1
|
Jadhav R, Mach RL, Mach-Aigner AR. Protein secretion and associated stress in industrially employed filamentous fungi. Appl Microbiol Biotechnol 2024; 108:92. [PMID: 38204136 PMCID: PMC10781871 DOI: 10.1007/s00253-023-12985-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 12/21/2023] [Accepted: 12/22/2023] [Indexed: 01/12/2024]
Abstract
Application of filamentous fungi for the production of commercial enzymes such as amylase, cellulase, or xylanase is on the rise due to the increasing demand to degrade several complex carbohydrates as raw material for biotechnological processes. Also, protein production by fungi for food and feed gains importance. In any case, the protein production involves both cellular synthesis and secretion outside of the cell. Unfortunately, the secretion of proteins or enzymes can be hampered due to accumulation of unfolded or misfolded proteins in the endoplasmic reticulum (ER) as a result of too high synthesis of enzymes or (heterologous) protein expression. To cope with this ER stress, the cell generates a response known as unfolded protein response (UPR). Even though this mechanism should re-establish the protein homeostasis equivalent to a cell under non-stress conditions, the enzyme expression might still suffer from repression under secretory stress (RESS). Among eukaryotes, Saccharomyces cerevisiae is the only fungus, which is studied quite extensively to unravel the UPR pathway. Several homologs of the proteins involved in this signal transduction cascade are also found in filamentous fungi. Since RESS seems to be absent in S. cerevisiae and was only reported in Trichoderma reesei in the presence of folding and glycosylation inhibitors such as dithiothreitol and tunicamycin, more in-depth study about this mechanism, specifically in filamentous fungi, is the need of the hour. Hence, this review article gives an overview on both, protein secretion and associated stress responses in fungi. KEY POINTS: • Enzymes produced by filamentous fungi are crucial in industrial processes • UPR mechanism is conserved among many fungi, but mediated by different proteins • RESS is not fully understood or studied in industrially relevant filamentous fungi.
Collapse
Affiliation(s)
- Reshma Jadhav
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Str. 1a, A-1060, Vienna, Austria
- Christian Doppler Laboratory for Optimized Expression of Carbohydrate-Active Enzymes, Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Str. 1a, A-1060, Vienna, Austria
| | - Robert L Mach
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Str. 1a, A-1060, Vienna, Austria
| | - Astrid R Mach-Aigner
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Str. 1a, A-1060, Vienna, Austria.
- Christian Doppler Laboratory for Optimized Expression of Carbohydrate-Active Enzymes, Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Str. 1a, A-1060, Vienna, Austria.
| |
Collapse
|
2
|
Sun X, Gao F, Fan C, Yang S, Zhao T, Tu T, Luo H, Yao B, Huang H, Su X. Sub-genomic RNAi-assisted strain evolution of filamentous fungi for enhanced protein production. Appl Environ Microbiol 2024:e0208223. [PMID: 38899886 DOI: 10.1128/aem.02082-23] [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: 11/18/2023] [Accepted: 05/27/2024] [Indexed: 06/21/2024] Open
Abstract
Genetic engineering at the genomic scale provides a rapid means to evolve microbes for desirable traits. However, in many filamentous fungi, such trials are daunted by low transformation efficiency. Differentially expressed genes under certain conditions may contain important regulatory factors. Accordingly, although manipulating these subsets of genes only can largely reduce the time and labor, engineering at such a sub-genomic level may also be able to improve the microbial performance. Herein, first using the industrially important cellulase-producing filamentous fungus Trichoderma reesei as a model organism, we constructed suppression subtractive hybridization (SSH) libraries enriched with differentially expressed genes under cellulase induction (MM-Avicel) and cellulase repression conditions (MM-Glucose). The libraries, in combination with RNA interference, enabled sub-genomic engineering of T. reesei for enhanced cellulase production. The ability of T. reesei to produce endoglucanase was improved by 2.8~3.3-fold. In addition, novel regulatory genes (tre49304, tre120391, and tre123541) were identified to affect cellulase expression in T. reesei. Iterative manipulation using the same strategy further increased the yield of endoglucanase activity to 75.6 U/mL, which was seven times as high as that of the wild type (10.8 U/mL). Moreover, using Humicola insolens as an example, such a sub-genomic RNAi-assisted strain evolution proved to be also useful in other industrially important filamentous fungi. H. insolens is a filamentous fungus commonly used to produce catalase, albeit with similarly low transformation efficiency and scarce knowledge underlying the regulation of catalase expression. By combining SSH and RNAi, a strain of H. insolens producing 28,500 ± 288 U/mL of catalase was obtained, which was 1.9 times as high as that of the parent strain.IMPORTANCEGenetic engineering at the genomic scale provides an unparalleled advantage in microbial strain improvement, which has previously been limited only to the organisms with high transformation efficiency such as Saccharomyces cerevisiae and Escherichia coli. Herein, using the filamentous fungus Trichoderma reesei as a model organism, we demonstrated that the advantage of suppression subtractive hybridization (SSH) to enrich differentially expressed genes and the convenience of RNA interference to manipulate a multitude of genes could be combined to overcome the inadequate transformation efficiency. With this sub-genomic evolution strategy, T. reesei could be iteratively engineered for higher cellulase production. Intriguingly, Humicola insolens, a fungus with even little knowledge in gene expression regulation, was also improved for catalase production. The same strategy may also be expanded to engineering other microorganisms for enhanced production of proteins, organic acids, and secondary metabolites.
Collapse
Affiliation(s)
- Xianhua Sun
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Fei Gao
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Chao Fan
- Key Laboratory of Birth Regulation and Control Technology of National Health Commission of China, Shandong Provincial Maternal and Child Health Care Hospital Affiliated to Qingdao University, Jinan, China
| | - Shuyan Yang
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Tong Zhao
- Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Tao Tu
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Huiying Luo
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Bin Yao
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Huoqing Huang
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiaoyun Su
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| |
Collapse
|
3
|
Hernando AV, Sun W, Abitbol T. "You Are What You Eat": How Fungal Adaptation Can Be Leveraged toward Myco-Material Properties. GLOBAL CHALLENGES (HOBOKEN, NJ) 2024; 8:2300140. [PMID: 38486929 PMCID: PMC10935908 DOI: 10.1002/gch2.202300140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 10/01/2023] [Indexed: 03/17/2024]
Abstract
Fungi adapt to their surroundings, modifying their behaviors and composition under different conditions like nutrient availability and environmental stress. This perspective examines how a basic understanding of fungal genetics and the different ways that fungi can be influenced by their surroundings can be leveraged toward the production of functional mycelium materials. Simply put, within the constraints of a given genetic script, both the quality and quantity of fungal mycelium are shaped by what they eat and where they grow. These two levers, encompassing their global growth environment, can be turned toward different materials outcomes. The final properties of myco-materials are thus intimately shaped by the conditions of their growth, enabling the design of new biobased and biodegradable material constructions for applications that have traditionally relied on petroleum-based chemicals.This perspective highlights aspects of fungal genetics and environmental adaptation that have potential materials science implications, along the way touching on key studies, both to situate the state of the art within the field and to punctuate the viewpoints of the authors. Finally, this work ends with future perspectives, reinforcing key topics deemed important to consider in emerging myco-materials research.
