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Sun P, Li X, Dilokpimol A, Henrissat B, de Vries RP, Kabel MA, Mäkelä MR. Fungal glycoside hydrolase family 44 xyloglucanases are restricted to the phylum Basidiomycota and show a distinct xyloglucan cleavage pattern. iScience 2022; 25:103666. [PMID: 35028537 PMCID: PMC8741620 DOI: 10.1016/j.isci.2021.103666] [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: 07/07/2021] [Revised: 11/23/2021] [Accepted: 12/16/2021] [Indexed: 11/26/2022] Open
Abstract
Xyloglucan is a prominent matrix heteropolysaccharide binding to cellulose microfibrils in primary plant cell walls. Hence, the hydrolysis of xyloglucan facilitates the overall lignocellulosic biomass degradation. Xyloglucanases (XEGs) are key enzymes classified in several glycoside hydrolase (GH) families. So far, family GH44 has been shown to contain bacterial XEGs only. Detailed genome analysis revealed GH44 members in fungal species from the phylum Basidiomycota, but not in other fungi, which we hypothesized to also be XEGs. Two GH44 enzymes from Dichomitus squalens and Pleurotus ostreatus were heterologously produced and characterized. They exhibited XEG activity and displayed a hydrolytic cleavage pattern different from that observed in fungal XEGs from other GH families. Specifically, the fungal GH44 XEGs were not hindered by substitution of neighboring glucosyl units and generated various "XXXG-type," "GXXX(G)-type," and "XXX-type" oligosaccharides. Overall, these fungal GH44 XEGs represent a novel class of enzymes for plant biomass conversion and valorization.
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Affiliation(s)
- Peicheng Sun
- Laboratory of Food Chemistry, Wageningen University and Research, Bornse Weilanden 9, 6708 WG Wageningen, the Netherlands
| | - Xinxin Li
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute and Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Adiphol Dilokpimol
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute and Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Bernard Henrissat
- DTU Bioengineering, Technical University of Denmark, Søltofts Plads, 2800 Kongens Lyngby, Denmark.,Department of Biological Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Ronald P de Vries
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute and Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Mirjam A Kabel
- Laboratory of Food Chemistry, Wageningen University and Research, Bornse Weilanden 9, 6708 WG Wageningen, the Netherlands
| | - Miia R Mäkelä
- Department of Microbiology, University of Helsinki, Viikinkaari 9, 00790 Helsinki, Finland
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2
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de Vries L, Guevara-Rozo S, Cho M, Liu LY, Renneckar S, Mansfield SD. Tailoring renewable materials via plant biotechnology. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:167. [PMID: 34353358 PMCID: PMC8344217 DOI: 10.1186/s13068-021-02010-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 07/06/2021] [Indexed: 05/03/2023]
Abstract
Plants inherently display a rich diversity in cell wall chemistry, as they synthesize an array of polysaccharides along with lignin, a polyphenolic that can vary dramatically in subunit composition and interunit linkage complexity. These same cell wall chemical constituents play essential roles in our society, having been isolated by a variety of evolving industrial processes and employed in the production of an array of commodity products to which humans are reliant. However, these polymers are inherently synthesized and intricately packaged into complex structures that facilitate plant survival and adaptation to local biogeoclimatic regions and stresses, not for ease of deconstruction and commercial product development. Herein, we describe evolving techniques and strategies for altering the metabolic pathways related to plant cell wall biosynthesis, and highlight the resulting impact on chemistry, architecture, and polymer interactions. Furthermore, this review illustrates how these unique targeted cell wall modifications could significantly extend the number, diversity, and value of products generated in existing and emerging biorefineries. These modifications can further target the ability for processing of engineered wood into advanced high performance materials. In doing so, we attempt to illuminate the complex connection on how polymer chemistry and structure can be tailored to advance renewable material applications, using all the chemical constituents of plant-derived biopolymers, including pectins, hemicelluloses, cellulose, and lignins.
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Affiliation(s)
- Lisanne de Vries
- Department of Wood Science, Faculty of Forestry, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- US Department of Energy (DOE) Great Lakes Bioenergy Research Center, the Wisconsin Energy Institute, University of Wisconsin - Madison, Madison, WI , 53726, USA
| | - Sydne Guevara-Rozo
- Department of Wood Science, Faculty of Forestry, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - MiJung Cho
- Department of Wood Science, Faculty of Forestry, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Li-Yang Liu
- Department of Wood Science, Faculty of Forestry, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Scott Renneckar
- Department of Wood Science, Faculty of Forestry, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Shawn D Mansfield
- Department of Wood Science, Faculty of Forestry, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
- US Department of Energy (DOE) Great Lakes Bioenergy Research Center, the Wisconsin Energy Institute, University of Wisconsin - Madison, Madison, WI , 53726, USA.
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3
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Ambaye TG, Vaccari M, Bonilla-Petriciolet A, Prasad S, van Hullebusch ED, Rtimi S. Emerging technologies for biofuel production: A critical review on recent progress, challenges and perspectives. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 290:112627. [PMID: 33991767 DOI: 10.1016/j.jenvman.2021.112627] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 04/10/2021] [Accepted: 04/11/2021] [Indexed: 05/08/2023]
Abstract
Due to increasing anthropogenic activities, especially industry and transport, the fossil fuel demand and consumption have increased proportionally, causing serious environmental issues. This attracted researchers and scientists to develop new alternative energy sources. Therefore, this review covers the biofuel production potential and challenges related to various feedstocks and advances in process technologies. It has been concluded that the biofuels such as biodiesel, ethanol, bio-oil, syngas, Fischer-Tropsch H2, and methane produced from crop plant residues, micro- and macroalgae and other biomass wastes using thermo-bio-chemical processes are an eco-friendly route for an energy source. Biofuels production and their uses in industries and transportation considerably minimize fossil fuel dependence. Literature analysis showed that biofuels generated from energy crops and microalgae could be the most efficient and attractive process. Recent progress in the field of biofuels using genetic engineering has larger perspectives in commercial-scale production. However, its large-scale production is still challenging; hence, to resolve this problem, it is essential to convert biomass in biofuels by developing novel technology to increase biofuel production to fulfil the current and future energy demand.
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Affiliation(s)
- Teklit Gebregiorgis Ambaye
- Department of Civil, Environmental, Architectural Engineering and Mathematics, University of Brescia, Via Branze 43, 25123, Brescia, Italy; Mekelle University, Department of Chemistry, Mekelle, Ethiopia.
| | - Mentore Vaccari
- Department of Civil, Environmental, Architectural Engineering and Mathematics, University of Brescia, Via Branze 43, 25123, Brescia, Italy
| | | | - Shiv Prasad
- Centre for Environment Science &Climate Resilient Agriculture (CESCRA) Indian Agricultural Research Institute New Delhi, 110012, India
| | | | - Sami Rtimi
- Ecole Polytechnique Fédérale de Lausanne, CH-1015, Lausanne, Switzerland.
