101
|
A two-stage pretreatment using dilute sodium hydroxide solution followed by an ionic liquid at low temperatures: Toward construction of lignin-first biomass pretreatment. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.biteb.2019.100286] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
102
|
Wightman R, Busse-Wicher M, Dupree P. Correlative FLIM-confocal-Raman mapping applied to plant lignin composition and autofluorescence. Micron 2019; 126:102733. [PMID: 31479919 DOI: 10.1016/j.micron.2019.102733] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 08/08/2019] [Accepted: 08/09/2019] [Indexed: 01/26/2023]
Abstract
Fluorescence lifetime imaging microscopy (FLIM) is a useful tool for discriminating fluorescent moieties, based on photon lifetimes, that cannot be otherwise resolved by looking solely at their excitation/emission characteristics. We present a method for correlative FLIM-confocal-Raman imaging and its application to lignin composition studies in the woody stems of the plant model Arabidopsis thaliana. Lignin is autofluorescent and exhibits characteristic fluorescence lifetimes attributed to its composition. Its composition can be further resolved by Raman microscopy to multiple peaks that represent different components. A lignin biosynthetic mutant is found to have a marked difference in fluorescence lifetime and corresponds to a change in composition as demonstrated by the Raman output.
Collapse
Affiliation(s)
- Raymond Wightman
- Microscopy Core Facility, Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge, CB2 1LR, UK.
| | - Marta Busse-Wicher
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK
| | - Paul Dupree
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK
| |
Collapse
|
103
|
Sipponen MH, Österberg M. Aqueous Ammonia Pre-treatment of Wheat Straw: Process Optimization and Broad Spectrum Dye Adsorption on Nitrogen-Containing Lignin. Front Chem 2019; 7:545. [PMID: 31428603 PMCID: PMC6687769 DOI: 10.3389/fchem.2019.00545] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 07/16/2019] [Indexed: 01/10/2023] Open
Abstract
Biorefineries need cost-efficient pretreatment processes that overcome the recalcitrance of plant biomass, while providing feasible valorization routes for lignin. Here we assessed aqueous ammonia for the separation of lignin from hydrothermally pretreated wheat straw prior to enzymatic saccharification. A combined severity parameter was used to determine the effects of ammonia concentration, treatment time and temperature on compositional and physicochemical changes [utilizing elemental analysis, cationic dye adsorption, FTIR spectroscopy, size-exclusion chromatography (SEC), and 31P nuclear magnetic resonance (NMR) spectroscopy] as well as enzymatic hydrolysability of straw. Pretreatment at the highest severity (20% NH3, 160°C) led to the maximum hydrolysability of 71% in a 24 h reaction time at an enzyme dosage of 15 FPU/g of pretreated straw. In contrast, hydrolysabilities remained low regardless of the severity when a low cellulase dosage was used, indicating competitive adsorption of cellulases on nitrogen-containing lignin. In turn, our results showed efficient adsorption of cationic, anionic and uncharged organic dyes on nitrogen-containing lignin, which opens new opportunities in practical water remediation applications.
Collapse
Affiliation(s)
- Mika Henrikki Sipponen
- Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, Espoo, Finland
| | | |
Collapse
|
104
|
Chanoca A, de Vries L, Boerjan W. Lignin Engineering in Forest Trees. FRONTIERS IN PLANT SCIENCE 2019; 10:912. [PMID: 31404271 PMCID: PMC6671871 DOI: 10.3389/fpls.2019.00912] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 06/27/2019] [Indexed: 05/19/2023]
Abstract
Wood is a renewable resource that is mainly composed of lignin and cell wall polysaccharides. The polysaccharide fraction is valuable as it can be converted into pulp and paper, or into fermentable sugars. On the other hand, the lignin fraction is increasingly being considered a valuable source of aromatic building blocks for the chemical industry. The presence of lignin in wood is one of the major recalcitrance factors in woody biomass processing, necessitating the need for harsh chemical treatments to degrade and extract it prior to the valorization of the cell wall polysaccharides, cellulose and hemicellulose. Over the past years, large research efforts have been devoted to engineering lignin amount and composition to reduce biomass recalcitrance toward chemical processing. We review the efforts made in forest trees, and compare results from greenhouse and field trials. Furthermore, we address the value and potential of CRISPR-based gene editing in lignin engineering and its integration in tree breeding programs.
Collapse
Affiliation(s)
- Alexandra Chanoca
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Lisanne de Vries
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Wout Boerjan
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| |
Collapse
|
105
|
Wang Y, Leng L, Islam MK, Liu F, Lin CSK, Leu SY. Substrate-Related Factors Affecting Cellulosome-Induced Hydrolysis for Lignocellulose Valorization. Int J Mol Sci 2019; 20:ijms20133354. [PMID: 31288425 PMCID: PMC6651384 DOI: 10.3390/ijms20133354] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 06/30/2019] [Accepted: 07/03/2019] [Indexed: 11/22/2022] Open
Abstract
Cellulosomes are an extracellular supramolecular multienzyme complex that can efficiently degrade cellulose and hemicelluloses in plant cell walls. The structural and unique subunit arrangement of cellulosomes can promote its adhesion to the insoluble substrates, thus providing individual microbial cells with a direct competence in the utilization of cellulosic biomass. Significant progress has been achieved in revealing the structures and functions of cellulosomes, but a knowledge gap still exists in understanding the interaction between cellulosome and lignocellulosic substrate for those derived from biorefinery pretreatment of agricultural crops. The cellulosomic saccharification of lignocellulose is affected by various substrate-related physical and chemical factors, including native (untreated) wood lignin content, the extent of lignin and xylan removal by pretreatment, lignin structure, substrate size, and of course substrate pore surface area or substrate accessibility to cellulose. Herein, we summarize the cellulosome structure, substrate-related factors, and regulatory mechanisms in the host cells. We discuss the latest advances in specific strategies of cellulosome-induced hydrolysis, which can function in the reaction kinetics and the overall progress of biorefineries based on lignocellulosic feedstocks.
