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Zhao C, Zhao J, Han J, Mei Y, Fang H. Improved consolidated bioprocessing for itaconic acid production by simultaneous optimization of cellulase and metabolic pathway of Neurospora crassa. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:57. [PMID: 38685114 PMCID: PMC11059683 DOI: 10.1186/s13068-024-02505-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 04/20/2024] [Indexed: 05/02/2024]
Abstract
Lignocellulose was directly used in itaconic acid production by a model filamentous fungus Neurospora crassa. The promoters of two clock control genes and cellobiohydrolase 1 gene were selected for heterologous genes expression by evaluating different types of promoters. The effect of overexpression of different cellulase was compared, and it was found that expression of cellobiohydrolase 2 from Trichoderma reesei increased the filter paper activity by 2 times, the cellobiohydrolase activity by 4.5 times, and that the itaconic acid titer was also significantly improved. A bidirectional cis-aconitic acid accumulation strategy was established by constructing the reverse glyoxylate shunt and expressing the transporter MTTA, which increased itaconic acid production to 637.2 mg/L. The simultaneous optimization of cellulase and metabolic pathway was more conducive to the improvement of cellulase activity than that of cellulase alone, so as to further increase itaconic acid production. Finally, through the combination of fermentation by optimized strains and medium optimization, the titers of itaconic acid using Avicel and corn stover as substrate were 1165.1 mg/L and 871.3 mg/L, respectively. The results prove the potential of the consolidated bioprocessing that directly converts lignocellulose to itaconic acid by a model cellulase synthesizing strain.
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Affiliation(s)
- Chen Zhao
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China.
- Biomass Energy Center for Arid and Semi-Arid Lands, Northwest A&F University, Yangling, 712100, Shaanxi, China.
| | - Jiajia Zhao
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China
- The Second Department of Vaccine, Lanzhou Institute of Biological Products Co., Ltd., Lanzhou, 730046, China
| | - Jingjing Han
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China
- Biomass Energy Center for Arid and Semi-Arid Lands, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Yaojie Mei
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China
- Biomass Energy Center for Arid and Semi-Arid Lands, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Hao Fang
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China.
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, 733 Jianshe 3rd Road, Hangzhou, 311200, Zhejiang, China.
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Jia J, Tan Y, Gao J, Han J, Shi P, Fang H, Zhao C. Cloning and expression of Neurospora crassa cellobiohydrolase II in Pichia pastoris. Protein Expr Purif 2024; 216:106416. [PMID: 38104790 DOI: 10.1016/j.pep.2023.106416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 12/07/2023] [Accepted: 12/09/2023] [Indexed: 12/19/2023]
Abstract
A major cellobiohydrolase of Neurospora crassa CBH2 was successfully expressed in Pichia pastoris. The maximum Avicelase activity in shake flask among seven transformants which selected on 4.0 g/L G418 plates was 0.61 U/mL. The optimal pH and temperature for Avicelase activity of the recombinant CBH2 were determined to be 4.8 and 60 °C, respectively. The new CBH2 maintained 63.5 % Avicelase activity in the range of pH 4.0-10.4, and 60.2 % Avicelase activity in the range of 30-90 °C. After incubation at 70-90 °C for 1 h, the Avicelase activity retained 60.5 % of its initial activity. The presence of Zn2+, Ca2+ or Cd2+ enhanced the Avicelase activity of the CBH2, of which Cd2+ at 10 mM causing the highest increase. The recombinant CBH2 was used to enhance the Avicel hydrolysis by improving the exo-exo-synergism between CBH2 and CBH1 in N.crassa cellulase. The enzymatic hydrolysis yield was increased by 38.1 % by adding recombinant CBH2 and CBH1, and the yield was increased by 215.4 % when the temperature is raised to 70 °C. This work provided a CBH2 with broader pH range and better heat resistance, which is a potential enzyme candidate in food, textile, pulp and paper industries, and other industrial fields.
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Affiliation(s)
- Jingsong Jia
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China; Biomass Energy Center for Arid and Semi-arid Lands, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China
| | - Yu Tan
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China; Biomass Energy Center for Arid and Semi-arid Lands, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China
| | - Jialun Gao
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China; Biomass Energy Center for Arid and Semi-arid Lands, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China
| | - Jingjing Han
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China; Biomass Energy Center for Arid and Semi-arid Lands, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China
| | - Peng Shi
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China
| | - Hao Fang
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China; Biomass Energy Center for Arid and Semi-arid Lands, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China; ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou, Zhejiang, China
| | - Chen Zhao
- College of Life Sciences, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China; Biomass Energy Center for Arid and Semi-arid Lands, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China.
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Waheed A, Chen Y, Rizwan HM, Adnan M, Ma X, Liu G. Genomic characterization and expression profiling of the lytic polysaccharide monooxygenases AA9 family in thermophilic fungi Thermothelomyces fergusii in response to carbon source media. Int J Biol Macromol 2024; 265:130740. [PMID: 38462117 DOI: 10.1016/j.ijbiomac.2024.130740] [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: 12/04/2023] [Revised: 02/16/2024] [Accepted: 03/06/2024] [Indexed: 03/12/2024]
Abstract
Enhancing enzyme activity and stability in biomass degradation can improve substrate saccharification and, increases biorefinery efficiency. For the first time, we identified 20 lytic polysaccharide monooxygenases (LPMOs) AA9 genes in the genome of Thermothelomyces fergusii. Our results showed that TfAA9 was categorized into LPMOs1, LPMOs2, and LPMOs3 subgroups based on protein diversity. Protein- 3D structure analysis showed strong interactions between Myceliophthora thermophila AA9 proteins and 17 TfAA9 proteins. Gene ontology analysis indicated a high enrichment of cellulase activity in TfAA9 genes. KEGG pathways analysis revealed the role of TfAA9 proteins in the endohydrolysis of 1,4-beta-D-glucosidic linkages in cellulose. Numerous TfAA9s gene transcripts were up-regulated on avicel, cellobiose, and glucose, with a higher proportion on avicel. Protein concentration, endoglucanase, and cellulase activity were also boosted on avicel. However, limited fungal biomass was observed on avicel, despite the abundance of AA9 LPMOs in the T. fergusii genome. These findings expand our understanding of fungal AA9 genes and their role in lignocellulolytic degradation. The disparity between biomass and enzymatic activity suggests screening TfAA9 genes for highly active enzymes and redundant genes via heterologous expression. In short, functional characterization of these genes could contribute to improving the saccharification process of industrial raw materials.
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Affiliation(s)
- Abdul Waheed
- Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Yi Chen
- Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China
| | - Hafiz Muhammad Rizwan
- College of Civil and Transportation Engineering, Shenzhen University, Shenzhen 518060, China; Shenzhen Key Laboratory of Food Nutrition and Health, College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Muhammad Adnan
- Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China
| | - Xuekun Ma
- Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China
| | - Gang Liu
- Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China.
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Dixit M, Shukla P. Analysis of endoglucanases production using metatranscriptomics and proteomics approach. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2023; 138:211-231. [PMID: 38220425 DOI: 10.1016/bs.apcsb.2023.04.005] [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: 01/16/2024]
Abstract
The cellulases are among the most used enzyme in industries for various purposes. They add up to the green economy perspective and cost-effective production of enterprises. Biorefineries, paper industries, and textile industries are foremost in their usage. The production of endoglucanases from microorganisms is a valuable resource and can be exploited with the help of biotechnology. The present review provides some insight into the uses of endoglucanases in different industries and the potent fungal source of these enzymes. The advances in the enzyme technology has helped towards understanding some pathways to increase the production of industrial enzymes from microorganisms. The proteomics analysis and systems biology tools also help to identify these pathways for the enhanced production of such enzymes. This review deciphers the use of proteomics tools to analyze the potent microorganisms and identify suitable culture conditions to increase the output of endoglucanases. The review also includes the role of quantitative proteomics which is a powerful technique to get results faster and more timely. The role of metatranscriptomic approaches are also described which are helpful in the enzyme engineering for their efficient use under industrial conditions. Conclusively, this review helps to understand the challenges faced in the industrial use of endoglucanases and their further improvement.
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Affiliation(s)
- Mandeep Dixit
- Department of Botany, Deen Dayal Upadhyaya College, University of Delhi, New Delhi, India
| | - Pratyoosh Shukla
- Enzyme Technology and Protein Bioinformatics Laboratory, School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, India.
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Yu NN, Ketya W, Park G. Intracellular Nitric Oxide and cAMP Are Involved in Cellulolytic Enzyme Production in Neurospora crassa. Int J Mol Sci 2023; 24:ijms24054503. [PMID: 36901932 PMCID: PMC10003064 DOI: 10.3390/ijms24054503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 02/16/2023] [Accepted: 02/22/2023] [Indexed: 03/03/2023] Open
Abstract
Although molecular regulation of cellulolytic enzyme production in filamentous fungi has been actively explored, the underlying signaling processes in fungal cells are still not clearly understood. In this study, the molecular signaling mechanism regulating cellulase production in Neurospora crassa was investigated. We found that the transcription and extracellular cellulolytic activity of four cellulolytic enzymes (cbh1, gh6-2, gh5-1, and gh3-4) increased in Avicel (microcrystalline cellulose) medium. Intracellular nitric oxide (NO) and reactive oxygen species (ROS) detected by fluorescent dyes were observed in larger areas of fungal hyphae grown in Avicel medium compared to those grown in glucose medium. The transcription of the four cellulolytic enzyme genes in fungal hyphae grown in Avicel medium was significantly decreased and increased after NO was intracellularly removed and extracellularly added, respectively. Furthermore, we found that the cyclic AMP (cAMP) level in fungal cells was significantly decreased after intracellular NO removal, and the addition of cAMP could enhance cellulolytic enzyme activity. Taken together, our data suggest that the increase in intracellular NO in response to cellulose in media may have promoted the transcription of cellulolytic enzymes and participated in the elevation of intracellular cAMP, eventually leading to improved extracellular cellulolytic enzyme activity.
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Affiliation(s)
- Nan-Nan Yu
- Plasma Bioscience Research Center, Department of Plasma-Bio Display, Kwangwoon University, Seoul 01897, Republic of Korea
| | - Wirinthip Ketya
- Plasma Bioscience Research Center, Department of Plasma-Bio Display, Kwangwoon University, Seoul 01897, Republic of Korea
| | - Gyungsoon Park
- Plasma Bioscience Research Center, Department of Plasma-Bio Display, Kwangwoon University, Seoul 01897, Republic of Korea
- Department of Electrical and Biological Physics, Kwangwoon University, Seoul 01897, Republic of Korea
- Correspondence: ; Tel.: +82-2-940-8324
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Chang H, Gacias Amengual N, Botz A, Schwaiger L, Kracher D, Scheiblbrandner S, Csarman F, Ludwig R. Investigating lytic polysaccharide monooxygenase-assisted wood cell wall degradation with microsensors. Nat Commun 2022; 13:6258. [PMID: 36271009 PMCID: PMC9586961 DOI: 10.1038/s41467-022-33963-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 10/10/2022] [Indexed: 12/25/2022] Open
Abstract
Lytic polysaccharide monooxygenase (LPMO) supports biomass hydrolysis by increasing saccharification efficiency and rate. Recent studies demonstrate that H2O2 rather than O2 is the cosubstrate of the LPMO-catalyzed depolymerization of polysaccharides. Some studies have questioned the physiological relevance of the H2O2-based mechanism for plant cell wall degradation. This study reports the localized and time-resolved determination of LPMO activity on poplar wood cell walls by measuring the H2O2 concentration in their vicinity with a piezo-controlled H2O2 microsensor. The investigated Neurospora crassa LPMO binds to the inner cell wall layer and consumes enzymatically generated H2O2. The results point towards a high catalytic efficiency of LPMO at a low H2O2 concentration that auxiliary oxidoreductases in fungal secretomes can easily generate. Measurements with a glucose microbiosensor additionally demonstrate that LPMO promotes cellobiohydrolase activity on wood cell walls and plays a synergistic role in the fungal extracellular catabolism and in industrial biomass degradation.