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4
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Pu J, Wang L, Zhang W, Ma J, Zhang X, Putnis CV. Organically-bound silicon enhances resistance to enzymatic degradation and nanomechanical properties of rice plant cell walls. Carbohydr Polym 2021; 266:118057. [PMID: 34044915 DOI: 10.1016/j.carbpol.2021.118057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 04/02/2021] [Accepted: 04/05/2021] [Indexed: 12/31/2022]
Abstract
Plant cell walls exhibit excellent mechanical properties, which form the structural basis for sustainable bioresources and multifunctional nanocelluloses. The wall nanomechanical properties of living cells through covalent modifications of hybrid inorganic elements, such as silicon, may confer significant influence on local mechano-response and enzymatic degradation. Here, we present a combination of ex situ measurements of enzyme-released oligosaccharide fragments using MALDI-TOF MS and in situ atomic force microscopy (AFM) imaging through PeakForce quantitative nanomechanical mapping of tip-functionalized single-molecule enzyme-polysaccharide substrate recognition and the nanoscale dissolution kinetics of individual cellulose microfibrils of living rice (Oryza sativa) cells following silicate cross-linking of cell wall xyloglucan. We find that xyloglucan-bound silicon enhances the resistance to degradation by cellulase and improves the wall nanomechanical properties in the elastic modulus at the single-cell level. The findings establish a direct link between an inorganic element of silicon and the nanoscale architecture of plant cell wall materials for sustainable utilization.
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Affiliation(s)
- Junbao Pu
- College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
| | - Lijun Wang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Wenjun Zhang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Jie Ma
- College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xiuqing Zhang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
| | - Christine V Putnis
- Institut für Mineralogie, University of Münster, 48149, Münster, Germany; School of Molecular and Life Science, Curtin University, 6845, Perth, Australia
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Lopes DCB, Carraro CB, Silva RN, de Paula RG. Molecular Characterization of Xyloglucanase cel74a from Trichoderma reesei. Int J Mol Sci 2021; 22:ijms22094545. [PMID: 33925273 PMCID: PMC8123685 DOI: 10.3390/ijms22094545] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 04/22/2021] [Accepted: 04/23/2021] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND The filamentous fungus Trichoderma reesei is used on an industrial scale to produce enzymes of biotechnological interest. This fungus has a complex cellulolytic system involved in the degradation of lignocellulosic biomass. However, several aspects related to the regulation of the expression of holocellulolytic genes and the production of cellulases by this fungus are still understood. METHODS Here, we constructed a null mutant strain for the xyloglucanase cel74a gene and performed the characterization of the Δcel74a strain to evaluate the genetic regulation of the holocellulases during sugarcane bagasse (SCB) cultivation. RESULTS Our results demonstrate that the deletion of xyloglucanase cel74a may impact the regulation of holocellulase expression during SCB cultivation. The expression of cellulases cel7a, cel7b, and cel6a was reduced in Δcel74a strain, while the hemicellulases xyn1 and xyn2 were increased in the presence of SCB. The cel74a mutation also affected the xyloglucan hydrolysis patterns. In addition, CEL74A activity was modulated in the presence of calcium, suggesting that this ion may be required for efficient degradation of xyloglucan. CONCLUSIONS CEL74A affects the regulation of holocellulolytic genes and the efficient degradation of SCB in T. reesei. This data makes a significant contribution to our understanding of the carbon utilization of fungal strains as a whole.
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Affiliation(s)
- Douglas Christian Borges Lopes
- Molecular Biotechnology Laboratory, Department of Biochemistry and Immunology, Ribeirao Preto Medical School (FMRP), University of Sao Paulo, Ribeirao Preto 14049-900, SP, Brazil; (D.C.B.L.); (C.B.C.); (R.G.d.P.)
| | - Cláudia Batista Carraro
- Molecular Biotechnology Laboratory, Department of Biochemistry and Immunology, Ribeirao Preto Medical School (FMRP), University of Sao Paulo, Ribeirao Preto 14049-900, SP, Brazil; (D.C.B.L.); (C.B.C.); (R.G.d.P.)
| | - Roberto Nascimento Silva
- Molecular Biotechnology Laboratory, Department of Biochemistry and Immunology, Ribeirao Preto Medical School (FMRP), University of Sao Paulo, Ribeirao Preto 14049-900, SP, Brazil; (D.C.B.L.); (C.B.C.); (R.G.d.P.)
- Correspondence:
| | - Renato Graciano de Paula
- Molecular Biotechnology Laboratory, Department of Biochemistry and Immunology, Ribeirao Preto Medical School (FMRP), University of Sao Paulo, Ribeirao Preto 14049-900, SP, Brazil; (D.C.B.L.); (C.B.C.); (R.G.d.P.)
- Department of Physiological Sciences, Health Sciences Centre, Federal University of Espirito Santo, Vitoria 29047-105, ES, Brazil
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Pramod S, Gandla ML, Derba-Maceluch M, Jönsson LJ, Mellerowicz EJ, Winestrand S. Saccharification Potential of Transgenic Greenhouse- and Field-Grown Aspen Engineered for Reduced Xylan Acetylation. FRONTIERS IN PLANT SCIENCE 2021; 12:704960. [PMID: 34557213 PMCID: PMC8454504 DOI: 10.3389/fpls.2021.704960] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 07/22/2021] [Indexed: 05/20/2023]
Abstract
High acetylation of xylan in hardwoods decreases their value as biorefinery feedstocks. To counter this problem, we have constitutively suppressed RWA genes encoding acetyl-CoA transporters using the 35S promoter, or constitutively and wood-specifically (using the WP promoter) expressed fungal acetyl xylan esterases of families CE1 (AnAXE1) and CE5 (HjAXE), to reduce acetylation in hybrid aspen. All these transformations improved the saccharification of wood from greenhouse-grown trees. Here, we describe the chemical properties and saccharification potential of the resulting lines grown in a five-year field trial, and one type of them (WP:AnAXE1) in greenhouse conditions. Chemically, the lignocellulose of the field- and greenhouse-field-grown plants slightly differed, but the reductions in acetylation and saccharification improvement of engineered trees were largely maintained in the field. The main novel phenotypic observation in the field was higher lignification in lines with the WP promoter than those with the 35S promoter. Following growth in the field, saccharification glucose yields were higher from most transformed lines than from wild-type (WT) plants with no pretreatment, but there was no improvement in saccharification with acid pretreatment. Thus, acid pretreatment removes most recalcitrance caused by acetylation. We found a complex relationship between acetylation and glucose yields in saccharification without pretreatment, suggesting that other variables, for example, the acetylation pattern, affect recalcitrance. Bigger gains in glucose yields were observed in lines with the 35S promoter than in those with the WP promoter, possibly due to their lower lignin content. However, better lignocellulose saccharification of these lines was offset by a growth penalty and their glucose yield per tree was lower. In a comparison of the best lines with each construct, WP:AnAXE1 provided the highest glucose yield per tree from saccharification, with and without pretreatment, WP:HjAXE yields were similar to those of WT plants, and yields of lines with other constructs were lower. These results show that lignocellulose properties of field-grown trees can be improved by reducing cell wall acetylation using various approaches, but some affect productivity in the field. Thus, better understanding of molecular and physiological consequences of deacetylation is needed to obtain quantitatively better results.
