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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.
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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.
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2
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Duque EDY, Aguirre M, Hood NC, Hood EE. Specific activity and utility of recombinant cellobiohydrolase II (Cel6A) produced in maize endosperm. Transgenic Res 2024; 33:47-57. [PMID: 38451380 DOI: 10.1007/s11248-024-00376-y] [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: 11/13/2023] [Accepted: 02/09/2024] [Indexed: 03/08/2024]
Abstract
Cellobiohydrolase II (CBH II) is an exo-glucanase that is part of a fungal mixture of enzymes from a wood-rot fungus, Trichoderma reesei. It is therefore difficult to purify and to establish a specific activity assay. The gene for this enzyme, driven by the rice Os glutelin promoter, was transformed into High II tissue culture competent corn, and the enzyme accumulated in the endosperm of the seed. The transgenic line recovered from tissue culture was bred into male and female elite Stine inbred corn lines, stiff stalk 16083-025 (female) and Lancaster MSO411 (male), for future production in their hybrid. The enzyme increases its accumulation throughout its 6 generations of back crosses, 27-266-fold between T1 and T2, and 2-10-fold between T2 and T3 generations with lesser increases in T4-T6. The germplasm of the inbred lines replaces the tissue culture corn variety germplasm with each generation, with the ultimate goal of producing a high-yielding hybrid with the transgene. The CBH II enzyme was purified from T5 inbred male grain 10-fold to homogeneity with 47.5% recovery. The specific activity was determined to be 1.544 units per µg protein. The corn-derived CBH II works in biopolishing of cotton by removing surface fibers to improve dyeability and increasing glucose from corn flour for increasing ethanol yield from starch-based first-generation processes.
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Affiliation(s)
- Enio Duque Y Duque
- GreenLab, Inc, 504 University Loop West, Suite 130F, Jonesboro, AR, 72401, USA
| | - Milena Aguirre
- GreenLab, Inc, 504 University Loop West, Suite 130F, Jonesboro, AR, 72401, USA
| | - Nathan C Hood
- GreenLab, Inc, 504 University Loop West, Suite 130F, Jonesboro, AR, 72401, USA
| | - Elizabeth E Hood
- GreenLab, Inc, 504 University Loop West, Suite 130F, Jonesboro, AR, 72401, USA.
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Luu XC, Shida Y, Suzuki Y, Kuwahara D, Fujimoto T, Takahashi Y, Sato N, Nakamura A, Ogasawara W. Ultrahigh-throughput screening of Trichoderma reesei strains capable of carbon catabolite repression release and cellulase hyperproduction using a microfluidic droplet platform. Biosci Biotechnol Biochem 2023; 87:1393-1406. [PMID: 37550222 DOI: 10.1093/bbb/zbad108] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 07/28/2023] [Indexed: 08/09/2023]
Abstract
Trichoderma reesei is the most well-known cellulase producer in the biorefinery industry. Its cellulase biosynthesis is repressed by glucose via carbon catabolite repression (CCR), making CCR-releasing strains with cellulase hyperproduction desirable. Here, we employed a microfluidic droplet platform to culture and screen T. reesei mutants capable of CCR release and cellulase overproduction from extensive mutagenesis libraries. With 3 mutagenesis rounds, about 6.20 × 103 droplets were sorted from a population of 1.51 × 106 droplets in a period of 4.4 h; 76 recovery mutants were screened on flask fermentation, and 2 glucose uptake retarded mutants, MG-9-3 and MG-9-3-30, were eventually isolated. We also generated a hypercellulase producer, M-5, with CCR release via a single mutagenesis round. The hyphal morphology and molecular mechanisms in the mutants were analyzed. This versatile approach combined with a comprehensive understanding of CCR release mechanisms will provide innovative and effective strategies for low-cost cellulase production.
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Affiliation(s)
- Xuan Chinh Luu
- Department of Science of Technology Innovation, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata, Japan
| | - Yosuke Shida
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata, Japan
| | - Yoshiyuki Suzuki
- Department of Science of Technology Innovation, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata, Japan
| | - Daiki Kuwahara
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata, Japan
| | - Takeshi Fujimoto
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata, Japan
| | - Yuka Takahashi
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata, Japan
| | - Naomi Sato
- Department of Science of Technology Innovation, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata, Japan
| | - Akihiro Nakamura
- Department of Science of Technology Innovation, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata, Japan
| | - Wataru Ogasawara
- Department of Science of Technology Innovation, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata, Japan
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata, Japan
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MacCready JS, Roggenkamp EM, Gdanetz K, Chilvers MI. Elucidating the Obligate Nature and Biological Capacity of an Invasive Fungal Corn Pathogen. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2023; 36:411-424. [PMID: 36853195 DOI: 10.1094/mpmi-10-22-0213-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Tar spot is a devasting corn disease caused by the obligate fungal pathogen Phyllachora maydis. Since its initial identification in the United States in 2015, P. maydis has become an increasing threat to corn production. Despite this, P. maydis has remained largely understudied at the molecular level, due to difficulties surrounding its obligate lifestyle. Here, we generated a significantly improved P. maydis nuclear and mitochondrial genome, using a combination of long- and short-read technologies, and also provide the first transcriptomic analysis of primary tar spot lesions. Our results show that P. maydis is deficient in inorganic nitrogen utilization, is likely heterothallic, and encodes for significantly more protein-coding genes, including secreted enzymes and effectors, than previous determined. Furthermore, our expression analysis suggests that, following primary tar spot lesion formation, P. maydis might reroute carbon flux away from DNA replication and cell division pathways and towards pathways previously implicated in having significant roles in pathogenicity, such as autophagy and secretion. Together, our results identified several highly expressed unique secreted factors that likely contribute to host recognition and subsequent infection, greatly increasing our knowledge of the biological capacity of P. maydis, which have much broader implications for mitigating tar spot of corn. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Joshua S MacCready
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, U.S.A
| | - Emily M Roggenkamp
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, U.S.A
| | - Kristi Gdanetz
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, U.S.A
| | - Martin I Chilvers
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, U.S.A
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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: 0] [Impact Index Per Article: 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.
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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.
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Subramanian V, Farmer SJ, Heiland KL, Moore KT, Wall TAV, Sun W, Chaudhari YB, Himmel ME, Decker SR. A multi-plex protein expression system for production of complex enzyme formulations in Trichoderma reesei. J Ind Microbiol Biotechnol 2022; 49:6895550. [PMID: 36513366 PMCID: PMC9923369 DOI: 10.1093/jimb/kuac027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 12/08/2022] [Indexed: 12/15/2022]
Abstract
Heterologous protein production has been challenging in the hyper-cellulolytic fungus, Trichoderma reesei as the species is known for poor transformation efficiency, low homologous recombination frequency, and marginal screening systems for the identification of successful transformants. We have applied the 2A-peptide multi-gene expression system to co-express four proteins, which include three cellulases: a cellobiohydrolase (CBH1), an endoglucanase (EG1), and a β-D-glucosidase (BGL1), as well as the enhanced green fluorescent protein (eGFP) marker protein. We designed a new chassis vector, pTrEno-4X-2A, for this work. Expression of these cellulase enzymes was confirmed by real-time quantitative reverse transcription PCR and immunoblot analysis. The activity of each cellulase was assessed using chromogenic substrates, which confirmed the functionality of the enzymes. Expression and activity of these enzymes were proportional to the level of eGFP fluorescence, thereby validating the reliability of this screening technique. An 18-fold differencein protein expression was observed between the first and third genes within the 2A-peptide construct. The availability of this new multi-gene expression and screening tool is expected to greatly impact multi-enzyme applications, such as the production of complex commercial enzyme formulations and metabolic pathway enzymes, especially those destined for cell-free applications.
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Affiliation(s)
| | - Samuel J Farmer
- Biosciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
| | - Kelsey L Heiland
- Biosciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
| | - Kyle T Moore
- Biosciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
| | - Todd A Vander Wall
- Biosciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
| | - Weiman Sun
- Biosciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
| | - Yogesh B Chaudhari
- Biosciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA,Biodiversity and Ecosystem Research, Institute of Advanced Study in Science and Technology (IASST), Guwahati 781035, India
| | - Michael E Himmel
- Biosciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
| | - Stephen R Decker
- Biosciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
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Wang H, Pang AP, Wang W, Li B, Li C, Wu FG, Lin F. Discovery of ER-localized sugar transporters for cellulase production with lac1 being essential. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:132. [PMID: 36443855 PMCID: PMC9706901 DOI: 10.1186/s13068-022-02230-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 11/12/2022] [Indexed: 11/30/2022]
Abstract
BACKGROUND In the process of cellulose hydrolysis, carbohydrate hydrolysates are transported into cells through membrane transporters, and then affect the expression of cellulase-encoding genes. Sugar transporters play a crucial role in cellulase production in lignocellulolytic fungi, of which relatively few have been functionally validated to date and are all reported to be on cell membrane. RESULT Through transcriptome analysis and qRT-PCR, three putative MFS sugar transporters GST, MFS, and LAC1 were found to display significantly higher mRNA levels in T. reesei grown on cellulose than on glucose. The individual deletion of these three genes compromised cellulase production and delayed sugar absorption by 24 h in T. reesei. Nevertheless, they transported pretty low level of sugars, including galactose, lactose, and mannose, and did not transport glucose, when expressed in yeast system. Meanwhile, all three transporters were unexpectedly found to be intracellular, being located in endoplasmic reticulum (ER). Particularly, the knockout of lac1 almost abolished cellulase production, and significantly inhibited biomass generation regardless of sugar types, indicating that lac1 is essential for cellulase production and biomass formation. The absence of lac1 upregulated genes involved in ribosome biogenesis, while downregulated genes in cellulase production, protein processing in ER (particularly protein glycosylation), and lipid biosynthesis. The inhibition of lac1 deletion on the transcriptional levels of genes related to cellulase biosynthesis was restored after 72 h, but the cellulase production was still inhibited, indicating lac1 might pose a post-transcription regulation on cellulase production that are independent on the known cellulase regulation mediated by CRT1 and XYR1. CONCLUSION For the first time, intracellular sugar transporters (mfs, gst, and lac1) facilitating cellulase production were identified, which was distributed in ER. Their sugar transporting ability was very weak, indicating that they might be related to sugar utilization inside cells rather than the cellular sugar uptake. More importantly, sugar transporter lac1 is first found to be essential for cellulase production and biomass formation by affecting protein processing in ER (particularly protein glycosylation) and lipid biosynthesis. The effect of LAC1 on cellulase production seems to be post-transcriptional at late stage of cellulase production, independent on the well-known cellulase regulation mediated by CRT1 and XYR1. These findings improve the understanding of intracellular sugar transporters in fungi and their important role in cellulase synthesis.
