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Jo C, Zhang J, Tam JM, Church GM, Khalil AS, Segrè D, Tang TC. Unlocking the magic in mycelium: Using synthetic biology to optimize filamentous fungi for biomanufacturing and sustainability. Mater Today Bio 2023; 19:100560. [PMID: 36756210 PMCID: PMC9900623 DOI: 10.1016/j.mtbio.2023.100560] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 01/19/2023] [Accepted: 01/20/2023] [Indexed: 01/22/2023] Open
Abstract
Filamentous fungi drive carbon and nutrient cycling across our global ecosystems, through its interactions with growing and decaying flora and their constituent microbiomes. The remarkable metabolic diversity, secretion ability, and fiber-like mycelial structure that have evolved in filamentous fungi have been increasingly exploited in commercial operations. The industrial potential of mycelial fermentation ranges from the discovery and bioproduction of enzymes and bioactive compounds, the decarbonization of food and material production, to environmental remediation and enhanced agricultural production. Despite its fundamental impact in ecology and biotechnology, molds and mushrooms have not, to-date, significantly intersected with synthetic biology in ways comparable to other industrial cell factories (e.g. Escherichia coli,Saccharomyces cerevisiae, and Komagataella phaffii). In this review, we summarize a suite of synthetic biology and computational tools for the mining, engineering and optimization of filamentous fungi as a bioproduction chassis. A combination of methods across genetic engineering, mutagenesis, experimental evolution, and computational modeling can be used to address strain development bottlenecks in established and emerging industries. These include slow mycelium growth rate, low production yields, non-optimal growth in alternative feedstocks, and difficulties in downstream purification. In the scope of biomanufacturing, we then detail previous efforts in improving key bottlenecks by targeting protein processing and secretion pathways, hyphae morphogenesis, and transcriptional control. Bringing synthetic biology practices into the hidden world of molds and mushrooms will serve to expand the limited panel of host organisms that allow for commercially-feasible and environmentally-sustainable bioproduction of enzymes, chemicals, therapeutics, foods, and materials of the future.
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Affiliation(s)
- Charles Jo
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
- Biological Design Center, Boston University, Boston, MA, USA
| | - Jing Zhang
- Biological Design Center, Boston University, Boston, MA, USA
- Graduate Program in Bioinformatics, Boston, MA, USA
| | - Jenny M. Tam
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - George M. Church
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Ahmad S. Khalil
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
- Biological Design Center, Boston University, Boston, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Daniel Segrè
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
- Biological Design Center, Boston University, Boston, MA, USA
- Graduate Program in Bioinformatics, Boston, MA, USA
- Department of Biology, Boston University, Boston, MA, USA
- Department of Physics, Boston University, Boston, MA, USA
| | - Tzu-Chieh Tang
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
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Wang L, Xie Y, Chang J, Wang J, Liu H, Shi M, Zhong Y. A novel sucrose-inducible expression system and its application for production of biomass-degrading enzymes in Aspergillus niger. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:23. [PMID: 36782304 PMCID: PMC9926565 DOI: 10.1186/s13068-023-02274-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 01/30/2023] [Indexed: 02/15/2023]
Abstract