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Affiliation(s)
- Sivan Pramod
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, Umeå, Sweden
| | | | - Marta Derba-Maceluch
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, Umeå, Sweden
| | | | - Ewa J. Mellerowicz
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, Umeå, Sweden
- *Correspondence: Ewa J. Mellerowicz,
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7
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Srivastava R, Akash, Parida AP, Chauhan PK, Kumar R. Identification, structure analysis, and transcript profiling of purple acid phosphatases under Pi deficiency in tomato (Solanum lycopersicum L.) and its wild relatives. Int J Biol Macromol 2020; 165:2253-2266. [PMID: 33098900 DOI: 10.1016/j.ijbiomac.2020.10.080] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 09/12/2020] [Accepted: 10/11/2020] [Indexed: 11/26/2022]
Abstract
Purple acid phosphatases (PAPs), a family of metallo-phosphoesterase enzymes, are involved in phosphorus nutrition in plants. In this study, we report that the tomato genome encodes 25 PAP members. Physio-biochemical analyses revealed relatively lower total root-associated acid phosphatase activity in the seedlings of Solanum pimpinellifolium than their cultivated tomato seedlings under Pi deficiency. Scrutiny of their transcript abundance shows that most of PAPs are activated, although to varying levels, under Pi deficiency in tomato. Further investigation demonstrates that the magnitude of induction of phosphate starvation inducible root-associated PAP homologs remains lower in the Pi-starved S. pimpinellifolium seedlings, hence, accounting for the lower acid phosphatase activity in this wild relative. Examination of their amino acid sequences revealed significant variation in their substrate-specificity defining residues. Among all members, only SlPAP15 possesses the critical lysine residue (R337) and atypical REKA motif in its C-terminal region. Homology modeling and docking studies revealed that ADP and ATP are preferred substrates of SlPAP15. We also identified other amino acid residues present in the vicinity of the active site, possibly facilitating such physical interactions. Altogether, the results presented here will help in the functional characterization of these genes in the tomato in the future.
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Affiliation(s)
- Rajat Srivastava
- PTRL, Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India
| | - Akash
- PTRL, Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India
| | - Adwaita Prasad Parida
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi 110021, India
| | - Pankaj Kumar Chauhan
- PTRL, Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India
| | - Rahul Kumar
- PTRL, Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India.
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Fullerton CG, Prakash R, Ninan AS, Atkinson RG, Schaffer RJ, Hallett IC, Schröder R. Fruit From Two Kiwifruit Genotypes With Contrasting Softening Rates Show Differences in the Xyloglucan and Pectin Domains of the Cell Wall. FRONTIERS IN PLANT SCIENCE 2020; 11:964. [PMID: 32714354 PMCID: PMC7343912 DOI: 10.3389/fpls.2020.00964] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Accepted: 06/11/2020] [Indexed: 06/11/2023]
Abstract
Fruit softening is controlled by hormonal and developmental cues, causing an upregulation of cell wall-associated enzymes that break down the complex sugar matrices in the cell wall. The regulation of this process is complex, with different genotypes demonstrating quite different softening patterns, even when they are closely related. Currently, little is known about the relationship between cell wall structure and the rate of fruit softening. To address this question, the softening of two Actinidia chinensis var. chinensis (kiwifruit) genotypes (a fast 'AC-F' and a slow 'AC-S' softening genotype) was examined using a range of compositional, biochemical, structural, and molecular techniques. Throughout softening, the cell wall structure of the two genotypes was fundamentally different at identical firmness stages. In the hemicellulose domain, xyloglucanase enzyme activity was higher in 'AC-F' at the firm unripe stage, a finding supported by differential expression of xyloglucan transglycosylase/hydrolase genes during softening. In the pectin domain, differences in pectin solubilization and location of methyl-esterified homogalacturonan in the cell wall between 'AC-S' and 'AC-F' were shown. Side chain analyses and molecular weight elution profiles of polyuronides and xyloglucans of cell wall extracts revealed fundamental differences between the genotypes, pointing towards a weakening of the structural integrity of cell walls in the fast softening 'AC-F' genotype even at the firm, unripe stage. As a consequence, the polysaccharides in the cell walls of 'AC-F' may be easier to access and hence more susceptible to enzymatic degradation than in 'AC-S', resulting in faster softening. Together these results suggest that the different rates of softening between 'AC-F' and 'AC-S' are not due to changes in enzyme activities alone, but that fundamental differences in the cell wall structure are likely to influence the rates of softening through differential modification and accessibility of specific cell wall polysaccharides during ripening.
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Affiliation(s)
- Christina G. Fullerton
- The New Zealand Institute For Plant & Food Research Limited (Plant & Food Research), Auckland, New Zealand
- Joint Graduate School of Plant and Food Science, University of Auckland, Auckland, New Zealand
| | - Roneel Prakash
- The New Zealand Institute For Plant & Food Research Limited (Plant & Food Research), Auckland, New Zealand
| | - Annu Smitha Ninan
- The New Zealand Institute For Plant & Food Research Limited (Plant & Food Research), Auckland, New Zealand
| | - Ross G. Atkinson
- The New Zealand Institute For Plant & Food Research Limited (Plant & Food Research), Auckland, New Zealand
| | - Robert J. Schaffer
- The New Zealand Institute For Plant & Food Research Limited (Plant & Food Research), Auckland, New Zealand
- Joint Graduate School of Plant and Food Science, University of Auckland, Auckland, New Zealand
| | - Ian C. Hallett
- The New Zealand Institute For Plant & Food Research Limited (Plant & Food Research), Auckland, New Zealand
| | - Roswitha Schröder
- The New Zealand Institute For Plant & Food Research Limited (Plant & Food Research), Auckland, New Zealand
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Brandon AG, Scheller HV. Engineering of Bioenergy Crops: Dominant Genetic Approaches to Improve Polysaccharide Properties and Composition in Biomass. FRONTIERS IN PLANT SCIENCE 2020; 11:282. [PMID: 32218797 PMCID: PMC7078332 DOI: 10.3389/fpls.2020.00282] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 02/25/2020] [Indexed: 05/24/2023]
Abstract
Large-scale, sustainable production of lignocellulosic bioenergy from biomass will depend on a variety of dedicated bioenergy crops. Despite their great genetic diversity, prospective bioenergy crops share many similarities in the polysaccharide composition of their cell walls, and the changes needed to optimize them for conversion are largely universal. Therefore, biomass modification strategies that do not depend on genetic background or require mutant varieties are extremely valuable. Due to their preferential fermentation and conversion by microorganisms downstream, the ideal bioenergy crop should contain a high proportion of C6-sugars in polysaccharides like cellulose, callose, galactan, and mixed-linkage glucans. In addition, the biomass should be reduced in inhibitors of fermentation like pentoses and acetate. Finally, the overall complexity of the plant cell wall should be modified to reduce its recalcitrance to enzymatic deconstruction in ways that do no compromise plant health or come at a yield penalty. This review will focus on progress in the use of a variety of genetically dominant strategies to reach these ideals. Due to the breadth and volume of research in the field of lignin bioengineering, this review will instead focus on approaches to improve polysaccharide component plant biomass. Carbohydrate content can be dramatically increased by transgenic overexpression of enzymes involved in cell wall polysaccharide biosynthesis. Additionally, the recalcitrance of the cell wall can be reduced via the overexpression of native or non-native carbohydrate active enzymes like glycosyl hydrolases or carbohydrate esterases. Some research in this area has focused on engineering plants that accumulate cell wall-degrading enzymes that are sequestered to organelles or only active at very high temperatures. The rationale being that, in order to avoid potential negative effects of cell wall modification during plant growth, the enzymes could be activated post-harvest, and post-maturation of the cell wall. A potentially significant limitation of this approach is that at harvest, the cell wall is heavily lignified, making the substrates for these enzymes inaccessible and their activity ineffective. Therefore, this review will only include research employing enzymes that are at least partially active under the ambient conditions of plant growth and cell wall development.