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Affiliation(s)
- Haiyan Wang
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
| | - Ai-Ping Pang
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
| | - Wei Wang
- State Key Lab of Bioreactor Engineering, New World Institute of Biotechnology, East China University of Science and Technology, Shanghai, China
| | - Bingzhi Li
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
| | - Chengcheng Li
- School of Light Ind. & Food Sci. and Joint International Research Lab of Lignocellulosic Functional Materials, Nanjing Forestry University, Nanjing, 210037, China
| | - Fu-Gen Wu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
| | - Fengming Lin
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China.
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MtTRC-1, a Novel Transcription Factor, Regulates Cellulase Production via Directly Modulating the Genes Expression of the Mthac-1 and Mtcbh-1 in Myceliophthora thermophila. Appl Environ Microbiol 2022; 88:e0126322. [PMID: 36165620 PMCID: PMC9552611 DOI: 10.1128/aem.01263-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
The thermophilic fungus Myceliophthora thermophila has been used to produce industrial enzymes and biobased chemicals. In saprotrophic fungi, the mechanisms regulating cellulase production have been studied, which revealed the involvement of multiple transcription factors. However, in M. thermophila, the transcription factors influencing cellulase gene expression and secretion remain largely unknown. In this study, we identified and characterized a novel cellulase regulator (MtTRC-1) in M. thermophila through a combination of functional genomics and genetic analyses. Deletion of Mttrc-1 resulted in significantly decreased cellulase production and activities. Transcriptome analysis revealed downregulation of not only the encoding genes of main cellulases but also the transcriptional regulator MtHAC-1 of UPR pathway after disruption of MtTRC-1 under cellulolytic induction conditions. Herein, we also characterized the ortholog of the yeast HAC1p in M. thermophila. We show that Mthac-1 mRNA undergoes an endoplasmic reticulum (ER) stress-induced splicing by removing a 23-nucleotide (nt) intron. Notably, the protein secretion on cellulose was dramatically impaired by the deletion of MtHAC-1. Moreover, the colonial growth on various carbon sources was defective in the absence of MtHAC-1. Electrophoretic mobility shift assays and chromatin immunoprecipitation assays verified MtTRC-1 regulates the transcription of Mthac-1 and the major cellulase gene Mtcbh-1 by binding directly to the promoters in vitro and in vivo. Furthermore, DNase I footprinting assays identified the putative consensus binding site (5′-GNG/C-3′). These results revealed the importance of MtTRC-1 for positively regulating cellulase production. This finding has clarified the complex regulatory pathways involved in cellulolytic enzyme production. IMPORTANCE In the present study, we characterized a novel regulator MtTRC-1 in M. thermophila, which regulated cellulase production through direct transcriptional regulation of the Mthac-1 and Mtcbh-1 genes. Our data demonstrated that MtHAC-1 is a key factor for the cellulase secretion capacity of M. thermophila. Our data indicate that this thermophilic fungus regulates cellulase production through a multilevels network, in which the protein secretory pathway is modulated by MtHAC-1-dependent UPR pathway and the cellulase gene expression is directly regulated in parallel by transcription factors. The conservation of Mttrc1 in filamentous fungi suggests this mechanism may be exploited to engineer filamentous fungal cell factories capable of producing proteins on an industrial scale.
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Chai S, Zhu Z, Tian E, Xiao M, Wang Y, Zou G, Zhou Z. Building a Versatile Protein Production Platform Using Engineered Trichoderma reesei. ACS Synth Biol 2022; 11:486-496. [PMID: 34928572 DOI: 10.1021/acssynbio.1c00570] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Trichoderma reesei has an extremely high capacity for synthesizing and secreting proteins, thus exhibiting promise as an expression platform for heterologous proteins. However, T. reesei secretes large amounts of native proteins, which hinders its widespread application for heterologous protein production. Here, we designed and built a series of T. reesei chassis using an iterative gene deletion approach based on an efficient genome editing system. Donor DNAs with specially designed construct facilitated screening of positive deletion strains without ectopic insertion. Finally, marker-free T. reesei chassis with lower rates of native protein secretion and low levels of extracellular protease activity were constructed after 11 consecutive rounds of gene deletion. Higher production levels of three heterologous proteins─a bacterial xylanase XYL7, a fungal immunomodulatory protein LZ8, and the human serum albumin HSA─were achieved with these chassis using the cbh1 promoter. It is possible that diverse high-value proteins might be produced at a high yield using this engineered platform.
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Affiliation(s)
- Shunxing Chai
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Rd, Shanghai 200032, China
- University of Chinese Academy of Sciences, 19(A) Yuquan Rd, Beijing 100049, China
| | - Zhihua Zhu
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Rd, Shanghai 200032, China
- University of Chinese Academy of Sciences, 19(A) Yuquan Rd, Beijing 100049, China
| | - Ernuo Tian
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Rd, Shanghai 200032, China
| | - Meili Xiao
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Rd, Shanghai 200032, China
- University of Chinese Academy of Sciences, 19(A) Yuquan Rd, Beijing 100049, China
| | - Yan Wang
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Rd, Shanghai 200032, China
| | - Gen Zou
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Rd, Shanghai 200032, China
- Shanghai Key Laboratory of Agricultural Genetics and Breeding, Institute of Edible Fungi, Shanghai Academy of Agricultural Sciences, 1000 Jinqi Rd, Shanghai 201403, China
| | - Zhihua Zhou
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Rd, Shanghai 200032, China
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Zhang W, Guo J, Wu X, Ren Y, Li C, Meng X, Liu W. Reformulating the Hydrolytic Enzyme Cocktail of Trichoderma reesei by Combining XYR1 Overexpression and Elimination of Four Major Cellulases to Improve Saccharification of Corn Fiber. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:211-222. [PMID: 34935374 DOI: 10.1021/acs.jafc.1c05946] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The industrial fungus Trichoderma reesei has an outstanding capability of secreting an enzyme cocktail comprising multiple plant biomass-degrading enzymes. Herein, the overexpression of XYR1, the master transactivator controlling (hemi)cellulase gene expression, was performed in T. reesei lacking four main cellulase-encoding genes. The resultant strain Δ4celOExyr1 was able to produce a dramatically different profile of secretory proteins on soluble glucose or lactose compared with that of the wild-type T. reesei. The Δ4celOExyr1 secretome included cellulases EGIII and BGLI as well as several hemicellulases and nonhydrolytic cellulose degradation-associated proteins that are not preferentially induced in the wild-type T. reesei strain. Δ4celOExyr1 produced a significant amount of α-arabinofuranosidase I on lactose, and the crude enzyme cocktail of Δ4celOExyr1 not only released a considerable quantity of glucose but also exhibited remarkable performance in the hydrolytic release of xylose, arabinose, and mannose from un-pretreated corn fiber. These results showed that the engineered T. reesei strain holds great potential for improving the saccharification efficiency of the hemicellulosic constituents within corn fiber.
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Affiliation(s)
- Weixin Zhang
- State Key Laboratory of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao 266237, P. R. China
| | - Junqi Guo
- State Key Laboratory of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao 266237, P. R. China
| | - Xiaoxiao Wu
- State Key Laboratory of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao 266237, P. R. China
| | - Yajing Ren
- State Key Laboratory of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao 266237, P. R. China
| | - Chunyan Li
- State Key Laboratory of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao 266237, P. R. China
| | - Xiangfeng Meng
- State Key Laboratory of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao 266237, P. R. China
| | - Weifeng Liu
- State Key Laboratory of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao 266237, P. R. China
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Li XH, Peng YJ, Ding JL, Feng MG, Ying SH. A homologue of yeast acyl-CoA synthetase Faa1 contributes to cytomembrane functionality involved in development and virulence in the insect pathogenic fungus Beauveria bassiana. Microb Pathog 2022; 164:105419. [DOI: 10.1016/j.micpath.2022.105419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 01/21/2022] [Accepted: 01/21/2022] [Indexed: 10/19/2022]
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Pragya, Sharma KK, Kumar A, Singh D, Kumar V, Singh B. Immobilized phytases: an overview of different strategies, support material, and their applications in improving food and feed nutrition. Crit Rev Food Sci Nutr 2021; 63:5465-5487. [PMID: 34965785 DOI: 10.1080/10408398.2021.2020719] [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] [Indexed: 10/19/2022]
Abstract
Phytases are the most widely used food and feed enzymes, which aid in nutritional improvement by reducing anti-nutritional factor. Despite the benefits, enzymes usage in the industry is restricted by several factors such as their short life-span and poor reusability, which result in high costs for large-scale utilization at commercial scale. Furthermore, under pelleting conditions such as high temperatures, pH, and other factors, the enzyme becomes inactive due to lesser stability. Immobilization of phytases has been suggested as a way to overcome these limitations with improved performance. Matrices used to immobilize phytases include inorganic (Hydroxypatite, zeolite, and silica), organic (Polyacrylamide, epoxy resins, alginate, chitosan, and starch agar), soluble matrix (Polyvinyl alcohol), and nanomaterials including nanoparticles, nanofibers, nanotubes. Several surface analysis methods, including thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), and FTIR analysis, have been used to characterize immobilized phytase. Immobilized phytases have been used in a broad range of biotechnological applications such as animal feed, biodegradation of food phytates, preparations of myo-inositol phosphates, and sulfoxidation by vanadate-substituted peroxidase. This article provides information on different matrices used for phytase immobilization from the last two decades, including the process of immobilization and support material, surface analysis techniques, and multifarious biotechnological applications of the immobilized phytases.
