulator LaeA is a useful tool in activating silent gene clusters in Penicillium strains to obtain previously undiscovered compounds.
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Affiliation(s)
- Jing Yu
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Huan Han
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Xianyan Zhang
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Chuanteng Ma
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Chunxiao Sun
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Qian Che
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Qianqun Gu
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Tianjiao Zhu
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
- Laboratory for Marine Drugs and Bioproducts, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, China
| | - Guojian Zhang
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
- Laboratory for Marine Drugs and Bioproducts, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, China
| | - Dehai Li
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China.
- Laboratory for Marine Drugs and Bioproducts, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, China.
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Farbo MG, Urgeghe PP, Fiori S, Marcello A, Oggiano S, Balmas V, Hassan ZU, Jaoua S, Migheli Q. Effect of yeast volatile organic compounds on ochratoxin A-producing Aspergillus carbonarius and A. ochraceus. Int J Food Microbiol 2018; 284:1-10. [DOI: 10.1016/j.ijfoodmicro.2018.06.023] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Revised: 06/25/2018] [Accepted: 06/29/2018] [Indexed: 01/17/2023]
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Li G, Lou HX. Strategies to diversify natural products for drug discovery. Med Res Rev 2017; 38:1255-1294. [PMID: 29064108 DOI: 10.1002/med.21474] [Citation(s) in RCA: 155] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 09/18/2017] [Accepted: 09/28/2017] [Indexed: 12/11/2022]
Abstract
Natural product libraries contain specialized metabolites derived from plants, animals, and microorganisms that play a pivotal role in drug discovery due to their immense structural diversity and wide variety of biological activities. The strategies to greatly extend natural product scaffolds through available biological and chemical approaches offer unique opportunities to access a new series of natural product analogues, enabling the construction of diverse natural product-like libraries. The affordability of these structurally diverse molecules has been a crucial step in accelerating drug discovery. This review provides an overview of various approaches to exploit the diversity of compounds for natural product-based drug development, drawing upon a series of examples to illustrate each strategy.
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Affiliation(s)
- Gang Li
- Department of Natural Medicine and Pharmacognosy, School of Pharmacy, Qingdao University, Qingdao, China
| | - Hong-Xiang Lou
- Department of Natural Medicine and Pharmacognosy, School of Pharmacy, Qingdao University, Qingdao, China.,Department of Natural Products Chemistry, Key Lab of Chemical Biology of Ministry of Education, School of Pharmaceutical Sciences, Shandong University, Jinan, China
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Martín JF. Key role of LaeA and velvet complex proteins on expression of β-lactam and PR-toxin genes in Penicillium chrysogenum : cross-talk regulation of secondary metabolite pathways. ACTA ACUST UNITED AC 2017; 44:525-35. [DOI: 10.1007/s10295-016-1830-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 08/15/2016] [Indexed: 01/11/2023]
Abstract
Abstract
Penicillium chrysogenum is an excellent model fungus to study the molecular mechanisms of control of expression of secondary metabolite genes. A key global regulator of the biosynthesis of secondary metabolites is the LaeA protein that interacts with other components of the velvet complex (VelA, VelB, VelC, VosA). These components interact with LaeA and regulate expression of penicillin and PR-toxin biosynthetic genes in P. chrysogenum. Both LaeA and VelA are positive regulators of the penicillin and PR-toxin biosynthesis, whereas VelB acts as antagonist of the effect of LaeA and VelA. Silencing or deletion of the laeA gene has a strong negative effect on penicillin biosynthesis and overexpression of laeA increases penicillin production. Expression of the laeA gene is enhanced by the P. chrysogenum autoinducers 1,3 diaminopropane and spermidine. The PR-toxin gene cluster is very poorly expressed in P. chrysogenum under penicillin-production conditions (i.e. it is a near-silent gene cluster). Interestingly, the downregulation of expression of the PR-toxin gene cluster in the high producing strain P. chrysogenum DS17690 was associated with mutations in both the laeA and velA genes. Analysis of the laeA and velA encoding genes in this high penicillin producing strain revealed that both laeA and velA acquired important mutations during the strain improvement programs thus altering the ratio of different secondary metabolites (e.g. pigments, PR-toxin) synthesized in the high penicillin producing mutants when compared to the parental wild type strain. Cross-talk of different secondary metabolite pathways has also been found in various Penicillium spp.: P. chrysogenum mutants lacking the penicillin gene cluster produce increasing amounts of PR-toxin, and mutants of P. roqueforti silenced in the PR-toxin genes produce large amounts of mycophenolic acid. The LaeA-velvet complex mediated regulation and the pathway cross-talk phenomenon has great relevance for improving the production of novel secondary metabolites, particularly of those secondary metabolites which are produced in trace amounts encoded by silent or near-silent gene clusters.