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Affiliation(s)
- Andrew G. Brandon
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, United States
- Feedstocks Division, Joint BioEnergy Institute, Emeryville, CA, United States
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Henrik V. Scheller
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, United States
- Feedstocks Division, Joint BioEnergy Institute, Emeryville, CA, United States
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
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10
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Badhan A, Huang J, Wang Y, Abbott DW, Di Falco M, Tsang A, McAllister T. Saccharification efficiencies of multi-enzyme complexes produced by aerobic fungi. N Biotechnol 2018; 46:1-6. [PMID: 29803771 DOI: 10.1016/j.nbt.2018.05.003] [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: 11/07/2017] [Revised: 05/08/2018] [Accepted: 05/09/2018] [Indexed: 11/16/2022]
Abstract
In the present study, we have characterized high molecular weight multi-enzyme complexes in two commercial enzymes produced by Trichoderma reesei (Spezyme CP) and Penicillium funiculosum (Accellerase XC). We successfully identified 146-1000 kDa complexes using Blue native polyacrylamide gel electrophoresis (BN-PAGE) to fractionate the protein profile in both preparations. Identified complexes dissociated into lower molecular weight constituents when loaded on SDS PAGE. Unfolding of the secondary structure of multi-enzyme complexes with trimethylamine (pH >10) suggested that they were not a result of unspecific protein aggregation. Cellulase (CMCase) profiles of extracts of BN-PAGE fractionated protein bands confirmed cellulase activity within the multi-enzyme complexes. A microassay was used to identify protein bands that promoted high levels of glucose release from barley straw. Those with high saccharification yield were subjected to LC-MS analysis to identify the principal enzymatic activities responsible. The results suggest that secretion of proteins by aerobic fungi leads to the formation of high molecular weight multi-enzyme complexes that display activity against carboxymethyl cellulose and barley straw.
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Affiliation(s)
- Ajay Badhan
- Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, Alberta, Canada
| | - Jiangli Huang
- Institute of Biological Resources, Jiangxi Academy of Sciences, Nanchang, 330096, China
| | - Yuxi Wang
- Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, Alberta, Canada
| | - D Wade Abbott
- Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, Alberta, Canada
| | - Marcos Di Falco
- Centre for Structural and Functional Genomics, Concordia University, Montreal, Quebec, H4B 1R6, Canada
| | - Adrian Tsang
- Institute of Biological Resources, Jiangxi Academy of Sciences, Nanchang, 330096, China
| | - Tim McAllister
- Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, Alberta, Canada.
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11
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Donev E, Gandla ML, Jönsson LJ, Mellerowicz EJ. Engineering Non-cellulosic Polysaccharides of Wood for the Biorefinery. FRONTIERS IN PLANT SCIENCE 2018; 9:1537. [PMID: 30405672 PMCID: PMC6206411 DOI: 10.3389/fpls.2018.01537] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 09/28/2018] [Indexed: 05/10/2023]
Abstract
Non-cellulosic polysaccharides constitute approximately one third of usable woody biomass for human exploitation. In contrast to cellulose, these substances are composed of several different types of unit monosaccharides and their backbones are substituted by various groups. Their structural diversity and recent examples of their modification in transgenic plants and mutants suggest they can be targeted for improving wood-processing properties, thereby facilitating conversion of wood in a biorefinery setting. Critical knowledge on their structure-function relationship is slowly emerging, although our understanding of molecular interactions responsible for observed phenomena is still incomplete. This review: (1) provides an overview of structural features of major non-cellulosic polysaccharides of wood, (2) describes the fate of non-cellulosic polysaccharides during biorefinery processing, (3) shows how the non-cellulosic polysaccharides impact lignocellulose processing focused on yields of either sugars or polymers, and (4) discusses outlooks for the improvement of tree species for biorefinery by modifying the structure of non-cellulosic polysaccharides.
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Affiliation(s)
- Evgeniy Donev
- Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, Sweden
| | | | | | - Ewa J. Mellerowicz
- Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, Sweden
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Van de Wouwer D, Boerjan W, Vanholme B. Plant cell wall sugars: sweeteners for a bio-based economy. PHYSIOLOGIA PLANTARUM 2018; 164:27-44. [PMID: 29430656 DOI: 10.1111/ppl.12705] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 02/07/2018] [Accepted: 02/07/2018] [Indexed: 05/23/2023]
Abstract
Global warming and the consequent climate change is one of the major environmental challenges we are facing today. The driving force behind the rise in temperature is our fossil-based economy, which releases massive amounts of the greenhouse gas carbon dioxide into the atmosphere. In order to reduce greenhouse gas emission, we need to scale down our dependency on fossil resources, implying that we need other sources for energy and chemicals to feed our economy. Here, plants have an important role to play; by means of photosynthesis, plants capture solar energy to split water and fix carbon derived from atmospheric carbon dioxide. A significant fraction of the fixed carbon ends up as polysaccharides in the plant cell wall. Fermentable sugars derived from cell wall polysaccharides form an ideal carbon source for the production of bio-platform molecules. However, a major limiting factor in the use of plant biomass as feedstock for the bio-based economy is the complexity of the plant cell wall and its recalcitrance towards deconstruction. To facilitate the release of fermentable sugars during downstream biomass processing, the composition and structure of the cell wall can be engineered. Different strategies to reduce cell wall recalcitrance will be described in this review. The ultimate goal is to obtain a tailor-made biomass, derived from plants with a cell wall optimized for particular industrial or agricultural applications, without affecting plant growth and development.
