2201
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Crowley MF, Uberbacher EC, Brooks CL, Walker RC, Nimlos MR, Himmel ME. Developing improved MD codes for understanding processive cellulases. ACTA ACUST UNITED AC 2008. [DOI: 10.1088/1742-6596/125/1/012049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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2202
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Yuan JS, Tiller KH, Al-Ahmad H, Stewart NR, Stewart CN. Plants to power: bioenergy to fuel the future. TRENDS IN PLANT SCIENCE 2008; 13:421-9. [PMID: 18632303 DOI: 10.1016/j.tplants.2008.06.001] [Citation(s) in RCA: 150] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2008] [Revised: 05/22/2008] [Accepted: 06/02/2008] [Indexed: 05/18/2023]
Abstract
Bioenergy should play an essential part in reaching targets to replace petroleum-based transportation fuels with a viable alternative, and in reducing long-term carbon dioxide emissions, if environmental and economic sustainability are considered carefully. Here, we review different platforms, crops, and biotechnology-based improvements for sustainable bioenergy. Among the different platforms, there are two obvious advantages to using lignocellulosic biomass for ethanol production: higher net energy gain and lower production costs. However, the use of lignocellulosic ethanol as a viable alternative to petroleum-based transportation fuels largely depends on plant biotechnology breakthroughs. We examine how biotechnology, such as lignin modification, abiotic stress resistance, nutrition usage, in planta expression of cell wall digestion enzymes, biomass production, feedstock establishment, biocontainment of transgenes, metabolic engineering, and basic research, can be used to address the challenges faced by bioenergy crop production.
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Affiliation(s)
- Joshua S Yuan
- Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996, USA
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2203
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2204
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2205
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Gierlinger N, Goswami L, Schmidt M, Burgert I, Coutand C, Rogge T, Schwanninger M. In Situ FT-IR Microscopic Study on Enzymatic Treatment of Poplar Wood Cross-Sections. Biomacromolecules 2008; 9:2194-201. [DOI: 10.1021/bm800300b] [Citation(s) in RCA: 135] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Notburga Gierlinger
- Department of Biomaterials, Max-Planck Institute of Colloids and Interfaces, Potsdam, Germany, Institut National de la Recherche Agronomique (INRA), umr Physiologie Intégrative de l’Arbre Fruitier et Forestier (PIAF), 234 av. du Brézet, 63100 Clermont-Ferrand, France, Forschungszentrum Karlsruhe GmbH, Institut für Mikrostrukturtechnik, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany, and Department of Chemistry, Boku - University of Natural Resources and Applied Life Sciences,
| | - Luna Goswami
- Department of Biomaterials, Max-Planck Institute of Colloids and Interfaces, Potsdam, Germany, Institut National de la Recherche Agronomique (INRA), umr Physiologie Intégrative de l’Arbre Fruitier et Forestier (PIAF), 234 av. du Brézet, 63100 Clermont-Ferrand, France, Forschungszentrum Karlsruhe GmbH, Institut für Mikrostrukturtechnik, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany, and Department of Chemistry, Boku - University of Natural Resources and Applied Life Sciences,
| | - Martin Schmidt
- Department of Biomaterials, Max-Planck Institute of Colloids and Interfaces, Potsdam, Germany, Institut National de la Recherche Agronomique (INRA), umr Physiologie Intégrative de l’Arbre Fruitier et Forestier (PIAF), 234 av. du Brézet, 63100 Clermont-Ferrand, France, Forschungszentrum Karlsruhe GmbH, Institut für Mikrostrukturtechnik, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany, and Department of Chemistry, Boku - University of Natural Resources and Applied Life Sciences,
| | - Ingo Burgert
- Department of Biomaterials, Max-Planck Institute of Colloids and Interfaces, Potsdam, Germany, Institut National de la Recherche Agronomique (INRA), umr Physiologie Intégrative de l’Arbre Fruitier et Forestier (PIAF), 234 av. du Brézet, 63100 Clermont-Ferrand, France, Forschungszentrum Karlsruhe GmbH, Institut für Mikrostrukturtechnik, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany, and Department of Chemistry, Boku - University of Natural Resources and Applied Life Sciences,
| | - Catherine Coutand
- Department of Biomaterials, Max-Planck Institute of Colloids and Interfaces, Potsdam, Germany, Institut National de la Recherche Agronomique (INRA), umr Physiologie Intégrative de l’Arbre Fruitier et Forestier (PIAF), 234 av. du Brézet, 63100 Clermont-Ferrand, France, Forschungszentrum Karlsruhe GmbH, Institut für Mikrostrukturtechnik, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany, and Department of Chemistry, Boku - University of Natural Resources and Applied Life Sciences,
| | - Tilmann Rogge
- Department of Biomaterials, Max-Planck Institute of Colloids and Interfaces, Potsdam, Germany, Institut National de la Recherche Agronomique (INRA), umr Physiologie Intégrative de l’Arbre Fruitier et Forestier (PIAF), 234 av. du Brézet, 63100 Clermont-Ferrand, France, Forschungszentrum Karlsruhe GmbH, Institut für Mikrostrukturtechnik, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany, and Department of Chemistry, Boku - University of Natural Resources and Applied Life Sciences,
| | - Manfred Schwanninger