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Affiliation(s)
- Hucheng Chang
- grid.5173.00000 0001 2298 5320Department of Food Science and Technology, Institute of Food Technology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Neus Gacias Amengual
- grid.5173.00000 0001 2298 5320Department of Food Science and Technology, Institute of Food Technology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Alexander Botz
- grid.5173.00000 0001 2298 5320Department of Food Science and Technology, Institute of Food Technology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Lorenz Schwaiger
- grid.5173.00000 0001 2298 5320Department of Food Science and Technology, Institute of Food Technology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Daniel Kracher
- grid.5173.00000 0001 2298 5320Department of Food Science and Technology, Institute of Food Technology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria ,grid.410413.30000 0001 2294 748XPresent Address: Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
| | - Stefan Scheiblbrandner
- grid.5173.00000 0001 2298 5320Department of Food Science and Technology, Institute of Food Technology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Florian Csarman
- grid.5173.00000 0001 2298 5320Department of Food Science and Technology, Institute of Food Technology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Roland Ludwig
- grid.5173.00000 0001 2298 5320Department of Food Science and Technology, Institute of Food Technology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
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Plasma Promotes Fungal Cellulase Production by Regulating the Levels of Intracellular NO and Ca 2. Int J Mol Sci 2022; 23:ijms23126668. [PMID: 35743111 PMCID: PMC9223429 DOI: 10.3390/ijms23126668] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 06/12/2022] [Accepted: 06/14/2022] [Indexed: 12/04/2022] Open
Abstract
For the industrial-scale production of useful enzymes by microorganisms, technological development is required for overcoming a technical bottleneck represented by poor efficiency in the induction of enzyme gene expression and secretion. In this study, we evaluated the potential of a non-thermal atmospheric pressure plasma jet to improve the production efficiency of cellulolytic enzymes in Neurospora crassa, a filamentous fungus. The total activity of cellulolytic enzymes and protein concentration were significantly increased (1.1~1.2 times) in media containing Avicel 24–72 h after 2 and 5 min of plasma treatment. The mRNA levels of four cellulolytic enzymes in fungal hyphae grown in media with Avicel were significantly increased (1.3~17 times) 2–4 h after a 5 min of plasma treatment. The levels of intracellular NO and Ca2+ were increased in plasma-treated fungal hyphae grown in Avicel media after 48 h, and the removal of intracellular NO decreased the activity of cellulolytic enzymes in media and the level of vesicles in fungal hyphae. Our data suggest that plasma treatment can promote the transcription and secretion of cellulolytic enzymes into the culture media in the presence of Avicel (induction condition) by enhancing the intracellular level of NO and Ca2+.
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Sagarika MS, Parameswaran C, Senapati A, Barala J, Mitra D, Prabhukarthikeyan SR, Kumar A, Nayak AK, Panneerselvam P. Lytic polysaccharide monooxygenases (LPMOs) producing microbes: A novel approach for rapid recycling of agricultural wastes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:150451. [PMID: 34607097 DOI: 10.1016/j.scitotenv.2021.150451] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 09/12/2021] [Accepted: 09/15/2021] [Indexed: 06/13/2023]
Abstract
Out of the huge quantity of agricultural wastes produced globally, rice straw is one of the most abundant ligno-cellulosic waste. For efficient utilization of these wastes, several cost-effective biological processes are available. The practice of field level in-situ or ex-situ decomposition of rice straw is having less degree of adoption due to its poor decomposition ability within a short time span between rice harvest and sowing of the next crop. Agricultural wastes including rice straw are in general utilized by using lignocellulose degrading microbes for industrial metabolite or compost production. However, bioconversion of crystalline cellulose and lignin present in the waste, into simple molecules is a challenging task. To resolve this issue, researchers have identified a novel new generation microbial enzyme i.e., lytic polysaccharide monooxygenases (LPMOs) and reported that the combination of LPMOs with other glycolytic enzymes are found efficient. This review explains the progress made in LPMOs and their role in lignocellulose bioconversion and the possibility of exploring LPMOs producers for rapid decomposition of agricultural wastes. Also, it provides insights to identify the knowledge gaps in improving the potential of the existing ligno-cellulolytic microbial consortium for efficient utilization of agricultural wastes at industrial and field levels.
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Affiliation(s)
- Mahapatra Smruthi Sagarika
- ICAR - National Rice Research Institute, Cuttack, Odisha 753006, India; Indira Gandhi Agricultural University, Raipur, Chhattisgarh 492012, India
| | | | - Ansuman Senapati
- ICAR - National Rice Research Institute, Cuttack, Odisha 753006, India
| | - Jatiprasad Barala
- ICAR - National Rice Research Institute, Cuttack, Odisha 753006, India
| | - Debasis Mitra
- ICAR - National Rice Research Institute, Cuttack, Odisha 753006, India
| | | | - Anjani Kumar
- ICAR - National Rice Research Institute, Cuttack, Odisha 753006, India
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Filiatrault-Chastel C, Heiss-Blanquet S, Margeot A, Berrin JG. From fungal secretomes to enzymes cocktails: The path forward to bioeconomy. Biotechnol Adv 2021; 52:107833. [PMID: 34481893 DOI: 10.1016/j.biotechadv.2021.107833] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 08/30/2021] [Accepted: 08/31/2021] [Indexed: 12/17/2022]
Abstract
Bioeconomy is seen as a way to mitigate the carbon footprint of human activities by reducing at least part of the fossil resources-based economy. In this new paradigm of sustainable development, the use of enzymes as biocatalysts will play an increasing role to provide services and goods. In industry, most of multicomponent enzyme cocktails are of fungal origin. Filamentous fungi secrete complex enzyme sets called "secretomes" that can be utilized as enzyme cocktails to valorize different types of bioresources. In this review, we highlight recent advances in the study of fungal secretomes using improved computational and experimental secretomics methods, the progress in the understanding of industrially important fungi, and the discovery of new enzymatic mechanisms and interplays to degrade renewable resources rich in polysaccharides (e.g. cellulose). We review current biotechnological applications focusing on the benefits and challenges of fungal secretomes for industrial applications with some examples of commercial cocktails of fungal origin containing carbohydrate-active enzymes (CAZymes) and we discuss future trends.
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Affiliation(s)
- Camille Filiatrault-Chastel
- INRAE, Aix Marseille Univ., Biodiversité et Biotechnologie Fongiques, UMR1163, Marseille, France; IFP Energies nouvelles, 1 et 4 avenue de Bois-Préau, 92852 Rueil-Malmaison, France.
| | - Senta Heiss-Blanquet
- IFP Energies nouvelles, 1 et 4 avenue de Bois-Préau, 92852 Rueil-Malmaison, France.
| | - Antoine Margeot
- IFP Energies nouvelles, 1 et 4 avenue de Bois-Préau, 92852 Rueil-Malmaison, France.
| | - Jean-Guy Berrin
- INRAE, Aix Marseille Univ., Biodiversité et Biotechnologie Fongiques, UMR1163, Marseille, France.
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10
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Sethupathy S, Morales GM, Li Y, Wang Y, Jiang J, Sun J, Zhu D. Harnessing microbial wealth for lignocellulose biomass valorization through secretomics: a review. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:154. [PMID: 34225772 PMCID: PMC8256616 DOI: 10.1186/s13068-021-02006-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 06/26/2021] [Indexed: 05/10/2023]
Abstract
The recalcitrance of lignocellulosic biomass is a major constraint to its high-value use at industrial scale. In nature, microbes play a crucial role in biomass degradation, nutrient recycling and ecosystem functioning. Therefore, the use of microbes is an attractive way to transform biomass to produce clean energy and high-value compounds. The microbial degradation of lignocelluloses is a complex process which is dependent upon multiple secreted enzymes and their synergistic activities. The availability of the cutting edge proteomics and highly sensitive mass spectrometry tools make possible for researchers to probe the secretome of microbes and microbial consortia grown on different lignocelluloses for the identification of hydrolytic enzymes of industrial interest and their substrate-dependent expression. This review summarizes the role of secretomics in identifying enzymes involved in lignocelluloses deconstruction, the development of enzyme cocktails and the construction of synthetic microbial consortia for biomass valorization, providing our perspectives to address the current challenges.
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Affiliation(s)
- Sivasamy Sethupathy
- School of the Environment and Safety Engineering, Biofuels Institute, Jiangsu University, Zhenjiang, 212013, Jiangsu, China
| | - Gabriel Murillo Morales
- School of the Environment and Safety Engineering, Biofuels Institute, Jiangsu University, Zhenjiang, 212013, Jiangsu, China
| | - Yixuan Li
- School of the Environment and Safety Engineering, Biofuels Institute, Jiangsu University, Zhenjiang, 212013, Jiangsu, China
| | - Yongli Wang
- School of the Environment and Safety Engineering, Biofuels Institute, Jiangsu University, Zhenjiang, 212013, Jiangsu, China
| | - Jianxiong Jiang
- School of the Environment and Safety Engineering, Biofuels Institute, Jiangsu University, Zhenjiang, 212013, Jiangsu, China
| | - Jianzhong Sun
- School of the Environment and Safety Engineering, Biofuels Institute, Jiangsu University, Zhenjiang, 212013, Jiangsu, China
| | - Daochen Zhu
- School of the Environment and Safety Engineering, Biofuels Institute, Jiangsu University, Zhenjiang, 212013, Jiangsu, China.
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11
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Manavalan T, Stepnov AA, Hegnar OA, Eijsink VGH. Sugar oxidoreductases and LPMOs - two sides of the same polysaccharide degradation story? Carbohydr Res 2021; 505:108350. [PMID: 34049079 DOI: 10.1016/j.carres.2021.108350] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 05/13/2021] [Accepted: 05/14/2021] [Indexed: 12/20/2022]
Abstract
Lytic polysaccharide monooxygenases (LPMOs) catalyze the oxidative cleavage of glycosidic bonds in recalcitrant polysaccharides such as chitin and cellulose and their discovery has revolutionized our understanding of enzymatic biomass conversion. The discovery of LPMOs raises interesting new questions regarding the roles of other oxidoreductases and abiotic redox processes in biomass conversion. LPMOs need reducing power and an oxygen co-substrate and biomass degrading ecosystems contain a multitude of redox enzymes that affect the availability of both. For example, biomass degrading fungi produce multiple sugar oxidoreductases whose biological functions so far have remained somewhat enigmatic. It is now conceivable that these redox enzymes, in particular H2O2-producing sugar oxidases, could play a role in fueling and controlling LPMO reactions. Here, we shortly review contemporary issues in the LPMO field, paying particular attention to the possible roles of sugar oxidoreductases.
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Affiliation(s)
- Tamilvendan Manavalan
- Faculty of Chemistry, Biotechnology and Food Science, NMBU - Norwegian University of Life Science, N-1432, Ås, Norway
| | - Anton A Stepnov
- Faculty of Chemistry, Biotechnology and Food Science, NMBU - Norwegian University of Life Science, N-1432, Ås, Norway
| | - Olav A Hegnar
- Faculty of Chemistry, Biotechnology and Food Science, NMBU - Norwegian University of Life Science, N-1432, Ås, Norway
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, NMBU - Norwegian University of Life Science, N-1432, Ås, Norway.