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Affiliation(s)
- Dorien Van de Wouwer
- Ghent University, Department of Plant Biotechnology and Bioinformatics, (Technologiepark 927), 9052, Ghent, Belgium
- VIB Center for Plant Systems Biology, (Technologiepark 927), 9052, Ghent, Belgium
| | - Wout Boerjan
- Ghent University, Department of Plant Biotechnology and Bioinformatics, (Technologiepark 927), 9052, Ghent, Belgium
- VIB Center for Plant Systems Biology, (Technologiepark 927), 9052, Ghent, Belgium
| | - Bartel Vanholme
- Ghent University, Department of Plant Biotechnology and Bioinformatics, (Technologiepark 927), 9052, Ghent, Belgium
- VIB Center for Plant Systems Biology, (Technologiepark 927), 9052, Ghent, Belgium
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13
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Wang Y, Fan C, Hu H, Li Y, Sun D, Wang Y, Peng L. Genetic modification of plant cell walls to enhance biomass yield and biofuel production in bioenergy crops. Biotechnol Adv 2016; 34:997-1017. [PMID: 27269671 DOI: 10.1016/j.biotechadv.2016.06.001] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 05/31/2016] [Accepted: 06/01/2016] [Indexed: 02/06/2023]
Abstract
Plant cell walls represent an enormous biomass resource for the generation of biofuels and chemicals. As lignocellulose property principally determines biomass recalcitrance, the genetic modification of plant cell walls has been posed as a powerful solution. Here, we review recent progress in understanding the effects of distinct cell wall polymers (cellulose, hemicelluloses, lignin, pectin, wall proteins) on the enzymatic digestibility of biomass under various physical and chemical pretreatments in herbaceous grasses, major agronomic crops and fast-growing trees. We also compare the main factors of wall polymer features, including cellulose crystallinity (CrI), hemicellulosic Xyl/Ara ratio, monolignol proportion and uronic acid level. Furthermore, the review presents the main gene candidates, such as CesA, GH9, GH10, GT61, GT43 etc., for potential genetic cell wall modification towards enhancing both biomass yield and enzymatic saccharification in genetic mutants and transgenic plants. Regarding cell wall modification, it proposes a novel groove-like cell wall model that highlights to increase amorphous regions (density and depth) of the native cellulose microfibrils, providing a general strategy for bioenergy crop breeding and biofuel processing technology.
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Affiliation(s)
- Yanting Wang
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan 430070, China; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Chunfen Fan
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan 430070, China; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Huizhen Hu
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan 430070, China; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Ying Li
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan 430070, China; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Dan Sun
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan 430070, China; College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; College of Chemistry and Chemical Engineering, Hubei University of Technology, Wuhan, Hubei 430068, China
| | - Youmei Wang
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan 430070, China; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Liangcai Peng
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan 430070, China; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
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Marriott PE, Gómez LD, McQueen-Mason SJ. Unlocking the potential of lignocellulosic biomass through plant science. THE NEW PHYTOLOGIST 2016; 209:1366-81. [PMID: 26443261 DOI: 10.1111/nph.13684] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Accepted: 08/24/2015] [Indexed: 05/17/2023]
Abstract
The aim of producing sustainable liquid biofuels and chemicals from lignocellulosic biomass remains high on the sustainability agenda, but is challenged by the costs of producing fermentable sugars from these materials. Sugars from plant biomass can be fermented to alcohols or even alkanes, creating a liquid fuel in which carbon released on combustion is balanced by its photosynthetic capture. Large amounts of sugar are present in the woody, nonfood parts of crops and could be used for fuel production without compromising global food security. However, the sugar in woody biomass is locked up in the complex and recalcitrant lignocellulosic plant cell wall, making it difficult and expensive to extract. In this paper, we review what is known about the major polymeric components of woody plant biomass, with an emphasis on the molecular interactions that contribute to its recalcitrance to enzymatic digestion. In addition, we review the extensive research that has been carried out in order to understand and reduce lignocellulose recalcitrance and enable more cost-effective production of fuel from woody plant biomass.
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Affiliation(s)
- Poppy E Marriott
- CNAP, Department of Biology, University of York, Heslington, York, YO10 5DD, UK
| | - Leonardo D Gómez
- CNAP, Department of Biology, University of York, Heslington, York, YO10 5DD, UK
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Tavares EQP, De Souza AP, Buckeridge MS. How endogenous plant cell-wall degradation mechanisms can help achieve higher efficiency in saccharification of biomass. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:4133-43. [PMID: 25922489 DOI: 10.1093/jxb/erv171] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Cell-wall recalcitrance to hydrolysis still represents one of the major bottlenecks for second-generation bioethanol production. This occurs despite the development of pre-treatments, the prospect of new enzymes, and the production of transgenic plants with less-recalcitrant cell walls. Recalcitrance, which is the intrinsic resistance to breakdown imposed by polymer assembly, is the result of inherent limitations in its three domains. These consist of: (i) porosity, associated with a pectin matrix impairing trafficking through the wall; (ii) the glycomic code, which refers to the fine-structural emergent complexity of cell-wall polymers that are unique to cells, tissues, and species; and (iii) cellulose crystallinity, which refers to the organization in micro- and/or macrofibrils. One way to circumvent recalcitrance could be by following cell-wall hydrolysis strategies underlying plant endogenous mechanisms that are optimized to precisely modify cell walls in planta. Thus, the cell-wall degradation that occurs during fruit ripening, abscission, storage cell-wall mobilization, and aerenchyma formation are reviewed in order to highlight how plants deal with recalcitrance and which are the routes to couple prospective enzymes and cocktail designs with cell-wall features. The manipulation of key enzyme levels in planta can help achieving biologically pre-treated walls (i.e. less recalcitrant) before plants are harvested for bioethanol production. This may be helpful in decreasing the costs associated with producing bioethanol from biomass.
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Affiliation(s)
- Eveline Q P Tavares
- Laboratory of Plant Physiological Ecology (LAFIECO), Department of Botany, Institute of Biosciences, University of São Paulo, Rua do Matão 277, São Paulo, SP, Brazil
| | - Amanda P De Souza
- Laboratory of Plant Physiological Ecology (LAFIECO), Department of Botany, Institute of Biosciences, University of São Paulo, Rua do Matão 277, São Paulo, SP, Brazil
| | - Marcos S Buckeridge
- Laboratory of Plant Physiological Ecology (LAFIECO), Department of Botany, Institute of Biosciences, University of São Paulo, Rua do Matão 277, São Paulo, SP, Brazil
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16
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Porth I, El-Kassaby YA. Using Populus as a lignocellulosic feedstock for bioethanol. Biotechnol J 2015; 10:510-24. [PMID: 25676392 DOI: 10.1002/biot.201400194] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 11/11/2014] [Accepted: 12/30/2014] [Indexed: 11/10/2022]
Abstract
Populus species along with species from the sister genus Salix will provide valuable feedstock resources for advanced second-generation biofuels. Their inherent fast growth characteristics can particularly be exploited for short rotation management, a time and energy saving cultivation alternative for lignocellulosic feedstock supply. Salicaceae possess inherent cell wall characteristics with favorable cellulose to lignin ratios for utilization as bioethanol crop. We review economically important traits relevant for intensively managed biofuel crop plantations, genomic and phenotypic resources available for Populus, breeding strategies for forest trees dedicated to bioenergy provision, and bioprocesses and downstream applications related to opportunities using Salicaceae as a renewable resource. Challenges need to be resolved for every single step of the conversion process chain, i.e., starting from tree domestication for improved performance as a bioenergy crop, bioconversion process, policy development for land use changes associated with advanced biofuels, and harvest and supply logistics associated with industrial-scale biorefinery plants using Populus as feedstock. Significant hurdles towards cost and energy efficiency, environmental friendliness, and yield maximization with regards to biomass pretreatment, saccharification, and fermentation of celluloses and the sustainability of biorefineries as a whole still need to be overcome.