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Affiliation(s)
- Pragya
- Laboratory of Bioprocess Technology, Department of Microbiology, Maharshi Dayanand University, Rohtak, India
| | - Krishna Kant Sharma
- Laboratory of Enzymology and Recombinant DNA Technology, Department of Microbiology, Maharshi Dayanand University, Rohtak, India
| | - Anil Kumar
- Department of Botany, Pt. N.R.S. Govt. College, Rohtak, India
| | - Davender Singh
- Department of Physics, RPS Degree College, Mahendergarh, India
| | - Vijay Kumar
- Department of Botany, Shivaji College, University of Delhi, New Delhi, India
| | - Bijender Singh
- Laboratory of Bioprocess Technology, Department of Microbiology, Maharshi Dayanand University, Rohtak, India
- Department of Biotechnology, Central University of Haryana, Jant-Pali, India
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Fuchs T, Melcher F, Rerop ZS, Lorenzen J, Shaigani P, Awad D, Haack M, Prem SA, Masri M, Mehlmer N, Brueck TB. Identifying carbohydrate-active enzymes of Cutaneotrichosporon oleaginosus using systems biology. Microb Cell Fact 2021; 20:205. [PMID: 34711240 PMCID: PMC8555327 DOI: 10.1186/s12934-021-01692-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 10/05/2021] [Indexed: 11/30/2022] Open
Abstract
Background The oleaginous yeast Cutaneotrichosporon oleaginosus represents one of the most promising microbial platforms for resource-efficient and scalable lipid production, with the capacity to accept a wide range of carbohydrates encapsulated in complex biomass waste or lignocellulosic hydrolysates. Currently, data related to molecular aspects of the metabolic utilisation of oligomeric carbohydrates are sparse. In addition, comprehensive proteomic information for C. oleaginosus focusing on carbohydrate metabolism is not available. Results In this study, we conducted a systematic analysis of carbohydrate intake and utilisation by C. oleaginosus and investigated the influence of different di- and trisaccharide as carbon sources. Changes in the cellular growth and morphology could be observed, depending on the selected carbon source. The greatest changes in morphology were observed in media containing trehalose. A comprehensive proteomic analysis of secreted, cell wall-associated, and cytoplasmatic proteins was performed, which highlighted differences in the composition and quantity of secreted proteins, when grown on different disaccharides. Based on the proteomic data, we performed a relative quantitative analysis of the identified proteins (using glucose as the reference carbon source) and observed carbohydrate-specific protein distributions. When using cellobiose or lactose as the carbon source, we detected three- and five-fold higher diversity in terms of the respective hydrolases released. Furthermore, the analysis of the secreted enzymes enabled identification of the motif with the consensus sequence LALL[LA]L[LA][LA]AAAAAAA as a potential signal peptide. Conclusions Relative quantification of spectral intensities from crude proteomic datasets enabled the identification of new enzymes and provided new insights into protein secretion, as well as the molecular mechanisms of carbo-hydrolases involved in the cleavage of the selected carbon oligomers. These insights can help unlock new substrate sources for C. oleaginosus, such as low-cost by-products containing difficult to utilize carbohydrates. In addition, information regarding the carbo-hydrolytic potential of C. oleaginosus facilitates a more precise engineering approach when using targeted genetic approaches. This information could be used to find new and more cost-effective carbon sources for microbial lipid production by the oleaginous yeast C. oleaginosus. Supplementary Information The online version contains supplementary material available at 10.1186/s12934-021-01692-2.
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Affiliation(s)
- Tobias Fuchs
- Werner Siemens-Chair of Synthetic Biotechnology (WSSB), Technical University of Munich, Lichtenbergstraße 4, 85748, Garching, Germany
| | - Felix Melcher
- Werner Siemens-Chair of Synthetic Biotechnology (WSSB), Technical University of Munich, Lichtenbergstraße 4, 85748, Garching, Germany
| | - Zora Selina Rerop
- Werner Siemens-Chair of Synthetic Biotechnology (WSSB), Technical University of Munich, Lichtenbergstraße 4, 85748, Garching, Germany
| | - Jan Lorenzen
- Werner Siemens-Chair of Synthetic Biotechnology (WSSB), Technical University of Munich, Lichtenbergstraße 4, 85748, Garching, Germany
| | - Pariya Shaigani
- Werner Siemens-Chair of Synthetic Biotechnology (WSSB), Technical University of Munich, Lichtenbergstraße 4, 85748, Garching, Germany
| | - Dania Awad
- Werner Siemens-Chair of Synthetic Biotechnology (WSSB), Technical University of Munich, Lichtenbergstraße 4, 85748, Garching, Germany
| | - Martina Haack
- Werner Siemens-Chair of Synthetic Biotechnology (WSSB), Technical University of Munich, Lichtenbergstraße 4, 85748, Garching, Germany
| | - Sophia Alice Prem
- Werner Siemens-Chair of Synthetic Biotechnology (WSSB), Technical University of Munich, Lichtenbergstraße 4, 85748, Garching, Germany
| | - Mahmoud Masri
- Werner Siemens-Chair of Synthetic Biotechnology (WSSB), Technical University of Munich, Lichtenbergstraße 4, 85748, Garching, Germany
| | - Norbert Mehlmer
- Werner Siemens-Chair of Synthetic Biotechnology (WSSB), Technical University of Munich, Lichtenbergstraße 4, 85748, Garching, Germany.
| | - Thomas B Brueck
- Werner Siemens-Chair of Synthetic Biotechnology (WSSB), Technical University of Munich, Lichtenbergstraße 4, 85748, Garching, Germany.
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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.
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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.
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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: 8] [Impact Index Per Article: 2.7] [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.
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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.
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Primerano P, Juric M, Mach R, Mach-Aigner A, Derntl C. Expanding the toolbox: another auxotrophic marker for targeted gene integrations in Trichoderma reesei. Fungal Biol Biotechnol 2021; 8:9. [PMID: 34521467 PMCID: PMC8442374 DOI: 10.1186/s40694-021-00116-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 09/06/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The filamentous ascomycete Trichoderma reesei is used for the industrial production of cellulases and holds the promise for heterologous gene expression due to its outstandingly high protein secretion rates and its long-term application in industry and science. A prerequisite for successful heterologous gene expression is the ability to insert a corresponding expression cassette at suitable loci in the genome of T. reesei. RESULTS In this study, we test and demonstrate the applicability of the his1 gene [encoding for the ATP phosphoribosyltransferase (EC 2.4.2.17), part of the histidine biosynthesis pathway] and locus for targeted gene insertion. Deletion of the his1 promoter and a part of the coding region leads to histidine auxotrophy. Reestablishment of the his1 locus restores prototrophy. We designed a matching plasmid that allows integration of an expression cassette at the his1 locus. This is demonstrated by the usage of the reporter EYFP (enhanced yellow fluorescence protein). Further, we describe a minimal effort and seamless marker recycling method. Finally, we test the influence of the integration site on the gene expression by comparing three strains bearing the same EYFP expression construct at different loci. CONCLUSION With the establishment of his1 as integration locus and auxotrophic marker, we could expand the toolbox for strain design in T. reesei. This facilitates future strain constructions with the aim of heterologous gene expression.
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Affiliation(s)
- Paul Primerano
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Strasse 1a, 1060 Wien, Austria
| | - Melani Juric
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Strasse 1a, 1060 Wien, Austria
| | - Robert Mach
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Strasse 1a, 1060 Wien, Austria
| | - Astrid 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
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Fang H, Li C, Zhao J, Zhao C. Biotechnological Advances and Trends in Engineering Trichoderma reesei towards Cellulase Hyperproducer. BIOTECHNOL BIOPROC E 2021. [DOI: 10.1007/s12257-020-0243-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Sukumaran RK, Christopher M, Kooloth-Valappil P, Sreeja-Raju A, Mathew RM, Sankar M, Puthiyamadam A, Adarsh VP, Aswathi A, Rebinro V, Abraham A, Pandey A. Addressing challenges in production of cellulases for biomass hydrolysis: Targeted interventions into the genetics of cellulase producing fungi. BIORESOURCE TECHNOLOGY 2021; 329:124746. [PMID: 33610429 DOI: 10.1016/j.biortech.2021.124746] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 01/12/2021] [Accepted: 01/15/2021] [Indexed: 06/12/2023]
Abstract
Lignocellulosic materials are the favoured feedstock for biorefineries due to their abundant availability and non-completion with food. Biobased technologies for refining these materials are limited mainly by the cost of biomass hydrolyzing enzymes, typically sourced from filamentous fungi. Therefore, considerable efforts have been directed at improving the quantity and quality of secreted lignocellulose degrading enzymes from fungi in order to attain overall economic viability. Process improvements and media engineering probably have reached their thresholds and further production enhancements require modifying the fungal metabolism to improve production and secretion of these enzymes. This review focusses on the types and mechanisms of action of known fungal biomass degrading enzymes, our current understanding of the genetic control exerted on their expression, and possible routes for intervention, especially on modulating catabolite repression, transcriptional regulators, signal transduction, secretion pathways etc., in order to improve enzyme productivity, activity and stability.
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Affiliation(s)
- Rajeev K Sukumaran
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India.
| | - Meera Christopher
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - Prajeesh Kooloth-Valappil
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - AthiraRaj Sreeja-Raju
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - Reshma M Mathew
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - Meena Sankar
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - Anoop Puthiyamadam
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India
| | - Velayudhanpillai-Prasannakumari Adarsh
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India
| | - Aswathi Aswathi
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - Valan Rebinro
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India
| | - Amith Abraham
- Department of Chemical Engineering, Hanyang University, Seoul, Republic of Korea
| | - Ashok Pandey
- Centre for Innovation and Translational Research, CSIR-Indian Institute of Toxicology Research, Lucknow, India
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Lin MC, Kuo HW, Kao MR, Lin WD, Li CW, Hung KS, Yang SC, Yu SM, Ho THD. From simple and specific zymographic detections to the annotation of a fungus Daldinia caldariorum D263 that encodes a wide range of highly bioactive cellulolytic enzymes. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:120. [PMID: 34020690 PMCID: PMC8140500 DOI: 10.1186/s13068-021-01959-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Accepted: 04/20/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND Lignocellulolytic enzymes are essential for agricultural waste disposal and production of renewable bioenergy. Many commercialized cellulase mixtures have been developed, mostly from saprophytic or endophytic fungal species. The cost of complete cellulose digestion is considerable because a wide range of cellulolytic enzymes is needed. However, most fungi can only produce limited range of highly bioactive cellulolytic enzymes. We aimed to investigate a simple yet specific method for discovering unique enzymes so that fungal species producing a diverse group of cellulolytic enzymes can be identified. RESULTS The culture medium of an endophytic fungus, Daldinia caldariorum D263, contained a complete set of cellulolytic enzymes capable of effectively digesting cellulose residues into glucose. By taking advantage of the unique product inhibition property of β-glucosidases, we have established an improved zymography method that can easily distinguish β-glucosidase and exoglucanase activity. Our zymography method revealed that D263 can secrete a wide range of highly bioactive cellulases. Analyzing the assembled genome of D263, we found over 100 potential genes for cellulolytic enzymes that are distinct from those of the commercially used fungal species Trichoderma reesei and Aspergillus niger. We further identified several of these cellulolytic enzymes by mass spectrometry. CONCLUSIONS The genome of Daldinia caldariorum D263 has been sequenced and annotated taking advantage of a simple yet specific zymography method followed by mass spectrometry analysis, and it appears to encode and secrete a wide range of bioactive cellulolytic enzymes. The genome and cellulolytic enzyme secretion of this unique endophytic fungus should be of value for identifying active cellulolytic enzymes that can facilitate conversion of agricultural wastes to fermentable sugars for the industrial production of biofuels.