- Department of Biomaterials, Max-Planck Institute of Colloids and Interfaces, Potsdam, Germany, Institut National de la Recherche Agronomique (INRA), umr Physiologie Intégrative de l’Arbre Fruitier et Forestier (PIAF), 234 av. du Brézet, 63100 Clermont-Ferrand, France, Forschungszentrum Karlsruhe GmbH, Institut für Mikrostrukturtechnik, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany, and Department of Chemistry, Boku - University of Natural Resources and Applied Life Sciences,
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2206
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Yue ZB, Liu RH, Yu HQ, Chen HZ, Yu B, Harada H, Li YY. Enhanced Anaerobic Ruminal Degradation of Bulrush through Steam Explosion Pretreatment. Ind Eng Chem Res 2008. [DOI: 10.1021/ie800202c] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Zheng-Bo Yue
- Department of Chemistry, University of Science & Technology of China, Hefei 230026, China, National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100080 China, and Department of Civil Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Rong-Hua Liu
- Department of Chemistry, University of Science & Technology of China, Hefei 230026, China, National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100080 China, and Department of Civil Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Han-Qing Yu
- Department of Chemistry, University of Science & Technology of China, Hefei 230026, China, National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100080 China, and Department of Civil Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Hong-Zhang Chen
- Department of Chemistry, University of Science & Technology of China, Hefei 230026, China, National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100080 China, and Department of Civil Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Bin Yu
- Department of Chemistry, University of Science & Technology of China, Hefei 230026, China, National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100080 China, and Department of Civil Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Hideki Harada
- Department of Chemistry, University of Science & Technology of China, Hefei 230026, China, National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100080 China, and Department of Civil Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Yu-You Li
- Department of Chemistry, University of Science & Technology of China, Hefei 230026, China, National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100080 China, and Department of Civil Engineering, Tohoku University, Sendai 980-8579, Japan
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2207
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Molecular simulation evidence for processive motion of Trichoderma reesei Cel7A during cellulose depolymerization. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2008.05.060] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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2208
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Taylor LE, Dai Z, Decker SR, Brunecky R, Adney WS, Ding SY, Himmel ME. Heterologous expression of glycosyl hydrolases in planta: a new departure for biofuels. Trends Biotechnol 2008; 26:413-24. [PMID: 18579242 DOI: 10.1016/j.tibtech.2008.05.002] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2008] [Revised: 05/01/2008] [Accepted: 05/07/2008] [Indexed: 11/18/2022]
Abstract
The concept of expressing non-plant glycosyl hydrolase genes in plant tissue is nearly two decades old, yet relatively little work in this field has been reported. However, resurgent interest in technologies aimed at enabling processes that convert biomass to sugars and fuels has turned attention toward this intuitive solution. There are several challenges facing researchers in this field, including the development of better and more specifically targeted delivery systems for hydrolytic genes, the successful folding and post-translational modification of heterologous proteins and the development of cost-effective process strategies utilizing these transformed plants. The integration of these concepts, from the improvement of biomass production and conversion characteristics to the heterologous production of glycosyl hydrolases in a high yielding bioenergy crop, holds considerable promise for improving the lignocellulosic conversion of biomass to ethanol and subsequently to fuels.
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Affiliation(s)
- Larry E Taylor
- Chemical and Biosciences Center, National Renewable Energy Laboratory, 1617 Cole Blvd, Golden, CO 80401, USA
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2209
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Orts WJ, Holtman KM, Seiber JN. Agricultural chemistry and bioenergy. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2008; 56:3892-3899. [PMID: 18473470 DOI: 10.1021/jf8006695] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Renewed interest in converting biomass to biofuels such as ethanol, other forms of bioenergy, and bioenergy byproducts or coproducts of commercial value opens opportunities for chemists, including agricultural chemists and related disciplines. Applications include feedstock characterization and quantification of structural changes resulting from genetic modification and of the intermediates formed during enzymatic and chemical processing; development of improved processes for utilizing chemical coproducts such as lactic acid and glycerol; development of alternative biofuels such as methanol, butanol, and hydrogen; and ways to reduce greenhouse gas emission and/or use carbon dioxide beneficially. Chemists will also be heavily involved in detailing the phytochemical composition of alternative energy crops and genetically improved crops. A resurgence of demand for agricultural chemistry and related disciplines argues for increasing output through targeted programs and on-the-job training.