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Affiliation(s)
- Ilga Porth
- Forest and Conservation Sciences, University of British Columbia, Vancouver, Canada.
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Busk PK, Lange M, Pilgaard B, Lange L. Several genes encoding enzymes with the same activity are necessary for aerobic fungal degradation of cellulose in nature. PLoS One 2014; 9:e114138. [PMID: 25461894 PMCID: PMC4252092 DOI: 10.1371/journal.pone.0114138] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 11/03/2014] [Indexed: 12/30/2022] Open
Abstract
The cellulose-degrading fungal enzymes are glycoside hydrolases of the GH families and lytic polysaccharide monooxygenases. The entanglement of glycoside hydrolase families and functions makes it difficult to predict the enzymatic activity of glycoside hydrolases based on their sequence. In the present study we further developed the method Peptide Pattern Recognition to an automatic approach not only to find all genes encoding glycoside hydrolases and lytic polysaccharide monooxygenases in fungal genomes but also to predict the function of the genes. The functional annotation is an important feature as it provides a direct route to predict function from primary sequence. Furthermore, we used Peptide Pattern Recognition to compare the cellulose-degrading enzyme activities encoded by 39 fungal genomes. The results indicated that cellobiohydrolases and AA9 lytic polysaccharide monooxygenases are hallmarks of cellulose-degrading fungi except brown rot fungi. Furthermore, a high number of AA9, endocellulase and β-glucosidase genes were identified, not in what are known to be the strongest, specialized lignocellulose degraders but in saprophytic fungi that can use a wide variety of substrates whereas only few of these genes were found in fungi that have a limited number of natural, lignocellulotic substrates. This correlation suggests that enzymes with different properties are necessary for degradation of cellulose in different complex substrates. Interestingly, clustering of the fungi based on their predicted enzymes indicated that Ascomycota and Basidiomycota use the same enzymatic activities to degrade plant cell walls.
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Affiliation(s)
- Peter K. Busk
- Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, A.C. Meyers Vænge 15, 2450, Copenhagen SV, Denmark
- * E-mail:
| | - Mette Lange
- Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, A.C. Meyers Vænge 15, 2450, Copenhagen SV, Denmark
| | - Bo Pilgaard
- Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, A.C. Meyers Vænge 15, 2450, Copenhagen SV, Denmark
| | - Lene Lange
- Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, A.C. Meyers Vænge 15, 2450, Copenhagen SV, Denmark
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Biswal AK, Soeno K, Gandla ML, Immerzeel P, Pattathil S, Lucenius J, Serimaa R, Hahn MG, Moritz T, Jönsson LJ, Israelsson-Nordström M, Mellerowicz EJ. Aspen pectate lyase PtxtPL1-27 mobilizes matrix polysaccharides from woody tissues and improves saccharification yield. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:11. [PMID: 24450583 PMCID: PMC3909318 DOI: 10.1186/1754-6834-7-11] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 01/07/2014] [Indexed: 05/02/2023]
Abstract
BACKGROUND Wood cell walls are rich in cellulose, hemicellulose and lignin. Hence, they are important sources of renewable biomass for producing energy and green chemicals. However, extracting desired constituents from wood efficiently poses significant challenges because these polymers are highly cross-linked in cell walls and are not easily accessible to enzymes and chemicals. RESULTS We show that aspen pectate lyase PL1-27, which degrades homogalacturonan and is expressed at the onset of secondary wall formation, can increase the solubility of wood matrix polysaccharides. Overexpression of this enzyme in aspen increased solubility of not only pectins but also xylans and other hemicelluloses, indicating that homogalacturonan limits the solubility of major wood cell wall components. Enzymatic saccharification of wood obtained from PL1-27-overexpressing trees gave higher yields of pentoses and hexoses than similar treatment of wood from wild-type trees, even after acid pretreatment. CONCLUSIONS Thus, the modification of pectins may constitute an important biotechnological target for improved wood processing despite their low abundance in woody biomass.
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Affiliation(s)
- Ajaya K Biswal
- Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S901 83 Umeå, Sweden
- Complex Carbohydrate Research Center, BioEnergy Science Center (BESC), University of Georgia, 315 Riverbend Rd, Athens, GA30602-4712 USA
| | - Kazuo Soeno
- Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S901 83 Umeå, Sweden
- Present address: National Agricultural Research Center for Western Region, National Agriculture and Food Research Organization (NARO), Zentsuji, Kagawa 765-8508 Japan
| | | | - Peter Immerzeel
- Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S901 83 Umeå, Sweden
| | - Sivakumar Pattathil
- Complex Carbohydrate Research Center, BioEnergy Science Center (BESC), University of Georgia, 315 Riverbend Rd, Athens, GA30602-4712 USA
| | - Jessica Lucenius
- Department of Physics, University of Helsinki, POB. 64FI-00014 Helsinki, Finland
| | - Ritva Serimaa
- Department of Physics, University of Helsinki, POB. 64FI-00014 Helsinki, Finland
| | - Michael G Hahn
- Complex Carbohydrate Research Center, BioEnergy Science Center (BESC), University of Georgia, 315 Riverbend Rd, Athens, GA30602-4712 USA
| | - Thomas Moritz
- Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S901 83 Umeå, Sweden
| | - Leif J Jönsson
- Department of Chemistry, Umeå University, S901 87 Umeå, Sweden
| | - Maria Israelsson-Nordström
- Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S901 83 Umeå, Sweden
| | - Ewa J Mellerowicz
- Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S901 83 Umeå, Sweden
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Scientific Research Related to Genetically Modified Trees. CHALLENGES AND OPPORTUNITIES FOR THE WORLD'S FORESTS IN THE 21ST CENTURY 2014. [DOI: 10.1007/978-94-007-7076-8_22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Lambertz C, Garvey M, Klinger J, Heesel D, Klose H, Fischer R, Commandeur U. Challenges and advances in the heterologous expression of cellulolytic enzymes: a review. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:135. [PMID: 25356086 PMCID: PMC4212100 DOI: 10.1186/s13068-014-0135-5] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 09/03/2014] [Indexed: 05/03/2023]
Abstract
Second generation biofuel development is increasingly reliant on the recombinant expression of cellulases. Designing or identifying successful expression systems is thus of preeminent importance to industrial progress in the field. Recombinant production of cellulases has been performed using a wide range of expression systems in bacteria, yeasts and plants. In a number of these systems, particularly when using bacteria and plants, significant challenges have been experienced in expressing full-length proteins or proteins at high yield. Further difficulties have been encountered in designing recombinant systems for surface-display of cellulases and for use in consolidated bioprocessing in bacteria and yeast. For establishing cellulase expression in plants, various strategies are utilized to overcome problems, such as the auto-hydrolysis of developing plant cell walls. In this review, we investigate the major challenges, as well as the major advances made to date in the recombinant expression of cellulases across the commonly used bacterial, plant and yeast systems. We review some of the critical aspects to be considered for industrial-scale cellulase production.