Collapse
Affiliation(s)
- Ying Wang
- Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-Environmental Science & Technology, Guangzhou 510650, China
- Department of Civil and Environmental Engineering, the Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Ling Leng
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 6, Higashi 1-1-1, Tsukuba, Ibaraki 305-8566, Japan
| | - Md Khairul Islam
- Department of Civil and Environmental Engineering, the Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Fanghua Liu
- Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-Environmental Science & Technology, Guangzhou 510650, China
| | - Carol Sze Ki Lin
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Shao-Yuan Leu
- Department of Civil and Environmental Engineering, the Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China.
| |
Collapse
|
106
|
Bhatia R, Dalton S, Roberts LA, Moron-Garcia OM, Iacono R, Kosik O, Gallagher JA, Bosch M. Modified expression of ZmMYB167 in Brachypodium distachyon and Zea mays leads to increased cell wall lignin and phenolic content. Sci Rep 2019; 9:8800. [PMID: 31217516 PMCID: PMC6584667 DOI: 10.1038/s41598-019-45225-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 05/31/2019] [Indexed: 01/01/2023] Open
Abstract
One of the challenges to enable targeted modification of lignocellulosic biomass from grasses for improved biofuel and biochemical production lies within our limited understanding of the transcriptional control of secondary cell wall biosynthesis. Here, we investigated the role of the maize MYB transcription factor ZmMYB167 in secondary cell wall biosynthesis and how modified ZmMYB167 expression in two distinct grass model species affects plant biomass and growth phenotypes. Heterologous expression of ZmMYB167 in the C3 model system Brachypodium led to mild dwarf phenotypes, increased lignin (~7% to 13%) and S-lignin monomer (~11% to 16%) content, elevated concentrations of cell wall-bound p-coumaric acid (~15% to 24%) and reduced biomass sugar release (~20%) compared to controls. Overexpression of ZmMYB167 in the C4 model system Zea mays increased lignin (~4% to 13%), p-coumaric acid (~8% to 52%) and ferulic acid (~13% to 38%) content but did not affect plant growth and development nor biomass recalcitrance. Taken together, modifying ZmMYB167 expression represents a target to alter lignin and phenolic content in grasses. The ZmMYB167 expression-induced discrepancies in plant phenotypic and biomass properties between the two grass model systems highlight the challenges and opportunities for MYB transcription factor-based genetic engineering approaches of grass biomass.
Collapse
Affiliation(s)
- Rakesh Bhatia
- Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Plas Gogerddan, Aberystwyth, SY23 3EE, UK.
| | - Sue Dalton
- Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Plas Gogerddan, Aberystwyth, SY23 3EE, UK
| | - Luned A Roberts
- Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Plas Gogerddan, Aberystwyth, SY23 3EE, UK
| | - Odin M Moron-Garcia
- Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Plas Gogerddan, Aberystwyth, SY23 3EE, UK
| | - Rosario Iacono
- Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Plas Gogerddan, Aberystwyth, SY23 3EE, UK
| | - Ondrej Kosik
- Rothamsted Research, West Common, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Joe A Gallagher
- Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Plas Gogerddan, Aberystwyth, SY23 3EE, UK
| | - Maurice Bosch
- Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Plas Gogerddan, Aberystwyth, SY23 3EE, UK.
| |
Collapse
|
107
|
Ohlsson JA, Hallingbäck HR, Jebrane M, Harman-Ware AE, Shollenberger T, Decker SR, Sandgren M, Rönnberg-Wästljung AC. Genetic variation of biomass recalcitrance in a natural Salix viminalis (L.) population. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:135. [PMID: 31171936 PMCID: PMC6545741 DOI: 10.1186/s13068-019-1479-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 05/25/2019] [Indexed: 05/21/2023]
Abstract
BACKGROUND Salix spp. are high-productivity crops potentially used for lignocellulosic biofuels such as bioethanol. In general, pretreatment is needed to facilitate the enzymatic depolymerization process. Biomass resistance to degradation, i.e., biomass recalcitrance, is a trait which can be assessed by measuring the sugar released after combined pretreatment and enzymatic hydrolysis. We have examined genetic parameters of enzymatic sugar release and other traits related to biorefinery use in a population of 286 natural Salix viminalis clones. Furthermore, we have evaluated phenotypic and genetic correlations between these traits and performed a genomewide association mapping analysis using a set of 19,411 markers. RESULTS Sugar release (glucose and xylose) after pretreatment and enzymatic saccharification proved highly variable with large genetic and phenotypic variations, and chip heritability estimates (h 2) of 0.23-0.29. Lignin syringyl/guaiacyl (S/G) ratio and wood density were the most heritable traits (h 2 = 0.42 and 0.59, respectively). Sugar release traits were positively correlated, phenotypically and genetically, with biomass yield and lignin S/G ratio. Association mapping revealed seven marker-trait associations below a suggestive significance threshold, including one marker associated with glucose release. CONCLUSIONS We identified lignin S/G ratio and shoot diameter as heritable traits that could be relatively easily evaluated by breeders, making them suitable proxy traits for developing low-recalcitrance varieties. One marker below the suggestive threshold for marker associations was identified for sugar release, meriting further investigation while also highlighting the difficulties in employing genomewide association mapping for complex traits.