BACKGROUND Filamentous fungi are extensively exploited as important enzyme producers due to the superior secretory capability. However, the complexity of their secretomes greatly impairs the titer and purity of heterologous enzymes. Meanwhile, high-efficient evaluation and production of bulk enzymes, such as biomass-degrading enzymes, necessitate constructing powerful expression systems for bio-refinery applications. RESULTS A novel sucrose-inducible expression system based on the host strain Aspergillus niger ATCC 20611 and the β-fructofuranosidase promoter (PfopA) was constructed. A. niger ATCC 20611 preferentially utilized sucrose for rapid growth and β-fructofuranosidase production. Its secretory background was relatively clean because β-fructofuranosidase, the key enzyme responsible for sucrose utilization, was essentially not secreted into the medium and the extracellular protease activity was low. Furthermore, the PfopA promoter showed a sucrose concentration-dependent induction pattern and was not subject to glucose repression. Moreover, the strength of PfopA was 7.68-fold higher than that of the commonly used glyceraldehyde-3-phosphate dehydrogenase promoter (PgpdA) with enhanced green fluorescence protein (EGFP) as a reporter. Thus, A. niger ATCC 20611 coupled with the PfopA promoter was used as an expression system to express a β-glucosidase gene (bgla) from A. niger C112, allowing the production of β-glucosidase at a titer of 17.84 U/mL. The crude β-glucosidase preparation could remarkably improve glucose yield in the saccharification of pretreated corncob residues when added to the cellulase mixture of Trichoderma reesei QM9414. The efficacy of this expression system was further demonstrated by co-expressing the T. reesei-derived chitinase Chi46 and β-N-acetylglucosaminidase Nag1 to obtain an efficient chitin-degrading enzyme cocktail, which could achieve the production of N-acetyl-D-glucosamine from colloidal chitin with a conversion ratio of 91.83%. Besides, the purity of the above-secreted biomass-degrading enzymes in the crude culture supernatant was over 86%. CONCLUSIONS This PfopA-driven expression system expands the genetic toolbox of A. niger and broadens the application field of the traditional fructo-oligosaccharides-producing strain A. niger ATCC 20611, advancing it to become a high-performing enzyme-producing cell factory. In particular, the sucrose-inducible expression system possessed the capacity to produce biomass-degrading enzymes at a high level and evade endogenous protein interference, providing a potential purification-free enzyme production platform for bio-refinery applications.
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Affiliation(s)
- Lu Wang
- grid.27255.370000 0004 1761 1174State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237 People’s Republic of China
| | - Yijia Xie
- Qingdao Academy, Qingdao, 266111 People’s Republic of China
| | - Jingjing Chang
- grid.27255.370000 0004 1761 1174State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237 People’s Republic of China
| | - Juan Wang
- grid.27255.370000 0004 1761 1174State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237 People’s Republic of China
| | - Hong Liu
- grid.27255.370000 0004 1761 1174State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237 People’s Republic of China
| | - Mei Shi
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China.
| | - Yaohua Zhong
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China.
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Lübeck M, Lübeck PS. Fungal Cell Factories for Efficient and Sustainable Production of Proteins and Peptides. Microorganisms 2022; 10:753. [PMID: 35456803 PMCID: PMC9025306 DOI: 10.3390/microorganisms10040753] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/24/2022] [Accepted: 03/28/2022] [Indexed: 01/12/2023] Open
Abstract
Filamentous fungi are a large and diverse taxonomically group of microorganisms found in all habitats worldwide. They grow as a network of cells called hyphae. Since filamentous fungi live in very diverse habitats, they produce different enzymes to degrade material for their living, for example hydrolytic enzymes to degrade various kinds of biomasses. Moreover, they produce defense proteins (antimicrobial peptides) and proteins for attaching surfaces (hydrophobins). Many of them are easy to cultivate in different known setups (submerged fermentation and solid-state fermentation) and their secretion of proteins and enzymes are often much larger than what is seen from yeast and bacteria. Therefore, filamentous fungi are in many industries the preferred production hosts of different proteins and enzymes. Edible fungi have traditionally been used as food, such as mushrooms or in fermented foods. New trends are to use edible fungi to produce myco-protein enriched foods. This review gives an overview of the different kinds of proteins, enzymes, and peptides produced by the most well-known fungi used as cell factories for different purposes and applications. Moreover, we describe some of the challenges that are important to consider when filamentous fungi are optimized as efficient cell factories.