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Affiliation(s)
- Camilla Lambertz
- />Institute for Molecular Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Megan Garvey
- />Institute for Molecular Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
- />Present address: School of Medicine, Deakin University, CSIRO Australian Animal Health Laboratory, 5 Portarlington Rd, Newcomb, VIC 3219 Australia
| | - Johannes Klinger
- />Institute for Molecular Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Dirk Heesel
- />Institute for Molecular Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Holger Klose
- />Institute for Molecular Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
- />Present address: Institute for Botany and Molecular Genetics, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany
| | - Rainer Fischer
- />Institute for Molecular Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
- />Fraunhofer Institute for Molecular Biology and Applied Ecology, Forckenbeckstrasse 6, 52074 Aachen, Germany
| | - Ulrich Commandeur
- />Institute for Molecular Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
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Komatsu T, Kikuchi J. Comprehensive signal assignment of 13C-labeled lignocellulose using multidimensional solution NMR and 13C chemical shift comparison with solid-state NMR. Anal Chem 2013; 85:8857-65. [PMID: 24010724 DOI: 10.1021/ac402197h] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
A multidimensional solution NMR method has been developed using various pulse programs including HCCH-COSY and (13)C-HSQC-NOESY for the structural characterization of commercially available (13)C labeled lignocellulose from potatoes (Solanum tuberosum L.), chicory (Cichorium intybus), and corn (Zea mays). This new method allowed for 119 of the signals in the (13)C-HSQC spectrum of lignocelluloses to be assigned and was successfully used to characterize the structures of lignocellulose samples from three plants in terms of their xylan and xyloglucan structures, which are the major hemicelluloses in angiosperm. Furthermore, this new method provided greater insight into fine structures of lignin by providing a high resolution to the aromatic signals of the β-aryl ether and resinol moieties, as well as the diastereomeric signals of the β-aryl ether. Finally, the (13)C chemical shifts assigned in this study were compared with those from solid-state NMR and indicated the presence of heterogeneous dynamics in the polysaccharides where rigid cellulose and mobile hemicelluloses moieties existed together.
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Affiliation(s)
- Takanori Komatsu
- RIKEN Center for Sustainable Resource Science , 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 235-0045, Japan
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Hu J, Arantes V, Pribowo A, Saddler JN. The synergistic action of accessory enzymes enhances the hydrolytic potential of a "cellulase mixture" but is highly substrate specific. BIOTECHNOLOGY FOR BIOFUELS 2013; 6:112. [PMID: 23915398 PMCID: PMC3750293 DOI: 10.1186/1754-6834-6-112] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Accepted: 08/02/2013] [Indexed: 05/05/2023]
Abstract
BACKGROUND Currently, the amount of protein/enzyme required to achieve effective cellulose hydrolysis is still too high. One way to reduce the amount of protein/enzyme required is to formulate a more efficient enzyme cocktail by adding so-called accessory enzymes such as xylanase, lytic polysaccharide monooxygenase (AA9, formerly known as GH61), etc., to the cellulase mixture. Previous work has shown the strong synergism that can occur between cellulase and xylanase mixtures during the hydrolysis of steam pretreated corn stover, requiring lower protein loading to achieve effective hydrolysis. However, relatively high loadings of xylanases were required. When family 10 and 11 endo-xylanases and family 5 xyloglucanase were supplemented to a commercial cellulase mixture varying degrees of improved hydrolysis over a range of pretreated, lignocellulosic substrates were observed. RESULTS The potential synergistic interactions between cellulase monocomponents and hemicellulases from family 10 and 11 endo-xylanases (GH10 EX and GH11 EX) and family 5 xyloglucanase (GH5 XG), during hydrolysis of various steam pretreated lignocellulosic substrates, were assessed. It was apparent that the hydrolytic activity of cellulase monocomponents was enhanced by the addition of accessory enzymes although the "boosting" effect was highly substrate specific. The GH10 EX and GH5 XG both exhibited broad substrate specificity and showed strong synergistic interaction with the cellulases when added individually. The GH10 EX was more effective on steam pretreated agriculture residues and hardwood substrates whereas GH5 XG addition was more effective on softwood substrates. The synergistic interaction between GH10 EX and GH5 XG when added together further enhanced the hydrolytic activity of the cellulase enzymes over a range of pretreated lignocellulosic substrates. GH10 EX addition could also stimulate further cellulose hydrolysis when added to the hydrolysis reactions when the rate of hydrolysis had levelled off. CONCLUSIONS Endo-xylanases and xyloglucanases interacted synergistically with cellulases to improve the hydrolysis of a range of pretreated lignocellulosic substrates. However, the extent of improved hydrolysis was highly substrate dependent. It appears that those accessory enzymes, such as GH10 EX and GH5 XG, with broader substrate specificities promoted the greatest improvements in the hydrolytic performance of the cellulase mixture on all of the pretreated biomass substrates.
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Affiliation(s)
- Jinguang Hu
- Forestry Products Biotechnology/Bioenergy Group, Wood Science Department, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada
| | - Valdeir Arantes
- Forestry Products Biotechnology/Bioenergy Group, Wood Science Department, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada
| | - Amadeus Pribowo
- Forestry Products Biotechnology/Bioenergy Group, Wood Science Department, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada
| | - Jack N Saddler
- Forestry Products Biotechnology/Bioenergy Group, Wood Science Department, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada
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Poplar genetic engineering: promoting desirable wood characteristics and pest resistance. Appl Microbiol Biotechnol 2013; 97:5669-79. [DOI: 10.1007/s00253-013-4940-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 04/17/2013] [Accepted: 04/18/2013] [Indexed: 10/26/2022]
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Jung YH, Cho HJ, Lee JS, Noh EW, Park OK, Kim KH. Evaluation of a transgenic poplar as a potential biomass crop for biofuel production. BIORESOURCE TECHNOLOGY 2013; 129:639-641. [PMID: 23298768 DOI: 10.1016/j.biortech.2012.12.074] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 12/08/2012] [Accepted: 12/10/2012] [Indexed: 06/01/2023]
Abstract
A transgenic poplar, in which the RabG3bCA gene from Arabidopsis was overexpressed, was analyzed for its biomass composition and enzymatic digestibility after chemical pretreatment. In comparison with a wild-type poplar (WT), the transgenic poplar (OX8) showed 9.8% higher glucan content. The levels of other biomass components did not differ greatly between WT and OX8. When WT and OX8 samples were pretreated by sulfuric acid (1%, w/v at 190 °C), sodium hydroxide (1%, w/v at 190 °C), or ammonia (14%, w/w at 80 °C), the washed pretreated solids of OX8 exhibited a higher enzymatic digestibility than those of WT in each chemical pretreatment. The sodium hydroxide pretreatment was the most effective among the three pretreatment processes, showing 58.7% and 69.4% of theoretical glucose yield from the saccharification of pretreated OX8 and WT, respectively. The transgenic poplar, growing faster and taller, was found to contain more glucan and have a higher enzymatic digestibility than WT.