Collapse
Affiliation(s)
- Alicia Vivas Hernando
- Institute of Materials (IMX)École Polytechnique Fédérale de Lausanne (EPFL)Lausanne1015Switzerland
| | - Wenjing Sun
- Institute of Materials (IMX)École Polytechnique Fédérale de Lausanne (EPFL)Lausanne1015Switzerland
| | - Tiffany Abitbol
- Institute of Materials (IMX)École Polytechnique Fédérale de Lausanne (EPFL)Lausanne1015Switzerland
| |
Collapse
|
4
|
Zhang J, Li K, Sun Y, Yao C, Liu W, Liu H, Zhong Y. An efficient CRISPR/Cas9 genome editing system based on a multiple sgRNA processing platform in Trichoderma reesei for strain improvement and enzyme production. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:22. [PMID: 38342915 DOI: 10.1186/s13068-024-02468-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Accepted: 01/29/2024] [Indexed: 02/13/2024]
Abstract
BACKGROUND The CRISPR/Cas9 technology is being employed as a convenient tool for genetic engineering of the industrially important filamentous fungus Trichoderma reesei. However, multiplex gene editing is still constrained by the sgRNA processing capability, hindering strain improvement of T. reesei for the production of lignocellulose-degrading enzymes and recombinant proteins. RESULTS Here, a CRISPR/Cas9 system based on a multiple sgRNA processing platform was established for genome editing in T. reesei. The platform contains the arrayed tRNA-sgRNA architecture directed by a 5S rRNA promoter to generate multiple sgRNAs from a single transcript by the endogenous tRNA processing system. With this system, two sgRNAs targeting cre1 (encoding the carbon catabolite repressor 1) were designed and the precise deletion of cre1 was obtained, demonstrating the efficiency of sgRNAs processing in the tRNA-sgRNA architecture. Moreover, overexpression of xyr1-A824V (encoding a key activator for cellulase/xylanase expression) at the ace1 (encoding a repressor for cellulase/xylanase expression) locus was achieved by designing two sgRNAs targeting ace1 in the system, resulting in the significantly enhanced production of cellulase (up to 1- and 18-fold on the Avicel and glucose, respectively) and xylanase (up to 11- and 41-fold on the Avicel and glucose, respectively). Furthermore, heterologous expression of the glucose oxidase gene from Aspergillus niger ATCC 9029 at the cbh1 locus with the simultaneous deletion of cbh1 and cbh2 (two cellobiohydrolase coding genes) by designing four sgRNAs targeting cbh1 and cbh2 in the system was acquired, and the glucose oxidase produced by T. reesei reached 43.77 U/mL. Besides, it was found the ER-associated protein degradation (ERAD) level was decreased in the glucose oxidase-producing strain, which was likely due to the reduction of secretion pressure by deletion of the major endogenous cellulase-encoding genes. CONCLUSIONS The tRNA-gRNA array-based CRISPR-Cas9 editing system was successfully developed in T. reesei. This system would accelerate engineering of T. reesei for high-level production of enzymes including lignocellulose-degrading enzymes and other recombinant enzymes. Furthermore, it would expand the CRISPR toolbox for fungal genome editing and synthetic biology.
Collapse
Affiliation(s)
- Jiaxin Zhang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Kehang Li
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Yu Sun
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Cheng Yao
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Weifeng Liu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China
| | - Hong Liu
- 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.
| |
Collapse
|
5
|
Liu D, Garrigues S, de Vries RP. Heterologous protein production in filamentous fungi. Appl Microbiol Biotechnol 2023:10.1007/s00253-023-12660-8. [PMID: 37405433 PMCID: PMC10386965 DOI: 10.1007/s00253-023-12660-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 06/16/2023] [Accepted: 06/21/2023] [Indexed: 07/06/2023]
Abstract
Filamentous fungi are able to produce a wide range of valuable proteins and enzymes for many industrial applications. Recent advances in fungal genomics and experimental technologies are rapidly changing the approaches for the development and use of filamentous fungi as hosts for the production of both homologous and heterologous proteins. In this review, we highlight the benefits and challenges of using filamentous fungi for the production of heterologous proteins. We review various techniques commonly employed to improve the heterologous protein production in filamentous fungi, such as strong and inducible promoters, codon optimization, more efficient signal peptides for secretion, carrier proteins, engineering of glycosylation sites, regulation of the unfolded protein response and endoplasmic reticulum associated protein degradation, optimization of the intracellular transport process, regulation of unconventional protein secretion, and construction of protease-deficient strains. KEY POINTS: • This review updates the knowledge on heterologous protein production in filamentous fungi. • Several fungal cell factories and potential candidates are discussed. • Insights into improving heterologous gene expression are given.
Collapse
Affiliation(s)
- Dujuan Liu
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands
| | - Sandra Garrigues
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands
- Department of Food Biotechnology, Instituto de Agroquímica Y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain
| | - Ronald P de Vries
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands.
| |
Collapse
|
6
|
Yang J, Yue HR, Pan LY, Feng JX, Zhao S, Suwannarangsee S, Chempreda V, Liu CG, Zhao XQ. Fungal strain improvement for efficient cellulase production and lignocellulosic biorefinery: Current status and future prospects. BIORESOURCE TECHNOLOGY 2023:129449. [PMID: 37406833 DOI: 10.1016/j.biortech.2023.129449] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 06/29/2023] [Accepted: 07/01/2023] [Indexed: 07/07/2023]
Abstract
Lignocellulosic biomass (LCB) has been recognized as a valuable carbon source for the sustainable production of biofuels and value-added biochemicals. Crude enzymes produced by fungal cell factories benefit economic LCB degradation. However, high enzyme production cost remains a great challenge. Filamentous fungi have been widely used to produce cellulolytic enzymes. Metabolic engineering of fungi contributes to efficient cellulase production for LCB biorefinery. Here the latest progress in utilizing fungal cell factories for cellulase production was summarized, including developing genome engineering tools to improve the efficiency of fungal cell factories, manipulating promoters, and modulating transcription factors. Multi-omics analysis of fungi contributes to identifying novel genetic elements for enhancing cellulase production. Furthermore, the importance of translation regulation of cellulase production are emphasized. Efficient development of fungal cell factories based on integrative strain engineering would benefit the overall bioconversion efficacy of LCB for sustainable bioproduction.
Collapse
Affiliation(s)
- Jie Yang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hou-Ru Yue
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Li-Ya Pan
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Research Center for Microbial and Enzyme Engineering Technology, College of Life Science and Technology, Guangxi University, Nanning 530004, China
| | - Jia-Xun Feng
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Research Center for Microbial and Enzyme Engineering Technology, College of Life Science and Technology, Guangxi University, Nanning 530004, China
| | - Shuai Zhao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Research Center for Microbial and Enzyme Engineering Technology, College of Life Science and Technology, Guangxi University, Nanning 530004, China
| | - Surisa Suwannarangsee
- National Center for Genetic Engineering and Biotechnology (BIOTEC), 113 Thailand Science Park, Phaholyothin Road, Khlong Luang, Pathumthani 12120, Thailand
| | - Verawat Chempreda
- National Center for Genetic Engineering and Biotechnology (BIOTEC), 113 Thailand Science Park, Phaholyothin Road, Khlong Luang, Pathumthani 12120, Thailand
| | - Chen-Guang Liu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xin-Qing Zhao
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.
| |
Collapse
|
7
|
Adnan M, Islam W, Waheed A, Hussain Q, Shen L, Wang J, Liu G. SNARE Protein Snc1 Is Essential for Vesicle Trafficking, Membrane Fusion and Protein Secretion in Fungi. Cells 2023; 12:1547. [PMID: 37296667 PMCID: PMC10252874 DOI: 10.3390/cells12111547] [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: 04/08/2023] [Revised: 05/24/2023] [Accepted: 05/30/2023] [Indexed: 06/12/2023] Open
Abstract
Fungi are an important group of microorganisms that play crucial roles in a variety of ecological and biotechnological processes. Fungi depend on intracellular protein trafficking, which involves moving proteins from their site of synthesis to the final destination within or outside the cell. The soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNARE) proteins are vital components of vesicle trafficking and membrane fusion, ultimately leading to the release of cargos to the target destination. The v-SNARE (vesicle-associated SNARE) Snc1 is responsible for anterograde and retrograde vesicle trafficking between the plasma membrane (PM) and Golgi. It allows for the fusion of exocytic vesicles to the PM and the subsequent recycling of Golgi-localized proteins back to the Golgi via three distinct and parallel recycling pathways. This recycling process requires several components, including a phospholipid flippase (Drs2-Cdc50), an F-box protein (Rcy1), a sorting nexin (Snx4-Atg20), a retromer submit, and the COPI coat complex. Snc1 interacts with exocytic SNAREs (Sso1/2, Sec9) and the exocytic complex to complete the process of exocytosis. It also interacts with endocytic SNAREs (Tlg1 and Tlg2) during endocytic trafficking. Snc1 has been extensively investigated in fungi and has been found to play crucial roles in various aspects of intracellular protein trafficking. When Snc1 is overexpressed alone or in combination with some key secretory components, it results in enhanced protein production. This article will cover the role of Snc1 in the anterograde and retrograde trafficking of fungi and its interactions with other proteins for efficient cellular transportation.