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12
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Felice AKG, Schuster C, Kadek A, Filandr F, Laurent CVFP, Scheiblbrandner S, Schwaiger L, Schachinger F, Kracher D, Sygmund C, Man P, Halada P, Oostenbrink C, Ludwig R. Chimeric Cellobiose Dehydrogenases Reveal the Function of Cytochrome Domain Mobility for the Electron Transfer to Lytic Polysaccharide Monooxygenase. ACS Catal 2021; 11:517-532. [PMID: 33489432 PMCID: PMC7818652 DOI: 10.1021/acscatal.0c05294] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 12/11/2020] [Indexed: 12/11/2022]
Abstract
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The natural function of cellobiose
dehydrogenase (CDH) to donate
electrons from its catalytic flavodehydrogenase (DH) domain via its
cytochrome (CYT) domain to lytic polysaccharide monooxygenase (LPMO)
is an example of a highly efficient extracellular electron transfer
chain. To investigate the function of the CYT domain movement in the
two occurring electron transfer steps, two CDHs from the ascomycete Neurospora crassa (NcCDHIIA and NcCDHIIB) and five chimeric CDH enzymes created by domain
swapping were studied in combination with the fungus’ own LPMOs
(NcLPMO9C and NcLPMO9F). Kinetic
and electrochemical methods and hydrogen/deuterium exchange mass spectrometry
were used to study the domain movement, interaction, and electron
transfer kinetics. Molecular docking provided insights into the protein–protein
interface, the orientation of domains, and binding energies. We find
that the first, interdomain electron transfer step from the catalytic
site in the DH domain to the CYT domain depends on steric and electrostatic
interface complementarity and the length of the protein linker between
both domains but not on the redox potential difference between the
FAD and heme b cofactors. After CYT reduction, a
conformational change of CDH from its closed state to an open state
allows the second, interprotein electron transfer (IPET) step from
CYT to LPMO to occur by direct interaction of the b-type heme and the type-2 copper center. Chimeric CDH enzymes favor
the open state and achieve higher IPET rates by exposing the heme b cofactor to LPMO. The IPET, which is influenced by interface
complementarity and the heme b redox potential, is
very efficient with bimolecular rates between 2.9 × 105 and 1.1 × 106 M–1 s–1.
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Affiliation(s)
- Alfons K. G. Felice
- Biocatalysis and Biosensing Research Group, Department of Food Science and Technology, BOKU−University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Christian Schuster
- Biocatalysis and Biosensing Research Group, Department of Food Science and Technology, BOKU−University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Alan Kadek
- BIOCEV−Institute of Microbiology, The Czech Academy of Sciences, Prumyslova 595, 252 50 Vestec, Czech Republic
- Department of Biochemistry, Faculty of Science, Charles University in Prague, Hlavova 8, 128 43 Prague, Czech Republic
| | - Frantisek Filandr
- BIOCEV−Institute of Microbiology, The Czech Academy of Sciences, Prumyslova 595, 252 50 Vestec, Czech Republic
- Department of Biochemistry, Faculty of Science, Charles University in Prague, Hlavova 8, 128 43 Prague, Czech Republic
| | - Christophe V. F. P. Laurent
- Biocatalysis and Biosensing Research Group, Department of Food Science and Technology, BOKU−University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
- Department of Material Sciences and Process Engineering, BOKU−University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Stefan Scheiblbrandner
- Biocatalysis and Biosensing Research Group, Department of Food Science and Technology, BOKU−University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Lorenz Schwaiger
- Biocatalysis and Biosensing Research Group, Department of Food Science and Technology, BOKU−University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Franziska Schachinger
- Biocatalysis and Biosensing Research Group, Department of Food Science and Technology, BOKU−University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Daniel Kracher
- Biocatalysis and Biosensing Research Group, Department of Food Science and Technology, BOKU−University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Christoph Sygmund
- Biocatalysis and Biosensing Research Group, Department of Food Science and Technology, BOKU−University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Petr Man
- BIOCEV−Institute of Microbiology, The Czech Academy of Sciences, Prumyslova 595, 252 50 Vestec, Czech Republic
- Department of Biochemistry, Faculty of Science, Charles University in Prague, Hlavova 8, 128 43 Prague, Czech Republic
| | - Petr Halada
- BIOCEV−Institute of Microbiology, The Czech Academy of Sciences, Prumyslova 595, 252 50 Vestec, Czech Republic
| | - Chris Oostenbrink
- Department of Material Sciences and Process Engineering, BOKU−University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Roland Ludwig
- Biocatalysis and Biosensing Research Group, Department of Food Science and Technology, BOKU−University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
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13
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Abstract
Filamentous fungi are critical for the recycling of plant litter in the biosphere by degrading lignocellulosic biomass into simpler compounds for metabolism. Both saprophytic and pathogenic fungi utilize plant cell wall-degrading enzymes to liberate carbon for metabolism. Several studies have demonstrated a role for cellulase enzymes during infection of economically relevant crops by fungal pathogens. Especially in developing countries, severe plant disease means loss of entire crops, sometimes leading to starvation. In this study, we demonstrate that G-protein signaling is a key component of cellulase production. Therefore, understanding the role of G-protein signaling in the regulation of the unique metabolism of cellulose by these organisms can inform innovations in strain engineering of industrially relevant species for biofuel production and in combatting food shortages caused by plant pathogens. The filamentous fungus Neurospora crassa decomposes lignocellulosic biomass to generate soluble sugars as carbon sources. In this study, we investigated a role for heterotrimeric G-protein signaling in cellulose degradation. Loss of the Gα subunit genes gna-1 and gna-3, the Gβ subunit genes gnb-1 and cpc-2, the Gγ gene gng-1, or the gene for downstream effector adenylyl cyclase (cr-1) resulted in loss of detectable cellulase activity. This defect was also observed in strains expressing a constitutively active version of gna-3 (gna-3Q208L). We found that GNA-1 levels are greatly reduced in Δgna-3, Δgnb-1, and Δgng-1 strains, likely contributing to cellulase defects in these genetic backgrounds. The observation that gna-3Q208L Δgnb-1 strains exhibit cellulase activity, despite greatly reduced levels of GNA-1 protein, is consistent with positive control of cellulase production by GNA-3 that is manifested in the absence of gnb-1. Expression patterns for five cellulase genes showed that Δgna-1, Δgnb-1, and Δgna-3 mutants produce less cellulase mRNA than the wild type, consistent with transcriptional regulation. Δcpc-2 mutants had wild-type levels of cellulase transcripts, suggesting posttranscriptional control. In contrast, results for Δcr-1 mutants support both transcriptional and posttranscriptional control of cellulase activity by cAMP signaling. Cellulase activity defects in Δgna-3 mutants were fully remediated by cAMP supplementation, consistent with GNA-3 operating upstream of cAMP signaling. In contrast, cAMP addition only partially corrected cellulase activity defects in Δgna-1 and Δgnb-1 mutants, suggesting participation of GNA-1 and GNB-1 in additional cAMP-independent pathways that control cellulase activity.
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14
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Arntzen MØ, Bengtsson O, Várnai A, Delogu F, Mathiesen G, Eijsink VGH. Quantitative comparison of the biomass-degrading enzyme repertoires of five filamentous fungi. Sci Rep 2020; 10:20267. [PMID: 33219291 PMCID: PMC7679414 DOI: 10.1038/s41598-020-75217-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 10/07/2020] [Indexed: 12/26/2022] Open
Abstract
The efficiency of microorganisms to degrade lignified plants is of great importance in the Earth's carbon cycle, but also in industrial biorefinery processes, such as for biofuel production. Here, we present a large-scale proteomics approach to investigate and compare the enzymatic response of five filamentous fungi when grown on five very different substrates: grass (sugarcane bagasse), hardwood (birch), softwood (spruce), cellulose and glucose. The five fungi included the ascomycetes Aspergillus terreus, Trichoderma reesei, Myceliophthora thermophila, Neurospora crassa and the white-rot basidiomycete Phanerochaete chrysosporium, all expressing a diverse repertoire of enzymes. In this study, we present comparable quantitative protein abundance values across five species and five diverse substrates. The results allow for direct comparison of fungal adaptation to the different substrates, give indications as to the substrate specificity of individual carbohydrate-active enzymes (CAZymes), and reveal proteins of unknown function that are co-expressed with CAZymes. Based on the results, we present a quantitative comparison of 34 lytic polysaccharide monooxygenases (LPMOs), which are crucial enzymes in biomass deconstruction.
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Affiliation(s)
- Magnus Ø Arntzen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Ås, Norway.
| | - Oskar Bengtsson
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Ås, Norway
| | - Anikó Várnai
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Ås, Norway
| | - Francesco Delogu
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Ås, Norway
| | - Geir Mathiesen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Ås, Norway
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Ås, Norway
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15
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Gangwar R, Rasool S, Mishra S. Purified cellobiose dehydrogenase of Termitomyces sp. OE147 fuels cellulose degradation resulting in the release of reducing sugars. Prep Biochem Biotechnol 2020; 51:488-496. [PMID: 33063604 DOI: 10.1080/10826068.2020.1833343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Termitomyces sp. OE 147 is one of the active cellulose degraders in the ecosphere and produces large amount of cellobiose dehydrogenase (CDH) and β-glucosidases when cultivated on cellulose. In order to investigate its effect on cellulose, a highly purified preparation of CDH was obtained from the culture supernatant of the fungus cultivated on cellulose. A combination of ultrafiltration, ion-exchange and gel-filtration chromatography was used to purify CDH by ∼172-fold to a high specific activity of ∼324 U/mg protein on lactose which was used for routine measurement of enzyme activity. The enzyme displayed a pH optimum of 5.0 and stability between pH 5.0 and 8.0 with maximum catalytic efficiency (kcat/Km) of 397 mM-1 s-1 on cellobiose. Incubation of microcrystalline cellulose with the purified CDH led to production of reducing sugars which was accelerated by the addition of FeCl3 during the early stages of incubation. A mass spectrometric analysis revealed fragmentation products of cellulose which were concluded to be cellodextrins, sugars, and corresponding aldonic acids suggesting that CDH can release reducing sugars in the absence of externally added lytic polysaccharide monooxygenases. Polymerized products of glucose were also detected at low intensity.
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Affiliation(s)
- Rishabh Gangwar
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi, India.,School of Biotechnology, Shri Mata Vaishno Devi University, Katra, India
| | - Shafaq Rasool
- School of Biotechnology, Shri Mata Vaishno Devi University, Katra, India
| | - Saroj Mishra
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi, India
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16
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Li X, Han C, Li W, Chen G, Wang L. Insights into the cellulose degradation mechanism of the thermophilic fungus Chaetomium thermophilum based on integrated functional omics. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:143. [PMID: 32817759 PMCID: PMC7425565 DOI: 10.1186/s13068-020-01783-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 08/04/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Lignocellulose is the most abundant and renewable biomass resource on the planet. Lignocellulose can be converted into biofuels and high-value compounds; however, its recalcitrance makes its breakdown a challenge. Lytic polysaccharide monooxygenases (LPMOs) offer tremendous promise for the degradation of recalcitrant polysaccharides. Chaetomium thermophilum, having many LPMO-coding genes, is a dominant thermophilic fungus in cellulose-rich and self-heating habitats. This study explores the genome, secretomes and transcript levels of specific genes of C. thermophilum. RESULTS The genome of C. thermophilum encoded a comprehensive set of cellulose- and xylan-degrading enzymes, especially 18 AA9 LPMOs that belonged to different subfamilies. Extracellular secretomes showed that arabinose and microcrystalline cellulose (MCC) could specifically induce the secretion of carbohydrate-active enzymes (CAZymes), especially AA9 LPMOs, by C. thermophilum under different carbon sources. Temporal analyses of secretomes and transcripts revealed that arabinose induced the secretion of xylanases by C. thermophilum, which was obviously different from other common filamentous fungi. MCC could efficiently induce the specific secretion of LPMO2s, possibly because the insert in loop3 on the substrate-binding surface of LPMO2s strengthened its binding capacity to cellulose. LPMO2s, cellobio hydrolases (CBHs) and cellobiose dehydrogenases (CDHs) were cosecreted, forming an efficient cellulose degradation system of oxidases and hydrolases under thermophilic conditions. CONCLUSIONS The specific expression of LPMO2s and cosecretion of hydrolases and oxidases by the thermophilic fungus C. thermophilum play an important role in cellulose degradation. This insight increases our understanding of the cellulose degradation under thermophilic conditions and may inspire the design of the optimal enzyme cocktails for more efficient exploration of biomass resources in industrial applications.