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Affiliation(s)
- Meng-Chun Lin
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, ROC
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, ROC
| | - Hsion-Wen Kuo
- Department of Environmental Science and Engineering, Tunghai University, Taichung, Taiwan, ROC
| | - Mu-Rong Kao
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, ROC
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, ROC
| | - Wen-Dar Lin
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, ROC
| | - Chen-Wei Li
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, ROC
| | - Kuo-Sheng Hung
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, ROC
| | - Sheng-Chih Yang
- Institute of Tropical Plant Science, National Cheng Kung University, Tainan, Taiwan, ROC
| | - Su-May Yu
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, ROC
- Biotechnology Research Center, National Chung Hsing University, Taichung, Taiwan, ROC
| | - Tuan-Hua David Ho
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, ROC.
- Biotechnology Research Center, National Chung Hsing University, Taichung, Taiwan, ROC.
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Novy V, Nielsen F, Cullen D, Sabat G, Houtman CJ, Hunt CG. The characteristics of insoluble softwood substrates affect fungal morphology, secretome composition, and hydrolytic efficiency of enzymes produced by Trichoderma reesei. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:105. [PMID: 33902680 PMCID: PMC8074412 DOI: 10.1186/s13068-021-01955-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 04/11/2021] [Indexed: 05/04/2023]
Abstract
BACKGROUND On-site enzyme production using Trichoderma reesei can improve yields and lower the overall cost of lignocellulose saccharification by exploiting the fungal gene regulatory mechanism that enables it to continuously adapt enzyme secretion to the substrate used for cultivation. To harness this, the interrelation between substrate characteristics and fungal response must be understood. However, fungal morphology or gene expression studies often lack structural and chemical substrate characterization. Here, T. reesei QM6a was cultivated on three softwood substrates: northern bleached softwood Kraft pulp (NBSK) and lodgepole pine pretreated either by dilute-acid-catalyzed steam pretreatment (LP-STEX) or mild alkaline oxidation (LP-ALKOX). With different pretreatments of similar starting materials, we presented the fungus with systematically modified substrates. This allowed the elucidation of substrate-induced changes in the fungal response and the testing of the secreted enzymes' hydrolytic strength towards the same substrates. RESULTS Enzyme activity time courses correlated with hemicellulose content and cellulose accessibility. Specifically, increased amounts of side-chain-cleaving hemicellulolytic enzymes in the protein produced on the complex substrates (LP-STEX; LP-ALKOX) was observed by secretome analysis. Confocal laser scanning micrographs showed that fungal micromorphology responded to changes in cellulose accessibility and initial culture viscosity. The latter was caused by surface charge and fiber dimensions, and likely restricted mass transfer, resulting in morphologies of fungi in stress. Supplementing a basic cellulolytic enzyme mixture with concentrated T. reesei supernatant improved saccharification efficiencies of the three substrates, where cellulose, xylan, and mannan conversion was increased by up to 27, 45, and 2800%, respectively. The improvement was most pronounced for proteins produced on LP-STEX and LP-ALKOX on those same substrates, and in the best case, efficiencies reached those of a state-of-the-art commercial enzyme preparation. CONCLUSION Cultivation of T. reesei on LP-STEX and LP-ALKOX produced a protein mixture that increased the hydrolytic strength of a basic cellulase mixture to state-of-the-art performance on softwood substrates. This suggests that the fungal adaptation mechanism can be exploited to achieve enhanced performance in enzymatic hydrolysis without a priori knowledge of specific substrate requirements.
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Affiliation(s)
- Vera Novy
- US Department of Agriculture, Forest Products Laboratory, One Gifford Pinchot Drive, Madison, WI, 53726, USA.
- Department of Biology and Bioengineering, Division of Industrial Biotechnology, Chalmers University of Technology, Kemivägen 10, 412 96, Göteborg, Sweden.
| | - Fredrik Nielsen
- US Department of Agriculture, Forest Products Laboratory, One Gifford Pinchot Drive, Madison, WI, 53726, USA
| | - Daniel Cullen
- US Department of Agriculture, Forest Products Laboratory, One Gifford Pinchot Drive, Madison, WI, 53726, USA
| | - Grzegorz Sabat
- University of Wisconsin Biotechnology Center, Madison, WI, 53706, USA
| | - Carl J Houtman
- US Department of Agriculture, Forest Products Laboratory, One Gifford Pinchot Drive, Madison, WI, 53726, USA
| | - Christopher G Hunt
- US Department of Agriculture, Forest Products Laboratory, One Gifford Pinchot Drive, Madison, WI, 53726, USA
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Wei H, Wu M, Fan A, Su H. Recombinant protein production in the filamentous fungus Trichoderma. Chin J Chem Eng 2021. [DOI: 10.1016/j.cjche.2020.11.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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22
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Deciphering Trichoderma-Plant-Pathogen Interactions for Better Development of Biocontrol Applications. J Fungi (Basel) 2021; 7:jof7010061. [PMID: 33477406 PMCID: PMC7830842 DOI: 10.3390/jof7010061] [Citation(s) in RCA: 72] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 12/31/2020] [Accepted: 01/02/2021] [Indexed: 12/18/2022] Open
Abstract
Members of the fungal genus Trichoderma (Ascomycota, Hypocreales, Hypocreaceae) are ubiquitous and commonly encountered as soil inhabitants, plant symbionts, saprotrophs, and mycoparasites. Certain species have been used to control diverse plant diseases and mitigate negative growth conditions. The versatility of Trichoderma’s interactions mainly relies on their ability to engage in inter- and cross-kingdom interactions. Although Trichoderma is by far the most extensively studied fungal biocontrol agent (BCA), with a few species already having been commercialized as bio-pesticides or bio-fertilizers, their wide application has been hampered by an unpredictable efficacy under field conditions. Deciphering the dialogues within and across Trichoderma ecological interactions by identification of involved effectors and their underlying effect is of great value in order to be able to eventually harness Trichoderma’s full potential for plant growth promotion and protection. In this review, we focus on the nature of Trichoderma interactions with plants and pathogens. Better understanding how Trichoderma interacts with plants, other microorganisms, and the environment is essential for developing and deploying Trichoderma-based strategies that increase crop production and protection.
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Kostyleva EV, Sereda AS, Velikoretskaya IA, Aisina AM, Tsurikova NV, Rubtsova EA, Satrutdinov AD, Sinitsyn AP. Obtainment of a Complex Enzyme Preparation with Enhanced Pectinase Activity Based on the New Mutant Strain T. reesei Co-44. APPL BIOCHEM MICRO+ 2021. [DOI: 10.1134/s0003683821010130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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24
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V. D. dos Santos AC, Heydenreich R, Derntl C, Mach-Aigner AR, Mach RL, Ramer G, Lendl B. Nanoscale Infrared Spectroscopy and Chemometrics Enable Detection of Intracellular Protein Distribution. Anal Chem 2020; 92:15719-15725. [PMID: 33259186 PMCID: PMC7745202 DOI: 10.1021/acs.analchem.0c02228] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 11/16/2020] [Indexed: 02/08/2023]
Abstract
Determination of the intracellular location of proteins is one of the fundamental tasks of microbiology. Conventionally, label-based microscopy and super-resolution techniques are employed. In this work, we demonstrate a new technique that can determine intracellular protein distribution at nanometer spatial resolution. This method combines nanoscale spatial resolution chemical imaging using the photothermal-induced resonance (PTIR) technique with multivariate modeling to reveal the intracellular distribution of cell components. Here, we demonstrate its viability by imaging the distribution of major cellulases and xylanases in Trichoderma reesei using the colocation of a fluorescent label (enhanced yellow fluorescence protein, EYFP) with the target enzymes to calibrate the chemometric model. The obtained partial least squares model successfully shows the distribution of these proteins inside the cell and opens the door for further studies on protein secretion mechanisms using PTIR.
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Affiliation(s)
| | - Rosa Heydenreich
- Institute
of Chemical, Environmental and Bioscience Engineering, TU Wien, Vienna 1060, Austria
| | - Christian Derntl
- Institute
of Chemical, Environmental and Bioscience Engineering, TU Wien, Vienna 1060, Austria
| | - Astrid R. Mach-Aigner
- Institute
of Chemical, Environmental and Bioscience Engineering, TU Wien, Vienna 1060, Austria
| | - Robert L. Mach
- Institute
of Chemical, Environmental and Bioscience Engineering, TU Wien, Vienna 1060, Austria
| | - Georg Ramer
- Institute
of Chemical Technologies and Analytics, TU Wien, Vienna 1060, Austria
| | - Bernhard Lendl
- Institute
of Chemical Technologies and Analytics, TU Wien, Vienna 1060, Austria
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Use of Auxotrophic Markers for Targeted Gene Insertions in Trichoderma reesei. Methods Mol Biol 2020. [PMID: 33165779 DOI: 10.1007/978-1-0716-1048-0_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
In this chapter, we describe a routinely used strategy for targeted gene insertions in Trichoderma reesei using auxotrophic markers. Generally, targeted gene integrations are advantageous over random, ectopic integration, because the copy number and locus of integration are controlled, abolishing the risk of pleiotropic effects. The use of auxotrophic markers allows a direct, cheap, and easy method for selection. The first step is the construction of recipient strains in a NHEJ-deficient strain. We routinely use deletion strains of pyr4, encoding for the orotidine 5'-phosphate decarboxylase (EC 4.1.1.23) and/or asl1, encoding for the argininosuccinate lyase (EC 4.3.2.1). In the second step, the gene of interest is inserted together with the marker gene. Here we describe the necessary strategy for the construction of the recipient strains and insertion constructs, a PEG-mediated transformation protocol, and a protocol for genetic confirmation of the gene insertion.