Collapse
Affiliation(s)
- Muhammad Adnan
- Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; (M.A.); (A.W.); (J.W.)
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Waqar Islam
- Xinjiang Key Laboratory of Desert Plant Roots Ecology and Vegetation Restoration, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China;
| | - Abdul Waheed
- Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; (M.A.); (A.W.); (J.W.)
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Quaid Hussain
- Shenzhen Key Laboratory of Marine Bioresource and Eco-Environmental Science, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China;
| | - Ling Shen
- School of Life Science, Jiangsu Normal University, Xuzhou 221116, China;
| | - Juan Wang
- Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; (M.A.); (A.W.); (J.W.)
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Gang Liu
- Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; (M.A.); (A.W.); (J.W.)
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| |
Collapse
|
8
|
Ji W, Wang X, Liu X, Wang Y, Liu F, Xu B, Luo H, Tu T, Zhang W, Xu X, Su X. Combining manipulation of integration loci and secretory pathway on expression of an Aspergillus niger glucose oxidase gene in Trichoderma reesei. Microb Cell Fact 2023; 22:38. [PMID: 36841771 PMCID: PMC9960163 DOI: 10.1186/s12934-023-02046-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 02/18/2023] [Indexed: 02/27/2023] Open
Abstract
Trichoderma reesei (T. reesei) is well-known for its excellent ability to secret a large quantity of cellulase. However, unlike the endogenous proteins, little is known about the molecular mechanisms governing heterologous protein production. Herein, we focused on the integration loci and the secretory pathway, and investigated their combinatorial effects on heterologous gene expression in T. reesei using a glucose oxidase from Aspergillus niger as a model protein. Integration in the cel3c locus was more efficient than the cbh1 locus in expressing the AnGOx by increasing the transcription of AnGOx in the early stage. In addition, we discovered that interruption of the cel3c locus has an additional effect by increasing the expression of the secretory pathway component genes. Accordingly, overexpressing three secretory pathway component genes, that were snc1, sso2, and rho3, increased AnGOx expression in the cbh1 transformant but not in the cel3c transformant.
Collapse
Affiliation(s)
- Wangli Ji
- grid.410727.70000 0001 0526 1937Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, No.12 South Zhongguancun St., Haidian District, Beijing, 100081 China
| | - Xiaolu Wang
- grid.410727.70000 0001 0526 1937Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, No. 2 West Yuanmingyuan Road, Haidian District, Beijing, 100193 China
| | - Xiaoqing Liu
- grid.410727.70000 0001 0526 1937Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, No.12 South Zhongguancun St., Haidian District, Beijing, 100081 China
| | - Yuan Wang
- grid.410727.70000 0001 0526 1937Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, No. 2 West Yuanmingyuan Road, Haidian District, Beijing, 100193 China
| | - Fangui Liu
- grid.459577.d0000 0004 1757 6559College of Biological and Food Engineering, Guangdong University of Petrochemical Technology, Maoming, 525000 Guangdong China
| | - Bo Xu
- grid.459577.d0000 0004 1757 6559College of Biological and Food Engineering, Guangdong University of Petrochemical Technology, Maoming, 525000 Guangdong China
| | - Huiying Luo
- grid.410727.70000 0001 0526 1937Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, No. 2 West Yuanmingyuan Road, Haidian District, Beijing, 100193 China
| | - Tao Tu
- grid.410727.70000 0001 0526 1937Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, No. 2 West Yuanmingyuan Road, Haidian District, Beijing, 100193 China
| | - Wei Zhang
- grid.410727.70000 0001 0526 1937Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, No.12 South Zhongguancun St., Haidian District, Beijing, 100081 China
| | - Xinxin Xu
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, No.12 South Zhongguancun St., Haidian District, Beijing, 100081, China.
| | - Xiaoyun Su
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, No. 2 West Yuanmingyuan Road, Haidian District, Beijing, 100193, China.
| |
Collapse
|
9
|
Madhavan A, Arun KB, Sindhu R, Nair BG, Pandey A, Awasthi MK, Szakacs G, Binod P. Design and genome engineering of microbial cell factories for efficient conversion of lignocellulose to fuel. BIORESOURCE TECHNOLOGY 2023; 370:128555. [PMID: 36586428 DOI: 10.1016/j.biortech.2022.128555] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/26/2022] [Accepted: 12/27/2022] [Indexed: 06/17/2023]
Abstract
The gradually increasing need for fossil fuels demands renewable biofuel substitutes. This has fascinated an increasing investigation to design innovative energy fuels that have comparable Physico-chemical and combustion characteristics with fossil-derived fuels. The efficient microbes for bioenergy synthesis desire the proficiency to consume a large quantity of carbon substrate, transfer various carbohydrates through efficient metabolic pathways, capability to withstand inhibitory components and other degradation compounds, and improve metabolic fluxes to synthesize target compounds. Metabolically engineered microbes could be an efficient methodology for synthesizing biofuel from cellulosic biomass by cautiously manipulating enzymes and metabolic pathways. This review offers a comprehensive perspective on the trends and advances in metabolic and genetic engineering technologies for advanced biofuel synthesis by applying various heterologous hosts. Probable technologies include enzyme engineering, heterologous expression of multiple genes, CRISPR-Cas technologies for genome editing, and cell surface display.
Collapse
Affiliation(s)
- Aravind Madhavan
- School of Biotechnology, Amrita Vishwa Vidyapeetham, Amritapuri, Kollam 690525 Kerala, India.
| | - K B Arun
- Department of Life Sciences, CHRIST (Deemed to be University), Bengaluru 560029, Karnataka, India
| | - Raveendran Sindhu
- Department of Food Technology, TKM Institute of Technology, Kollam 689 122, India
| | - Bipin G Nair
- School of Biotechnology, Amrita Vishwa Vidyapeetham, Amritapuri, Kollam 690525 Kerala, India
| | - Ashok Pandey
- Center for Innovation and Translational Research, CSIR-Indian Institute of Toxicology Research, Lucknow 226 001, India; Sustainability Cluster, School of Engineering, University of Petroleum and Energy Studies, Dehradun 248007, Uttarkhand, India; Centre for Energy and Environmental Sustainability, Lucknow 226 029, Uttar Pradesh, India
| | - Mukesh Kumar Awasthi
- College of Natural Resources and Environment, Northwest A & F University, Yangling, Shaanxi 712 100, China
| | - George Szakacs
- Budapest University of Technology and Economics, Department of Applied Biotechnology and Food Science, 1111 Budapest, Szent Gellert ter 4, Hungary
| | - Parameswaran Binod
- Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Trivandrum 695 019, India
| |
Collapse
|
10
|
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: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [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.
