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Donohoe BS, Wei H, Mittal A, Shollenberger T, Lunin VV, Himmel ME, Brunecky R. Towards an Understanding of Enhanced Biomass Digestibility by In Planta Expression of a Family 5 Glycoside Hydrolase. Sci Rep 2017; 7:4389. [PMID: 28663545 PMCID: PMC5491509 DOI: 10.1038/s41598-017-04502-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 05/17/2017] [Indexed: 12/21/2022] Open
Abstract
In planta expression of a thermophilic endoglucanase (AcCel5A) reduces recalcitrance by creating voids and other irregularities in cell walls of Arabidopsis thaliana that increase enzyme accessibility without negative impacts on plant growth or cell wall composition. Our results suggest that cellulose β-1-4 linkages can be cut sparingly in the assembling wall and that these minimal changes, made at the proper time, have an impact on plant cell wall recalcitrance without negative effects on overall plant development.
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Affiliation(s)
- Bryon S Donohoe
- Biosciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado, 80401, United States
| | - Hui Wei
- Biosciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado, 80401, United States
| | - Ashutosh Mittal
- Biosciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado, 80401, United States
| | - Todd Shollenberger
- Biosciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado, 80401, United States
| | - Vladimir V Lunin
- Biosciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado, 80401, United States
| | - Michael E Himmel
- Biosciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado, 80401, United States
| | - Roman Brunecky
- Biosciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado, 80401, United States.
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Kingsbury NJ, McDonald KA. Quantitative evaluation of E1 endoglucanase recovery from tobacco leaves using the vacuum infiltration-centrifugation method. BIOMED RESEARCH INTERNATIONAL 2014; 2014:483596. [PMID: 24971334 PMCID: PMC4058203 DOI: 10.1155/2014/483596] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 04/04/2014] [Accepted: 04/29/2014] [Indexed: 01/23/2023]
Abstract
As a production platform for recombinant proteins, plant leaf tissue has many advantages, but commercialization of this technology has been hindered by high recovery and purification costs. Vacuum infiltration-centrifugation (VI-C) is a technique to obtain extracellularly-targeted products from the apoplast wash fluid (AWF). Because of its selective recovery of secreted proteins without homogenizing the whole tissue, VI-C can potentially reduce downstream production costs. Lab scale experiments were conducted to quantitatively evaluate the VI-C method and compared to homogenization techniques in terms of product purity, concentration, and other desirable characteristics. From agroinfiltrated Nicotiana benthamiana leaves, up to 81% of a truncated version of E1 endoglucanase from Acidothermus cellulolyticus was recovered with VI-C versus homogenate extraction, and average purity and concentration increases of 4.2-fold and 3.1-fold, respectively, were observed. Formulas were developed to predict recovery yields of secreted protein obtained by performing multiple rounds of VI-C on the same leaf tissue. From this, it was determined that three rounds of VI-C recovered 97% of the total active recombinant protein accessible to the VI-C procedure. The results suggest that AWF recovery is an efficient process that could reduce downstream processing steps and costs for plant-made recombinant proteins.
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Affiliation(s)
- Nathaniel J. Kingsbury
- Department of Chemical Engineering and Materials Science, University of California at Davis, 1 Shields Avenue, Davis, CA 95616, USA
| | - Karen A. McDonald
- Department of Chemical Engineering and Materials Science, University of California at Davis, 1 Shields Avenue, Davis, CA 95616, USA
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Yennamalli RM, Rader AJ, Kenny AJ, Wolt JD, Sen TZ. Endoglucanases: insights into thermostability for biofuel applications. BIOTECHNOLOGY FOR BIOFUELS 2013; 6:136. [PMID: 24070146 PMCID: PMC3856469 DOI: 10.1186/1754-6834-6-136] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 09/24/2013] [Indexed: 05/03/2023]
Abstract
Obtaining bioethanol from cellulosic biomass involves numerous steps, among which the enzymatic conversion of the polymer to individual sugar units has been a main focus of the biotechnology industry. Among the cellulases that break down the polymeric cellulose are endoglucanases that act synergistically for subsequent hydrolytic reactions. The endoglucanases that have garnered relatively more attention are those that can withstand high temperatures, i.e., are thermostable. Although our understanding of thermostability in endoglucanases is incomplete, some molecular features that are responsible for increased thermostability have been recently identified. This review focuses on the investigations of endoglucanases and their implications for biofuel applications.
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Affiliation(s)
- Ragothaman M Yennamalli
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames 50011, IA, USA
- Present Address: Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77005, USA
| | - Andrew J Rader
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis 46202, IN, USA
- Present Address: State Farm Insurance, Indianapolis 46240, IN, USA
| | - Adam J Kenny
- Biosafety Institute for Genetically Modified Agricultural Products and Department of Agronomy, Iowa State University, Ames 50011, IA, USA
- Present Address: Brownells, Inc, Montezuma, IA 50171, USA
| | - Jeffrey D Wolt
- Biosafety Institute for Genetically Modified Agricultural Products and Department of Agronomy, Iowa State University, Ames 50011, IA, USA
| | - Taner Z Sen
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames 50011, IA, USA
- Bioinformatics and Computational Biology Program, Iowa State University, Ames 50011, IA, USA
- 1025 Crop Genome Informatics Lab, Iowa State University, Ames 50011, IA, USA
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Brunecky R, Selig MJ, Vinzant TB, Himmel ME, Lee D, Blaylock MJ, Decker SR. In planta expression of A. cellulolyticus Cel5A endocellulase reduces cell wall recalcitrance in tobacco and maize. BIOTECHNOLOGY FOR BIOFUELS 2011; 4:1. [PMID: 22185437 PMCID: PMC3037329 DOI: 10.1186/1754-6834-4-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Accepted: 01/26/2011] [Indexed: 05/03/2023]
Abstract
The glycoside hydrolase family 5 endocellulase, E1 (Cel5A), from Acidothermus cellulolyticus was transformed into both Nicotiana tabacum and Zea mays with expression targeted to the cell wall under a constitutive promoter. Here we explore the possibility that in planta expression of endocellulases will allow these enzymes to access their substrates during cell wall construction, rendering cellulose more amenable to pretreatment and enzyme digestion. Tobacco and maize plants were healthy and developed normally compared with the wild type (WT). After thermochemical pretreatment and enzyme digestion, transformed plants were clearly more digestible than WT, requiring lower pretreatment severity to achieve comparable conversion levels. Furthermore, the decreased recalcitrance was not due to post-pretreatment residual E1 activity and could not be reproduced by the addition of exogenous E1 to the biomass prior to pretreatment, indicating that the expression of E1 during cell wall construction altered the inherent recalcitrance of the cell wall.