Collapse
Affiliation(s)
- Jonas A. Ohlsson
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Henrik R. Hallingbäck
- Department of Plant Biology, Uppsala BioCenter, Linnean Centre for Plant Biology, Swedish University of Agricultural Sciences, P.O. Box 7080, 750 07 Uppsala, Sweden
- Department of Plant Physiology and Forest Genetics, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Mohamed Jebrane
- Department of Forest Biomaterials and Technology/Wood Science, Swedish University of Agricultural Sciences, Box 7008, 750 07 Uppsala, Sweden
| | - Anne E. Harman-Ware
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO USA
- Center for Bioenergy Innovation, National Renewable Energy Laboratory, Golden, CO USA
| | - Todd Shollenberger
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO USA
| | - Stephen R. Decker
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO USA
| | - Mats Sandgren
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Ann-Christin Rönnberg-Wästljung
- Department of Plant Biology, Uppsala BioCenter, Linnean Centre for Plant Biology, Swedish University of Agricultural Sciences, P.O. Box 7080, 750 07 Uppsala, Sweden
| |
Collapse
|
108
|
Xie H, Engle NL, Venketachalam S, Yoo CG, Barros J, Lecoultre M, Howard N, Li G, Sun L, Srivastava AC, Pattathil S, Pu Y, Hahn MG, Ragauskas AJ, Nelson RS, Dixon RA, Tschaplinski TJ, Blancaflor EB, Tang Y. Combining loss of function of FOLYLPOLYGLUTAMATE SYNTHETASE1 and CAFFEOYL- COA 3- O- METHYLTRANSFERASE1 for lignin reduction and improved saccharification efficiency in Arabidopsis thaliana. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:108. [PMID: 31073332 PMCID: PMC6498598 DOI: 10.1186/s13068-019-1446-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Accepted: 04/20/2019] [Indexed: 05/07/2023]
Abstract
BACKGROUND Downregulation of genes involved in lignin biosynthesis and related biochemical pathways has been used as a strategy to improve biofuel production. Plant C1 metabolism provides the methyl units used for the methylation reactions carried out by two methyltransferases in the lignin biosynthetic pathway: caffeic acid 3-O-methyltransferase (COMT) and caffeoyl-CoA 3-O-methyltransferase (CCoAOMT). Mutations in these genes resulted in lower lignin levels and altered lignin compositions. Reduced lignin levels can also be achieved by mutations in the C1 pathway gene, folylpolyglutamate synthetase1 (FPGS1), in both monocotyledons and dicotyledons, indicating a link between the C1 and lignin biosynthetic pathways. To test if lignin content can be further reduced by combining genetic mutations in C1 metabolism and the lignin biosynthetic pathway, fpgs1ccoaomt1 double mutants were generated and functionally characterized. RESULTS Double fpgs1ccoaomt1 mutants had lower thioacidolysis lignin monomer yield and acetyl bromide lignin content than the ccoaomt1 or fpgs1 mutants and the plants themselves displayed no obvious long-term negative growth phenotypes. Moreover, extracts from the double mutants had dramatically improved enzymatic polysaccharide hydrolysis efficiencies than the single mutants: 15.1% and 20.7% higher than ccoaomt1 and fpgs1, respectively. The reduced lignin and improved sugar release of fpgs1ccoaomt1 was coupled with changes in cell-wall composition, metabolite profiles, and changes in expression of genes involved in cell-wall and lignin biosynthesis. CONCLUSION Our observations demonstrate that additional reduction in lignin content and improved sugar release can be achieved by simultaneous downregulation of a gene in the C1 (FPGS1) and lignin biosynthetic (CCOAOMT) pathways. These improvements in sugar accessibility were achieved without introducing unwanted long-term plant growth and developmental defects.
Collapse
Affiliation(s)
- Hongli Xie
- Noble Research Institute, LLC, 2510 Sam Noble Parkway, Ardmore, OK 73401 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Nancy L. Engle
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
- The Center for Bioenergy Innovation, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Sivasankari Venketachalam
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
- The Center for Bioenergy Innovation, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Chang Geun Yoo
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
- The Center for Bioenergy Innovation, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Jaime Barros
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, TX 76203 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
- The Center for Bioenergy Innovation, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Mitch Lecoultre
- Noble Research Institute, LLC, 2510 Sam Noble Parkway, Ardmore, OK 73401 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Nikki Howard
- Noble Research Institute, LLC, 2510 Sam Noble Parkway, Ardmore, OK 73401 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Guifen Li
- Noble Research Institute, LLC, 2510 Sam Noble Parkway, Ardmore, OK 73401 USA
| | - Liang Sun
- Noble Research Institute, LLC, 2510 Sam Noble Parkway, Ardmore, OK 73401 USA
| | - Avinash C. Srivastava
- Noble Research Institute, LLC, 2510 Sam Noble Parkway, Ardmore, OK 73401 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Sivakumar Pattathil
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Yunqiao Pu
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
- The Center for Bioenergy Innovation, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Michael G. Hahn
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
- The Center for Bioenergy Innovation, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Arthur J. Ragauskas
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
- The Center for Bioenergy Innovation, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Richard S. Nelson
- Noble Research Institute, LLC, 2510 Sam Noble Parkway, Ardmore, OK 73401 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Richard A. Dixon
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, TX 76203 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
- The Center for Bioenergy Innovation, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Timothy J. Tschaplinski
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
- The Center for Bioenergy Innovation, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Elison B. Blancaflor
- Noble Research Institute, LLC, 2510 Sam Noble Parkway, Ardmore, OK 73401 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Yuhong Tang
- Noble Research Institute, LLC, 2510 Sam Noble Parkway, Ardmore, OK 73401 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
| |
Collapse
|
109
|
Anderson EM, Stone ML, Katahira R, Reed M, Muchero W, Ramirez KJ, Beckham GT, Román-Leshkov Y. Differences in S/G ratio in natural poplar variants do not predict catalytic depolymerization monomer yields. Nat Commun 2019. [PMID: 31048697 DOI: 10.1016/j.joule.2017.10.004] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2023] Open
Abstract
The ratio of syringyl (S) and guaiacyl (G) units in lignin has been regarded as a major factor in determining the maximum monomer yield from lignin depolymerization. This limit arises from the notion that G units are prone to C-C bond formation during lignin biosynthesis, resulting in less ether linkages that generate monomers. This study uses reductive catalytic fractionation (RCF) in flow-through reactors as an analytical tool to depolymerize lignin in poplar with naturally varying S/G ratios, and directly challenges the common conception that the S/G ratio predicts monomer yields. Rather, this work suggests that the plant controls C-O and C-C bond content by regulating monomer transport during lignin biosynthesis. Overall, our results indicate that additional factors beyond the monomeric composition of native lignin are important in developing a fundamental understanding of lignin biosynthesis.