Collapse
|
11
|
Sun X, Liang Y, Wang Y, Zhang H, Zhao T, Yao B, Luo H, Huang H, Su X. Simultaneous manipulation of multiple genes within a same regulatory stage for iterative evolution of Trichoderma reesei. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:26. [PMID: 35248141 PMCID: PMC8898424 DOI: 10.1186/s13068-022-02122-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 02/19/2022] [Indexed: 11/12/2022]
Abstract
Background While there is growing interest in developing non-canonical filamentous fungi as hosts for producing secretory proteins, genetic engineering of filamentous fungi for improved expression often relies heavily on the understanding of regulatory mechanisms. Results In this study, using the cellulase-producing filamentous fungus Trichoderma reesei as a model system, we designed a semi-rational strategy by arbitrarily dividing the regulation of cellulase production into three main stages-transcription, secretion, and cell metabolism. Selected regulatory or functional genes that had been experimentally verified or predicted to enhance cellulase production were overexpressed using strong inducible or constitutive promoters, while those that would inhibit cellulase production were repressed via RNAi-mediated gene silencing. A T. reesei strain expressing the surface-displayed DsRed fluorescent protein was used as the recipient strain. After three consecutive rounds of engineering, the cellulase activity increased to up to 4.35-fold and the protein concentration increased to up to 2.97-fold in the genetically modified strain. Conclusions We demonstrated that, as a proof-of-concept, selected regulatory or functional genes within an arbitrarily defined stage could be pooled to stimulate secretory cellulase production, and moreover, this method could be iteratively used for further improvement. This method is semi-rational and can essentially be used in filamentous fungi with little regulatory information. Supplementary Information The online version contains supplementary material available at 10.1186/s13068-022-02122-0.
Collapse
|
12
|
Insights into the Structures, Inhibitors, and Improvement Strategies of Glucose Oxidase. Int J Mol Sci 2022; 23:ijms23179841. [PMID: 36077243 PMCID: PMC9456440 DOI: 10.3390/ijms23179841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 08/18/2022] [Accepted: 08/26/2022] [Indexed: 11/17/2022] Open
Abstract
Glucose oxidase, which uses molecular oxygen as an electron acceptor to specifically catalyze the conversion of β-d-glucose to gluconic acid and hydrogen peroxide (H2O2), has been considered an important enzyme in increasing environmental sustainability and food security. However, achieving the high yield, low price and high activity required for commercial viability remains challenging. In this review, we first present a brief introduction, looking at the sources, characteristics, catalytic process, and applications of glucose oxidase. Then, the predictive structures of glucose oxidase from two different sources are comparatively discussed. We summarize the inhibitors of glucose oxidase. Finally, we highlight how the production of glucose oxidase can be improved by optimizing the culture conditions and microbial metabolic engineering.
Collapse
|
13
|
Chetty BJ, Inokuma K, Hasunuma T, van Zyl WH, den Haan R. Improvement of cell-tethered cellulase activity in recombinant strains of Saccharomyces cerevisiae. Appl Microbiol Biotechnol 2022; 106:6347-6361. [PMID: 35951080 DOI: 10.1007/s00253-022-12114-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 07/27/2022] [Accepted: 07/28/2022] [Indexed: 11/30/2022]
Abstract
Consolidated bioprocessing (CBP) remains an attractive option for the production of commodity products from pretreated lignocellulose if a process-suitable organism can be engineered. The yeast Saccharomyces cerevisiae requires engineered cellulolytic activity to enable its use in CBP production of second-generation (2G) bioethanol. A promising strategy for heterologous cellulase production in yeast entails displaying enzymes on the cell surface by means of glycosylphosphatidylinositol (GPI) anchors. While strains producing a core set of cell-adhered cellulases that enabled crystalline cellulose hydrolysis have been created, secreted levels of enzyme were insufficient for complete cellulose hydrolysis. In fact, all reported recombinant yeast CBP candidates must overcome the drawback of generally low secretion titers. Rational strain engineering can be applied to enhance the secretion phenotype. This study aimed to improve the amount of cell-adhered cellulase activities of recombinant S. cerevisiae strains expressing a core set of four cellulases, through overexpression of genes that were previously shown to enhance cellulase secretion. Results showed significant increases in cellulolytic activity for all cell-adhered cellulase enzyme types. Cell-adhered cellobiohydrolase activity was improved by up to 101%, β-glucosidase activity by up to 99%, and endoglucanase activity by up to 231%. Improved hydrolysis of crystalline cellulose of up to 186% and improved ethanol yields from this substrate of 40-50% in different strain backgrounds were also observed. In addition, improvement in resistance to fermentation stressors was noted in some strains. These strains represent a step towards more efficient organisms for use in 2G biofuel production. KEY POINTS: • Cell-surface-adhered cellulase activity was improved in strains engineered for CBP. • Levels of improvement of activity were strain and enzyme dependent. • Crystalline cellulose conversion to ethanol could be improved up to 50%.
Collapse
Affiliation(s)
- Bronwyn Jean Chetty
- Department of Biotechnology, University of the Western Cape, Bellville, South Africa
| | - Kentaro Inokuma
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan
| | - Tomohisa Hasunuma
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan
- Engineering Biology Research Center, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan
| | | | - Riaan den Haan
- Department of Biotechnology, University of the Western Cape, Bellville, South Africa.
| |
Collapse
|
14
|
Liang Z, Yan Y, Zhang W, Luo H, Yao B, Huang H, Tu T. Review of glucose oxidase as a feed additive: production, engineering, applications, growth-promoting mechanisms, and outlook. Crit Rev Biotechnol 2022:1-18. [PMID: 35723581 DOI: 10.1080/07388551.2022.2057275] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The regulation and prohibition of antibiotics used as growth promoters (AGP) in the feed field are increasing because they cause antimicrobial resistance and drug residue issues and threaten community health. Recently, glucose oxidase (GOx) has attracted increasing interest in the feed industry as an alternative to antibiotics. GOx specifically catalyzes the production of gluconic acid (GA) and hydrogen peroxide (H2O2) by consuming molecular oxygen, and plays an important role in relieving oxidative stress, preserving health, and promoting animal growth. To expand the application of GOx in the feed field, considerable efforts have been made to mine new genetic resources. Efforts have also been made to heterologously overexpress relevant genes to reduce production costs and to engineer proteins by modifying enzyme properties, both of which are bottleneck problems that limit industrial feed applications. Herein, the: different sources, diverse biochemical properties, distinct structural features, and various strategies of GOx engineering and heterologous overexpression are summarized. The mechanism through which GOx promotes growth in animal production, including the improvement of antioxidant capacity, maintenance of intestinal microbiota homeostasis, and enhancement of gut function, are also systematically addressed. Finally, a new perspective is provided for the future development of GOx applications in the feed field.