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Affiliation(s)
- Young Hoon Jung
- School of Life Sciences and Biotechnology, Korea University, Seoul 136-713, Republic of Korea
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Xie G, Yang B, Xu Z, Li F, Guo K, Zhang M, Wang L, Zou W, Wang Y, Peng L. Global identification of multiple OsGH9 family members and their involvement in cellulose crystallinity modification in rice. PLoS One 2013; 8:e50171. [PMID: 23308094 PMCID: PMC3537678 DOI: 10.1371/journal.pone.0050171] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 10/22/2012] [Indexed: 11/19/2022] Open
Abstract
Plant glycoside hydrolase family 9 (GH9) comprises typical endo-β-1,4-glucanase (EGases, EC3.2.1.4). Although GH9A (KORRIGAN) family genes have been reported to be involved in cellulose biosynthesis in plants, much remains unknown about other GH9 subclasses. In this study, we observed a global gene co-expression profiling and conducted a correlation analysis between OsGH9 and OsCESA among 66 tissues covering most periods of life cycles in 2 rice varieties. Our results showed that OsGH9A3 and B5 possessed an extremely high co-expression with OsCESA1, 3, and 8 typical for cellulose biosynthesis in rice. Using two distinct rice non-GH9 mutants and wild type, we performed integrative analysis of gene expression level by qRT-PCR, cellulase activities in situ and in vitro, and lignocellulose crystallinity index (CrI) in four internodes of stem tissues. For the first time, OsGH9B1, 3, and 16 were characterized with the potential role in lignocellulose crystallinity alteration in rice, whereas OsGH9A3 and B5 were suggested for cellulose biosynthesis. In addition, phylogenetic analysis and gene co-expression comparison revealed GH9 function similarity in Arabidopsis and rice. Hence, the data can provide insights into GH9 function in plants and offer the potential strategy for genetic manipulation of plant cell wall using the five aforementioned novel OsGH9 genes.
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Affiliation(s)
- Guosheng Xie
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research (Wuhan), Biomass and Bioenergy Research Centre, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Bo Yang
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research (Wuhan), Biomass and Bioenergy Research Centre, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Zhengdan Xu
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research (Wuhan), Biomass and Bioenergy Research Centre, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Fengcheng Li
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research (Wuhan), Biomass and Bioenergy Research Centre, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Kai Guo
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research (Wuhan), Biomass and Bioenergy Research Centre, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Mingliang Zhang
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research (Wuhan), Biomass and Bioenergy Research Centre, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Lingqiang Wang
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research (Wuhan), Biomass and Bioenergy Research Centre, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Weihua Zou
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research (Wuhan), Biomass and Bioenergy Research Centre, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Yanting Wang
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research (Wuhan), Biomass and Bioenergy Research Centre, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Liangcai Peng
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research (Wuhan), Biomass and Bioenergy Research Centre, College of Plant Science and Technology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, People's Republic of China
- * E-mail:
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Biomass Converting Enzymes as Industrial Biocatalysts for Fuels and Chemicals: Recent Developments. Catalysts 2012. [DOI: 10.3390/catal2020244] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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Cook C, Devoto A. Fuel from plant cell walls: recent developments in second generation bioethanol research. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2011; 91:1729-32. [PMID: 21681755 DOI: 10.1002/jsfa.4455] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
As bioethanol from sugarcane and wheat falls out of favour due to concerns about food security, research is ongoing into genetically engineering model plants and microorganisms to find the optimum cell wall structure for the ultimate second generation bioethanol crop. Charis Cook and Alessandra Devoto highlight here the progress made to tailor the plant cell wall to improve the accessibility of cellulose by acting on the regulation, the structure or the relative composition of other cell wall components to ultimately improve saccharification efficiency. They also consider possible side effects of cell wall modification and focus on the latest advances made to improve the efficiency of digestion of lignocellulosic materials by cell wall degrading microorganisms.
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Affiliation(s)
- Charis Cook
- Biological Sciences, Royal Holloway, University of London, Egham Hill, Egham, Surrey TW200EX, UK.
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Alonso-Simón A, Neumetzler L, García-Angulo P, Encina AE, Acebes JL, Álvarez JM, Hayashi T. Plasticity of xyloglucan composition in bean (Phaseolus vulgaris)-cultured cells during habituation and dehabituation to lethal concentrations of dichlobenil. MOLECULAR PLANT 2010; 3:603-609. [PMID: 20507938 DOI: 10.1093/mp/ssq011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Bean cells that have been habituated to grow in a lethal concentration (12 μM) of 2,6-dichlorobenzonitrile (dichlobenil or DCB, a cellulose biosynthesis inhibitor) are known to have decreased cellulose content in their cell walls. Xyloglucan, which is bound to cellulose and together with it forms the main loading network of plant cell walls, has also been described to decrease in habituated cells, but whether the change on cellulose affects the xyloglucan structure besides its abundance has not been analyzed. Fragmentation analysis with xyloglucan-specific endoglucanase (XEG) and endocellulase revealed that habituation to DCB caused a change in the fine structure of xyloglucan, namely a decrease in fucosyl residues attached to the galactosyl-xylosyl residues along the glucan backbone. After the removal of herbicide from the medium (dehabituated cells), xyloglucan recovered its fucosyl residues. In addition, some cello-oligosaccharides could be detected only in habituated cells' xyloglucan digested by XEG and endocellulase, corresponding to a glucan covalently bound or co-precipitated with the hemicelluloses. These results show that structural flexibility of cell walls relies in part on the plasticity of xyloglucan composition and opens up new perspectives to further research in this field.
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Affiliation(s)
- A Alonso-Simón
- Área de Fisiología Vegetal, Universidad de León, E-24071, León, Spain
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Vega-Sánchez ME, Ronald PC. Genetic and biotechnological approaches for biofuel crop improvement. Curr Opin Biotechnol 2010; 21:218-24. [PMID: 20181473 DOI: 10.1016/j.copbio.2010.02.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Revised: 01/29/2010] [Accepted: 02/02/2010] [Indexed: 10/19/2022]
Abstract
Research and development efforts for biofuel production are targeted at converting plant biomass into renewable liquid fuels. Major obstacles for biofuel production include lack of biofuel crop domestication, low oil yields from crop plants as well as recalcitrance of lignocellulose to chemical and enzymatic breakdown. Researchers are expanding the genetic and genomic resources available for crop improvement, elucidating lipid metabolism to facilitate manipulation of fatty acid biosynthetic pathways and studying how plant cell walls are synthesized and assembled. This knowledge will be used to produce the next generation of biofuel crops by increasing fatty acid content and by optimizing the hydrolysis of plant cell walls to release fermentable sugars.
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Affiliation(s)
- Miguel E Vega-Sánchez
- Department of Plant Pathology, University of California, One Shields Ave., Davis, CA 95616, USA
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