Collapse
Affiliation(s)
- Eric M Anderson
- Department of Chemical Engineering, Massachusetts Institute of Technology, 25 Ames St, Cambridge, MA, 02139, USA
| | - Michael L Stone
- Department of Chemical Engineering, Massachusetts Institute of Technology, 25 Ames St, Cambridge, MA, 02139, USA
| | - Rui Katahira
- National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver W Pkwy, Golden, CO, 80401, USA
| | - Michelle Reed
- National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver W Pkwy, Golden, CO, 80401, USA
| | - Wellington Muchero
- Oak Ridge National Laboratory, 1 Bethel Valley Rd, Oak Ridge, TN, 37830, USA
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Kelsey J Ramirez
- National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver W Pkwy, Golden, CO, 80401, USA
| | - Gregg T Beckham
- National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver W Pkwy, Golden, CO, 80401, USA.
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA.
| | - Yuriy Román-Leshkov
- Department of Chemical Engineering, Massachusetts Institute of Technology, 25 Ames St, Cambridge, MA, 02139, USA.
| |
Collapse
|
110
|
Anderson EM, Stone ML, Katahira R, Reed M, Muchero W, Ramirez KJ, Beckham GT, Román-Leshkov Y. Differences in S/G ratio in natural poplar variants do not predict catalytic depolymerization monomer yields. Nat Commun 2019; 10:2033. [PMID: 31048697 PMCID: PMC6497657 DOI: 10.1038/s41467-019-09986-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 04/09/2019] [Indexed: 01/08/2023] Open
Abstract
The ratio of syringyl (S) and guaiacyl (G) units in lignin has been regarded as a major factor in determining the maximum monomer yield from lignin depolymerization. This limit arises from the notion that G units are prone to C-C bond formation during lignin biosynthesis, resulting in less ether linkages that generate monomers. This study uses reductive catalytic fractionation (RCF) in flow-through reactors as an analytical tool to depolymerize lignin in poplar with naturally varying S/G ratios, and directly challenges the common conception that the S/G ratio predicts monomer yields. Rather, this work suggests that the plant controls C-O and C-C bond content by regulating monomer transport during lignin biosynthesis. Overall, our results indicate that additional factors beyond the monomeric composition of native lignin are important in developing a fundamental understanding of lignin biosynthesis.
Collapse
Affiliation(s)
- Eric M Anderson
- Department of Chemical Engineering, Massachusetts Institute of Technology, 25 Ames St, Cambridge, MA, 02139, USA
| | - Michael L Stone
- Department of Chemical Engineering, Massachusetts Institute of Technology, 25 Ames St, Cambridge, MA, 02139, USA
| | - Rui Katahira
- National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver W Pkwy, Golden, CO, 80401, USA
| | - Michelle Reed
- National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver W Pkwy, Golden, CO, 80401, USA
| | - Wellington Muchero
- Oak Ridge National Laboratory, 1 Bethel Valley Rd, Oak Ridge, TN, 37830, USA
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Kelsey J Ramirez
- National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver W Pkwy, Golden, CO, 80401, USA
| | - Gregg T Beckham
- National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver W Pkwy, Golden, CO, 80401, USA.
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA.
| | - Yuriy Román-Leshkov
- Department of Chemical Engineering, Massachusetts Institute of Technology, 25 Ames St, Cambridge, MA, 02139, USA.
| |
Collapse
|
111
|
Yang J, Ching YC, Chuah CH. Applications of Lignocellulosic Fibers and Lignin in Bioplastics: A Review. Polymers (Basel) 2019; 11:E751. [PMID: 31035331 PMCID: PMC6572173 DOI: 10.3390/polym11050751] [Citation(s) in RCA: 95] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 04/02/2019] [Accepted: 04/06/2019] [Indexed: 11/16/2022] Open
Abstract
Lignocellulosic fibers and lignin are two of the most important natural bioresources in the world. They show tremendous potential to decrease energy utilization/pollution and improve biodegradability by replacing synthetic fibers in bioplastics. The compatibility between the fiber-matrix plays an important part in the properties of the bioplastics. The improvement of lignocellulosic fiber properties by most surface treatments generally removes lignin. Due to the environmental pollution and high cost of cellulose modification, focus has been directed toward the use of lignocellulosic fibers in bioplastics. In addition, lignin-reinforced bioplastics are fabricated with varying success. These applications confirm there is no need to remove lignin from lignocellulosic fibers when preparing the bioplastics from a technical point of view. In this review, characterizations of lignocellulosic fibers and lignin related to their applications in bioplastics are covered. Then, we generalize the developments and problems of lignin-reinforced bioplastics and modification of lignin to improve the interaction of lignin-matrix. As for lignocellulosic fiber-reinforced bioplastics, we place importance on the low compatibility of the lignocellulosic fiber-matrix. The applications of lignin-containing cellulose and lignocellulosic fibers without delignification in the bioplastics are reviewed. A comparison between lignocellulosic fibers and lignin in the bioplastics is given.