Collapse
Affiliation(s)
- Ziqi Liang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China.,College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Yaru Yan
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Wei Zhang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Huiying Luo
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Bin Yao
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Huoqing Huang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Tao Tu
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| |
Collapse
|
15
|
Promoter regulation and genetic engineering strategies for enhanced cellulase expression in Trichoderma reesei. Microbiol Res 2022; 259:127011. [DOI: 10.1016/j.micres.2022.127011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 03/15/2022] [Accepted: 03/16/2022] [Indexed: 01/18/2023]
|
16
|
Karimiabar M, Ahari H, Amini K. Molecular Cloning, Expression, and Enzyme Activity of Glucose Oxidase Gene from Soil Thermophilic Streptomyces. IRANIAN JOURNAL OF BIOTECHNOLOGY 2022; 20:e2979. [PMID: 35891952 PMCID: PMC9284247 DOI: 10.30498/ijb.2021.272122.2979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Background Glucose oxidase is an oxidoreductase that depletes oxygen in food processing and is used in biosensors, glucose diagnostic kits, food processing, cosmetics, and chemical industries. This enzyme is often isolated from fungi, such as Penicillium and Aspergillus Niger. Objectives The objective of this study was to clone and express a full-length GOX gene from soil thermophilic streptomyces for bioinformatic and enzyme activity evaluations. Materials and Methods After collecting samples from the Gandom Beryan area of Kerman province, Iran, Streptomyces strains were identified with specific biochemical and molecular tests. Streptomyces strains with glucose oxidase gene were detected by PCR, and the amplified gene fragment was cloned into Escherichia coli host bacterium using TA cloning technique. The expression of the cloned GOX gene in the host bacterium was measured using real-time PCR, and the recombinant plasmids were sequenced. The enzymatic activity was measured in the extracts of E. coli cells carrying the plasmids. Results After screening the samples, 12 strains of Streptomyces were identified, 4 of which carried the GOX gene. The GOX open reading frame, obtained by PCR, was cloned into a vector and transformed into Escherichia coli origami to generate GOX-producing bacteria. Enzyme activity was confirmed and a phylogenetic tree showed the degree of kinship between Streptomyces species and other species, including Streptomyces SP MI02-7b. The expression levels of GOX genes mRNA were found to be approximately 4-fold higher in transformed E. coli than in soil thermophilic Streptomyces (P <0.001). Conclusion This study showed that natural thermostable streptomyces producing glucose oxidase enzyme could be found in Iran. The enzyme gene was successfully transformed into Escherichia coli generating a recombinant host with high yield capability that can be a major step towards the production of this enzyme from indigenous strains. It should be emphasized that the GOX enzyme produced by these strains is profitable due to high production levels correlated to the optimum condition in cheap culture media, short fermentation cycles, high expression capability, and ease of growth.
Collapse
Affiliation(s)
- Mahsa Karimiabar
- Department of Food Science and Technology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Hamed Ahari
- Department of Food Science and Technology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Kumarss Amini
- Department of Microbiology, Faculty of Basic Science, Saveh Branch, Islamic Azad University, Saveh, Iran
| |
Collapse
|
17
|
Madhavan A, Arun KB, Sindhu R, Alphonsa Jose A, Pugazhendhi A, Binod P, Sirohi R, Reshmy R, Kumar Awasthi M. Engineering interventions in industrial filamentous fungal cell factories for biomass valorization. BIORESOURCE TECHNOLOGY 2022; 344:126209. [PMID: 34715339 DOI: 10.1016/j.biortech.2021.126209] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/18/2021] [Accepted: 10/20/2021] [Indexed: 05/15/2023]
Abstract
Filamentous fungi possess versatile capabilities for synthesizing a variety of valuable bio compounds, including enzymes, organic acids and small molecule secondary metabolites. The advancements of genetic and metabolic engineering techniques and the availability of sequenced genomes discovered their potential as expression hosts for recombinant protein production. Remarkably, plant-biomass degrading filamentous fungi show the unique capability to decompose lignocellulose, an extremely recalcitrant biopolymer. The basic biochemical approaches have motivated several industrial processes for lignocellulose biomass valorisation into fermentable sugars and other biochemical for biofuels, biomolecules, and biomaterials. The review gives insight into current trends in engineering filamentous fungi for enzymes, fuels, and chemicals from lignocellulose biomass. This review describes the variety of enzymes and compounds that filamentous fungi produce, engineering of filamentous fungi for biomass valorisation with a special focus on lignocellulolytic enzymes and other bulk chemicals.
Collapse
Affiliation(s)
- Aravind Madhavan
- Rajiv Gandhi Centre for Biotechnology, Jagathy, Trivandrum 695 014, India.
| | - K B Arun
- Rajiv Gandhi Centre for Biotechnology, Jagathy, Trivandrum 695 014, India
| | - Raveendran Sindhu
- Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Trivandrum 695 019, India
| | - Anju Alphonsa Jose
- Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Trivandrum 695 019, India
| | | | - Parameswaran Binod
- Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Trivandrum 695 019, India
| | - Ranjna Sirohi
- Department of Chemical & Biological Engineering, Korea University, Seoul 136713, Republic of Korea; Centre for Energy & Environmental Sustainability, Lucknow 226001. Uttar Pradesh, India
| | - R Reshmy
- Post Graduate and Research Department of Chemistry, Bishop Moore College, Mavelikara 690 110, Kerala, India
| | - Mukesh Kumar Awasthi
- College of Natural Resources and Environment, Northwest A & F University, Yangling, Shaanxi 712 100, PR China
| |
Collapse
|
18
|
Tomico-Cuenca I, Mach RL, Mach-Aigner AR, Derntl C. An overview on current molecular tools for heterologous gene expression in Trichoderma. Fungal Biol Biotechnol 2021; 8:11. [PMID: 34702369 PMCID: PMC8549263 DOI: 10.1186/s40694-021-00119-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 10/16/2021] [Indexed: 11/10/2022] Open
Abstract
Fungi of the genus Trichoderma are routinely used as biocontrol agents and for the production of industrial enzymes. Trichoderma spp. are interesting hosts for heterologous gene expression because their saprotrophic and mycoparasitic lifestyles enable them to thrive on a large number of nutrient sources and some members of this genus are generally recognized as safe (GRAS status). In this review, we summarize and discuss several aspects involved in heterologous gene expression in Trichoderma, including transformation methods, genome editing strategies, native and synthetic expression systems and implications of protein secretion. This review focuses on the industrial workhorse Trichoderma reesei because this fungus is the best-studied member of this genus for protein expression and secretion. However, the discussed strategies and tools can be expected to be transferable to other Trichoderma species.
Collapse
Affiliation(s)
- Irene Tomico-Cuenca
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Strasse 1a, 1060, Wien, Austria
| | - Robert L Mach
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Strasse 1a, 1060, Wien, Austria
| | - Astrid R Mach-Aigner
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Strasse 1a, 1060, Wien, Austria
| | - Christian Derntl
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Strasse 1a, 1060, Wien, Austria.
| |
Collapse
|
19
|
Shen L, Gao J, Wang Y, Li X, Liu H, Zhong Y. Engineering the endoplasmic reticulum secretory pathway in Trichoderma reesei for improved cellulase production. Enzyme Microb Technol 2021; 152:109923. [PMID: 34688089 DOI: 10.1016/j.enzmictec.2021.109923] [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: 08/03/2021] [Revised: 09/18/2021] [Accepted: 09/29/2021] [Indexed: 10/20/2022]
Abstract
The filamentous fungus Trichoderma reesei is an extraordinarily efficient cell factory of industrial cellulase for production of biofuels and other bio-based products because of its excellent potential to secrete cellulolytic enzymes. Engineering the protein secretory pathway may be a powerful means for efficient protein production. However, it is uncertain whether this engineering approach could improve cellulase production in T. reesei. Herein, the endoplasmic reticulum (ER) secretory pathway was engineered for the production of cellulolytic enzymes by multiple strategies, including: (I) overexpression of the key components of protein folding (Pdi1, Ero1 and BiP); (II) overexpression of the glycosylation-related elements (Gpt1 and Gls2); (III) knockout of the ER mannosidase I (Mns1) encoding gene mns1. By utilizing these ER engineering strategies, the secretion of β-glucosidase was remarkably elevated in the engineered strains, ranging from 29.2 % to 112.5 %. Furthermore, it was found that engineering these components also regulated the ER stress resistance. More importantly, the total cellulase production was increased with varying degrees, which reached a maximum of 149.4 %, using the filter paper assay (FPA) as a characterization method. These results demonstrated that engineering the ER secretory pathway can enhance protein secretion, particularly for cellulase production, which shed light for the development of high-efficient cellulolytic enzymes for economically feasible bioethanol production from lignocellulosic biomass.