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Affiliation(s)
- William J Orts
- Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Albany, CA 94710, USA
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2210
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Plant genetic engineering for biofuel production: towards affordable cellulosic ethanol. Nat Rev Genet 2008; 9:433-43. [DOI: 10.1038/nrg2336] [Citation(s) in RCA: 396] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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2211
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Ding SY, Xu Q, Crowley M, Zeng Y, Nimlos M, Lamed R, Bayer EA, Himmel ME. A biophysical perspective on the cellulosome: new opportunities for biomass conversion. Curr Opin Biotechnol 2008; 19:218-27. [PMID: 18513939 DOI: 10.1016/j.copbio.2008.04.008] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Revised: 04/28/2008] [Accepted: 04/29/2008] [Indexed: 11/28/2022]
Abstract
The cellulosome is a multiprotein complex, produced primarily by anaerobic microorganisms, which functions to degrade lignocellulosic materials. An important topic of current debate is whether cellulosomal systems display greater ability to deconstruct complex biomass materials (e.g. plant cell walls) than nonaggregated enzymes, and in so doing would be appropriate for improved, commercial bioconversion processes. To sufficiently understand the complex macromolecular processes between plant cell wall polymers, cellulolytic microbes, and their secreted enzymes, a highly concerted research approach is required. Adaptation of existing biophysical techniques and development of new science tools must be applied to this system. This review focuses on strategies likely to permit improved understanding of the bacterial cellulosome using biophysical approaches, with emphasis on advanced imaging and computational techniques.
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Affiliation(s)
- Shi-You Ding
- Chemical and Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA.
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2212
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Sørensen I, Pettolino FA, Wilson SM, Doblin MS, Johansen B, Bacic A, Willats WGT. Mixed-linkage (1-->3),(1-->4)-beta-D-glucan is not unique to the Poales and is an abundant component of Equisetum arvense cell walls. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2008; 54:510-21. [PMID: 18284587 DOI: 10.1111/j.1365-313x.2008.03453.x] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Mixed-linkage (1-->3),(1-->4)-beta-D-glucan (MLG) is widely considered to be a defining feature of the cell walls of plants in the Poales order. However, we conducted an extensive survey of cell-wall composition in diverse land plants and discovered that MLG is also abundant in the walls of the horsetail Equisetum arvense. MALDI-TOF MS and monosaccharide linkage analysis revealed that MLG in E. arvense is an unbranched homopolymer that consists of short blocks of contiguous 1,4-beta-linked glucose residues joined by 1,3-beta linkages. However, in contrast to Poaceae species, MLG in E. arvense consists mostly of cellotetraose rather than cellotetriose, and lacks long 1,4-beta-linked glucan blocks. Monosaccharide linkage analyses and immunochemical profiling indicated that, in E. arvense, MLG is a component of cell walls that have a novel architecture that differs significantly from that of the generally recognized type I and II cell walls. Unlike in type II walls, MLG in E. arvense does not appear to be co-extensive with glucuroarabinoxylans but occurs in walls that are rich in pectin. Immunofluorescence and immunogold localization showed that MLG occurs in both young and old regions of E. arvense stems, and is present in most cell types apart from cells in the vascular tissues. These findings have important implications for our understanding of cell-wall evolution, and also demonstrate that plant cell walls can be constructed in a way not previously envisaged.