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Affiliation(s)
- Xin Li
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, No. 72 Jimo Binhai Road, Qingdao, 266237 Shandong People’s Republic of China
| | - Chao Han
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, No. 72 Jimo Binhai Road, Qingdao, 266237 Shandong People’s Republic of China
| | - Weiguang Li
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, No. 72 Jimo Binhai Road, Qingdao, 266237 Shandong People’s Republic of China
| | - Guanjun Chen
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, No. 72 Jimo Binhai Road, Qingdao, 266237 Shandong People’s Republic of China
| | - Lushan Wang
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, No. 72 Jimo Binhai Road, Qingdao, 266237 Shandong People’s Republic of China
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17
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Díaz RD, Larrondo LF. A circadian clock in Neurospora crassa functions during plant cell wall deconstruction. Fungal Biol 2020; 124:501-508. [PMID: 32389313 DOI: 10.1016/j.funbio.2020.03.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 03/05/2020] [Accepted: 03/07/2020] [Indexed: 01/24/2023]
Abstract
Circadian clocks are autonomous timers that are believed to confer organisms a selective advantage by enabling processes to occur at appropriate times of the day. In the model fungus Neurospora crassa, 20-40 % of its genes are reported to be under circadian regulation, as assayed in simple sugar media. Although it has been well-described that Neurospora efficiently deconstructs plant cell wall components, little is known regarding the status of the clock when Neurospora grows on cellulosic material, or whether such a clock has an impact on any of the genes involved in this process. Through luciferase-based reporters and fluorescent detection assays, we show that a clock is functioning when Neurospora grows on cellulose-containing wheat straw as the only carbon and nitrogen source. Additionally, we found that the major cellobiohydrolase encoding gene involved in plant cell wall deconstruction, cbh-1, is rhythmically regulated by the Neurospora clock, in a manner that depends on cellulose concentration and on the transcription factor CRE-1, known as a key player in carbon-catabolite repression in this fungus. Our findings are a step towards a more comprehensive understanding on how clock regulation modulates cellulose degradation, and thus Neurospora's physiology.
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Affiliation(s)
- Rodrigo D Díaz
- Millennium Institute for Integrative Biology, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile
| | - Luis F Larrondo
- Millennium Institute for Integrative Biology, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile.
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18
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Filandr F, Man P, Halada P, Chang H, Ludwig R, Kracher D. The H 2O 2-dependent activity of a fungal lytic polysaccharide monooxygenase investigated with a turbidimetric assay. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:37. [PMID: 32158501 PMCID: PMC7057652 DOI: 10.1186/s13068-020-01673-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 02/01/2020] [Indexed: 05/18/2023]
Abstract
BACKGROUND Lytic polysaccharide monooxygenases (LPMOs) are copper-dependent redox enzymes that cleave recalcitrant biopolymers such as cellulose, chitin, starch and hemicelluloses. Although LPMOs receive ample interest in industry and academia, their reaction mechanism is not yet fully understood. Recent studies showed that H2O2 is a more efficient cosubstrate for the enzyme than O2, which could greatly affect the utilization of LPMOs in industrial settings. RESULTS We probe the reactivity of LPMO9C from the cellulose-degrading fungus Neurospora crassa with a turbidimetric assay using phosphoric acid-swollen cellulose (PASC) as substrate and H2O2 as a cosubstrate. The measurements were also followed by continuous electrochemical H2O2 detection and LPMO reaction products were analysed by mass spectrometry. Different systems for the in situ generation of H2O2 and for the reduction of LPMO's active-site copper were employed, including glucose oxidase, cellobiose dehydrogenase, and the routinely used reductant ascorbate. CONCLUSIONS We found for all systems that the supply of H2O2 limited LPMO's cellulose depolymerization activity, which supports the function of H2O2 as the relevant cosubstrate. The turbidimetric assay allowed rapid determination of LPMO activity on a cellulosic substrate without the need for time-consuming and instrumentally elaborate analysis methods.
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Affiliation(s)
- Frantisek Filandr
- BioCeV-Institute of Microbiology, The Czech Academy of Sciences, Prumyslova 595, 252 50 Vestec, Czech Republic
- Faculty of Science, Charles University, Hlavova 2030/8, 128 43 Prague 2, Czech Republic
- Biocatalysis and Biosensing Research Group, Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Petr Man
- BioCeV-Institute of Microbiology, The Czech Academy of Sciences, Prumyslova 595, 252 50 Vestec, Czech Republic
| | - Petr Halada
- BioCeV-Institute of Microbiology, The Czech Academy of Sciences, Prumyslova 595, 252 50 Vestec, Czech Republic
| | - Hucheng Chang
- Biocatalysis and Biosensing Research Group, Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Roland Ludwig
- Biocatalysis and Biosensing Research Group, Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Daniel Kracher
- Biocatalysis and Biosensing Research Group, Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
- The University of Manchester, Manchester Institute of Biotechnology, Manchester, M1 7DN UK
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19
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Yang J, Deng L, Zhao C, Fang H. Heterologous expression of Neurospora crassa cbh1 gene in Pichia pastoris resulted in production of a neutral cellobiohydrolase I. Biotechnol Prog 2019; 35:e2795. [PMID: 30816014 DOI: 10.1002/btpr.2795] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Revised: 01/14/2019] [Accepted: 02/20/2019] [Indexed: 11/10/2022]
Abstract
The high production cost of cellulase is one of the limitations that hinder the commercialization of lignocellulose-based biorefineries. As one of the important cellulases, Neurospora crassa cellulase is not so intensively investigated as T. reesei cellulase. In this study, the cbh1gene (NCU07340) cloned from N. crassa was expressed in Pichia pastoris under the control of alcohol oxidase 1 (AOX1) promotor. Six transformants with the highest resistance to G418 were selected by two rounds of transformant screening, among which the most robust producer of the recombinant cellobiohydrolase I (CBHI) has an Avicelase activity of 0.22 U/mL. After fermentation optimization, it was improved to 0.30 U/mL. Interestingly, the optimal temperature and pH of the recombinant CBHI were 60°C and 7.2, respectively, and it was quite stable within the wide ranges of temperature and pH. This work is a good example for the future improvement and optimization of N. crassa cellulase.
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Affiliation(s)
- Jie Yang
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China.,Biomass Energy Center for Arid and Semi-arid Lands, Northwest A&F University, Yangling, Shaanxi, China
| | - Lu Deng
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China.,Biomass Energy Center for Arid and Semi-arid Lands, Northwest A&F University, Yangling, Shaanxi, China
| | - Chen Zhao
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China.,Biomass Energy Center for Arid and Semi-arid Lands, Northwest A&F University, Yangling, Shaanxi, China
| | - Hao Fang
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China.,Biomass Energy Center for Arid and Semi-arid Lands, Northwest A&F University, Yangling, Shaanxi, China
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20
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In-Situ Vacuum Assisted Gas Stripping Recovery System for Ethanol Removal from a Column Bioreactor. FIBERS 2018. [DOI: 10.3390/fib6040088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A three-step process consisting of biomass hydrolysis, fermentation and in-situ gas stripping by a vacuum assisted recovery system, was optimized to increase the ethanol production from sugar beet pulp. The process combines the advantages of stripping and vacuum separation and enhances the fermentation productivity through in-situ ethanol removal. Using the design of experiment and response surface methodology, the effect of major factors in the process, such as pressure, recycling ratio and solids concentration, was tested to efficiently remove ethanol after the combined hydrolysis and fermentation step. Statistical analysis indicates that a decreased pressure rate and an increased liquid phase recycling ratio enhance the productivity and the yield of the strip-vacuum fermentation process. The results also highlight further possibilities of this process to improve integrated bioethanol production processes. According to the statistical analysis, ethanol production is strongly influenced by recycling ratio and vacuum ratio. Mathematical models that were established for description of investigated processes can be used for the optimization of the ethanol production.
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21
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Lin L, Sun Z, Li J, Chen Y, Liu Q, Sun W, Tian C. Disruption of gul-1 decreased the culture viscosity and improved protein secretion in the filamentous fungus Neurospora crassa. Microb Cell Fact 2018; 17:96. [PMID: 29908565 PMCID: PMC6004096 DOI: 10.1186/s12934-018-0944-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 06/12/2018] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND The cellulolytic fungus Neurospora crassa is considered a potential host for enzyme and bioethanol production. However, large scale applications are hindered by its filamentous growth. Although previous investigations have shown that mycelial morphology in submerged culture can be controlled by altering physical factors, there is little knowledge available about the potential for morphology control by genetic modification. RESULTS In this study, we screened morphological mutants in the filamentous fungus N. crassa. Of the 90 morphological mutants screened, 14 mutants exhibited considerably higher viscosity compared with that of the wild type strain, and only two mutants showed low-viscosity morphologies in submerged culture. We observed that disruption of gul-1 (NCU01197), which encodes an mRNA binding protein involved in cell wall remodeling, caused pellet formation as the fermentation progressed, and resulted in the most significant decrease in viscosity of culture broth. Moreover, over-expression of gul-1 caused dramatically increased viscosity, suggesting that the gul-1 had an important function in mycelial morphology during submerged cultivation. Transcriptional profiling showed that expression of genes encoding eight GPI-anchored cell wall proteins was lowered in Δgul-1 while expression of genes associated with two non-anchored cell wall proteins was elevated. Meanwhile, the expression levels of two hydrophobin genes were also significantly altered. These results suggested that GUL-1 affected the transcription of cell wall-related genes, thereby influencing cell wall structure and mycelial morphology. Additionally, the deletion of gul-1 caused increased protein secretion, probably due to a defect in cell wall integrity, suggesting this as an alternative strategy of strain improvement for enzyme production. To confirm practical applications, deletion of gul-1 in the hyper-cellulase producing strain (∆ncw-1∆Ncap3m) significantly reduced the viscosity of culture broth. CONCLUSIONS Using the model filamentous fungus N. crassa, genes that affect mycelial morphology in submerged culture were explored through systematic screening of morphological mutants. Disrupting several candidate genes altered viscosities in submerged culture. This work provides an example for controlling fungal morphology in submerged fermentation by genetic engineering, and will be beneficial for industrial fungal strain improvement.
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Affiliation(s)
- Liangcai Lin
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Zhiyong Sun
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Jingen Li
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Yong Chen
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Qian Liu
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Wenliang Sun
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Chaoguang Tian
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
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22
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Loose JSM, Arntzen MØ, Bissaro B, Ludwig R, Eijsink VGH, Vaaje-Kolstad G. Multipoint Precision Binding of Substrate Protects Lytic Polysaccharide Monooxygenases from Self-Destructive Off-Pathway Processes. Biochemistry 2018; 57:4114-4124. [DOI: 10.1021/acs.biochem.8b00484] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jennifer S. M. Loose
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), 1432 Ås, Norway
| | - Magnus Ø. Arntzen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), 1432 Ås, Norway
| | - Bastien Bissaro
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), 1432 Ås, Norway
| | - Roland Ludwig
- BOKU-University of Natural Resources and Life Sciences, Department of Food Science and Technology, Biocatalysis and Biosensing Laboratory, 1180 Vienna, Austria
| | - Vincent G. H. Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), 1432 Ås, Norway
| | - Gustav Vaaje-Kolstad
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), 1432 Ås, Norway
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23
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Identification of Key Components for the Optimization of Cellulase Mixtures Using a Proteomic Strategy. Methods Mol Biol 2018. [PMID: 29856050 DOI: 10.1007/978-1-4939-7877-9_9] [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
Efficient degradation of complex lignocellulosic materials requires the synergistic action of different types of enzymes. Characterizing the compositions of lignocellulolytic enzyme mixtures could provide comprehensive understandings about the enzymatic degradation of lignocelluloses. In this chapter, we present a proteomic strategy for the analysis of enzyme mixtures produced by lignocellulolytic fungi. The described method is easy to carry out and is suitable to determine the composition of lignocellulolytic enzyme mixtures in a semiquantitative manner. Comparison of the compositions of enzyme mixtures with different degrading efficiencies allows for the identification of candidate targets for the optimization of lignocellulolytic enzyme mixtures.