Collapse
Affiliation(s)
- Linjing Shen
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, PR China
| | - Jia Gao
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, PR China
| | - Yifan Wang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, PR China
| | - Xihai Li
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, PR China
| | - Hong Liu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, PR China.
| | - Yaohua Zhong
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, PR China
| |
Collapse
|
20
|
den Haan R, Rose SH, Cripwell RA, Trollope KM, Myburgh MW, Viljoen-Bloom M, van Zyl WH. Heterologous production of cellulose- and starch-degrading hydrolases to expand Saccharomyces cerevisiae substrate utilization: Lessons learnt. Biotechnol Adv 2021; 53:107859. [PMID: 34678441 DOI: 10.1016/j.biotechadv.2021.107859] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 10/14/2021] [Accepted: 10/15/2021] [Indexed: 12/28/2022]
Abstract
Selected strains of Saccharomyces cerevisiae are used for commercial bioethanol production from cellulose and starch, but the high cost of exogenous enzymes for substrate hydrolysis remains a challenge. This can be addressed through consolidated bioprocessing (CBP) where S. cerevisiae strains are engineered to express recombinant glycoside hydrolases during fermentation. Looking back at numerous strategies undertaken over the past four decades to improve recombinant protein production in S. cerevisiae, it is evident that various steps in the protein production "pipeline" can be manipulated depending on the protein of interest and its anticipated application. In this review, we briefly introduce some of the strategies and highlight lessons learned with regards to improved transcription, translation, post-translational modification and protein secretion of heterologous hydrolases. We examine how host strain selection and modification, as well as enzyme compatibility, are crucial determinants for overall success. Finally, we discuss how lessons from heterologous hydrolase expression can inform modern synthetic biology and genome editing tools to provide process-ready yeast strains in future. However, it is clear that the successful expression of any particular enzyme is still unpredictable and requires a trial-and-error approach.
Collapse
Affiliation(s)
- Riaan den Haan
- Department of Biotechnology, University of the Western Cape, Bellville, South Africa
| | - Shaunita H Rose
- Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa
| | - Rosemary A Cripwell
- Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa
| | - Kim M Trollope
- Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa
| | - Marthinus W Myburgh
- Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa
| | | | - Willem H van Zyl
- Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa.
| |
Collapse
|
21
|
Yan S, Xu Y, Yu XW. From induction to secretion: a complicated route for cellulase production in Trichoderma reesei. BIORESOUR BIOPROCESS 2021; 8:107. [PMID: 38650205 PMCID: PMC10991602 DOI: 10.1186/s40643-021-00461-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 10/16/2021] [Indexed: 11/10/2022] Open
Abstract
The filamentous fungus Trichoderma reesei has been widely used for cellulase production that has extensive applications in green and sustainable development. Increasing costs and depletion of fossil fuels provoke the demand for hyper-cellulase production in this cellulolytic fungus. To better manipulate T. reesei for enhanced cellulase production and to lower the cost for large-scale fermentation, it is wise to have a comprehensive understanding of the crucial factors and complicated biological network of cellulase production that could provide new perspectives for further exploration and modification. In this review, we summarize recent progress and give an overview of the cellular process of cellulase production in T. reesei, including the carbon source-dependent cellulase induction, complicated transcriptional regulation network, and efficient protein assembly and trafficking. Among that, the key factors involved in cellulase production were emphasized, shedding light on potential perspectives for further engineering.
Collapse
Affiliation(s)
- Su Yan
- Lab of Brewing Microbiology and Applied Enzymology, School of Biotechnology, Jiangnan University, Wuxi, 214122, People's Republic of China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, People's Republic of China
| | - Yan Xu
- Lab of Brewing Microbiology and Applied Enzymology, School of Biotechnology, Jiangnan University, Wuxi, 214122, People's Republic of China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, People's Republic of China
| | - Xiao-Wei Yu
- Lab of Brewing Microbiology and Applied Enzymology, School of Biotechnology, Jiangnan University, Wuxi, 214122, People's Republic of China.
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, People's Republic of China.
| |
Collapse
|
22
|
|
23
|
Wang Y, Wang J, Leng F, Ma J, Bagadi A. Expression of Aspergillus niger glucose oxidase in Pichia pastoris and its antimicrobial activity against Agrobacterium and Escherichia coli. PeerJ 2020; 8:e9010. [PMID: 32832258 PMCID: PMC7413082 DOI: 10.7717/peerj.9010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 03/27/2020] [Indexed: 12/11/2022] Open
Abstract
The gene encoding glucose oxidase from Aspergillus niger ZM-8 was cloned and transferred to Pichia pastoris GS115, a transgenic strain P. pastoris GS115-His-GOD constructed. The growth curve of P. pastoris GS115-His-GOD was consistent with that of Pichia pastoris GS115-pPIC9K under non-induced culture conditions. Under methanol induction conditions, the growth of the GOD-transgenic strain was significantly lowered than P. pastoris GS115-pPIC9K with the induced-culture time increase, and the optical densities of GOD-transgenic strain reached one-third of that of the P. pastoris GS115-pPIC9K at 51 h. The activity of glucose oxidase in the cell-free supernatant, the supernatant of cell lysate, and the precipitation of cell lysate was 14.3 U/mL, 18.2 U/mL and 0.48 U/mL, respectively. The specific activity of glucose oxidase was 8.3 U/mg, 6.52 U/mg and 0.73 U/mg, respectively. The concentration of hydrogen peroxide formed by glucose oxidase from supernatant of the fermentation medium, the supernatant of the cell lysate, and the precipitation of cell lysate catalyzing 0.2 M glucose was 14.3 μg/mL, 18.2 μg/mL, 0.48 μg/mL, respectively. The combination of different concentrations of glucose oxidase and glucose could significantly inhibit the growth of Agrobacterium and Escherichia coli in logarithmic phase. The filter article containing supernatant of the fermentation medium, supernatant of the cell lysate, and precipitation of cell lysate had no inhibitory effect on Agrobacterium and E. coli. The minimum inhibitory concentration of hydrogen peroxide on the plate culture of Agrobacterium and E. coli was 5.6 × 103 μg/mL and 6.0 × 103 μg/mL, respectively.
Collapse
Affiliation(s)
- Yonggang Wang
- School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou, Gansu, China.,Key Laboratory of Drug Screening and Deep Processing for Traditional Chinese and Tibetan Medicine of Gansu Province, Lanzhou University of Technology, Lanzhou, Gansu, China
| | - Jiangqin Wang
- School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou, Gansu, China.,Key Laboratory of Drug Screening and Deep Processing for Traditional Chinese and Tibetan Medicine of Gansu Province, Lanzhou University of Technology, Lanzhou, Gansu, China
| | - Feifan Leng
- School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou, Gansu, China.,Key Laboratory of Drug Screening and Deep Processing for Traditional Chinese and Tibetan Medicine of Gansu Province, Lanzhou University of Technology, Lanzhou, Gansu, China
| | - Jianzhong Ma
- School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou, Gansu, China.,Key Laboratory of Drug Screening and Deep Processing for Traditional Chinese and Tibetan Medicine of Gansu Province, Lanzhou University of Technology, Lanzhou, Gansu, China
| | - Alnoor Bagadi
- School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou, Gansu, China
| |
Collapse
|
24
|
Exploiting strain diversity and rational engineering strategies to enhance recombinant cellulase secretion by Saccharomyces cerevisiae. Appl Microbiol Biotechnol 2020; 104:5163-5184. [PMID: 32337628 DOI: 10.1007/s00253-020-10602-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 03/26/2020] [Accepted: 03/31/2020] [Indexed: 12/14/2022]
Abstract
Consolidated bioprocessing (CBP) of lignocellulosic material into bioethanol has progressed in the past decades; however, several challenges still exist which impede the industrial application of this technology. Identifying the challenges that exist in all unit operations is crucial and needs to be optimised, but only the barriers related to the secretion of recombinant cellulolytic enzymes in Saccharomyces cerevisiae will be addressed in this review. Fundamental principles surrounding CBP as a biomass conversion platform have been established through the successful expression of core cellulolytic enzymes, namely β-glucosidases, endoglucanases, and exoglucanases (cellobiohydrolases) in S. cerevisiae. This review will briefly address the challenges involved in the construction of an efficient cellulolytic yeast, with particular focus on the secretion efficiency of cellulases from this host. Additionally, strategies for studying enhanced cellulolytic enzyme secretion, which include both rational and reverse engineering approaches, will be discussed. One such technique includes bio-engineering within genetically diverse strains, combining the strengths of both natural strain diversity and rational strain development. Furthermore, with the advancement in next-generation sequencing, studies that utilise this method of exploiting intra-strain diversity for industrially relevant traits will be reviewed. Finally, future prospects are discussed for the creation of ideal CBP strains with high enzyme production levels.Key Points• Several challenges are involved in the construction of efficient cellulolytic yeast, in particular, the secretion efficiency of cellulases from the hosts.• Strategies for enhancing cellulolytic enzyme secretion, a core requirement for CBP host microorganism development, include both rational and reverse engineering approaches.• One such technique includes bio-engineering within genetically diverse strains, combining the strengths of both natural strain diversity and rational strain development.