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Affiliation(s)
- Iben Sørensen
- Department of Biology, The University of Copenhagen, Ole Maaløes vej 5, Copenhagen DK-2200, Denmark
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2213
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Wackett LP. Microbial-based motor fuels: science and technology. Microb Biotechnol 2008; 1:211-25. [PMID: 21261841 PMCID: PMC3815883 DOI: 10.1111/j.1751-7915.2007.00020.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2007] [Revised: 11/16/2007] [Accepted: 11/26/2007] [Indexed: 11/30/2022] Open
Abstract
The production of biofuels via microbial biotechnology is a very active field of research. A range of fuel molecule types are currently under consideration: alcohols, ethers, esters, isoprenes, alkenes and alkanes. At the present, the major alcohol biofuel is ethanol. The ethanol fermentation is an old technology. Ongoing efforts aim to increase yield and energy efficiency of ethanol production from biomass. n-Butanol, another microbial fermentation product, is potentially superior to ethanol as a fuel but suffers from low yield and unwanted side-products currently. In general, biodiesel fuels consist of fatty acid methyl esters in which the carbon derives from plants, not microbes. A new biodiesel product, called microdiesel, can be generated in engineered bacterial cells that condense ethanol with fatty acids. Perhaps the best fuel type to generate from biomass would be biohydrocarbons. Microbes are known to produce hydrocarbons such as isoprenes, long-chain alkenes and alkanes. The biochemical mechanisms of microbial hydrocarbon biosynthesis are currently under study. Hydrocarbons and minimally oxygenated molecules may also be produced by hybrid chemical and biological processes. A broad interest in novel fuel molecules is also driving the development of new bioinformatics tools to facilitate biofuels research.
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Affiliation(s)
- Lawrence P Wackett
- Department of Biochemistry, Molecular Biology and Biophysics and BioTechnology Institute, University of Minnesota, St. Paul, MN 551088, USA.
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2214
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Pauly M, Keegstra K. Cell-wall carbohydrates and their modification as a resource for biofuels. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2008; 54:559-68. [PMID: 18476863 DOI: 10.1111/j.1365-313x.2008.03463.x] [Citation(s) in RCA: 437] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Plant cell walls represent the most abundant renewable resource on this planet. Despite their great abundance, only 2% of this resource is currently used by humans. Hence, research into the feasibility of using plant cell walls in the production of cost-effective biofuels is desirable. The main bottleneck for using wall materials is the recalcitrance of walls to efficient degradation into fermentable sugars. Manipulation of the wall polysaccharide biosynthetic machinery or addition of wall structure-altering agents should make it possible to tailor wall composition and architecture to enhance sugar yields upon wall digestion for biofuel fermentation. Study of the biosynthetic machinery and its regulation is still in its infancy and represents a major scientific and technical research challenge. Of course, any change in wall structure to accommodate cost-efficient biofuel production may have detrimental effects on plant growth and development due to the diverse roles of walls in the life of a plant. However, the diversity and abundance of wall structures present in the plant kingdom gives hope that this challenge can be met.
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Affiliation(s)
- Markus Pauly
- Department of Energy Plant Research Laboratory and Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA.
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2215
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Kristensen JB, Thygesen LG, Felby C, Jørgensen H, Elder T. Cell-wall structural changes in wheat straw pretreated for bioethanol production. BIOTECHNOLOGY FOR BIOFUELS 2008; 1:5. [PMID: 18471316 PMCID: PMC2375870 DOI: 10.1186/1754-6834-1-5] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2008] [Accepted: 04/16/2008] [Indexed: 05/03/2023]
Abstract
BACKGROUND Pretreatment is an essential step in the enzymatic hydrolysis of biomass and subsequent production of bioethanol. Recent results indicate that only a mild pretreatment is necessary in an industrial, economically feasible system. The Integrated Biomass Utilisation System hydrothermal pretreatment process has previously been shown to be effective in preparing wheat straw for these processes without the application of additional chemicals. In the current work, the effect of the pretreatment on the straw cell-wall matrix and its components are characterised microscopically (atomic force microscopy and scanning electron microscopy) and spectroscopically (attenuated total reflectance Fourier transform infrared spectroscopy) in order to understand this increase in digestibility. RESULTS The hydrothermal pretreatment does not degrade the fibrillar structure of cellulose but causes profound lignin re-localisation. Results from the current work indicate that wax has been removed and hemicellulose has been partially removed. Similar changes were found in wheat straw pretreated by steam explosion. CONCLUSION Results indicate that hydrothermal pretreatment increases the digestibility by increasing the accessibility of the cellulose through a re-localisation of lignin and a partial removal of hemicellulose, rather than by disruption of the cell wall.