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Kilaru S, Schuster M, Murray R, Steinberg G. Optimal timing for Agrobacterium-mediated DNA transformation of Trichoderma reesei conidia revealed by live cell imaging. Fungal Genet Biol 2020; 142:103448. [PMID: 32866613 DOI: 10.1016/j.fgb.2020.103448] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/15/2020] [Accepted: 08/20/2020] [Indexed: 11/19/2022]
Abstract
Trichoderma reesei is the foremost fungal producer of enzymes for industrial processes. Here, we use fluorescent live cell imaging of germinating conidia to improve Agrobacterium tumefaciens-mediated transformation (ATMT) efficiency. We define the timing of (a) morphological changes and (b) nuclear reorganisation during initial conidia germination. This reveals that conidia swell for 7 h, during which nuclei undergo 2 non-synchronised mitotic divisions. Histones are recruited to the nucleus during the first 2 h, suggesting that conidia enter S-phase immediately after activation. This correlates with a significantly increased ATMT efficiency at 2 h after germination initiation. This finding promises to improve genetic manipulation efficiency in T. reesei.
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Affiliation(s)
- Sreedhar Kilaru
- School of Biosciences, University of Exeter, Exeter EX4 4QD, UK.
| | - Martin Schuster
- School of Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - Rachael Murray
- School of Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - Gero Steinberg
- School of Biosciences, University of Exeter, Exeter EX4 4QD, UK; University of Utrecht, Padualaan 8, Utrecht 3584 CH, the Netherlands.
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Zhao G, Xu Y, Ouyang H, Luo Y, Sun S, Wang Z, Yang J, Jin C. Protein O-mannosylation affects protein secretion, cell wall integrity and morphogenesis in Trichoderma reesei. Fungal Genet Biol 2020; 144:103440. [PMID: 32758529 DOI: 10.1016/j.fgb.2020.103440] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 07/23/2020] [Accepted: 07/29/2020] [Indexed: 10/23/2022]
Abstract
Protein O-mannosyltransferases (PMTs) initiate O-mannosylation of proteins in the ER. Trichoderma reesei strains displayed a single representative of each PMT subfamily, Trpmt1, Trpmt2 and Trpmt4. In this work, two knockout strains ΔTrpmt1and ΔTrpmt4were obtained. Both mutants showed retarded growth, defective cell walls, reduced conidiation and decreased protein secretion. Additionally, the ΔTrpmt1strain displayed a thermosensitive growth phenotype, while the ΔTrpmt4 strain showed abnormal polarity. Meanwhile, OETrpmt2 strain, in which the Trpmt2 was over-expressed, exhibited increased conidiation, enhanced protein secretion and abnormal polarity. Using a lectin enrichment method and MS/MS analysis, 173 O-glycoproteins, 295 O-glycopeptides and 649 O-mannosylation sites were identified as the targets of PMTs in T. reesei. These identified O-mannoproteins are involved in various physiological processes such as protein folding, sorting, transport, quality control and secretion, as well as cell wall integrity and polarity. By comparing proteins identified in the mutants and its parent strain, the potential specific protein substrates of PMTs were identified. Based on our results, TrPMT1 is specifically involved inO-mannosylation of intracellular soluble proteins and secreted proteins, specially glycosidases. TrPMT2 is involved inO-mannosylation of secreted proteins and GPI-anchor proteins, and TrPMT4 mainly modifies multiple transmembrane proteins. The TrPMT1-TrPMT4 complex is responsible for O-mannosylation of proteins involved in cell wall integrity. Overexpression of TrPMT2 enhances protein secretion, which might be a new strategy to improve expression efficiency in T. reesei.
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Affiliation(s)
- Guangya Zhao
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing, China
| | - Yueqiang Xu
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing, China
| | - Haomiao Ouyang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yuanming Luo
- Public Technology Service Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Shutao Sun
- Public Technology Service Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhongfu Wang
- College of Food Science and Technology, Northwest University, Xi'an 710069, China
| | - Jinghua Yang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Cheng Jin
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing, China; National Engineering Research Center for Non-food Bio-refinery, Guangxi Academy of Sciences, Nanning 530007, Guangxi, China.
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28
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Ladics GS, Han KH, Jang MS, Park H, Marshall V, Dersjant-Li Y, Sewalt VJ. Safety evaluation of a novel variant of consensus bacterial phytase. Toxicol Rep 2020; 7:844-851. [PMID: 32714839 PMCID: PMC7372152 DOI: 10.1016/j.toxrep.2020.07.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 07/09/2020] [Accepted: 07/11/2020] [Indexed: 01/08/2023] Open
Abstract
90-day oral and genetic toxicology studies were conducted on a next generation bacterial biosynthetic 6-phytase as an animal feed additive. No test article-related adverse effects were observed and a NOAEL was established as 1000 mg Total Organic Solids/kg bw/day. A margin of safety value of 1613 was calculated based on the NOAEL and an estimate of broiler feed consumption. Data support the safety of PhyG as an animal feed additive.
A 90-day subchronic oral toxicity study was conducted to evaluate the safety of a consensus bacterial phytase variant 6-phytase (PhyG) for use as an animal feed additive. This phytase is produced by fermentation with a fungal (Trichoderma reesei) production strain expressing a biosynthetic variant of a consensus bacterial phytase gene assembled via ancestral reconstruction with sequence bias for the phytase from Buttiauxella sp. Rats were administered PhyG daily via oral gavage at dose-levels of 0 (distilled water), 250, 500 or 1000 mg total organic solids (TOS)/kg bodyweight (bw)/day (equivalent to 0, 112,500, 225,000 and 450,000 phytase units (FTU)/kg bw/day, respectively). No test article-related adverse effects were observed. A no-observed-adverse-effect level (NOAEL) for PhyG was established as 1000 mg TOS/kg bw/day, the highest test concentration. Based on this NOAEL and an estimate of broiler consumption determined from the proposed inclusion of the phytase in feed at the maximum recommended level (4000 FTU/kg), a margin of safety value of 1613 was calculated. Results of in vitro genotoxicity testing and in silico protein toxin evaluation further confirmed PhyG to be non-genotoxic and not likely to be a protein toxin upon consumption. These data support the safety of PhyG as an animal feed additive.
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Key Words
- BLAST, basic local alignment search tool
- DM, dry matter
- FTU, phytase units
- Genetic toxicology
- IP6, myo-inositol hexaphosphate
- MCP, monocalcium phosphate
- NOAEL
- NOAEL, no-observed-adverse-effect-level
- OECD, The Organisation for Economic Co-operation and Development
- Oral gavage
- Phytase
- SSL, safe strain lineage
- Subchronic study
- TOS, total organic solids
- UFC, ultra-filtered concentrate
- bw, body weight
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Affiliation(s)
- Gregory S Ladics
- DuPont Nutrition and Biosciences, 200 Powder Mill Road, Wilmington, DE, USA
| | - Kang-Hyun Han
- Department of Advanced Toxicology Research, Korea Institute of Toxicology, 141 Gajeong-ro, Yuseong-gu, Daejeon, 34114, Republic of Korea
| | - Min S Jang
- Department of Advanced Toxicology Research, Korea Institute of Toxicology, 141 Gajeong-ro, Yuseong-gu, Daejeon, 34114, Republic of Korea
| | - Heejin Park
- Department of Advanced Toxicology Research, Korea Institute of Toxicology, 141 Gajeong-ro, Yuseong-gu, Daejeon, 34114, Republic of Korea
| | - Valerie Marshall
- DuPont Nutrition and Biosciences, 1501 Larkin Center Drive, Midland, Michigan, USA
| | - Yueming Dersjant-Li
- DuPont Animal Nutrition, DuPont Nutrition and Biosciences, Archimedesweg, 30, 2333 CN, Leiden, the Netherlands
| | - Vincent J Sewalt
- DuPont Nutrition and Biosciences, 925 Page Mill Road, Palo Alto, CA, 94304, USA
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29
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Beier S, Hinterdobler W, Monroy AA, Bazafkan H, Schmoll M. The Kinase USK1 Regulates Cellulase Gene Expression and Secondary Metabolite Biosynthesis in Trichoderma reesei. Front Microbiol 2020; 11:974. [PMID: 32508786 PMCID: PMC7251307 DOI: 10.3389/fmicb.2020.00974] [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: 11/15/2019] [Accepted: 04/22/2020] [Indexed: 01/04/2023] Open
Abstract
The complex environment of fungi requires a delicate balance between the efforts to acquire nutrition, to reproduce, and to fend off competitors. In Trichoderma reesei, an interrelationship between regulation of enzyme gene expression and secondary metabolism was shown. In this study, we investigated the physiological relevance of the unique YPK1-type kinase USK1 of T. reesei. Usk1 is located in the vicinity of the SOR cluster and is involved in regulation of several genes from this secondary metabolite cluster as well as dihydrotrichotetronine and other secondary metabolites. Moreover, USK1 is required for biosynthesis of normal levels of secondary metabolites in liquid culture. USK1 positively influences cellulase gene regulation, secreted cellulase activity, and biomass formation upon growth in constant darkness on cellulose. Positive effects of USK1 on transcript abundance of the regulator of secondary metabolism, vel1, and the carbon catabolite repressor gene cre1 are in agreement with these functions. In summary, we found that with USK1, T. reesei comprises a unique kinase that adds an additional layer of regulation to the connection of secondary metabolism and enzyme production in fungi.
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Affiliation(s)
- Sabrina Beier
- Center for Health and Bioresources, AIT Austrian Institute of Technology GmbH, Tulln, Austria
| | - Wolfgang Hinterdobler
- Center for Health and Bioresources, AIT Austrian Institute of Technology GmbH, Tulln, Austria
| | - Alberto Alonso Monroy
- Center for Health and Bioresources, AIT Austrian Institute of Technology GmbH, Tulln, Austria
| | - Hoda Bazafkan
- Center for Health and Bioresources, AIT Austrian Institute of Technology GmbH, Tulln, Austria
| | - Monika Schmoll
- Center for Health and Bioresources, AIT Austrian Institute of Technology GmbH, Tulln, Austria
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30
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Kilaru S, Schuster M, Cannon S, Steinberg G. Optimised red- and green-fluorescent proteins for live cell imaging in the industrial enzyme-producing fungus Trichoderma reesei. Fungal Genet Biol 2020; 138:103366. [PMID: 32173466 DOI: 10.1016/j.fgb.2020.103366] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 03/09/2020] [Accepted: 03/10/2020] [Indexed: 11/30/2022]
Abstract
The filamentous fungus Trichoderma reesei is a major source of cellulolytic enzymes in biofuel production. Despite its economic relevance, our understanding of its secretory pathways is fragmentary. A major challenge is to visualise the dynamic behaviour of secretory vesicles in living cells. To this end, we establish a location juxtaposing the succinate dehydrogenase locus as a "soft-landing" site for controlled expression of 4 green-fluorescent and 5 red-fluorescent protein-encoding genes (GFPs, RFPs). Quantitative and comparative analysis of their fluorescent signals in living cells demonstrates that codon-optimised monomeric superfolder GFP (TrmsGFP) and codon-optimised mCherry (TrmCherry) combine highest signal intensity with significantly improved signal-to-noise ratios. Finally, we show that integration of plasmid near the sdi1 locus does not affect secretion of cellulase activity in RUT-C30. The molecular and live cell imaging tools generated in this study will help our understanding the secretory pathway in the industrial fungus T. reesei.