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Affiliation(s)
- Mette Lübeck
- Department of Chemistry and Bioscience, Aalborg University, DK-9100 Aalborg, Denmark;
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Phenotype to genotype in Neurospora crassa: Association of the scumbo phenotype with mutations in the gene encoding ceramide C9-methyltransferase. CURRENT RESEARCH IN MICROBIAL SCIENCES 2022; 3:100117. [PMID: 35909622 PMCID: PMC9325734 DOI: 10.1016/j.crmicr.2022.100117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Xu J, Yang J, Jiang Y, Wu M, Yang S, Yang L. A novel global transcriptional perturbation target identified by forward genetics reprograms Vibrio natriegens for improving recombinant protein production. Acta Biochim Biophys Sin (Shanghai) 2021; 53:1124-1133. [PMID: 34169308 DOI: 10.1093/abbs/gmab089] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Indexed: 12/26/2022] Open
Abstract
Vibrio natriegens is known to be the fastest-growing free-living bacterium with the potential to be a novel protein expression system other than Escherichia coli. Seven sampled genes of interest (GOIs) encoding biocatalyst enzymes, including Ochrobactrum anthropi-derived ω-transaminase (OATA), were strongly expressed in E. coli but weakly in V. natriegens using the pET expression system. In this study, we fused the C-terminal of OATA with green fluorescent protein (GFP) and obtained V. natriegens mutants that could increase both protein yield and enzyme activity of OATA as well as the other three GOIs by ultraviolet mutagenesis, fluorescence-activated cell sorting (FACS), and OATA colorimetric assay. Furthermore, next-generation sequencing and strain reconstruction revealed that the Y457 variants in the conserved site of endogenous RNA polymerase (RNAP) β' subunit rpoC are responsible for the increase in recombinant protein yield. We speculated that the mutation of rpoC Y457 may reprogram V. natriegens's innate gene transcription, thereby increasing the copy number of pET plasmids and soluble protein yield of certain GOIs. The increase in GOI expression may partly be attributed to the increase in copy number. In conclusion, GOI-GFP fusion combined with FACS is a powerful tool of forward genetics that can be used to obtain a superior expression chassis. If more high-expression-related targets are found for more GOIs, it would make the construction of next-generation protein expression chassis more time-saving.
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Affiliation(s)
- Jiaqi Xu
- Institute of Bioengineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310007, China
| | - Junjie Yang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yu Jiang
- Huzhou Center of Industrial Biotechnology, Shanghai Institutes for Biological Sciences, Huzhou 313000, China
- Shanghai Taoyusheng Biotechnology Co. Ltd, Shanghai 201201, China
| | - Mianbin Wu
- Institute of Bioengineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310007, China
| | - Sheng Yang
- Huzhou Center of Industrial Biotechnology, Shanghai Institutes for Biological Sciences, Huzhou 313000, China
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Lirong Yang
- Institute of Bioengineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310007, China
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Filamentous fungi for the production of enzymes, chemicals and materials. Curr Opin Biotechnol 2019; 59:65-70. [DOI: 10.1016/j.copbio.2019.02.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 01/28/2019] [Accepted: 02/09/2019] [Indexed: 02/02/2023]
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Leynaud-Kieffer LMC, Curran SC, Kim I, Magnuson JK, Gladden JM, Baker SE, Simmons BA. A new approach to Cas9-based genome editing in Aspergillus niger that is precise, efficient and selectable. PLoS One 2019; 14:e0210243. [PMID: 30653574 PMCID: PMC6336261 DOI: 10.1371/journal.pone.0210243] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 12/19/2018] [Indexed: 02/06/2023] Open
Abstract
Aspergillus niger and other filamentous fungi are widely used in industry, but efficient genetic engineering of these hosts remains nascent. For example, while molecular genetic tools have been developed, including CRISPR/Cas9, facile genome engineering of A. niger remains challenging. To address these challenges, we have developed a simple Cas9-based gene targeting method that provides selectable, iterative, and ultimately marker-free generation of genomic deletions and insertions. This method leverages locus-specific “pop-out” recombination to suppress off-target integrations. We demonstrated the effectiveness of this method by targeting the phenotypic marker albA and validated it by targeting the glaA and mstC loci. After two selection steps, we observed 100% gene editing efficiency across all three loci. This method greatly reduces the effort required to engineer the A. niger genome and overcomes low Cas9 transformations efficiency by eliminating the need for extensive screening. This method represents a significant addition to the A. niger genome engineering toolbox and could be adapted for use in other organisms. It is expected that this method will impact several areas of industrial biotechnology, such as the development of new strains for the secretion of heterologous enzymes and the discovery and optimization of metabolic pathways.