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Affiliation(s)
- Jan B Kristensen
- Forest and Landscape Denmark, University of Copenhagen, Rolighedsvej 23, DK-1958 Frederiksberg, Denmark
| | - Lisbeth G Thygesen
- Forest and Landscape Denmark, University of Copenhagen, Rolighedsvej 23, DK-1958 Frederiksberg, Denmark
| | - Claus Felby
- Forest and Landscape Denmark, University of Copenhagen, Rolighedsvej 23, DK-1958 Frederiksberg, Denmark
| | - Henning Jørgensen
- Forest and Landscape Denmark, University of Copenhagen, Rolighedsvej 23, DK-1958 Frederiksberg, Denmark
| | - Thomas Elder
- Utilization of Southern Forest Products, USDA-Forest Service, Southern Research Station, Shreveport Highway, Pineville, LA 71360, USA
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2216
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Turon X, Rojas OJ, Deinhammer RS. Enzymatic kinetics of cellulose hydrolysis: a QCM-D study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:3880-7. [PMID: 18324851 DOI: 10.1021/la7032753] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The interactions between films of cellulose and cellulase enzymes were monitored using a quartz crystal microbalance (QCM). Real-time measurements of the coupled contributions of enzyme binding and hydrolytic reactions were fitted to a kinetic model that described closely significant cellulase activities. The proposed model combines simple Boltzmann sigmoidal and 1 - exp expressions. The obtained kinetics parameters were proven to be useful to discriminate the effects of incubation variables and also to perform enzyme screening. Furthermore, it is proposed that the energy dissipation of a film subject to enzymatic hydrolysis brings to light its structural changes. Overall, it is demonstrated that the variations registered in QCM frequency and dissipation of the film are indicative of mass and morphological transformations due to enzyme activities; these include binding phenomena, progressive degradation of the cellulose film, existence of residual, recalcitrant cellulose fragments, and the occurrence of other less apparent changes throughout the course of incubation.
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Affiliation(s)
- Xavier Turon
- North Carolina State University, Forest Biomaterials Laboratory, College of Natural Resources, Raleigh, NC 27695, USA
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2217
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Bowen TA, Zdunek JK, Medford JI. Cultivating plant synthetic biology from systems biology. THE NEW PHYTOLOGIST 2008; 179:583-587. [PMID: 18373648 DOI: 10.1111/j.1469-8137.2008.02433.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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2218
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Eijsink VGH, Vaaje-Kolstad G, Vårum KM, Horn SJ. Towards new enzymes for biofuels: lessons from chitinase research. Trends Biotechnol 2008; 26:228-35. [PMID: 18367275 DOI: 10.1016/j.tibtech.2008.02.004] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2007] [Revised: 02/08/2008] [Accepted: 02/15/2008] [Indexed: 10/22/2022]
Abstract
Enzymatic conversion of structural polysaccharides in plant biomass is a key issue in the development of second generation ('lignocellulosic') bioethanol. The efficiency of this process depends in part on the ability of enzymes to disrupt crystalline polysaccharides, thus gaining access to single polymer chains. Recently, new insights into how enzymes accomplish this have been obtained from studies on enzymatic conversion of chitin. First, chitinolytic microorganisms were shown to produce non-hydrolytic accessory proteins that increase enzyme efficiency. Second, it was shown that a processive mechanism, which is generally considered favorable because it improves substrate accessibility, might in fact slow down enzymes. These findings suggest new focal points for the development of enzyme technology for depolymerizing recalcitrant polysaccharide biomass. Improving substrate accessibility should be a key issue because this might reduce the need for using processive enzymes, which are intrinsically slow and abundantly present in current commercial enzyme preparations for biomass conversion. Furthermore, carefully selected substrate-disrupting accessory proteins or domains might provide novel tools to improve substrate accessibility and thus contribute to more efficient enzymatic processes.
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Affiliation(s)
- Vincent G H Eijsink
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, As, Norway.
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2219
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Abstract
Developing technologies to reduce the rate of increase of atmospheric concentration of carbon dioxide (CO2) from annual emissions of 8.6PgCyr-1 from energy, process industry, land-use conversion and soil cultivation is an important issue of the twenty-first century. Of the three options of reducing the global energy use, developing low or no-carbon fuel and sequestering emissions, this manuscript describes processes for carbon (CO2) sequestration and discusses abiotic and biotic technologies. Carbon sequestration implies transfer of atmospheric CO2 into other long-lived global pools including oceanic, pedologic, biotic and geological strata to reduce the net rate of increase in atmospheric CO2. Engineering techniques of CO2 injection in deep ocean, geological strata, old coal mines and oil wells, and saline aquifers along with mineral carbonation of CO2 constitute abiotic techniques. These techniques have a large potential of thousands of Pg, are expensive, have leakage risks and may be available for routine use by 2025 and beyond. In comparison, biotic techniques are natural and cost-effective processes, have numerous ancillary benefits, are immediately applicable but have finite sink capacity. Biotic and abiotic C sequestration options have specific nitches, are complementary, and have potential to mitigate the climate change risks.