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Affiliation(s)
- Sreedhar Kilaru
- Biosciences, University of Exeter, Stocker Road, EX4 4QD Exeter, United Kingdom
| | - Martin Schuster
- Biosciences, University of Exeter, Stocker Road, EX4 4QD Exeter, United Kingdom
| | - Stuart Cannon
- Biosciences, University of Exeter, Stocker Road, EX4 4QD Exeter, United Kingdom
| | - Gero Steinberg
- Biosciences, University of Exeter, Stocker Road, EX4 4QD Exeter, United Kingdom.
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31
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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.
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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
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32
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Tasirnafas M, Karimi K, Asgari Jafarabadi G, Seidavi A, Noorbakhsh F. Extraction and purification of β-glucanase from bovine rumen fungus Trichoderma reesei and its effect on performance, carcass characteristics, microbial flora, plasma biochemical parameters, and immunity in a local broiler hybrid Golpayegan-Ross. Trop Anim Health Prod 2020; 52:1833-1843. [PMID: 31938956 DOI: 10.1007/s11250-019-02186-5] [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: 02/12/2019] [Accepted: 12/22/2019] [Indexed: 10/25/2022]
Abstract
The enzyme β-glucanase was extracted from Trichoderma reesei in bovine rumen fluid samples collected from a slaughterhouse and its effect was investigated in broilers. Data collected was broiler performance, carcass characteristics, duodenum microbial flora, hematological, and immunological parameters. β-glucanase activity was assayed through spectrometry and was approximately 0.434 IU per gram culture medium. In the current study, endoglucanase enzymes were extracted from Trichoderma reesei. A total of 160 local broilers (Golpayegan-Ross hybrid) were allocated to 4 treatments with 4 replicates per treatment. Over a 49-day experimental period, broilers were fed a basal diet (T1), basal diet plus 20% barley (T2), basal diet with 10 IU extracted β-glucanase and 20% barley (T3), and basal diet with 10 IU commercial β-glucanase and 20% barley (T4). The T3 treatment resulted in the greatest body weight gain at the end of experiment (P < 0.01). No significant differences were for feed conversion (FCR; P > 0.05). The highest cholesterol, high density lipoprotein (HDL), low density lipoprotein (LDL), and LDL cholesterol ratio was observed in the T3 treatment. The highest concentrations of immunoglobulin G1 (IgG1), immunoglobulin G2 (IgG2), and immunoglobulin M1 (IgM1) were observed in the T4 treatment. The T3 treatment resulted in the best response for all measured carcass characteristics. The highest levels of aerobic bacteria, lactobacilli, anaerobic bacteria, and E. coli were associated with the T4, T3, T4, and T1 treatments, respectively. It is concluded that β-glucanase supplementation can be used to overcome the anti-nutritive effects of water soluble barley non-starch polysaccharides (NSPs) and consequently enhance broiler performance without any adverse effects on humoral immunity parameters.
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Affiliation(s)
- Mohammadebrahim Tasirnafas
- Department of Animal Science, Faculty of Agriculture, Varamin-Pishva Branch, Islamic Azad University, Varamin-Pishva, Iran
| | - Kazem Karimi
- Department of Animal Science, Faculty of Agriculture, Varamin-Pishva Branch, Islamic Azad University, Varamin-Pishva, Iran.
| | - Ghobad Asgari Jafarabadi
- Department of Animal Science, Faculty of Agriculture, Varamin-Pishva Branch, Islamic Azad University, Varamin-Pishva, Iran
| | - Alireza Seidavi
- Department of Animal Science, Rasht Branch, Islamic Azad University, Rasht, Iran
| | - Fatemeh Noorbakhsh
- Department of Microbiology, Biological Science College, Varamin-Pishva Branch, Islamic Azad University, Varamin-Pishva, Iran
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33
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Havukainen S, Valkonen M, Koivuranta K, Landowski CP. Studies on sugar transporter CRT1 reveal new characteristics that are critical for cellulase induction in Trichoderma reesei. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:158. [PMID: 32944074 PMCID: PMC7491124 DOI: 10.1186/s13068-020-01797-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 09/03/2020] [Indexed: 05/08/2023]
Abstract
BACKGROUND Trichoderma reesei is an ascomycete fungus that has a tremendous capability of secreting extracellular proteins, mostly lignocellulose-degrading enzymes. Although many aspects of the biology of this organism have been unfolded, the roles of the many sugar transporters coded in its genome are still a mystery with a few exceptions. One of the most interesting sugar transporters that has thus far been discovered is the cellulose response transporter 1 (CRT1), which has been suggested to be either a sugar transporter or a sensor due to its seemingly important role in cellulase induction. RESULTS Here we show that CRT1 is a high-affinity cellobiose transporter, whose function can be complemented by the expression of other known cellobiose transporters. Expression of two sequence variants of the crt1 gene in Saccharomyces cerevisiae revealed that only the variant listed in the RUT-C30 genome annotation has the capability to transport cellobiose and lactose. When expressed in the Δ crt1 strain, the variant listed in the QM6a genome annotation offers partial complementation of the cellulase induction, while the expression of the RUT-C30 variant or cellobiose transporters from two other fungal species fully restore the cellulase induction. CONCLUSIONS These results add to our knowledge about the fungal metabolism of cellulose-derived oligosaccharides, which have the capability of inducing the cellulase production in many species. They also help us to deepen our understanding of the T. reesei lactose metabolism, which can have important consequences as this sugar is used as the inducer of protein secretion in many industrial processes which employ this species.
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Affiliation(s)
- Sami Havukainen
- VTT Technical Research Center of Finland Ltd, Tietotie 2, 02150 Espoo, Finland
| | - Mari Valkonen
- VTT Technical Research Center of Finland Ltd, Tietotie 2, 02150 Espoo, Finland
| | - Kari Koivuranta
- VTT Technical Research Center of Finland Ltd, Tietotie 2, 02150 Espoo, Finland
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Schiano‐di‐Cola C, Kołaczkowski B, Sørensen TH, Christensen SJ, Cavaleiro AM, Windahl MS, Borch K, Morth JP, Westh P. Structural and biochemical characterization of a family 7 highly thermostable endoglucanase from the fungusRasamsonia emersonii. FEBS J 2019; 287:2577-2596. [DOI: 10.1111/febs.15151] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 11/01/2019] [Accepted: 11/20/2019] [Indexed: 01/21/2023]
Affiliation(s)
| | | | - Trine Holst Sørensen
- Department of Science and Environment Roskilde University Denmark
- Novozymes A/S Lyngby Denmark
| | | | | | - Michael Skovbo Windahl
- Department of Science and Environment Roskilde University Denmark
- Novozymes A/S Lyngby Denmark
| | | | - Jens Preben Morth
- Department of Biotechnology and Biomedicine Technical University of Denmark Lyngby Denmark
| | - Peter Westh
- Department of Science and Environment Roskilde University Denmark
- Department of Biotechnology and Biomedicine Technical University of Denmark Lyngby Denmark
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35
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Fitz E, Gamauf C, Seiboth B, Wanka F. Deletion of the small GTPase rac1 in Trichoderma reesei provokes hyperbranching and impacts growth and cellulase production. Fungal Biol Biotechnol 2019; 6:16. [PMID: 31641527 PMCID: PMC6798449 DOI: 10.1186/s40694-019-0078-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 10/03/2019] [Indexed: 11/21/2022] Open
Abstract
Background Trichoderma reesei is widely known for its enormous protein secretion capacity and as an industrially relevant producer of cellulases and hemicellulases. Over the last decades, rational strain engineering was applied to further enhance homologous and heterologous enzyme yields. The introduction of hyperbranching is believed to increase protein secretion, since most exocytosis is located at the hyphal apical tip. There are several genetic modifications which can cause hyperbranching, for example the deletion of the small Rho GTPase rac. Rac plays a crucial role in actin dynamics and is involved in polarisation of the cell during germination and apical extension of the hyphae. Results We deleted rac1 in a T. reesei strain with an ectopically overexpressed endoglucanase, CEL12A, under Pcdna1 control. This deletion provoked a hyperbranching phenotype and strong apolar growth during germination and in mature hyphae. The strains displayed dichotomous branching and shorter total mycelium length with a larger hyphal diameter. Δrac1 strains exhibited a decreased radial growth on solid media. Biomass formation in liquid cultures was carbon source dependent; similar to the reference strain during growth on lactose, increased on d-glucose and slightly enhanced on cellulose. While extracellular cellulase activities remained at parental strain levels on d-glucose and cellulose, the specific activity on lactose cultures was increased up to three times at 72 h accompanied by an upregulation of transcription of the main cellulases. Although the morphology of the Δrac1 strains was considerably altered, the viscosity of the culture broth in fed-batch cultivations were not significantly different in comparison to the parental strain. Conclusions Deletion of the small Rho GTPase rac1 changes the morphology of the hyphae and provokes hyperbranching without affecting viscosity, independent of the carbon source. In contrast, biomass formation and cellulase production are altered in a carbon source dependent manner in the Δrac1 strains.