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Affiliation(s)
- Laure M. C. Leynaud-Kieffer
- Swiss Federal Institute of Technology Lausanne, Lausanne, Vaud, Switzerland
- Joint Bioenergy Institute, Emeryville, CA, United States of America
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States of America
| | - Samuel C. Curran
- Joint Bioenergy Institute, Emeryville, CA, United States of America
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States of America
- Comparative Biochemistry Graduate Group, University of California Berkeley, Berkeley, CA, United States of America
| | - Irene Kim
- Department of Chemistry, University of California, Berkeley, CA, United States of America
| | - Jon K. Magnuson
- Joint Bioenergy Institute, Emeryville, CA, United States of America
- Chemical and Biological Process Development Group, Pacific Northwest National Laboratory, Richland, WA, United States of America
| | - John M. Gladden
- Joint Bioenergy Institute, Emeryville, CA, United States of America
- Department of Biomass Science and Conversion Technology, Sandia National Laboratories, Livermore, CA, United States of America
| | - Scott E. Baker
- Joint Bioenergy Institute, Emeryville, CA, United States of America
- Biosystems Design and Simulation Group, Environmental Molecular Sciences Division, Pacific Northwest National Laboratory, Richland, WA, United States of America
| | - Blake A. Simmons
- Joint Bioenergy Institute, Emeryville, CA, United States of America
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States of America
- * E-mail:
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Baker SE. Protein hyperproduction in fungi by design. Appl Microbiol Biotechnol 2018; 102:8621-8628. [PMID: 30078136 PMCID: PMC6153651 DOI: 10.1007/s00253-018-9265-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 07/17/2018] [Accepted: 07/19/2018] [Indexed: 12/16/2022]
Abstract
The secretion of enzymes used by fungi to digest their environment has been exploited by humans for centuries for food and beverage production. More than a century after the first biotechnology patent, we know that the enzyme cocktails secreted by these amazing organisms have tremendous use across a number of industrial processes. Secreting the maximum titer of enzymes is critical to the economic feasibility of these processes. Traditional mutagenesis and screening approaches have generated the vast majority of strains used by industry for the production of enzymes. Until the emergence of economical next generation DNA sequencing platforms, the majority of the genes mutated in these screens remained uncharacterized at the sequence level. In addition, mutagenesis comes with a cost to an organism’s fitness, making tractable rational strain design approaches an attractive alternative. As an alternative to traditional mutagenesis and screening, controlled manipulation of multiple genes involved in processes that impact the ability of a fungus to sense its environment, regulate transcription of enzyme-encoding genes, and efficiently secrete these proteins will allow for rational design of improved fungal protein production strains.
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Affiliation(s)
- Scott E Baker
- Department of Energy Joint BioEnergy Institute, Emeryville, CA, 94608, USA.
- Biosystems Design and Simulation Group, Environmental Molecular Sciences Division, Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
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Cao F, Cheng JT, Chen XA, Li YQ, Mao XM. Development of an efficient genetic system in a gene cluster-rich endophytic fungus Calcarisporium arbuscula NRRL 3705. J Microbiol Methods 2018; 151:1-6. [DOI: 10.1016/j.mimet.2018.05.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Revised: 05/29/2018] [Accepted: 05/29/2018] [Indexed: 12/11/2022]
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Inducible promoters and functional genomic approaches for the genetic engineering of filamentous fungi. Appl Microbiol Biotechnol 2018; 102:6357-6372. [PMID: 29860590 PMCID: PMC6061484 DOI: 10.1007/s00253-018-9115-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 05/17/2018] [Accepted: 05/18/2018] [Indexed: 12/15/2022]
Abstract
In industry, filamentous fungi have a prominent position as producers of economically relevant primary or secondary metabolites. Particularly, the advent of genetic engineering of filamentous fungi has led to a growing number of molecular tools to adopt filamentous fungi for biotechnical applications. Here, we summarize recent developments in fungal biology, where fungal host systems were genetically manipulated for optimal industrial applications. Firstly, available inducible promoter systems depending on carbon sources are mentioned together with various adaptations of the Tet-Off and Tet-On systems for use in different industrial fungal host systems. Subsequently, we summarize representative examples, where diverse expression systems were used for the production of heterologous products, including proteins from mammalian systems. In addition, the progressing usage of genomics and functional genomics data for strain improvement strategies are addressed, for the identification of biosynthesis genes and their related metabolic pathways. Functional genomic data are further used to decipher genomic differences between wild-type and high-production strains, in order to optimize endogenous metabolic pathways that lead to the synthesis of pharmaceutically relevant end products. Lastly, we discuss how molecular data sets can be used to modify products for optimized applications.
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