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Affiliation(s)
- Rattan Lal
- Carbon Management and Sequestration Center, The Ohio State University, Columbus, OH 43210, USA.
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2220
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Mazeau K, Rivet A. Wetting the (110) and (100) Surfaces of Iβ Cellulose Studied by Molecular Dynamics. Biomacromolecules 2008; 9:1352-4. [DOI: 10.1021/bm7013872] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Karim Mazeau
- Centre de Recherches sur les Macromolécules Végétales (CERMAV-CNRS), ICMG FR 2607, BP 53, 38041 Grenoble Cedex 9, France, Affiliated with the Joseph Fourier University
| | - Alain Rivet
- Centre de Recherches sur les Macromolécules Végétales (CERMAV-CNRS), ICMG FR 2607, BP 53, 38041 Grenoble Cedex 9, France, Affiliated with the Joseph Fourier University
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2221
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Xu F, Ding H, Osborn D, Tejirian A, Brown K, Albano W, Sheehy N, Langston J. Partition of enzymes between the solvent and insoluble substrate during the hydrolysis of lignocellulose by cellulases. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/j.molcatb.2007.10.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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2222
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2223
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Qian X. The effect of cooperativity on hydrogen bonding interactions in native cellulose Iβ fromab initiomolecular dynamics simulations. MOLECULAR SIMULATION 2008. [DOI: 10.1080/08927020801961476] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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2224
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Regulation of transcription of cellulases- and hemicellulases-encoding genes in Aspergillus niger and Hypocrea jecorina (Trichoderma reesei). Appl Microbiol Biotechnol 2008; 78:211-20. [PMID: 18197406 DOI: 10.1007/s00253-007-1322-0] [Citation(s) in RCA: 182] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Revised: 12/06/2007] [Accepted: 12/08/2007] [Indexed: 10/22/2022]
Abstract
The filamentous fungi Aspergillus niger and Hypocrea jecorina (Trichoderma reesei) have been the subject of many studies investigating the mechanism of transcriptional regulation of hemicellulase- and cellulase-encoding genes. The transcriptional regulator XlnR that was initially identified in A. niger as the transcriptional regulator of xylanase-encoding genes controls the transcription of about 20-30 genes encoding hemicellulases and cellulases. The orthologous xyr1 (xylanase regulator 1-encoding) gene product of H. jecorina has a similar function as XlnR, although at points, the mechanisms seems to be different. Specifically in H. jecorina, the interaction of Xyr1 and the co-regulators Ace1 and Ace2 in the regulation of transcription of xylanases and cellulases has been studied. This paper describes the similarities and differences in the transcriptional regulation of expression of hemicellulases and cellulases in A. niger and H. jecorina.
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2225
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Microbial diversity and genomics in aid of bioenergy. J Ind Microbiol Biotechnol 2008; 35:403-419. [PMID: 18193465 DOI: 10.1007/s10295-007-0300-y] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2007] [Accepted: 12/14/2007] [Indexed: 12/27/2022]
Abstract
In view of the realization that fossil fuels reserves are limited, various options of generating energy are being explored. Biological methods for producing fuels such as ethanol, diesel, hydrogen (H2), methane, etc. have the potential to provide a sustainable energy system for the society. Biological H2 production appears to be the most promising as it is non-polluting and can be produced from water and biological wastes. The major limiting factors are low yields, lack of industrially robust organisms, and high cost of feed. Actually, H2 yields are lower than theoretically possible yields of 4 mol/mol of glucose because of the associated fermentation products such as lactic acid, propionic acid and ethanol. The efficiency of energy production can be improved by screening microbial diversity and easily fermentable feed materials. Biowastes can serve as feed for H2 production through a set of microbial consortia: (1) hydrolytic bacteria, (2) H2 producers (dark fermentative and photosynthetic). The efficiency of the bioconversion process may be enhanced further by the production of value added chemicals such as polydroxyalkanoate and anaerobic digestion. Discovery of enormous microbial diversity and sequencing of a wide range of organisms may enable us to realize genetic variability, identify organisms with natural ability to acquire and transmit genes. Such organisms can be exploited through genome shuffling for transgenic expression and efficient generation of clean fuel and other diverse biotechnological applications.