Collapse
Affiliation(s)
- Jianlei Yang
- Department of Chemical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia.
| | - Yern Chee Ching
- Department of Chemical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia.
| | - Cheng Hock Chuah
- Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia.
| |
Collapse
|
112
|
Abstract
Production of fuels and chemicals from renewable lignocellulosic feedstocks is a promising alternative to petroleum-derived compounds. Due to the complexity of lignocellulosic feedstocks, microbial conversion of all potential substrates will require substantial metabolic engineering. Non-model microbes offer desirable physiological traits, but also increase the difficulty of heterologous pathway engineering and optimization. The development of modular design principles that allow metabolic pathways to be used in a variety of novel microbes with minimal strain-specific optimization will enable the rapid construction of microbes for commercial production of biofuels and bioproducts. In this review, we discuss variability of lignocellulosic feedstocks, pathways for catabolism of lignocellulose-derived compounds, challenges to heterologous engineering of catabolic pathways, and opportunities to apply modular pathway design. Implementation of these approaches will simplify the process of modifying non-model microbes to convert diverse lignocellulosic feedstocks.
Collapse
|
113
|
Pesquet E, Wagner A, Grabber JH. Cell culture systems: invaluable tools to investigate lignin formation and cell wall properties. Curr Opin Biotechnol 2019; 56:215-222. [DOI: 10.1016/j.copbio.2019.02.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 01/22/2019] [Accepted: 02/01/2019] [Indexed: 12/20/2022]
|
114
|
Bergs M, Völkering G, Kraska T, Pude R, Do XT, Kusch P, Monakhova Y, Konow C, Schulze M. Miscanthus x giganteus Stem Versus Leaf-Derived Lignins Differing in Monolignol Ratio and Linkage. Int J Mol Sci 2019; 20:E1200. [PMID: 30857288 PMCID: PMC6429407 DOI: 10.3390/ijms20051200] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 02/28/2019] [Accepted: 03/05/2019] [Indexed: 11/19/2022] Open
Abstract
As a renewable, Miscanthus offers numerous advantages such as high photosynthesis activity (as a C₄ plant) and an exceptional CO₂ fixation rate. These properties make Miscanthus very attractive for industrial exploitation, such as lignin generation. In this paper, we present a systematic study analyzing the correlation of the lignin structure with the Miscanthus genotype and plant portion (stem versus leaf). Specifically, the ratio of the three monolignols and corresponding building blocks as well as the linkages formed between the units have been studied. The lignin amount has been determined for M. x giganteus (Gig17, Gig34, Gig35), M. nagara (NagG10), M. sinensis (Sin2), and M. robustus (Rob4) harvested at different time points (September, December, and April). The influence of the Miscanthus genotype and plant component (leaf vs. stem) has been studied to develop corresponding structure-property relationships (i.e., correlations in molecular weight, polydispersity, and decomposition temperature). Lignin isolation was performed using non-catalyzed organosolv pulping and the structure analysis includes compositional analysis, Fourier transform infradred (FTIR), ultraviolet/visible (UV-Vis), hetero-nuclear single quantum correlation nuclear magnetic resonsnce (HSQC-NMR), thermogravimetric analysis (TGA), and pyrolysis gaschromatography/mass spectrometry (GC/MS). Structural differences were found for stem and leaf-derived lignins. Compared to beech wood lignins, Miscanthus lignins possess lower molecular weight and narrow polydispersities (<1.5 Miscanthus vs. >2.5 beech) corresponding to improved homogeneity. In addition to conventional univariate analysis of FTIR spectra, multivariate chemometrics revealed distinct differences for aromatic in-plane deformations of stem versus leaf-derived lignins. These results emphasize the potential of Miscanthus as a low-input resource and a Miscanthus-derived lignin as promising agricultural feedstock.
Collapse
Affiliation(s)
- Michel Bergs
- Department of Natural Sciences, Bonn-Rhein-Sieg University of Applied Sciences, von-Liebig-Strasse 20, D-53359 Rheinbach, Germany.
- Institute of Crop Science and Resource Conservation, Faculty of Agriculture, University of Bonn, Klein-Altendorf 2, D-53359 Rheinbach, Germany.
| | - Georg Völkering
- Institute of Crop Science and Resource Conservation, Faculty of Agriculture, University of Bonn, Klein-Altendorf 2, D-53359 Rheinbach, Germany.
| | - Thorsten Kraska
- Field Lab Campus Klein-Altendorf, Faculty of Agriculture, University of Bonn, Campus Klein-Altendorf 1, D-53359 Rheinbach, Germany.
| | - Ralf Pude
- Institute of Crop Science and Resource Conservation, Faculty of Agriculture, University of Bonn, Klein-Altendorf 2, D-53359 Rheinbach, Germany.