Collapse
|
25
|
Wang Q, Zhong C, Xiao H. Genetic Engineering of Filamentous Fungi for Efficient Protein Expression and Secretion. Front Bioeng Biotechnol 2020; 8:293. [PMID: 32322579 PMCID: PMC7156587 DOI: 10.3389/fbioe.2020.00293] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 03/19/2020] [Indexed: 02/05/2023] Open
Abstract
Filamentous fungi are considered as unique cell factories for protein production due to the high efficiency of protein secretion and superior capability of post-translational modifications. In this review, we firstly introduce the secretory pathway in filamentous fungi. We next summarize the current state-of-the-art works regarding how various genetic engineering strategies are applied for enhancing protein expression and secretion in filamentous fungi. Finally, in a future perspective, we discuss the great potential of genome engineering for further improving protein expression and secretion in filamentous fungi.
Collapse
Affiliation(s)
- Qin Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, and Laboratory of Molecular Biochemical Engineering, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Chao Zhong
- Materials and Physical Biology Division, School of Physical Science and Technology, ShanghaiTech University, Shanghai, China
- Materials Synthetic Biology Center, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Han Xiao
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, and Laboratory of Molecular Biochemical Engineering, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| |
Collapse
|
26
|
Characterization, stability improvement, and bread baking applications of a novel cold-adapted glucose oxidase from Cladosporium neopsychrotolerans SL16. Food Chem 2020; 310:125970. [DOI: 10.1016/j.foodchem.2019.125970] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 10/17/2019] [Accepted: 11/27/2019] [Indexed: 11/20/2022]
|
27
|
Sun X, Zhang X, Huang H, Wang Y, Tu T, Bai Y, Wang Y, Zhang J, Luo H, Yao B, Su X. Engineering the cbh1 Promoter of Trichoderma reesei for Enhanced Protein Production by Replacing the Binding Sites of a Transcription Repressor ACE1 to Those of the Activators. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:1337-1346. [PMID: 31933359 DOI: 10.1021/acs.jafc.9b05452] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The strong and inducible cbh1 promoter is most widely used to express heterologous proteins, useful in food and feed industries, in Trichoderma reesei. Enhancing its ability to direct transcription provides a general strategy to improve protein production in T. reesei. The cbh1 promoter was engineered by replacing eight binding sites of the transcription repressor ACE1 to those of the activators ACE2, Hap2/3/5, and Xyr1. While changing ACE1 to Hap2/3/5-binding sites completely abolished the transcription ability, replacements with ACE2- and Xyr1-binding sites (designated cbh1pA and cbh1pX promoters, respectively) largely improved the promoter transcription efficiency, as reflected by expression of a reporter gene DsRed. The cbh1pA and cbh1pX promoters were applied to improve secretory expression of a codon-optimized mannanase from Aspergillus niger to 3.6- and 5.0-fold higher, respectively, which has high application potential in feed industry.
Collapse
Affiliation(s)
- Xianhua Sun
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute , Chinese Academy of Agricultural Sciences , Beijing 100081 , China
| | - Xuhuan Zhang
- Biotechnology Research Institute , Chinese Academy of Agricultural Sciences , Beijing 100081 , People's Republic of China
| | - Huoqing Huang
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute , Chinese Academy of Agricultural Sciences , Beijing 100081 , China
| | - Yuan Wang
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute , Chinese Academy of Agricultural Sciences , Beijing 100081 , China
| | - Tao Tu
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute , Chinese Academy of Agricultural Sciences , Beijing 100081 , China
| | - Yingguo Bai
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute , Chinese Academy of Agricultural Sciences , Beijing 100081 , China
| | - Yaru Wang
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute , Chinese Academy of Agricultural Sciences , Beijing 100081 , China
| | - Jie Zhang
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute , Chinese Academy of Agricultural Sciences , Beijing 100081 , China
| | - Huiying Luo
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute , Chinese Academy of Agricultural Sciences , Beijing 100081 , China
| | - Bin Yao
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute , Chinese Academy of Agricultural Sciences , Beijing 100081 , China
| | - Xiaoyun Su
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute , Chinese Academy of Agricultural Sciences , Beijing 100081 , China
| |
Collapse
|
28
|
Gopalakrishnan RM, Manavalan T, Ramesh J, Thangavelu KP, Heese K. Improvement of Saccharification and Delignification Efficiency of Trichoderma reesei Rut-C30 by Genetic Bioengineering. Microorganisms 2020; 8:microorganisms8020159. [PMID: 31979278 PMCID: PMC7074786 DOI: 10.3390/microorganisms8020159] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 01/20/2020] [Accepted: 01/22/2020] [Indexed: 11/16/2022] Open
Abstract
Trichoderma reesei produces various saccharification enzymes required for biomass degradation. However, the lack of an effective lignin-degrading enzyme system reduces the species’ efficiency in producing fermentable sugars and increases the pre-treatment costs for biofuel production. In this study, we heterologously expressed the Ganoderma lucidum RMK1 versatile peroxidase gene (vp1) in the Rut-C30 strain of T. reesei. The expression of purified 6×His-tag–containing recombinant G. lucidum-derived protein (rVP1) was confirmed through western blot, which exhibited a single band with a relative molecular weight of 39 kDa. In saccharification and delignification studies using rice straw, the transformant (tVP7, T. reesei Rut-C30 expressing G. lucidum-derived rVP1) showed significant improvement in the yield of total reducing sugar and delignification, compared with that of the parent T. reesei Rut-C30 strain. Scanning electron microscopy (SEM) of tVP7-treated paddy straw showed extensive degradation of several layers of its surface compared with the parent strain due to the presence of G. lucidum-derived rVP1. Our results suggest that the expression of ligninolytic enzymes in cellulase hyperproducing systems helps to integrate the pre-treatment and saccharification steps that may ultimately reduce the costs of bioethanol production.