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2226
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Zhang YHP. Reviving the carbohydrate economy via multi-product lignocellulose biorefineries. J Ind Microbiol Biotechnol 2008; 35:367-375. [PMID: 18180967 DOI: 10.1007/s10295-007-0293-6] [Citation(s) in RCA: 222] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2007] [Accepted: 12/04/2007] [Indexed: 11/27/2022]
Abstract
Before the industrial revolution, the global economy was largely based on living carbon from plants. Now the economy is mainly dependent on fossil fuels (dead carbon). Biomass is the only sustainable bioresource that can provide sufficient transportation fuels and renewable materials at the same time. Cellulosic ethanol production from less costly and most abundant lignocellulose is confronted with three main obstacles: (1) high processing costs (dollars /gallon of ethanol), (2) huge capital investment (dollars approximately 4-10/gallon of annual ethanol production capacity), and (3) a narrow margin between feedstock and product prices. Both lignocellulose fractionation technology and effective co-utilization of acetic acid, lignin and hemicellulose will be vital to the realization of profitable lignocellulose biorefineries, since co-product revenues would increase the margin up to 6.2-fold, where all purified lignocellulose co-components have higher selling prices (> approximately 1.0/kg) than ethanol ( approximately 0.5/kg of ethanol). Isolation of large amounts of lignocellulose components through lignocellulose fractionation would stimulate R&D in lignin and hemicellulose applications, as well as promote new markets for lignin- and hemicellulose-derivative products. Lignocellulose resource would be sufficient to replace significant fractionations (e.g., 30%) of transportation fuels through liquid biofuels, internal combustion engines in the short term, and would provide 100% transportation fuels by sugar-hydrogen-fuel cell systems in the long term.
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Affiliation(s)
- Y-H Percival Zhang
- Biological Systems Engineering Department, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA.
- Institute for Critical Technology and Applied Science (ICTAS), Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA.
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2227
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Lee D, Chen A, Nair R. Genetically Engineered Crops for Biofuel Production: Regulatory Perspectives. Biotechnol Genet Eng Rev 2008; 25:331-61. [DOI: 10.5661/bger-25-331] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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2228
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Hu ZH, Liu SY, Yue ZB, Yan LF, Yang MT, Yu HQ. Microscale analysis of in vitro anaerobic degradation of lignocellulosic wastes by rumen microorganisms. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:276-81. [PMID: 18350908 DOI: 10.1021/es071915h] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Anaerobic degradation of lignin in waste straw by ruminal microbes was directly observed using atomic force microscope (AFM). A series of high-resolution AFM images of the straw surface in the biodegradation show that the wax flakelets and lignin granules covering the straw surface were removed by the rumen microorganisms. Such degradation resulted in an exposure of cellulose fibers located inside the straw. The appearance of holes and microfibers in fermentation reveals that tunneling might be one of the ways for rumen microorganisms to attack the straw. Increases in the atomic ratio of oxygen to carbon (O/C) and the ratio C2/C3 in C1s spectra of X-ray photoelectron spectroscopy confirm that more cellulose was exposed on the surface after the anaerobic fermentation of straw. Gas chromatography/mass spectrometry analytical results demonstrate the decomposition of lignin by rumen microorganisms. Fourier transform infrared spectroscopy spectra and the measurement of degradation efficiency of the main straw components further verify these microscaled observations.
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Affiliation(s)
- Zhen-Hu Hu
- Laboratory of Environmental Engineering, School of Chemistry, University of Science & Technology of China, Hefei 230026, China
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2229
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Chang MCY. Harnessing energy from plant biomass. Curr Opin Chem Biol 2007; 11:677-84. [PMID: 17942363 DOI: 10.1016/j.cbpa.2007.08.039] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2007] [Accepted: 08/30/2007] [Indexed: 11/24/2022]
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2230
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High-resolution Thermogravimetric Analysis For Rapid Characterization of Biomass Composition and Selection of Shrub Willow Varieties. Appl Biochem Biotechnol 2007; 145:3-11. [DOI: 10.1007/s12010-007-8061-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2007] [Accepted: 09/19/2007] [Indexed: 11/25/2022]
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2231
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Ivanov R, Tiedemann J, Czihal A, Schallau A, Diep LH, Mock HP, Claus B, Tewes A, Bäumlein H. EFFECTOR OF TRANSCRIPTION2 is involved in xylem differentiation and includes a functional DNA single strand cutting domain. Dev Biol 2007; 313:93-106. [PMID: 17991462 DOI: 10.1016/j.ydbio.2007.09.061] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2007] [Revised: 09/26/2007] [Accepted: 09/26/2007] [Indexed: 12/30/2022]
Abstract
EFFECTORS OF TRANSCRIPTION2 (ET) are plant-specific regulatory proteins characterized by the presence of two to five C-terminal DNA- and Zn-binding repeats, and a highly conserved cysteine pattern. We describe the structural characterization of the three member Arabidopsis thaliana ET gene family and reveal some allelic sequence polymorphisms. A mutation analysis showed that AtET2 affects the expression of various KNAT genes involved in the maintenance of the undifferentiated state of cambial meristem cells. It also plays a role in the regulation of GA5 (gibberellin 3-beta-dioxygenase) and the cell-cycle-related GASA4. A correlation was established between AtET2 expression and the cellular differentiation state. AtET-GFP fusion proteins shuttle between the cytoplasm and nucleus, with the AtET2 product prevented from entering the nucleus in non-differentiating cells. Within the nucleus, AtET2 probably acts via a single strand cutting domain. A more general regulatory role for ET factors is proposed, governing cell differentiation in cambial meristems, a crucial process for the development of plant vascular tissues.