- Field Lab Campus Klein-Altendorf, Faculty of Agriculture, University of Bonn, Campus Klein-Altendorf 1, D-53359 Rheinbach, Germany.
| | - Xuan Tung Do
- Department of Natural Sciences, Bonn-Rhein-Sieg University of Applied Sciences, von-Liebig-Strasse 20, D-53359 Rheinbach, Germany.
| | - Peter Kusch
- Department of Natural Sciences, Bonn-Rhein-Sieg University of Applied Sciences, von-Liebig-Strasse 20, D-53359 Rheinbach, Germany.
| | - Yulia Monakhova
- Spectral Service AG, Emil-Hoffmann-Strasse 33, D-50996 Köln, Germany.
- Institute of Chemistry, Saratov State University, Astrakhanskaya Street 83, 410012 Saratov, Russia.
| | - Christopher Konow
- Department of Chemistry, MS 015, Brandeis University, 415 South Street, Waltham, MA 02453, USA.
| | - Margit Schulze
- Department of Natural Sciences, Bonn-Rhein-Sieg University of Applied Sciences, von-Liebig-Strasse 20, D-53359 Rheinbach, Germany.
| |
Collapse
|
115
|
Immobilization of cellulase in the non-natural ionic liquid environments to enhance cellulase activity and functional stability. Appl Microbiol Biotechnol 2019; 103:2483-2492. [PMID: 30685813 DOI: 10.1007/s00253-019-09647-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 01/16/2019] [Indexed: 10/27/2022]
Abstract
Ionic liquids (ILs) have been applied as an environmentally friendly solvent in the pretreatment of lignocellulosic biomass for more than a decade. The ILs involved pretreatment processes for cellulases mediated saccharification lead to both the breakdown of cellulose crystallinity and the decrease of lignin content, thereby improving the solubility of cellulose and the accessibility of cellulase. However, most cellulases are partially or completely inactivated in the presence of even low amount of ILs. Immobilized cellulases are found to perform improved stability and higher apparent activity in practical application compared with its free counterparts. Enzyme immobilization therefore has become a promising way to relieve the deactivation of cellulase in ILs. Various immobilization carriers and methods have been developed and achieved satisfactory results in improving the stability, activity, and recycling of cellulases in IL pretreatment systems. This review aims to provide detailed introduction of immobilization methods and carrier materials of cellulase, including natural polysaccharides, synthetic polymers, inorganic materials, magnetic materials, and newly developed composite materials, and illustrate key methodologies in improving the performance of cellulase in the presence of ILs. Especially, novel materials and concepts from the recently representative researches are focused and discussed comprehensively, and future trends in immobilization of cellulases in non-natural ILs environments are speculated in the end.
Collapse
|
116
|
Li M, Yoo CG, Pu Y, Biswal AK, Tolbert AK, Mohnen D, Ragauskas AJ. Downregulation of pectin biosynthesis gene GAUT4 leads to reduced ferulate and lignin-carbohydrate cross-linking in switchgrass. Commun Biol 2019; 2:22. [PMID: 30675520 PMCID: PMC6336719 DOI: 10.1038/s42003-018-0265-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 12/07/2018] [Indexed: 11/09/2022] Open
Abstract
Knockdown (KD) expression of GAlactUronosylTransferase 4 (GAUT4) in switchgrass improves sugar yield and ethanol production from the biomass. The reduced recalcitrance of GAUT4-KD transgenic biomass is associated with reduced cell wall pectic homogalacturonan and rhamnogalacturonan II content and cross-linking, and the associated increases in accessibility of cellulose to enzymatic deconstruction. To further probe the molecular basis for the reduced recalcitrance of GAUT4-KD biomass, potential recalcitrance-related factors including the physicochemical properties of lignin and hemicellulose are investigated. We show that the transgenic switchgrass have a lower abundance of ferulate and lignin-carbohydrate complex cross-linkages, reduced amounts of residual arabinan and xylan in lignin-enriched fractions after enzymatic hydrolysis, and greater coalescence and migration of lignin after hydrothermal pretreatment in comparison to the wild-type switchgrass control. The results reveal the roles of both decreased lignin-polymer and pectin cross-links in the reduction of recalcitrance in PvGAUT4-KD switchgrass.