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Yang L, Christakou E, Vang J, Lübeck M, Lübeck PS. Overexpression of a C 4-dicarboxylate transporter is the key for rerouting citric acid to C 4-dicarboxylic acid production in Aspergillus carbonarius. Microb Cell Fact 2017; 16:43. [PMID: 28288640 DOI: 10.1186/s12934-017-0660-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 03/08/2017] [Indexed: 11/24/2022] Open
Abstract
Background C4-dicarboxylic acids, including malic acid, fumaric acid and succinic acid, are valuable organic acids that can be produced and secreted by a number of microorganisms. Previous studies on organic acid production by Aspergillus carbonarius, which is capable of producing high amounts of citric acid from varieties carbon sources, have revealed its potential as a fungal cell factory. Earlier attempts to reroute citric acid production into C4-dicarboxylic acids have been with limited success. Results In this study, a glucose oxidase deficient strain of A. carbonarius was used as the parental strain to overexpress a native C4-dicarboxylate transporter and the gene frd encoding fumarate reductase from Trypanosoma brucei individually and in combination. Impacts of the introduced genetic modifications on organic acid production were investigated in a defined medium and in a hydrolysate of wheat straw containing high concentrations of glucose and xylose. In the defined medium, overexpression of the C4-dicarboxylate transporter alone and in combination with the frd gene significantly increased the production of C4-dicarboxylic acids and reduced the accumulation of citric acid, whereas expression of the frd gene alone did not result in any significant change of organic acid production profile. In the wheat straw hydrolysate after 9 days of cultivation, similar results were obtained as in the defined medium. High amounts of malic acid and succinic acid were produced by the same strains. Conclusions This study demonstrates that the key to change the citric acid production into production of C4-dicarboxylic acids in A. carbonarius is the C4-dicarboxylate transporter. Furthermore it shows that the C4-dicarboxylic acid production by A. carbonarius can be further increased via metabolic engineering and also shows the potential of A. carbonarius to utilize lignocellulosic biomass as substrates for C4-dicarboxylic acid production.
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Benocci T, Aguilar-Pontes MV, Zhou M, Seiboth B, de Vries RP. Regulators of plant biomass degradation in ascomycetous fungi. Biotechnol Biofuels 2017; 10:152. [PMID: 28616076 PMCID: PMC5468973 DOI: 10.1186/s13068-017-0841-x] [Citation(s) in RCA: 122] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 06/06/2017] [Indexed: 05/05/2023]
Abstract
Fungi play a major role in the global carbon cycle because of their ability to utilize plant biomass (polysaccharides, proteins, and lignin) as carbon source. Due to the complexity and heterogenic composition of plant biomass, fungi need to produce a broad range of degrading enzymes, matching the composition of (part of) the prevalent substrate. This process is dependent on a network of regulators that not only control the extracellular enzymes that degrade the biomass, but also the metabolic pathways needed to metabolize the resulting monomers. This review will summarize the current knowledge on regulation of plant biomass utilization in fungi and compare the differences between fungal species, focusing in particular on the presence or absence of the regulators involved in this process.
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Affiliation(s)
- Tiziano Benocci
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Maria Victoria Aguilar-Pontes
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Miaomiao Zhou
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Bernhard Seiboth
- Research Area Biochemical Technology, Institute of Chemical and Biological Engineering, TU Wien, 1060 Vienna, Austria
| | - Ronald P. de Vries
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
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Chen C, Hong M, Chu J, Huang M, Ouyang L, Tian X, Zhuang Y. Blocking the flow of propionate into TCA cycle through a mutB knockout leads to a significant increase of erythromycin production by an industrial strain of Saccharopolyspora erythraea. Bioprocess Biosyst Eng 2016; 40:201-209. [DOI: 10.1007/s00449-016-1687-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 09/23/2016] [Indexed: 11/28/2022]
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