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Affiliation(s)
- Elisabeth Fitz
- 1Research Division Biochemical Technology, Institute of Chemical, Environmental & Bioscience Engineering, TU Wien, Vienna, Austria.,2Austrian Centre of Industrial Biotechnology (ACIB) GmbH c/o Research Division Biochemical Technology, Institute of Chemical, Environmental & Bioscience Engineering, TU Wien, Vienna, Austria
| | - Christian Gamauf
- 3Group Biotechnology, Clariant Produkte (Deutschland) GmbH, Planegg, Germany
| | - Bernhard Seiboth
- 1Research Division Biochemical Technology, Institute of Chemical, Environmental & Bioscience Engineering, TU Wien, Vienna, Austria.,2Austrian Centre of Industrial Biotechnology (ACIB) GmbH c/o Research Division Biochemical Technology, Institute of Chemical, Environmental & Bioscience Engineering, TU Wien, Vienna, Austria
| | - Franziska Wanka
- 2Austrian Centre of Industrial Biotechnology (ACIB) GmbH c/o Research Division Biochemical Technology, Institute of Chemical, Environmental & Bioscience Engineering, TU Wien, Vienna, Austria
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Wang F, Zhang R, Han L, Guo W, Du Z, Niu K, Liu Y, Jia C, Fang X. Use of fusion transcription factors to reprogram cellulase transcription and enable efficient cellulase production in Trichoderma reesei. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:244. [PMID: 31636703 PMCID: PMC6792246 DOI: 10.1186/s13068-019-1589-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 10/09/2019] [Indexed: 05/23/2023]
Abstract
BACKGROUND Trichoderma reesei is widely used for cellulase production and accepted as an example for cellulase research. Cre1-mediated carbon catabolite repression (CCR) can significantly inhibit the transcription of cellulase genes during cellulase fermentation in T. reesei. Early efforts have been undertaken to modify Cre1 for the release of CCR; however, this approach leads to arrested hyphal growth and decreased biomass accumulation, which negatively affects cellulase production. RESULTS In this study, novel fusion transcription factors (fTFs) were designed to release or attenuate CCR inhibition in cellulase transcription, while Cre1 was left intact to maintain normal hyphal growth. Four designed fTFs were introduced into the T. reesei genome, which generated several transformants, named Kuace3, Kuclr2, Kuace2, and Kuxyr1. No obvious differences in growth were observed between the parent and transformant strains. However, the transcription levels of cel7a, a major cellulase gene, were significantly elevated in all the transformants, particularly in Kuace2 and Kuxyr1, when grown on lactose as a carbon source. This suggested that CCR inhibition was released or attenuated in the transformant strains. The growth of Kuace2 and Kuxyr1 was approximately equivalent to that of the parent strain in fed-batch fermentation process. However, we observed a 3.2- and 2.1-fold increase in the pNPCase titers of the Kuace2 and Kuxyr1 strains, respectively, compared with that of the parent strain. Moreover, we observed a 6.1- and 3.9-fold increase in the pNPCase titers of the Kuace2 and Kuxyr1 strains, respectively, compared with that of Δcre1 strain. CONCLUSIONS A new strategy based on fTFs was successfully established in T. reesei to improve cellulase titers without impairing fungal growth. This study will be valuable for lignocellulosic biorefining and for guiding the development of engineering strategies for producing other important biochemical compounds in fungal species.
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Affiliation(s)
- Fangzhong Wang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237 China
- Center for Biosafety Research and Strategy, Tianjin University, Tianjin, China
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong China
| | - Ruiqin Zhang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237 China
| | - Lijuan Han
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237 China
| | - Wei Guo
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237 China
| | - Zhiqiang Du
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237 China
| | - Kangle Niu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237 China
| | - Yucui Liu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237 China
| | - Chunjiang Jia
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong China
| | - Xu Fang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237 China
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Rantasalo A, Landowski CP, Kuivanen J, Korppoo A, Reuter L, Koivistoinen O, Valkonen M, Penttilä M, Jäntti J, Mojzita D. A universal gene expression system for fungi. Nucleic Acids Res 2019; 46:e111. [PMID: 29924368 PMCID: PMC6182139 DOI: 10.1093/nar/gky558] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 06/07/2018] [Indexed: 12/02/2022] Open
Abstract
Biotechnological production of fuels, chemicals and proteins is dependent on efficient production systems, typically genetically engineered microorganisms. New genome editing methods are making it increasingly easy to introduce new genes and functionalities in a broad range of organisms. However, engineering of all these organisms is hampered by the lack of suitable gene expression tools. Here, we describe a synthetic expression system (SES) that is functional in a broad spectrum of fungal species without the need for host-dependent optimization. The SES consists of two expression cassettes, the first providing a weak, but constitutive level of a synthetic transcription factor (sTF), and the second enabling strong, at will tunable expression of the target gene via an sTF-dependent promoter. We validated the SES functionality in six yeast and two filamentous fungi species in which high (levels beyond organism-specific promoters) as well as adjustable expression levels of heterologous and native genes was demonstrated. The SES is an unprecedentedly broadly functional gene expression regulation method that enables significantly improved engineering of fungi. Importantly, the SES system makes it possible to take in use novel eukaryotic microbes for basic research and various biotechnological applications.
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Affiliation(s)
- Anssi Rantasalo
- VTT Technical Research Centre of Finland, Espoo, P.O. Box 1000, FI-02044 VTT, Finland
| | | | - Joosu Kuivanen
- VTT Technical Research Centre of Finland, Espoo, P.O. Box 1000, FI-02044 VTT, Finland
| | - Annakarin Korppoo
- VTT Technical Research Centre of Finland, Espoo, P.O. Box 1000, FI-02044 VTT, Finland
| | - Lauri Reuter
- VTT Technical Research Centre of Finland, Espoo, P.O. Box 1000, FI-02044 VTT, Finland
| | - Outi Koivistoinen
- VTT Technical Research Centre of Finland, Espoo, P.O. Box 1000, FI-02044 VTT, Finland
| | - Mari Valkonen
- VTT Technical Research Centre of Finland, Espoo, P.O. Box 1000, FI-02044 VTT, Finland
| | - Merja Penttilä
- VTT Technical Research Centre of Finland, Espoo, P.O. Box 1000, FI-02044 VTT, Finland
| | - Jussi Jäntti
- VTT Technical Research Centre of Finland, Espoo, P.O. Box 1000, FI-02044 VTT, Finland
| | - Dominik Mojzita
- VTT Technical Research Centre of Finland, Espoo, P.O. Box 1000, FI-02044 VTT, Finland
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Novel genetic tools that enable highly pure protein production in Trichoderma reesei. Sci Rep 2019; 9:5032. [PMID: 30902998 PMCID: PMC6430808 DOI: 10.1038/s41598-019-41573-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 03/08/2019] [Indexed: 01/31/2023] Open
Abstract
Trichoderma reesei is an established protein production host with high natural capacity to secrete enzymes. The lack of efficient genome engineering approaches and absence of robust constitutive gene expression systems limits exploitation of this organism in some protein production applications. Here we report engineering of T. reesei for high-level production of highly enriched lipase B of Candida antarctica (calB) using glucose as a carbon source. Multiplexed CRISPR/Cas9 in combination with the use of our recently established synthetic expression system (SES) enabled accelerated construction of strains, which produced high amounts of highly pure calB. Using SES, calB production levels in cellulase-inducing medium were comparable to the levels obtained by using the commonly employed inducible cbh1 promoter, where a wide spectrum of native enzymes were co-produced. Due to highly constitutive expression provided by the SES, it was possible to carry out the production in cellulase-repressing glucose medium leading to around 4 grams per liter of fully functional calB and simultaneous elimination of unwanted background enzymes.
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39
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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.
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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.
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40
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Simultaneous enhancement of the beta-exo synergism and exo-exo synergism in Trichoderma reesei cellulase to increase the cellulose degrading capability. Microb Cell Fact 2019; 18:9. [PMID: 30657063 PMCID: PMC6337788 DOI: 10.1186/s12934-019-1060-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Accepted: 01/10/2019] [Indexed: 11/18/2022] Open
Abstract
Background Cellulase is the one of the largest contributors to the high production costs of the lignocellulose-based biorefineries. As the most widely used cellulase producer, Trichoderma reesei has two weaknesses, deficiencies in β-glucosidase and cellobiohydrolase II. This work aimed at solving this problem by simultaneous enhancement of the beta–exo synergism and exo–exo synergism in T. reesei cellulase to increase the cellulose degrading capability, i.e. enhanced co-expression of the β-glucosidase gene the cellobiohydrolase II gene of T. reesei. Results Enhanced co-expression of the β-glucosidase gene and the cellobiohydrolase II gene in T. reesei using the strong promoter Pcbh1 was found successful in overcoming the two weaknesses. Filter paper activities of T. reesei cellulase were greatly elevated, which were 7.21 ± 0.45 (E7, Aabgl1 and Trcbh2) and 7.69 ± 0.42 (F6, Anbgl1 and Trcbh2) FPIU/mL. They were much higher than that of the parental strain Rut-C30, 2.45 ± 0.36 FPIU/mL. Enzymatic hydrolysis yields were also improved, from 67.22 ± 1.61% by Rut-C30 cellulase to 87.98 ± 0.65% by E7 cellulase and 86.50 ± 1.01% by F6 cellulase. The substrate loading for 1 g glucose release from SECS were decreased, from 2.9637 g SECS using Rut-C30 cellulase to 2.0291 g SECS using E7 cellulase and 2.0573 g SECS using F6 cellulase. As a result, the efficiency of the process from SECS to glucose was substantially improved. Conclusions Enhanced co-expression of the β-glucosidase gene and the cellobiohydrolase II gene in T. reesei using the strong promoter Pcbh1 in T. reesei was proven triumphal in the simultaneous enhancement of the beta–exo synergism and exo–exo synergism in T. reesei cellulase. This strategy also improved the cellulase production, enzymatic hydrolysis yield and the efficiency of the process from SECS to glucose in the context of on-site cellulase production. This work is a commendable attempt in the cellulase composition optimization at the transcriptional level.
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Nevalainen H, Peterson R, Curach N. Overview of Gene Expression Using Filamentous Fungi. ACTA ACUST UNITED AC 2019; 92:e55. [PMID: 30040195 DOI: 10.1002/cpps.55] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Filamentous fungi are lower eukaryotes increasingly used for expression of foreign proteins ranging from industrial enzymes originating from other fungi and bacteria to proteins of mammalian origin, such as antibodies and growth factors. Their strengths include an excellent capacity for protein secretion and their eukaryotic protein processing machinery. Proteins secreted from filamentous fungi are modified in the secretory pathway, with folding, proteolytic processing, and addition of glycans being the main modifications. Unlike from many other expression systems, however, plasmids and host strains for expression of gene products in filamentous fungi are not readily available commercially, and the expression system must thus be stitched together in the laboratory. In this overview, the key elements of fungal expression systems are discussed from a practical point of view and with a view towards the future. The principles and considerations presented here can be applied to a range of filamentous fungi. © 2018 by John Wiley & Sons, Inc.