Collapse
Affiliation(s)
- Raja Mohan Gopalakrishnan
- Centre for Advanced Studies in Botany, University of Madras, Guindy Campus, Chennai, Tamil Nadu 600 025, India; (R.M.G.); (T.M.)
| | - Tamilvendan Manavalan
- Centre for Advanced Studies in Botany, University of Madras, Guindy Campus, Chennai, Tamil Nadu 600 025, India; (R.M.G.); (T.M.)
| | - Janani Ramesh
- Department of Medical Biochemistry, Dr ALM Postgraduate Institute of Biomedical Sciences, University of Madras, Chennai, Tamil Nadu 600 113, India;
| | - Kalaichelvan Puthupalayam Thangavelu
- Centre for Advanced Studies in Botany, University of Madras, Guindy Campus, Chennai, Tamil Nadu 600 025, India; (R.M.G.); (T.M.)
- Correspondence: (K.P.T.); (K.H.)
| | - Klaus Heese
- Graduate School of Biomedical Science and Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 133-791, Korea
- Correspondence: (K.P.T.); (K.H.)
| |
Collapse
|
29
|
Sun X, Su X. Harnessing the knowledge of protein secretion for enhanced protein production in filamentous fungi. World J Microbiol Biotechnol 2019; 35:54. [PMID: 30900052 DOI: 10.1007/s11274-019-2630-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 03/08/2019] [Indexed: 12/19/2022]
Abstract
Filamentous fungi are important microorganisms used in industrial production of proteins and enzymes. Among these organisms, Trichoderma reesei, Aspergilli, and more recently Myceliophthora thermophile are the most widely used and promising ones which have powerful protein secretion capability. In recent years, there have been tremendous achievements in understanding the molecular mechanisms of the secretory pathways in filamentous fungi. The acquired pieces of knowledge can be harnessed to enhance protein production in filamentous fungi with assistance of state-of-the-art genetic engineering techniques.
Collapse
Affiliation(s)
- Xianhua Sun
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, No. 12 South Zhongguancun Street, Beijing, 100081, China
| | - Xiaoyun Su
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, No. 12 South Zhongguancun Street, Beijing, 100081, China.
| |
Collapse
|
30
|
Abstract
The unfolded protein response (UPR) responds to the build-up of misfolded proteins in the endoplasmic reticulum. The UPR has wide-ranging functions from fungal pathogenesis to applications in biotechnology. The UPR is regulated through the splicing of an unconventional intron in the HAC1 gene. This intron has been described in many fungal species and is of variable length. Until now it was believed that some members of the CTG-Ser1 clade such as C. parapsilosis did not contain an intron in HAC1, suggesting that the UPR was regulated in a different manner. Here we demonstrate that HAC1 plays an important role in regulating the UPR in C. parapsilosis. We also identified an unusually long intron (626 bp) in C. parapsilosisHAC1. Further analysis showed that HAC1 orthologs in several species in the CTG-Ser1 clade contain long introns. The unfolded protein response (UPR) in the endoplasmic reticulum (ER) is well conserved in eukaryotes from metazoa to yeast. The transcription factor HAC1 is a major regulator of the UPR in many eukaryotes. Deleting HAC1 in the yeast Candida parapsilosis rendered cells more sensitive to DTT, a known inducer of the UPR. The deletion strain was also sensitive to Congo red, calcofluor white, and the antifungal drug ketoconazole, indicating that HAC1 has a role in cell wall maintenance. Transcriptomic analysis revealed that treatment of the wild type with DTT resulted in the increased expression of 368 genes. Comparison with mutant cells treated with DTT reveals that expression of 137 of these genes requires HAC1. Enriched GO term analysis includes response to ER stress, cell wall biogenesis and glycosylation. Orthologs of many of these are associated with UPR in Saccharomyces cerevisiae and Candida albicans. Unconventional splicing of an intron from HAC1 mRNA is required to produce a functional transcription factor. The spliced intron varies in length from 19 bases in C. albicans to 379 bases in Candida glabrata, but has not been previously identified in Candida parapsilosis and related species. We used RNA-seq data and in silico analysis to identify the HAC1 intron in 12 species in the CTG-Ser1 clade. We show that the intron has undergone major contractions and expansions in this clade, reaching up to 848 bases. Exposure to DTT induced splicing of the long intron in C. parapsilosisHAC1, inducing the UPR. IMPORTANCE The unfolded protein response (UPR) responds to the build-up of misfolded proteins in the endoplasmic reticulum. The UPR has wide-ranging functions from fungal pathogenesis to applications in biotechnology. The UPR is regulated through the splicing of an unconventional intron in the HAC1 gene. This intron has been described in many fungal species and is of variable length. Until now it was believed that some members of the CTG-Ser1 clade such as C. parapsilosis did not contain an intron in HAC1, suggesting that the UPR was regulated in a different manner. Here we demonstrate that HAC1 plays an important role in regulating the UPR in C. parapsilosis. We also identified an unusually long intron (626 bp) in C. parapsilosisHAC1. Further analysis showed that HAC1 orthologs in several species in the CTG-Ser1 clade contain long introns.
Collapse
|
31
|
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.
Collapse
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.
| |
Collapse
|
32
|
Gao F, Hao Z, Sun X, Qin L, Zhao T, Liu W, Luo H, Yao B, Su X. A versatile system for fast screening and isolation of Trichoderma reesei cellulase hyperproducers based on DsRed and fluorescence-assisted cell sorting. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:261. [PMID: 30258495 PMCID: PMC6151939 DOI: 10.1186/s13068-018-1264-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 09/19/2018] [Indexed: 05/16/2023]
Abstract
BACKGROUND In the biofuel industry, cellulase plays an indispensable role in hydrolyzing cellulose into fermentable glucose. Trichoderma reesei is a popular filamentous fungus with prominent ability to produce cellulase. While classical mutagenesis and modern multiplex genome engineering are both effective ways to improve cellulase production, successful obtaining of strains with improved cellulase-producing ability requires screening a large number of strains, which is time-consuming and labor intensive. RESULTS Herein, we developed a versatile method coupling expression of the red fluorescence protein (DsRed) in T. reesei and fluorescence-assisted cell sorting (FACS) of germinated spores. This method was first established by expressing DsRed intracellularly under the control of the major cellulase cbh1 promoter in T. reesei, which allowed us to rapidly isolate cellulase hyperproducers from T. reesei progenies transformed with a dedicated transcriptional activator ace3 and from an atmospheric and room temperature plasma-created mutant T. reesei library. Since intracellularly expressed DsRed was expected to isolate mutations mainly affecting cellulase transcription, this method was further improved by displaying DsRed on the T. reesei cell surface, enabling isolation of strains with beneficial genetic alterations (overexpressing hac1 and bip1) affecting regulatory stages beyond transcription. Using this method, T. reesei cellulase hyperproducers were also successfully isolated from an Agrobacterium-mediated random insertional mutant library. CONCLUSIONS The coupled DsRed-FACS high-throughput screening method proved to be an effective strategy for fast isolation of T. reesei cellulase hyperproducers and could also be applied in other industrially important filamentous fungi.
Collapse
Affiliation(s)
- Fei Gao
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, No. 12 South Zhongguancun Street, Beijing, 100081 People’s Republic of China
- College of Biological Sciences, China Agricultural University, Beijing, 100193 China
| | - Zhenzhen Hao
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, No. 12 South Zhongguancun Street, Beijing, 100081 People’s Republic of China
| | - Xianhua Sun
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, No. 12 South Zhongguancun Street, Beijing, 100081 People’s Republic of China
| | - Lina Qin
- Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101 China
| | - Tong Zhao
- Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101 China
| | - Weiquan Liu
- College of Biological Sciences, China Agricultural University, Beijing, 100193 China
| | - Huiying Luo
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, No. 12 South Zhongguancun Street, Beijing, 100081 People’s Republic of China
| | - Bin Yao
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, No. 12 South Zhongguancun Street, Beijing, 100081 People’s Republic of China
| | - Xiaoyun Su
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, No. 12 South Zhongguancun Street, Beijing, 100081 People’s Republic of China
| |
Collapse
|