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Hangasky JA, Iavarone AT, Marletta MA. Reactivity of O 2 versus H 2O 2 with polysaccharide monooxygenases. Proc Natl Acad Sci U S A 2018; 115:4915-4920. [PMID: 29686097 PMCID: PMC5949000 DOI: 10.1073/pnas.1801153115] [Citation(s) in RCA: 130] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Enzymatic conversion of polysaccharides into lower-molecular-weight, soluble oligosaccharides is dependent on the action of hydrolytic and oxidative enzymes. Polysaccharide monooxygenases (PMOs) use an oxidative mechanism to break the glycosidic bond of polymeric carbohydrates, thereby disrupting the crystalline packing and creating new chain ends for hydrolases to depolymerize and degrade recalcitrant polysaccharides. PMOs contain a mononuclear Cu(II) center that is directly involved in C-H bond hydroxylation. Molecular oxygen was the accepted cosubstrate utilized by this family of enzymes until a recent report indicated reactivity was dependent on H2O2 Reported here is a detailed analysis of PMO reactivity with H2O2 and O2, in conjunction with high-resolution MS measurements. The cosubstrate utilized by the enzyme is dependent on the assay conditions. PMOs will directly reduce O2 in the coupled hydroxylation of substrate (monooxygenase activity) and will also utilize H2O2 (peroxygenase activity) produced from the uncoupled reduction of O2 Both cosubstrates require Cu reduction to Cu(I), but the reaction with H2O2 leads to nonspecific oxidation of the polysaccharide that is consistent with the generation of a hydroxyl radical-based mechanism in Fenton-like chemistry, while the O2 reaction leads to regioselective substrate oxidation using an enzyme-bound Cu/O2 reactive intermediate. Moreover, H2O2 does not influence the ability of secretome from Neurospora crassa to degrade Avicel, providing evidence that molecular oxygen is a physiologically relevant cosubstrate for PMOs.
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Affiliation(s)
- John A Hangasky
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720
| | - Anthony T Iavarone
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720
- Department of Chemistry, University of California, Berkeley, CA 94720
| | - Michael A Marletta
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720;
- Department of Chemistry, University of California, Berkeley, CA 94720
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
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25
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Bodenheimer AM, O'Dell WB, Oliver RC, Qian S, Stanley CB, Meilleur F. Structural investigation of cellobiose dehydrogenase IIA: Insights from small angle scattering into intra- and intermolecular electron transfer mechanisms. Biochim Biophys Acta Gen Subj 2018; 1862:1031-1039. [DOI: 10.1016/j.bbagen.2018.01.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 12/18/2017] [Accepted: 01/23/2018] [Indexed: 01/08/2023]
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26
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Meier KK, Jones SM, Kaper T, Hansson H, Koetsier MJ, Karkehabadi S, Solomon EI, Sandgren M, Kelemen B. Oxygen Activation by Cu LPMOs in Recalcitrant Carbohydrate Polysaccharide Conversion to Monomer Sugars. Chem Rev 2018; 118:2593-2635. [PMID: 29155571 PMCID: PMC5982588 DOI: 10.1021/acs.chemrev.7b00421] [Citation(s) in RCA: 116] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Natural carbohydrate polymers such as starch, cellulose, and chitin provide renewable alternatives to fossil fuels as a source for fuels and materials. As such, there is considerable interest in their conversion for industrial purposes, which is evidenced by the established and emerging markets for products derived from these natural polymers. In many cases, this is achieved via industrial processes that use enzymes to break down carbohydrates to monomer sugars. One of the major challenges facing large-scale industrial applications utilizing natural carbohydrate polymers is rooted in the fact that naturally occurring forms of starch, cellulose, and chitin can have tightly packed organizations of polymer chains with low hydration levels, giving rise to crystalline structures that are highly recalcitrant to enzymatic degradation. The topic of this review is oxidative cleavage of carbohydrate polymers by lytic polysaccharide mono-oxygenases (LPMOs). LPMOs are copper-dependent enzymes (EC 1.14.99.53-56) that, with glycoside hydrolases, participate in the degradation of recalcitrant carbohydrate polymers. Their activity and structural underpinnings provide insights into biological mechanisms of polysaccharide degradation.
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Affiliation(s)
- Katlyn K. Meier
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Stephen M. Jones
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Thijs Kaper
- DuPont Industrial Biosciences, 925 Page Mill Road, Palo Alto, California 94304, United States
| | - Henrik Hansson
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, P.O. Box 7015, SE-750 07 Uppsala, Sweden
| | - Martijn J. Koetsier
- DuPont Industrial Biosciences, Netherlands, Nieuwe Kanaal 7-S, 6709 PA Wageningen, The Netherlands
| | - Saeid Karkehabadi
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, P.O. Box 7015, SE-750 07 Uppsala, Sweden
| | - Edward I. Solomon
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Mats Sandgren
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, P.O. Box 7015, SE-750 07 Uppsala, Sweden
| | - Bradley Kelemen
- DuPont Industrial Biosciences, 925 Page Mill Road, Palo Alto, California 94304, United States
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27
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Starr TL, Gonçalves AP, Meshgin N, Glass NL. The major cellulases CBH-1 and CBH-2 of Neurospora crassa rely on distinct ER cargo adaptors for efficient ER-exit. Mol Microbiol 2017; 107:229-248. [PMID: 29131484 DOI: 10.1111/mmi.13879] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2017] [Indexed: 12/17/2022]
Abstract
Filamentous fungi are native secretors of lignocellulolytic enzymes and are used as protein-producing factories in the industrial biotechnology sector. Despite the importance of these organisms in industry, relatively little is known about the filamentous fungal secretory pathway or how it might be manipulated for improved protein production. Here, we use Neurospora crassa as a model filamentous fungus to interrogate the requirements for trafficking of cellulase enzymes from the endoplasmic reticulum to the Golgi. We characterized the localization and interaction properties of the p24 and ERV-29 cargo adaptors, as well as their role in cellulase enzyme trafficking. We find that the two most abundantly secreted cellulases, CBH-1 and CBH-2, depend on distinct ER cargo adaptors for efficient exit from the ER. CBH-1 depends on the p24 proteins, whereas CBH-2 depends on the N. crassa homolog of yeast Erv29p. This study provides a first step in characterizing distinct trafficking pathways of lignocellulolytic enzymes in filamentous fungi.
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Affiliation(s)
- Trevor L Starr
- The Energy Biosciences Institute, The University of California, Berkeley, CA 94720, USA
| | - A Pedro Gonçalves
- The Energy Biosciences Institute, The University of California, Berkeley, CA 94720, USA.,Plant and Microbial Biology Department, The University of California, Berkeley, CA 94720, USA
| | - Neeka Meshgin
- The Energy Biosciences Institute, The University of California, Berkeley, CA 94720, USA
| | - N Louise Glass
- The Energy Biosciences Institute, The University of California, Berkeley, CA 94720, USA.,Plant and Microbial Biology Department, The University of California, Berkeley, CA 94720, USA.,Environmental Genomics and Systems Biology Division, The Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
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28
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Harada H, Onoda A, Uchihashi T, Watanabe H, Sunagawa N, Samejima M, Igarashi K, Hayashi T. Interdomain flip-flop motion visualized in flavocytochrome cellobiose dehydrogenase using high-speed atomic force microscopy during catalysis. Chem Sci 2017; 8:6561-6565. [PMID: 28989682 PMCID: PMC5627353 DOI: 10.1039/c7sc01672g] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 07/15/2017] [Indexed: 12/02/2022] Open
Abstract
To visualize the dynamic domain motion of class-I CDH from Phanerochaete chrysosporium (PcCDH) during catalysis using high-speed atomic force microscopy, the apo-form of PcCDH was anchored to a heme-immobilized flat gold surface that can fix the orientation of the CYT domain.
Cellobiose dehydrogenase (CDH) is a dual domain flavocytochrome, which consists of a dehydrogenase (DH) domain containing a flavin adenine dinucleotide and a cytochrome (CYT) domain containing b-type heme. To directly visualize the dynamic domain motion of class-I CDH from Phanerochaete chrysosporium (PcCDH) during catalysis using high-speed atomic force microscopy, the apo-form of PcCDH was anchored to a heme-immobilized flat gold surface that can specifically fix the orientation of the CYT domain. The two domains of CDH are found to be immobile in the absence of cellobiose, whereas the addition of cellobiose triggers an interdomain flip-flop motion involving domain–domain association and dissociation. Our results indicate that dynamic motion of a dual domain enzyme during catalysis induces efficient electron transfer to an external electron acceptor.
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Affiliation(s)
- Hirofumi Harada
- Department of Applied Chemistry , Graduate School of Engineering , Osaka University , 2-1 Yamadaoka , Suita , Osaka 565-0871 , Japan . ;
| | - Akira Onoda
- Department of Applied Chemistry , Graduate School of Engineering , Osaka University , 2-1 Yamadaoka , Suita , Osaka 565-0871 , Japan . ;
| | - Takayuki Uchihashi
- Department of Physics , Nagoya University , Furo-cho, Chikusa-ku , Nagoya , 464-8602 , Japan .
| | - Hiroki Watanabe
- Faculty of Natural Science and Technology , Kanazawa University , Kakuma , Kanazawa , 920-1192 , Japan
| | - Naoki Sunagawa
- Department of Biomaterials Sciences , Graduate School of Agricultural and Life Sciences , The University of Tokyo , Bunkyo-ku , 113-8657 , Japan .
| | - Masahiro Samejima
- Department of Biomaterials Sciences , Graduate School of Agricultural and Life Sciences , The University of Tokyo , Bunkyo-ku , 113-8657 , Japan .
| | - Kiyohiko Igarashi
- Department of Biomaterials Sciences , Graduate School of Agricultural and Life Sciences , The University of Tokyo , Bunkyo-ku , 113-8657 , Japan . .,VTT Technical Research Centre of Finland , P.O. Box 1000, Tietotie 2 , Espoo FI-02044 VTT , Finland
| | - Takashi Hayashi
- Department of Applied Chemistry , Graduate School of Engineering , Osaka University , 2-1 Yamadaoka , Suita , Osaka 565-0871 , Japan . ;
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Berrin JG, Rosso MN, Abou Hachem M. Fungal secretomics to probe the biological functions of lytic polysaccharide monooxygenases. Carbohydr Res 2017; 448:155-160. [DOI: 10.1016/j.carres.2017.05.010] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 05/12/2017] [Accepted: 05/12/2017] [Indexed: 11/29/2022]
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30
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Span EA, Suess DLM, Deller MC, Britt RD, Marletta MA. The Role of the Secondary Coordination Sphere in a Fungal Polysaccharide Monooxygenase. ACS Chem Biol 2017; 12:1095-1103. [PMID: 28257189 DOI: 10.1021/acschembio.7b00016] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Polysaccharide monooxygenases (PMOs) are secreted metalloenzymes that catalyze the oxidative degradation of polysaccharides in a copper-, oxygen-, and reductant-dependent manner. Cellulose-active fungal PMOs degrade cellulosic substrates to be utilized as a carbon source for fungal growth. To gain insight into the PMO mechanism, the role of conserved residues in the copper coordination sphere was investigated. Here, we report active-site hydrogen-bonding motifs in the secondary copper coordination sphere of MtPMO3*, a C1-oxidizing PMO from the ascomycete fungus Myceliophthora thermophila. A series of point substitutions that disrupt this conserved network are used to interrogate its function. Activity assays, in conjunction with EPR spectroscopy, demonstrate that residues H161 and Q167 are involved in stabilizing bound oxygen, and H161 appears to play a role in proton transfer. Additionally, Q167 increases the ligand donor strength of Y169 to the copper via a hydrogen-bonding interaction. Altogether, H161 and Q167 are important for oxygen activation, and the results are suggestive of a copper-oxyl active intermediate.