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Affiliation(s)
- Rumen Ivanov
- Leibniz-Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstr. 3, D-06466 Gatersleben, Germany
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2232
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Chapotin SM, Wolt JD. Genetically modified crops for the bioeconomy: meeting public and regulatory expectations. Transgenic Res 2007; 16:675-88. [PMID: 17701080 DOI: 10.1007/s11248-007-9122-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2007] [Accepted: 07/07/2007] [Indexed: 10/23/2022]
Abstract
As the United States moves toward a plant-based bioeconomy, a large research and development effort is focused on creating new feedstocks to meet biomass demand for biofuels, bioenergy, and specialized bioproducts, such as industrial compounds and biomaterial precursors. Most bioeconomy projections assume the widespread deployment of novel feedstocks developed through the use of modern molecular breeding techniques, but rarely consider the challenges involved with the use of genetically modified crops, which can include hurdles due to regulatory approvals, market adoption, and public acceptance. In this paper we consider the implications of various transgenic crops and traits under development for the bioeconomy that highlight these challenges. We believe that an awareness of the issues in crop and trait selection will allow developers to design crops with maximum stakeholder appeal and with the greatest potential for widespread adoption, while avoiding applications unlikely to meet regulatory approval or gain market and public acceptance.
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2233
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2234
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2235
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Jørgensen H, Vibe-Pedersen J, Larsen J, Felby C. Liquefaction of lignocellulose at high-solids concentrations. Biotechnol Bioeng 2007. [PMID: 16865734 DOI: 10.1002/bbb.4] [Citation(s) in RCA: 431] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
To improve process economics of the lignocellulose to ethanol process a reactor system for enzymatic liquefaction and saccharification at high-solids concentrations was developed. The technology is based on free fall mixing employing a horizontally placed drum with a horizontal rotating shaft mounted with paddlers for mixing. Enzymatic liquefaction and saccharification of pretreated wheat straw was tested with up to 40% (w/w) initial DM. In less than 10 h, the structure of the material was changed from intact straw particles (length 1-5 cm) into a paste/liquid that could be pumped. Tests revealed no significant effect of mixing speed in the range 3.3-11.5 rpm on the glucose conversion after 24 h and ethanol yield after subsequent fermentation for 48 h. Low-power inputs for mixing are therefore possible. Liquefaction and saccharification for 96 h using an enzyme loading of 7 FPU/g.DM and 40% DM resulted in a glucose concentration of 86 g/kg. Experiments conducted at 2%-40% (w/w) initial DM revealed that cellulose and hemicellulose conversion decreased almost linearly with increasing DM. Performing the experiments as simultaneous saccharification and fermentation also revealed a decrease in ethanol yield at increasing initial DM. Saccharomyces cerevisiae was capable of fermenting hydrolysates up to 40% DM. The highest ethanol concentration, 48 g/kg, was obtained using 35% (w/w) DM. Liquefaction of biomass with this reactor system unlocks the possibility of 10% (w/w) ethanol in the fermentation broth in future lignocellulose to ethanol plants.
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Affiliation(s)
- Henning Jørgensen
- Forestry and Forest Products, Faculty of Life Sciences, University of Copenhagen, Rolighedsvej 23, DK-1958 Frederiksberg, Denmark.
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2236
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Busov V, Tsai CJ. Perennial challenges and opportunities. THE NEW PHYTOLOGIST 2007; 176:3-6. [PMID: 17803637 DOI: 10.1111/j.1469-8137.2007.02221.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Affiliation(s)
- Victor Busov
- Biotechnology Research Center, School of Forest Resources and Environmental Science, Michigan Technological University, Houghton, MI 49931, USA
| | - Chung-Jui Tsai
- Biotechnology Research Center, School of Forest Resources and Environmental Science, Michigan Technological University, Houghton, MI 49931, USA
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