Collapse
Affiliation(s)
- Mi Li
- BioEnergy Science Center, Oak Ridge National Laboratory (ORNL), 1 Bethel Valley Road, Oak Ridge, TN 37831 USA
- Joint Institute for Biological Sciences, Biosciences Division, ORNL, 1 Bethel Valley Road, Oak Ridge, TN 37831 USA
| | - Chang Geun Yoo
- BioEnergy Science Center, Oak Ridge National Laboratory (ORNL), 1 Bethel Valley Road, Oak Ridge, TN 37831 USA
- Joint Institute for Biological Sciences, Biosciences Division, ORNL, 1 Bethel Valley Road, Oak Ridge, TN 37831 USA
- Center for Bioenergy Innovation, ORNL, 1 Bethel Valley Road, Oak Ridge, TN 37831 USA
- Present Address: Department of Paper and Bioprocess Engineering, State University of New York College of Environmental Science and Forestry, Syracuse, NY 13210-2781 USA
| | - Yunqiao Pu
- BioEnergy Science Center, Oak Ridge National Laboratory (ORNL), 1 Bethel Valley Road, Oak Ridge, TN 37831 USA
- Joint Institute for Biological Sciences, Biosciences Division, ORNL, 1 Bethel Valley Road, Oak Ridge, TN 37831 USA
- Center for Bioenergy Innovation, ORNL, 1 Bethel Valley Road, Oak Ridge, TN 37831 USA
| | - Ajaya K. Biswal
- BioEnergy Science Center, Oak Ridge National Laboratory (ORNL), 1 Bethel Valley Road, Oak Ridge, TN 37831 USA
- Center for Bioenergy Innovation, ORNL, 1 Bethel Valley Road, Oak Ridge, TN 37831 USA
- Department of Biochemistry and Molecular Biology and Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 USA
| | - Allison K. Tolbert
- BioEnergy Science Center, Oak Ridge National Laboratory (ORNL), 1 Bethel Valley Road, Oak Ridge, TN 37831 USA
- School of Chemistry and Biochemistry and Renewable Bioproducts Institute, Georgia Institute of Technology, 500 10th Street NW, Atlanta, GA 30332 USA
| | - Debra Mohnen
- BioEnergy Science Center, Oak Ridge National Laboratory (ORNL), 1 Bethel Valley Road, Oak Ridge, TN 37831 USA
- Center for Bioenergy Innovation, ORNL, 1 Bethel Valley Road, Oak Ridge, TN 37831 USA
- Department of Biochemistry and Molecular Biology and Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 USA
| | - Arthur J. Ragauskas
- BioEnergy Science Center, Oak Ridge National Laboratory (ORNL), 1 Bethel Valley Road, Oak Ridge, TN 37831 USA
- Joint Institute for Biological Sciences, Biosciences Division, ORNL, 1 Bethel Valley Road, Oak Ridge, TN 37831 USA
- Center for Bioenergy Innovation, ORNL, 1 Bethel Valley Road, Oak Ridge, TN 37831 USA
- Department of Chemical and Biomolecular Engineering, University of Tennessee, 1512 Middle Drive, Knoxville, TN 37996 USA
- Department of Forestry, Wildlife, and Fisheries, Center for Renewable Carbon, University of Tennessee Institute of Agriculture, 2506 Jacob Drive, Knoxville, TN 37996 USA
| |
Collapse
|
117
|
Schäfer J, Sattler M, Iqbal Y, Lewandowski I, Bunzel M. Characterization of Miscanthus cell wall polymers. GLOBAL CHANGE BIOLOGY. BIOENERGY 2019; 11:191-205. [PMID: 31007724 PMCID: PMC6472555 DOI: 10.1111/gcbb.12538] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 07/17/2018] [Accepted: 05/30/2018] [Indexed: 05/28/2023]
Abstract
Efficient utilization of lignocellulosic Miscanthus biomass for the production of biochemicals, such as ethanol, is challenging due to its recalcitrance, which is influenced by the individual plant cell wall polymers and their interactions. Lignocellulosic biomass composition differs depending on several factors, such as plant age, harvest date, organ type, and genotype. Here, four selected Miscanthus genotypes (Miscanthus sinensis, Miscanthus sacchariflorus, Miscanthus × giganteus, Miscanthus sinensis × Miscanthus sacchariflorus hybrid) were grown and harvested, separated into stems and leaves, and characterized for their non-starch polysaccharide composition and structures, lignin contents and structures, and hydroxycinnamate profiles (monomers and ferulic acid dehydrodimers). Polysaccharides of all genotypes are mainly composed of cellulose and low-substituted arabinoxylans. Ratios of hemicelluloses to cellulose were comparable, with the exception of Miscanthus sinensis that showed a higher hemicellulose/cellulose ratio. Lignin contents of Miscanthus stems were higher than those of Miscanthus leaves. Considering the same organs, the four genotypes did not differ in their Klason lignin contents, but Miscanthus × giganteus showed the highest acetylbromide soluble lignin content. Lignin polymers isolated from stems varied in their S/G ratios and linkage type distributions across genotypes. p-Coumaric acid was the most abundant ester-bound hydroxycinnamte monomer in all samples. Ferulic acid dehydrodimers were analyzed as cell wall cross-links, with 8-5-coupled diferulic acid being the main dimer, followed by 8-O-4-, and 5-5-diferulic acid. Contents of p-coumaric acid, ferulic acid, and ferulic acid dimers varied depending on genotype and organ type. The largest amount of cell wall cross-links was analyzed for Miscanthus sinensis.
Collapse
Affiliation(s)
- Judith Schäfer
- Department of Food Chemistry and Phytochemistry, Institute of Applied BiosciencesKarlsruhe Institute of Technology (KIT)KarlsruheGermany
| | - Melinda Sattler
- Department of Food Chemistry and Phytochemistry, Institute of Applied BiosciencesKarlsruhe Institute of Technology (KIT)KarlsruheGermany
| | - Yasir Iqbal
- Biobased Products and Energy Crops (340b), Institute of Crop ScienceUniversity of HohenheimStuttgartGermany
| | - Iris Lewandowski
- Biobased Products and Energy Crops (340b), Institute of Crop ScienceUniversity of HohenheimStuttgartGermany
| | - Mirko Bunzel
- Department of Food Chemistry and Phytochemistry, Institute of Applied BiosciencesKarlsruhe Institute of Technology (KIT)KarlsruheGermany
| |
Collapse
|
118
|
Paës G, Navarro D, Benoit Y, Blanquet S, Chabbert B, Chaussepied B, Coutinho PM, Durand S, Grigoriev IV, Haon M, Heux L, Launay C, Margeot A, Nishiyama Y, Raouche S, Rosso MN, Bonnin E, Berrin JG. Tracking of enzymatic biomass deconstruction by fungal secretomes highlights markers of lignocellulose recalcitrance. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:76. [PMID: 30976326 PMCID: PMC6442405 DOI: 10.1186/s13068-019-1417-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 03/23/2019] [Indexed: 05/12/2023]