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Affiliation(s)
- Elise A. Span
- Biophysics
Graduate Group, University of California, Berkeley, Berkeley, California 94720, United States
| | - Daniel L. M. Suess
- Department
of Chemistry, University of California, Davis, Davis, California 95616, United States
| | - Marc C. Deller
- The
Joint Center for Structural Genomics, The Scripps Research Institute, La
Jolla, California 92037, United States
| | - R. David Britt
- Department
of Chemistry, University of California, Davis, Davis, California 95616, United States
| | - Michael A. Marletta
- Department
of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
- Department
of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, United States
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31
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Ashwin NMR, Barnabas L, Ramesh Sundar A, Malathi P, Viswanathan R, Masi A, Agrawal GK, Rakwal R. Advances in proteomic technologies and their scope of application in understanding plant–pathogen interactions. JOURNAL OF PLANT BIOCHEMISTRY AND BIOTECHNOLOGY 2017. [DOI: 10.1007/s13562-017-0402-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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32
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Interdomain electron transfer in cellobiose dehydrogenase is governed by surface electrostatics. Biochim Biophys Acta Gen Subj 2017; 1861:157-167. [DOI: 10.1016/j.bbagen.2016.11.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 11/02/2016] [Accepted: 11/11/2016] [Indexed: 12/18/2022]
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33
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Identification of Glutaminyl Cyclase Genes Involved in Pyroglutamate Modification of Fungal Lignocellulolytic Enzymes. mBio 2017; 8:mBio.02231-16. [PMID: 28096492 PMCID: PMC5241404 DOI: 10.1128/mbio.02231-16] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The breakdown of plant biomass to simple sugars is essential for the production of second-generation biofuels and high-value bioproducts. Currently, enzymes produced from filamentous fungi are used for deconstructing plant cell wall polysaccharides into fermentable sugars for biorefinery applications. A post-translational N-terminal pyroglutamate modification observed in some of these enzymes occurs when N-terminal glutamine or glutamate is cyclized to form a five-membered ring. This modification has been shown to confer resistance to thermal denaturation for CBH-1 and EG-1 cellulases. In mammalian cells, the formation of pyroglutamate is catalyzed by glutaminyl cyclases. Using the model filamentous fungus Neurospora crassa, we identified two genes (qc-1 and qc-2) that encode proteins homologous to mammalian glutaminyl cyclases. We show that qc-1 and qc-2 are essential for catalyzing the formation of an N-terminal pyroglutamate on CBH-1 and GH5-1. CBH-1 and GH5-1 produced in a Δqc-1 Δqc-2 mutant, and thus lacking the N-terminal pyroglutamate modification, showed greater sensitivity to thermal denaturation, and for GH5-1, susceptibility to proteolytic cleavage. QC-1 and QC-2 are endoplasmic reticulum (ER)-localized proteins. The pyroglutamate modification is predicted to occur in a number of additional fungal proteins that have diverse functions. The identification of glutaminyl cyclases in fungi may have implications for production of lignocellulolytic enzymes, heterologous expression, and biotechnological applications revolving around protein stability. Pyroglutamate modification is the post-translational conversion of N-terminal glutamine or glutamate into a cyclized amino acid derivative. This modification is well studied in animal systems but poorly explored in fungal systems. In Neurospora crassa, we show that this modification takes place in the ER and is catalyzed by two well-conserved enzymes, ubiquitously conserved throughout the fungal kingdom. We demonstrate that the modification is important for the structural stability and aminopeptidase resistance of CBH-1 and GH5-1, two important cellulase enzymes utilized in industrial plant cell wall deconstruction. Many additional fungal proteins predicted in the genome of N. crassa and other filamentous fungi are predicted to carry an N-terminal pyroglutamate modification. Pyroglutamate addition may also be a useful way to stabilize secreted proteins and peptides, which can be easily produced in fungal production systems.
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34
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Samal A, Craig JP, Coradetti ST, Benz JP, Eddy JA, Price ND, Glass NL. Network reconstruction and systems analysis of plant cell wall deconstruction by Neurospora crassa. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:225. [PMID: 28947916 PMCID: PMC5609067 DOI: 10.1186/s13068-017-0901-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 09/05/2017] [Indexed: 05/21/2023]
Abstract
BACKGROUND Plant biomass degradation by fungal-derived enzymes is rapidly expanding in economic importance as a clean and efficient source for biofuels. The ability to rationally engineer filamentous fungi would facilitate biotechnological applications for degradation of plant cell wall polysaccharides. However, incomplete knowledge of biomolecular networks responsible for plant cell wall deconstruction impedes experimental efforts in this direction. RESULTS To expand this knowledge base, a detailed network of reactions important for deconstruction of plant cell wall polysaccharides into simple sugars was constructed for the filamentous fungus Neurospora crassa. To reconstruct this network, information was integrated from five heterogeneous data types: functional genomics, transcriptomics, proteomics, genetics, and biochemical characterizations. The combined information was encapsulated into a feature matrix and the evidence weighted to assign annotation confidence scores for each gene within the network. Comparative analyses of RNA-seq and ChIP-seq data shed light on the regulation of the plant cell wall degradation network, leading to a novel hypothesis for degradation of the hemicellulose mannan. The transcription factor CLR-2 was subsequently experimentally shown to play a key role in the mannan degradation pathway of N. crassa. CONCLUSIONS Here we built a network that serves as a scaffold for integration of diverse experimental datasets. This approach led to the elucidation of regulatory design principles for plant cell wall deconstruction by filamentous fungi and a novel function for the transcription factor CLR-2. This expanding network will aid in efforts to rationally engineer industrially relevant hyper-production strains.
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Affiliation(s)
- Areejit Samal
- Institute for Systems Biology, Seattle, WA 98109 USA
- Energy Biosciences Institute, University of California Berkeley, Berkeley, CA 94704 USA
- The Institute of Mathematical Sciences, Homi Bhabha National Institute, Chennai, 600113 India
- The Abdus Salam International Centre for Theoretical Physics, 34151 Trieste, Italy
| | - James P. Craig
- Energy Biosciences Institute, University of California Berkeley, Berkeley, CA 94704 USA
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720 USA
| | - Samuel T. Coradetti
- Energy Biosciences Institute, University of California Berkeley, Berkeley, CA 94704 USA
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720 USA
| | - J. Philipp Benz
- Energy Biosciences Institute, University of California Berkeley, Berkeley, CA 94704 USA
- Holzforschung München, TUM School of Life Sciences Weihenstephan, Technische Universität München, 85354 Freising, Germany
| | - James A. Eddy
- Institute for Systems Biology, Seattle, WA 98109 USA
| | | | - N. Louise Glass
- Energy Biosciences Institute, University of California Berkeley, Berkeley, CA 94704 USA
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720 USA
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35
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Disruption of non-anchored cell wall protein NCW-1 promotes cellulase production by increasing cellobiose uptake in Neurospora crassa. Biotechnol Lett 2016; 39:545-551. [DOI: 10.1007/s10529-016-2274-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 12/20/2016] [Indexed: 12/16/2022]
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36
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Loose JSM, Forsberg Z, Kracher D, Scheiblbrandner S, Ludwig R, Eijsink VGH, Vaaje‐Kolstad G. Activation of bacterial lytic polysaccharide monooxygenases with cellobiose dehydrogenase. Protein Sci 2016; 25:2175-2186. [PMID: 27643617 PMCID: PMC5119556 DOI: 10.1002/pro.3043] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 09/14/2016] [Indexed: 11/10/2022]
Abstract
Lytic polysaccharide monooxygenases (LPMOs) represent a recent addition to the carbohydrate-active enzymes and are classified as auxiliary activity (AA) families 9, 10, 11, and 13. LPMOs are crucial for effective degradation of recalcitrant polysaccharides like cellulose or chitin. These enzymes are copper-dependent and utilize a redox mechanism to cleave glycosidic bonds that is dependent on molecular oxygen and an external electron donor. The electrons can be provided by various sources, such as chemical compounds (e.g., ascorbate) or by enzymes (e.g., cellobiose dehydrogenases, CDHs, from fungi). Here, we demonstrate that a fungal CDH from Myriococcum thermophilum (MtCDH), can act as an electron donor for bacterial family AA10 LPMOs. We show that employing an enzyme as electron donor is advantageous since this enables a kinetically controlled supply of electrons to the LPMO. The rate of chitin oxidation by CBP21 was equal to that of cosubstrate (lactose) oxidation by MtCDH, verifying the usage of two electrons in the LPMO catalytic mechanism. Furthermore, since lactose oxidation correlates directly with the rate of LPMO catalysis, a method for indirect determination of LPMO activity is implicated. Finally, the one electron reduction of the CBP21 active site copper by MtCDH was determined to be substantially faster than chitin oxidation by the LPMO. Overall, MtCDH seems to be a universal electron donor for both bacterial and fungal LPMOs, indicating that their electron transfer mechanisms are similar.
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Affiliation(s)
- Jennifer S. M. Loose
- Department of ChemistryBiotechnology and Food Science, Norwegian University of Life SciencesNO‐1430 ÅsNorway
| | - Zarah Forsberg
- Department of ChemistryBiotechnology and Food Science, Norwegian University of Life SciencesNO‐1430 ÅsNorway
| | - Daniel Kracher
- Department of Food Science and Technology, Food Biotechnology LaboratoryUniversity of Natural Resources and Life SciencesViennaAustria
| | - Stefan Scheiblbrandner
- Department of Food Science and Technology, Food Biotechnology LaboratoryUniversity of Natural Resources and Life SciencesViennaAustria
| | - Roland Ludwig
- Department of Food Science and Technology, Food Biotechnology LaboratoryUniversity of Natural Resources and Life SciencesViennaAustria
| | - Vincent G. H. Eijsink
- Department of ChemistryBiotechnology and Food Science, Norwegian University of Life SciencesNO‐1430 ÅsNorway
| | - Gustav Vaaje‐Kolstad
- Department of ChemistryBiotechnology and Food Science, Norwegian University of Life SciencesNO‐1430 ÅsNorway
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37
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Reilly MC, Magnuson JK, Baker SE. Approaches to understanding protein hypersecretion in fungi. FUNGAL BIOL REV 2016. [DOI: 10.1016/j.fbr.2016.06.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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38
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The Post-genomic Era of Trichoderma reesei: What's Next? Trends Biotechnol 2016; 34:970-982. [PMID: 27394390 DOI: 10.1016/j.tibtech.2016.06.003] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 06/09/2016] [Accepted: 06/13/2016] [Indexed: 11/21/2022]
Abstract
The ascomycete Trichoderma reesei is one of the most well studied cellulolytic microorganisms. This fungus is widely used in the biotechnology industry, mainly in the production of biofuels. Due to its importance, its genome was sequenced in 2008, opening new avenues to study this microorganism. In this 'post-genomic' era, a transcriptomic and proteomic era has emerged. Here, we present an overview of new findings in the gene expression regulation network of T. reesei. We also discuss new rational strategies to obtain mutants that produce hydrolytic enzymes with a higher yield, using metabolic engineering. Finally, we present how synthetic biology strategies can be used to create engineered promoters to efficiently synthesize enzymes for biomass degradation to produce bioethanol.
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39
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Amores GR, Guazzaroni ME, Arruda LM, Silva-Rocha R. Recent Progress on Systems and Synthetic Biology Approaches to Engineer Fungi As Microbial Cell Factories. Curr Genomics 2016; 17:85-98. [PMID: 27226765 PMCID: PMC4864837 DOI: 10.2174/1389202917666151116212255] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 05/23/2015] [Accepted: 06/01/2015] [Indexed: 01/03/2023] Open
Abstract
Filamentous fungi are remarkable organisms naturally specialized in deconstructing plant
biomass and this feature has a tremendous potential for biofuel production from renewable sources.
The past decades have been marked by a remarkable progress in the genetic engineering of fungi to
generate industry-compatible strains needed for some biotech applications. In this sense, progress in
this field has been marked by the utilization of high-throughput techniques to gain deep understanding
of the molecular machinery controlling the physiology of these organisms, starting thus the Systems
Biology era of fungi. Additionally, genetic engineering has been extensively applied to modify wellcharacterized
promoters in order to construct new expression systems with enhanced performance under the conditions of
interest. In this review, we discuss some aspects related to significant progress in the understating and engineering of
fungi for biotechnological applications, with special focus on the construction of synthetic promoters and circuits in organisms
relevant for industry. Different engineering approaches are shown, and their potential and limitations for the construction
of complex synthetic circuits in these organisms are examined. Finally, we discuss the impact of engineered
promoter architecture in the single-cell behavior of the system, an often-neglected relationship with a tremendous impact
in the final performance of the process of interest. We expect to provide here some new directions to drive future research
directed to the construction of high-performance, engineered fungal strains working as microbial cell factories.