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Affiliation(s)
- Roman Brunecky
- Biosciences Center, National Renewable Energy Laboratory, 1617 Cole Boulevard, MS 3323, Golden, CO 80401, USA
| | - Michael J Selig
- Biosciences Center, National Renewable Energy Laboratory, 1617 Cole Boulevard, MS 3323, Golden, CO 80401, USA
| | - Todd B Vinzant
- Biosciences Center, National Renewable Energy Laboratory, 1617 Cole Boulevard, MS 3323, Golden, CO 80401, USA
| | - Michael E Himmel
- Biosciences Center, National Renewable Energy Laboratory, 1617 Cole Boulevard, MS 3323, Golden, CO 80401, USA
| | - David Lee
- Edenspace Systems Corporation, 3810 Concorde Parkway, Suite 100, Chantilly, VA 20151-1131, USA
| | - Michael J Blaylock
- Edenspace Systems Corporation, 3810 Concorde Parkway, Suite 100, Chantilly, VA 20151-1131, USA
| | - Stephen R Decker
- Biosciences Center, National Renewable Energy Laboratory, 1617 Cole Boulevard, MS 3323, Golden, CO 80401, USA
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Sun Y, Cheng JJ, Himmel ME, Skory CD, Adney WS, Thomas SR, Tisserat B, Nishimura Y, Yamamoto YT. Expression and characterization of Acidothermus cellulolyticus E1 endoglucanase in transgenic duckweed Lemna minor 8627. BIORESOURCE TECHNOLOGY 2007; 98:2866-72. [PMID: 17127051 DOI: 10.1016/j.biortech.2006.09.055] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2005] [Revised: 09/25/2006] [Accepted: 09/28/2006] [Indexed: 05/04/2023]
Abstract
Endoglucanase E1 from Acidothermus cellulolyticus was expressed cytosolically under control of the cauliflower mosaic virus 35S promoter in transgenic duckweed, Lemna minor 8627 without any obvious observable phenotypic effects on morphology or rate of growth. The recombinant enzyme co-migrated with the purified catalytic domain fraction of the native E1 protein on western blot analysis, revealing that the cellulose-binding domain was cleaved near or in the linker region. The duckweed-expressed enzyme was biologically active and the expression level was up to 0.24% of total soluble protein. The endoglucanase activity with carboxymethylcellulose averaged 0.2 units mg protein(-1) extracted from fresh duckweed. The optimal temperature and pH for E1 enzyme activity were about 80 degrees C and pH 5, respectively. While extraction with HEPES (N-[2-hydroxyethyl]piperazine-N'-[2-ethanesulfonic acid]) buffer (pH 8) resulted in the highest recovery of total soluble proteins and E1 enzyme, extraction with citrate buffer (pH 4.8) at 65 degrees C enriched relative amounts of E1 enzyme in the extract. This study demonstrates that duckweed may offer new options for the expression of cellulolytic enzymes in transgenic plants.
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Affiliation(s)
- Ye Sun
- Department of Biological and Agricultural Engineering, North Carolina State University, Raleigh, NC 27695, USA
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Lynd LR, Zhang Y. Quantitative determination of cellulase concentration as distinct from cell concentration in studies of microbial cellulose utilization: analytical framework and methodological approach. Biotechnol Bioeng 2002; 77:467-75. [PMID: 11787020 DOI: 10.1002/bit.10142] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In analyzing microbial cellulose utilization, it would be useful to independently measure the mass concentration of cells and cellulase enzymes. Such measurements would allow investigation of the allocation of cellular resources between synthesis of cells and cellulase, in vivo cell- and cellulase-specific cellulose hydrolysis rates, and bioenergetics. Methodological protocols are not established for independent determination of cell and cellulase concentrations for the common case in which a substantial fraction of cellulase is attached to the cell surface. Alternative analytical approaches by which to develop such protocols are examined from the perspective of error minimization. For cell concentration measurement, acceptable accuracy is expected when the concentrations of a cell-specific component (e.g., DNA) is determined or when total protein is determined in conjunction with a measurement specific to cellulase. For cellulase concentration measurement, acceptable accuracy is expected when a measurement specific to cellulase such as ELISA is used. Several analytical approaches are rejected based on large expected errors.
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Affiliation(s)
- Lee R Lynd
- Chemical and Biochemical Engineering, Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, USA.
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Biotechnological progress in producing fuels and valuable chemicals and in bioremediating environmental impacts. Appl Biochem Biotechnol 1995. [DOI: 10.1007/bf02933479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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