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Affiliation(s)
- Helena Nevalainen
- Department of Molecular Sciences, Macquarie University, Sydney, Australia.,Biomolecular Discovery and Design Research Centre, Macquarie University, Sydney, Australia
| | - Robyn Peterson
- Department of Molecular Sciences, Macquarie University, Sydney, Australia.,Biomolecular Discovery and Design Research Centre, Macquarie University, Sydney, Australia
| | - Natalie Curach
- Department of Molecular Sciences, Macquarie University, Sydney, Australia
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42
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Schiano-di-Cola C, Røjel N, Jensen K, Kari J, Sørensen TH, Borch K, Westh P. Systematic deletions in the cellobiohydrolase (CBH) Cel7A from the fungus Trichoderma reesei reveal flexible loops critical for CBH activity. J Biol Chem 2018; 294:1807-1815. [PMID: 30538133 DOI: 10.1074/jbc.ra118.006699] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 12/08/2018] [Indexed: 11/06/2022] Open
Abstract
Glycoside hydrolase family 7 (GH7) cellulases are some of the most efficient degraders of cellulose, making them particularly relevant for industries seeking to produce renewable fuels from lignocellulosic biomass. The secretome of the cellulolytic model fungus Trichoderma reesei contains two GH7s, termed TrCel7A and TrCel7B. Despite having high structural and sequence similarities, the two enzymes are functionally quite different. TrCel7A is an exolytic, processive cellobiohydrolase (CBH), with high activity on crystalline cellulose, whereas TrCel7B is an endoglucanase (EG) with a preference for more amorphous cellulose. At the structural level, these functional differences are usually ascribed to the flexible loops that cover the substrate-binding areas. TrCel7A has an extensive tunnel created by eight peripheral loops, and the absence of four of these loops in TrCel7B makes its catalytic domain a more open cleft. To investigate the structure-function relationships of these loops, here we produced and kinetically characterized several variants in which four loops unique to TrCel7A were individually deleted to resemble the arrangement in the TrCel7B structure. Analysis of a range of kinetic parameters consistently indicated that the B2 loop, covering the substrate-binding subsites -3 and -4 in TrCel7A, was a key determinant for the difference in CBH- or EG-like behavior between TrCel7A and TrCel7B. Conversely, the B3 and B4 loops, located closer to the catalytic site in TrCel7A, were less important for these activities. We surmise that these results could be useful both in further mechanistic investigations and for guiding engineering efforts of this industrially important enzyme family.
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Affiliation(s)
- Corinna Schiano-di-Cola
- From the Department of Science and Environment, Roskilde University, Universitetsvej 1, Building 28, DK-4000 Roskilde, Denmark
| | - Nanna Røjel
- From the Department of Science and Environment, Roskilde University, Universitetsvej 1, Building 28, DK-4000 Roskilde, Denmark
| | - Kenneth Jensen
- Novozymes A/S, Krogshøjvej 36, DK-2880 Bagsværd, Denmark, and
| | - Jeppe Kari
- From the Department of Science and Environment, Roskilde University, Universitetsvej 1, Building 28, DK-4000 Roskilde, Denmark
| | - Trine Holst Sørensen
- From the Department of Science and Environment, Roskilde University, Universitetsvej 1, Building 28, DK-4000 Roskilde, Denmark
| | - Kim Borch
- Novozymes A/S, Krogshøjvej 36, DK-2880 Bagsværd, Denmark, and
| | - Peter Westh
- the Department of Biotechnology and Biomedicine, Technical University of Denmark, Building 224, DK-2800 Kgs. Lyngby, Denmark
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43
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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.
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Kalbarczyk KZ, Mazeau EJ, Rapp KM, Marchand N, Koffas MAG, Collins CH. Engineering Bacillus megaterium Strains To Secrete Cellulases for Synergistic Cellulose Degradation in a Microbial Community. ACS Synth Biol 2018; 7:2413-2422. [PMID: 30226981 DOI: 10.1021/acssynbio.8b00186] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Recent environmental concerns have intensified the need to develop systems to degrade waste biomass for use as an inexpensive carbon source for microbial chemical production. Current approaches to biomass utilization rely on pretreatment processes that include expensive enzymatic purification steps for the requisite cellulases. We aimed to engineer a synthetic microbial community to synergistically degrade cellulose by compartmentalizing the system with multiple specialized Bacillus megaterium strains. EGI1, an endoglucanase, and Cel9AT, a multimodular cellulase, were targeted for secretion from B. megaterium. A small library of signal peptides (SPs) with five amino acid linkers was selected to tag each cellulase for secretion from B. megaterium. Cellulase activity against amorphous cellulose was confirmed through a series of bioassays, and the most active SP constructs were identified as EGI1 with the LipA SP and Cel9AT with the YngK SP. The activity of the optimized cellulase secretion strains was characterized individually and in tandem to assess synergistic cellulolytic activity. The combination of EGI1 and Cel9AT yielded higher activity than either single cellulase. A coculture of EGI1 and Cel9AT secreting B. megaterium strains demonstrated synergistic behavior with higher activity than either monoculture. This cellulose degradation module can be further integrated with bioproduct synthesis modules to build complex systems for the production of high value molecules.
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Affiliation(s)
- Karolina Z. Kalbarczyk
- Center for Biotechnology and Interdisciplinary Studies and Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Emily J. Mazeau
- Center for Biotechnology and Interdisciplinary Studies and Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Kent M. Rapp
- Center for Biotechnology and Interdisciplinary Studies and Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Nicholas Marchand
- Center for Biotechnology and Interdisciplinary Studies and Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Mattheos A. G. Koffas
- Center for Biotechnology and Interdisciplinary Studies and Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Cynthia H. Collins
- Center for Biotechnology and Interdisciplinary Studies and Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
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New Genomic Approaches to Enhance Biomass Degradation by the Industrial Fungus Trichoderma reesei. Int J Genomics 2018; 2018:1974151. [PMID: 30345291 PMCID: PMC6174759 DOI: 10.1155/2018/1974151] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 06/20/2018] [Accepted: 07/29/2018] [Indexed: 11/17/2022] Open
Abstract
The filamentous fungi Trichoderma reesei is one of the most well-studied cellulolytic microorganisms. It is the most important fungus for the industrial production of enzymes to biomass deconstruction being widely used in the biotechnology industry, mainly in the production of biofuels. Here, we performed an analytic review of the holocellulolytic system presented by T. reesei as well as the transcriptional and signaling mechanisms involved with holocellulase expression in this fungus. We also discuss new perspectives about control of secretion and cellulase expression based on RNA-seq and functional characterization data of T. reesei growth in different carbon sources, which comprise glucose, cellulose, sophorose, and sugarcane bagasse.
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46
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Kameshwar AKS, Qin W. Isolation and Screening of Cellulose-Degrading Microorganisms from Different Ecological Niches. Methods Mol Biol 2018; 1796:47-56. [PMID: 29856045 DOI: 10.1007/978-1-4939-7877-9_4] [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] [Indexed: 06/08/2023]
Abstract
Increased interest in developing cellulose-based ethanol over the last few years was the main reason behind inflated research to find cellulose-degrading microorganisms. Several methods have been developed in the past for efficient isolation and characterization of cellulolytic microorganisms. However, it is critical to choose a specific method from a list of qualitative methods for the characterization of cellulose degrading microorganisms. In this chapter, we have extensively listed various qualitative methods used for the isolation and characterization of the cellulolytic microorganisms isolated from different ecological niches such as soil, decaying wood, gut, and rumen.
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Affiliation(s)
| | - Wensheng Qin
- Department of Biology, Lakehead University, Thunder Bay, ON, Canada.
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47
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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.
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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
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48
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Wu Y, Sun X, Xue X, Luo H, Yao B, Xie X, Su X. Overexpressing key component genes of the secretion pathway for enhanced secretion of an Aspergillus niger glucose oxidase in Trichoderma reesei. Enzyme Microb Technol 2017; 106:83-87. [DOI: 10.1016/j.enzmictec.2017.07.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 07/13/2017] [Accepted: 07/14/2017] [Indexed: 11/29/2022]
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49
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Pathak VM, Navneet. Review on the current status of polymer degradation: a microbial approach. BIORESOUR BIOPROCESS 2017. [DOI: 10.1186/s40643-017-0145-9] [Citation(s) in RCA: 308] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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Ramoni J, Marchetti-Deschmann M, Seidl-Seiboth V, Seiboth B. Trichoderma reesei xylanase 5 is defective in the reference strain QM6a but functional alleles are present in other wild-type strains. Appl Microbiol Biotechnol 2017; 101:4139-4149. [PMID: 28229208 PMCID: PMC5403845 DOI: 10.1007/s00253-017-8161-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 01/23/2017] [Accepted: 01/27/2017] [Indexed: 11/07/2022]
Abstract
Trichoderma reesei is a paradigm for the regulation and industrial production of plant cell wall-degrading enzymes. Among these, five xylanases, including the glycoside hydrolase (GH) family 11 XYN1 and XYN2, the GH10 XYN3, and the GH30 XYN4 and XYN6, were described. By genome mining and transcriptome analysis, a further putative xylanase, encoded by xyn5, was identified. Analysis of xyn5 from the genome-sequenced reference strain T. reesei QM6a shows that it encodes a non-functional, truncated form of XYN5. However, non-truncated orthologues are present in other genome sequenced Trichoderma spp., and sequencing of xyn5 in other T. reesei wild-type isolates shows that they harbor a putative functional xyn5 allele. In silico analysis and 3D modeling revealed that the encoded XYN5 has significant structural similarities to xylanases of the GH11 family, including a GH-typical substrate binding groove and a carboxylate pair in the active site. The xyn5 of wild-type strain TUCIM1282 was recombinantly expressed in a T. reesei strain with a (hemi)cellulase-free background and the corresponding protein purified to apparent homogeneity. The pH and temperature optima and the kinetic parameters of the purified XYN5 were pH 4, 50 °C, and Vmax = 2646 nkat/mg with a Km of 9.68 mg/ml. This functional xyn5 allele was used to replace the mutated version which led to an overall increase of the xylanolytic activity. These findings are of particular importance as GH11 xylanases are of high biotechnological relevance, and T. reesei is one of the main industrial producers of such lignocellulose-degrading enzymes.
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Affiliation(s)
- Jonas Ramoni
- Molecular Biotechnology, Research Division Biochemical Technology, Institute of Chemical Engineering, TU Wien, Gumpendorferstraße 1a, 1060, Vienna, Austria
| | | | - Verena Seidl-Seiboth
- Molecular Biotechnology, Research Division Biochemical Technology, Institute of Chemical Engineering, TU Wien, Gumpendorferstraße 1a, 1060, Vienna, Austria
| | - Bernhard Seiboth
- Molecular Biotechnology, Research Division Biochemical Technology, Institute of Chemical Engineering, TU Wien, Gumpendorferstraße 1a, 1060, Vienna, Austria.
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