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40
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Kracher D, Scheiblbrandner S, Felice AKG, Breslmayr E, Preims M, Ludwicka K, Haltrich D, Eijsink VGH, Ludwig R. Extracellular electron transfer systems fuel cellulose oxidative degradation. Science 2016; 352:1098-101. [DOI: 10.1126/science.aaf3165] [Citation(s) in RCA: 257] [Impact Index Per Article: 32.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 04/15/2016] [Indexed: 01/19/2023]
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Forsberg Z, Nelson CE, Dalhus B, Mekasha S, Loose JSM, Crouch LI, Røhr ÅK, Gardner JG, Eijsink VGH, Vaaje-Kolstad G. Structural and Functional Analysis of a Lytic Polysaccharide Monooxygenase Important for Efficient Utilization of Chitin in Cellvibrio japonicus. J Biol Chem 2016; 291:7300-12. [PMID: 26858252 DOI: 10.1074/jbc.m115.700161] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Indexed: 01/11/2023] Open
Abstract
Cellvibrio japonicusis a Gram-negative soil bacterium that is primarily known for its ability to degrade plant cell wall polysaccharides through utilization of an extensive repertoire of carbohydrate-active enzymes. Several putative chitin-degrading enzymes are also found among these carbohydrate-active enzymes, such as chitinases, chitobiases, and lytic polysaccharide monooxygenases (LPMOs). In this study, we have characterized the chitin-active LPMO,CjLPMO10A, a tri-modular enzyme containing a catalytic family AA10 LPMO module, a family 5 chitin-binding module, and a C-terminal unclassified module of unknown function. Characterization of the latter module revealed tight and specific binding to chitin, thereby unraveling a new family of chitin-binding modules (classified as CBM73). X-ray crystallographic elucidation of theCjLPMO10A catalytic module revealed that the active site of the enzyme combines structural features previously only observed in either cellulose or chitin-active LPMO10s. Analysis of the copper-binding site by EPR showed a signal signature more similar to those observed for cellulose-cleaving LPMOs. The full-length LPMO shows no activity toward cellulose but is able to bind and cleave both α- and β-chitin. Removal of the chitin-binding modules reduced LPMO activity toward α-chitin compared with the full-length enzyme. Interestingly, the full-length enzyme and the individual catalytic LPMO module boosted the activity of an endochitinase equally well, also yielding similar amounts of oxidized products. Finally, gene deletion studies show thatCjLPMO10A is needed byC. japonicusto obtain efficient growth on both purified chitin and crab shell particles.
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Affiliation(s)
- Zarah Forsberg
- From the Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, 1432 Ås, Norway
| | - Cassandra E Nelson
- the Department of Biological Sciences, University of Maryland at Baltimore County, Baltimore, Maryland 21250
| | - Bjørn Dalhus
- the Department of Medical Biochemistry, Institute for Clinical Medicine, University of Oslo, P. O. Box 4950, Nydalen, N-0424 Oslo, Norway, the Department of Microbiology, Clinic for Diagnostics and Intervention, Oslo University Hospital, Rikshospitalet, P. O. Box 4950, Nydalen, N-0424 Oslo, Norway, and
| | - Sophanit Mekasha
- From the Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, 1432 Ås, Norway
| | - Jennifer S M Loose
- From the Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, 1432 Ås, Norway
| | - Lucy I Crouch
- the Institute for Cell and Molecular Biosciences, University of Newcastle upon Tyne, Framlington Place, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Åsmund K Røhr
- From the Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, 1432 Ås, Norway
| | - Jeffrey G Gardner
- the Department of Biological Sciences, University of Maryland at Baltimore County, Baltimore, Maryland 21250
| | - Vincent G H Eijsink
- From the Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, 1432 Ås, Norway
| | - Gustav Vaaje-Kolstad
- From the Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, 1432 Ås, Norway,
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42
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Tang SL, Bubner P, Bauer S, Somerville CR. O-Glycan analysis of cellobiohydrolase I from Neurospora crassa. Glycobiology 2016; 26:670-7. [PMID: 26762173 DOI: 10.1093/glycob/cww004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 01/08/2016] [Indexed: 11/14/2022] Open
Abstract
We describe here the composition of the O-linked glycans on the Neurospora crassa cellobiohydrolase I (CBHI), which accounts for approximately 40% of the protein secreted by cells growing in the presence of cellulose. CBHI is O-glycosylated with six types of linear, and three types of branched, O-glycans containing approximately equal amounts of mannose and galactose. In addition to the classic fungal O-glycans with reducing end mannoses, we also identified reducing end galactoses which suggest the existence of a protein-O-galactosyltransferase in N. crassa Because of the excellent genetic resources available for N. crassa, the knowledge of the CBHI O-glycans may enable the future evaluation of the role of O-glycosylation on cellulase function and the development of directed O-glycan/cellulase engineering.
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Affiliation(s)
- Shu-Lun Tang
- Energy Biosciences Institute, University of California Berkeley, 2151 Berkeley Way MC 5230, Berkeley, CA 94720, USA
| | - Patricia Bubner
- Energy Biosciences Institute, University of California Berkeley, 2151 Berkeley Way MC 5230, Berkeley, CA 94720, USA
| | - Stefan Bauer
- Energy Biosciences Institute, University of California Berkeley, 2151 Berkeley Way MC 5230, Berkeley, CA 94720, USA
| | - Chris R Somerville
- Energy Biosciences Institute, University of California Berkeley, 2151 Berkeley Way MC 5230, Berkeley, CA 94720, USA
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Yao G, Wu R, Kan Q, Gao L, Liu M, Yang P, Du J, Li Z, Qu Y. Production of a high-efficiency cellulase complex via β-glucosidase engineering in Penicillium oxalicum. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:78. [PMID: 27034716 PMCID: PMC4815182 DOI: 10.1186/s13068-016-0491-4] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 03/18/2016] [Indexed: 05/07/2023]
Abstract
BACKGROUND Trichoderma reesei is a widely used model cellulolytic fungus, supplying a highly effective cellulase production system. Recently, the biofuel industry discovered filamentous fungi from the Penicillium genus as a promising alternative to T. reesei. RESULTS In our study, we present a systematic over-expression analysis of nine β-glucosidase encoding genes in the wild-type strain 114-2 of Penicillium oxalicum. We found that the over-expression of BGL1, BGL4, or BGL5 significantly enhanced both β-glucosidase activity and hydrolysis efficiency of the enzyme system on filter paper. We utilised two strategies to over-express β-glucosidase in the strain RE-10 that-although over-producing cellulase, does so at the cost of the cellulase mixture deficiency. The constitutive promoter of gene pde_02864 encoding 40S ribosomal protein S8 was used to over-express three β-glucosidases: BGL1, BGL4, and BGL5. We found that all mutants show significantly enhanced levels of β-glucosidase at transcriptional, protein, and activity levels. Furthermore, the inducible promoter from bgl2 was used to conditionally over-express the β-glucosidases BGL1 and BGL4. Surprisingly, this induced expression strategy enables significantly improved expression efficiency. The BGL1 over-expressing mutant I1-13 particularly improved the β-glucosidase activity at a factor of 65-folds, resulting in levels of up to 150 U/ml. All our BGL over-expression mutants displayed significant enhancement of cellulolytic ability on both microcrystalline cellulose and filter paper. In addition, they substantially reduced the enzyme loads in the saccharification of a natural lignocellulose material delignified corncob residue (DCCR). The mutant I4-32 with over-expression of BGL4 achieved the highest glucose yield in the saccharification of DCCR at only 25 % enzyme load compared to the parental strain RE-10. CONCLUSIONS In summary, genetically engineering P. oxalicum to significantly improve β-glucosidase activity is a potent strategy to substantially boost the hydrolytic efficiency of the cellulase cocktail, which will ultimately lead to a considerable reduction of cost for biomass-based biofuel.
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Affiliation(s)
- Guangshan Yao
- />State Key Laboratory of Microbial Technology, Shandong University, Jinan City, 250100 Shandong Province China
| | - Ruimei Wu
- />State Key Laboratory of Microbial Technology, Shandong University, Jinan City, 250100 Shandong Province China
| | - Qinbiao Kan
- />State Key Laboratory of Microbial Technology, Shandong University, Jinan City, 250100 Shandong Province China
| | - Liwei Gao
- />State Key Laboratory of Microbial Technology, Shandong University, Jinan City, 250100 Shandong Province China
| | - Meng Liu
- />State Key Laboratory of Microbial Technology, Shandong University, Jinan City, 250100 Shandong Province China
| | - Piao Yang
- />State Key Laboratory of Microbial Technology, Shandong University, Jinan City, 250100 Shandong Province China
| | - Jian Du
- />State Key Laboratory of Microbial Technology, Shandong University, Jinan City, 250100 Shandong Province China
| | - Zhonghai Li
- />Department of Bioengineering, Qilu University of Technology, Jinan City, 250353 Shandong Province China
| | - Yinbo Qu
- />State Key Laboratory of Microbial Technology, Shandong University, Jinan City, 250100 Shandong Province China
- />National Glycoengineering Research Center, Shandong University, Jinan City, 250100 Shandong Province China
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Direct target network of the Neurospora crassa plant cell wall deconstruction regulators CLR-1, CLR-2, and XLR-1. mBio 2015; 6:e01452-15. [PMID: 26463163 PMCID: PMC4620465 DOI: 10.1128/mbio.01452-15] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
Fungal deconstruction of the plant cell requires a complex orchestration of a wide array of intracellular and extracellular enzymes. In Neurospora crassa, CLR-1, CLR-2, and XLR-1 have been identified as key transcription factors regulating plant cell wall degradation in response to soluble sugars. The XLR-1 regulon was defined using a constitutively active mutant allele, resulting in hemicellulase gene expression and secretion under noninducing conditions. To define genes directly regulated by CLR-1, CLR-2, and XLR-1, we performed chromatin immunoprecipitation and next-generation sequencing (ChIPseq) on epitope-tagged constructs of these three transcription factors. When N. crassa is exposed to plant cell wall material, CLR-1, CLR-2, and XLR-1 individually bind to the promoters of the most strongly induced genes in their respective regulons. These include promoters of genes encoding cellulases for CLR-1 and CLR-2 (CLR-1/CLR-2) and promoters of genes encoding hemicellulases for XLR-1. CLR-1 bound to its regulon under noninducing conditions; however, this binding alone did not translate into gene expression and enzyme secretion. Motif analysis of the bound genes revealed conserved DNA binding motifs, with the CLR-2 motif matching that of its closest paralog in Saccharomyces cerevisiae, Gal4p. Coimmunoprecipitation studies showed that CLR-1 and CLR-2 act in a homocomplex but not as a CLR-1/CLR-2 heterocomplex. Understanding fungal regulation of complex plant cell wall deconstruction pathways in response to multiple environmental signals via interconnected transcriptional circuits provides insight into fungus/plant interactions and eukaryotic nutrient sensing. Coordinated optimization of these regulatory networks is likely required for optimal microbial enzyme production.
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Pei X, Fan F, Lin L, Chen Y, Sun W, Zhang S, Tian C. Involvement of the adaptor protein 3 complex in lignocellulase secretion in Neurospora crassa revealed by comparative genomic screening. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:124. [PMID: 26300971 PMCID: PMC4545925 DOI: 10.1186/s13068-015-0302-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 07/30/2015] [Indexed: 06/02/2023]
Abstract
BACKGROUND Lignocellulase hypersecretion has been achieved in industrial fungal workhorses such as Trichoderma reesei, but the underlying mechanism associated with this process is not well understood. Although previous comparative genomic studies have revealed that the mutagenic T. reesei strain RUT-C30 harbors hundreds of mutations compared with its parental strain QM6a, how these mutations actually contribute to the hypersecretion phenotype remains to be elucidated. RESULTS In this study, we systematically screened gene knockout (KO) mutants in the cellulolytic fungus Neurospora crassa, which contains orthologs of potentially defective T. reesei RUT-C30 mutated genes. Of the 86 deletion mutants screened in N. crassa, 12 exhibited lignocellulase production more than 25% higher than in the wild-type (WT) strain and 4 showed nearly 25% lower secretion. We observed that the deletion of Ncap3m (NCU03998), which encodes the μ subunit of the adaptor protein 3 (AP-3) complex in N. crassa, led to the most significant increase in lignocellulase secretion under both Avicel and xylan culture conditions. Moreover, strains lacking the β subunit of the AP-3 complex, encoded by Ncap3b (NCU06569), had a similar phenotype to ΔNcap3m, suggesting that the AP-3 complex is involved in lignocellulase secretion in N. crassa. We also found that the transcriptional abundance of major lignocellulase genes in ΔNcap3m was maintained at a relatively higher level during the late stage of fermentation compared with the WT, which might add to the hypersecretion phenotype. Finally, we found that importation of the T. reesei ap3m ortholog Trap3m into ΔNcap3m can genetically restore secretion of lignocellulases to normal levels, which suggests that the effect of the AP-3 complex on lignocellulase secretion is conserved in cellulolytic ascomycetes. CONCLUSIONS Using the model cellulolytic fungus N. crassa, we explored potential hypersecretion-related mutations in T. reesei strain RUT-C30. Through systematic genetic screening of 86 corresponding orthologous KO mutants in N. crassa, we identified several genes, particularly those encoding the AP-3 complex that contribute to lignocellulase secretion. These findings will be useful for strain improvement in future lignocellulase and biomass-based chemical production.
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Affiliation(s)
- Xue Pei
- />College of Plant Sciences, Jilin University, Changchun, 130062 China
- />Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Feiyu Fan
- />Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Liangcai Lin
- />Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Yong Chen
- />Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Wenliang Sun
- />Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Shihong Zhang
- />College of Plant Sciences, Jilin University, Changchun, 130062 China
| | - Chaoguang Tian
- />Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
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46
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Liu D, Li M, Xi B, Zhao Y, Wei Z, Song C, Zhu C. Metaproteomics reveals major microbial players and their biodegradation functions in a large-scale aerobic composting plant. Microb Biotechnol 2015; 8:950-60. [PMID: 25989417 PMCID: PMC4621448 DOI: 10.1111/1751-7915.12290] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Revised: 03/31/2015] [Accepted: 04/06/2015] [Indexed: 01/14/2023] Open
Abstract
Composting is an appropriate management alternative for municipal solid waste; however, our knowledge about the microbial regulation of this process is still scare. We employed metaproteomics to elucidate the main biodegradation pathways in municipal solid waste composting system across the main phases in a large-scale composting plant. The investigation of microbial succession revealed that Bacillales, Actinobacteria and Saccharomyces increased significantly with respect to abundance in composting process. The key microbiologic population for cellulose degradation in different composting stages was different. Fungi were found to be the main producers of cellulase in earlier phase. However, the cellulolytic fungal communities were gradually replaced by a purely bacterial one in active phase, which did not support the concept that the thermophilic fungi are active through the thermophilic phase. The effective decomposition of cellulose required the synergy between bacteria and fungi in the curing phase.
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Affiliation(s)
- Dongming Liu
- College of Life Sciences, Northeast Agricultural University, Harbin, 150030, China.,Innovation Base of Groundwater and Environmental System Engineering, Chinese Research Academy of Environmental Science, Beijing, 100012, China
| | - Mingxiao Li
- Innovation Base of Groundwater and Environmental System Engineering, Chinese Research Academy of Environmental Science, Beijing, 100012, China
| | - Beidou Xi
- Innovation Base of Groundwater and Environmental System Engineering, Chinese Research Academy of Environmental Science, Beijing, 100012, China
| | - Yue Zhao
- College of Life Sciences, Northeast Agricultural University, Harbin, 150030, China
| | - Zimin Wei
- College of Life Sciences, Northeast Agricultural University, Harbin, 150030, China
| | - Caihong Song
- College of Life Sciences, Northeast Agricultural University, Harbin, 150030, China.,Innovation Base of Groundwater and Environmental System Engineering, Chinese Research Academy of Environmental Science, Beijing, 100012, China
| | - Chaowei Zhu
- Innovation Base of Groundwater and Environmental System Engineering, Chinese Research Academy of Environmental Science, Beijing, 100012, China
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47
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Kim IJ, Nam KH, Yun EJ, Kim S, Youn HJ, Lee HJ, Choi IG, Kim KH. Optimization of synergism of a recombinant auxiliary activity 9 from Chaetomium globosum with cellulase in cellulose hydrolysis. Appl Microbiol Biotechnol 2015; 99:8537-47. [PMID: 25936375 PMCID: PMC4768223 DOI: 10.1007/s00253-015-6592-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Revised: 03/14/2015] [Accepted: 04/01/2015] [Indexed: 01/16/2023]
Abstract
Auxiliary activity family 9 (AA9, formerly known as glycoside hydrolase family 61 or polysaccharide monooxygenase) is a group of fungal proteins that were recently found to have a significant synergism with cellulase in cellulose hydrolysis via the oxidative cleavage of glycosidic bonds of cellulose chains. In this study, we report the active expression of a recombinant fungal AA9 from Chaetomium globosum (CgAA9) in a bacterial host, Escherichia coli, and the optimization of its synergistic activity in cellulose hydrolysis by using cellulase. The recombinant CgAA9 (0.9 mg/g cellulose) exhibited 1.7-fold synergism in the hydrolysis of Avicel when incubated with 0.9 filter paper units of Celluclast 1.5 L/g cellulose. The first study of the active expression of AA9 using a bacterial host and its synergistic optimization could be useful for the industrial application of AA9 for the saccharification of lignocellulose.
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Affiliation(s)
- In Jung Kim
- Department of Biotechnology, Korea University Graduate School, Seoul, 136-713, Republic of Korea
| | - Ki Hyun Nam
- Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang, 790-784, Republic of Korea
| | - Eun Ju Yun
- Department of Biotechnology, Korea University Graduate School, Seoul, 136-713, Republic of Korea
| | - Sooah Kim
- Department of Biotechnology, Korea University Graduate School, Seoul, 136-713, Republic of Korea
| | - Hak Jin Youn
- Department of Biotechnology, Korea University Graduate School, Seoul, 136-713, Republic of Korea
| | - Hee Jin Lee
- Department of Biotechnology, Korea University Graduate School, Seoul, 136-713, Republic of Korea
| | - In-Geol Choi
- Department of Biotechnology, Korea University Graduate School, Seoul, 136-713, Republic of Korea
| | - Kyoung Heon Kim
- Department of Biotechnology, Korea University Graduate School, Seoul, 136-713, Republic of Korea.
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48
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Bianco L, Perrotta G. Methodologies and perspectives of proteomics applied to filamentous fungi: from sample preparation to secretome analysis. Int J Mol Sci 2015; 16:5803-29. [PMID: 25775160 PMCID: PMC4394507 DOI: 10.3390/ijms16035803] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 02/17/2015] [Accepted: 03/03/2015] [Indexed: 11/17/2022] Open
Abstract
Filamentous fungi possess the extraordinary ability to digest complex biomasses and mineralize numerous xenobiotics, as consequence of their aptitude to sensing the environment and regulating their intra and extra cellular proteins, producing drastic changes in proteome and secretome composition. Recent advancement in proteomic technologies offers an exciting opportunity to reveal the fluctuations of fungal proteins and enzymes, responsible for their metabolic adaptation to a large variety of environmental conditions. Here, an overview of the most commonly used proteomic strategies will be provided; this paper will range from sample preparation to gel-free and gel-based proteomics, discussing pros and cons of each mentioned state-of-the-art technique. The main focus will be kept on filamentous fungi. Due to the biotechnological relevance of lignocellulose degrading fungi, special attention will be finally given to their extracellular proteome, or secretome. Secreted proteins and enzymes will be discussed in relation to their involvement in bio-based processes, such as biomass deconstruction and mycoremediation.
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Affiliation(s)
- Linda Bianco
- UTTRI-GENER Genetics and Genomics for Energy and Environment Laboratory-ENEA TRISAIA Research Center, 75025 Rotondella (Matera), Italy.
| | - Gaetano Perrotta
- UTTRI-GENER Genetics and Genomics for Energy and Environment Laboratory-ENEA TRISAIA Research Center, 75025 Rotondella (Matera), Italy.
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49
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Chen L, Zhai L, Li Y, Li N, Zhang C, Ping L, Chang L, Wu J, Li X, Shi D, Xu P. Development of gel-filter method for high enrichment of low-molecular weight proteins from serum. PLoS One 2015; 10:e0115862. [PMID: 25723528 PMCID: PMC4344347 DOI: 10.1371/journal.pone.0115862] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Accepted: 12/02/2014] [Indexed: 11/18/2022] Open
Abstract
The human serum proteome has been extensively screened for biomarkers. However, the large dynamic range of protein concentrations in serum and the presence of highly abundant and large molecular weight proteins, make identification and detection changes in the amount of low-molecular weight proteins (LMW, molecular weight ≤ 30kDa) difficult. Here, we developed a gel-filter method including four layers of different concentration of tricine SDS-PAGE-based gels to block high-molecular weight proteins and enrich LMW proteins. By utilizing this method, we identified 1,576 proteins (n = 2) from 10 μL serum. Among them, 559 (n = 2) proteins belonged to LMW proteins. Furthermore, this gel-filter method could identify 67.4% and 39.8% more LMW proteins than that in representative methods of glycine SDS-PAGE and optimized-DS, respectively. By utilizing SILAC-AQUA approach with labeled recombinant protein as internal standard, the recovery rate for GST spiked in serum during the treatment of gel-filter, optimized-DS, and ProteoMiner was 33.1 ± 0.01%, 18.7 ± 0.01% and 9.6 ± 0.03%, respectively. These results demonstrate that the gel-filter method offers a rapid, highly reproducible and efficient approach for screening biomarkers from serum through proteomic analyses.
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Affiliation(s)
- Lingsheng Chen
- State Key Laboratory of Proteomics, National Engineering Research Center for Protein Drugs, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Radiation Medicine, Beijing, 102206, P. R. China
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning, 530005, P. R. China
| | - Linhui Zhai
- State Key Laboratory of Proteomics, National Engineering Research Center for Protein Drugs, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Radiation Medicine, Beijing, 102206, P. R. China
| | - Yanchang Li
- State Key Laboratory of Proteomics, National Engineering Research Center for Protein Drugs, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Radiation Medicine, Beijing, 102206, P. R. China
| | - Ning Li
- State Key Laboratory of Proteomics, National Engineering Research Center for Protein Drugs, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Radiation Medicine, Beijing, 102206, P. R. China
| | - Chengpu Zhang
- State Key Laboratory of Proteomics, National Engineering Research Center for Protein Drugs, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Radiation Medicine, Beijing, 102206, P. R. China
| | - Lingyan Ping
- State Key Laboratory of Proteomics, National Engineering Research Center for Protein Drugs, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Radiation Medicine, Beijing, 102206, P. R. China
| | - Lei Chang
- State Key Laboratory of Proteomics, National Engineering Research Center for Protein Drugs, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Radiation Medicine, Beijing, 102206, P. R. China
| | - Junzhu Wu
- Department of Biochemistry, School of Medicine, Wuhan University, Wuhan, 430071, P. R. China
| | - Xiangping Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning, 530005, P. R. China
| | - Deshun Shi
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning, 530005, P. R. China
- * E-mail: (DSS); (PX)
| | - Ping Xu
- State Key Laboratory of Proteomics, National Engineering Research Center for Protein Drugs, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Radiation Medicine, Beijing, 102206, P. R. China
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University), Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, P. R. China
- * E-mail: (DSS); (PX)
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50
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Zoglowek M, Lübeck PS, Ahring BK, Lübeck M. Heterologous expression of cellobiohydrolases in filamentous fungi – An update on the current challenges, achievements and perspectives. Process Biochem 2015. [DOI: 10.1016/j.procbio.2014.12.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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