Abstract
BACKGROUND Lignocellulose biomass is known as a recalcitrant material towards enzymatic hydrolysis, increasing the process cost in biorefinery. In nature, filamentous fungi naturally degrade lignocellulose, using an arsenal of hydrolytic and oxidative enzymes. Assessment of enzyme hydrolysis efficiency generally relies on the yield of glucose for a given biomass. To better understand the markers governing recalcitrance to enzymatic degradation, there is a need to enlarge the set of parameters followed during deconstruction. RESULTS Industrially-pretreated biomass feedstocks from wheat straw, miscanthus and poplar were sequentially hydrolysed following two steps. First, standard secretome from Trichoderma reesei was used to maximize cellulose hydrolysis, producing three recalcitrant lignin-enriched solid substrates. Then fungal secretomes from three basidiomycete saprotrophs (Laetisaria arvalis, Artolenzites elegans and Trametes ljubarskyi) displaying various hydrolytic and oxidative enzymatic profiles were applied to these recalcitrant substrates, and compared to the T. reesei secretome. As a result, most of the glucose was released after the first hydrolysis step. After the second hydrolysis step, half of the remaining glucose amount was released. Overall, glucose yield after the two sequential hydrolyses was more dependent on the biomass source than on the fungal secretomes enzymatic profile. Solid residues obtained after the two hydrolysis steps were characterized using complementary methodologies. Correlation analysis of several physico-chemical parameters showed that released glucose yield was negatively correlated with lignin content and cellulose crystallinity while positively correlated with xylose content and water sorption. Water sorption appears as a pivotal marker of the recalcitrance as it reflects chemical and structural properties of lignocellulosic biomass. CONCLUSIONS Fungal secretomes applied to highly recalcitrant biomass samples can further extend the release of the remaining glucose. The glucose yield can be correlated to chemical and physical markers, which appear to be independent from the biomass type and secretome. Overall, correlations between these markers reveal how nano-scale properties (polymer content and organization) influence macro-scale properties (particle size and water sorption). Further systematic assessment of these markers during enzymatic degradation will foster the development of novel cocktails to unlock the degradation of lignocellulose biomass.
Collapse
Affiliation(s)
- Gabriel Paës
- FARE Laboratory, INRA, Université de Reims Champagne-Ardenne, Reims, France
| | - David Navarro
- INRA, Aix Marseille Univ., UMR1163, BBF, Biodiversité et Biotechnologie Fongiques, Marseille, France
- INRA, Aix-Marseille Univ., UMR1163, CIRM-CF, Marseille, France
| | - Yves Benoit
- IFP Energies Nouvelles, Rueil-Malmaison, France
| | | | - Brigitte Chabbert
- FARE Laboratory, INRA, Université de Reims Champagne-Ardenne, Reims, France
| | | | - Pedro M. Coutinho
- CNRS, Aix-Marseille Univ., UMR7857 AFMB, Architecture et Fonction des Macromolécules Biologiques, Marseille, France
| | - Sylvie Durand
- INRA, UR1268 Biopolymères Interactions Assemblages, Nantes, France
| | - Igor V. Grigoriev
- US Department of Energy Joint Genome Institute, Walnut Creek, CA USA
- Department of Plant and Microbial Biology, University of California Berkeley, Berkeley, CA USA
| | - Mireille Haon
- INRA, Aix Marseille Univ., UMR1163, BBF, Biodiversité et Biotechnologie Fongiques, Marseille, France
| | - Laurent Heux
- CNRS, Univ. Grenoble Alpes, CERMAV, Grenoble, France
| | - Charlène Launay
- INRA, UR1268 Biopolymères Interactions Assemblages, Nantes, France
| | | | | | - Sana Raouche
- INRA, Aix Marseille Univ., UMR1163, BBF, Biodiversité et Biotechnologie Fongiques, Marseille, France
| | - Marie-Noëlle Rosso
- INRA, Aix Marseille Univ., UMR1163, BBF, Biodiversité et Biotechnologie Fongiques, Marseille, France
| | - Estelle Bonnin
- INRA, UR1268 Biopolymères Interactions Assemblages, Nantes, France
| | - Jean-Guy Berrin
- INRA, Aix Marseille Univ., UMR1163, BBF, Biodiversité et Biotechnologie Fongiques, Marseille, France
| |
Collapse
|
119
|
Hodgson-Kratky K, Papa G, Rodriguez A, Stavila V, Simmons B, Botha F, Furtado A, Henry R. Relationship between sugarcane culm and leaf biomass composition and saccharification efficiency. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:247. [PMID: 31636706 PMCID: PMC6796448 DOI: 10.1186/s13068-019-1588-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 10/05/2019] [Indexed: 05/06/2023]
Abstract
BACKGROUND Lignocellulosic biomass is recognized as a promising renewable feedstock for the production of biofuels. However, current methods for converting biomass into fermentable sugars are considered too expensive and inefficient due to the recalcitrance of the secondary cell wall. Biomass composition can be modified to create varieties that are efficiently broken down to release cell wall sugars. This study focused on identifying the key biomass components influencing plant cell wall recalcitrance that can be targeted for selection in sugarcane, an important and abundant source of biomass. RESULTS Biomass composition and the amount of glucan converted into glucose after saccharification were measured in leaf and culm tissues from seven sugarcane genotypes varying in fiber composition after no pretreatment and dilute acid, hydrothermal and ionic liquid pretreatments. In extractives-free sugarcane leaf and culm tissue, glucan, xylan, acid-insoluble lignin (AIL) and acid-soluble lignin (ASL) ranged from 20 to 32%, 15% to 21%, 14% to 20% and 2% to 4%, respectively. The ratio of syringyl (S) to guaiacyl (G) content in the lignin ranged from 1.5 to 2.2 in the culm and from 0.65 to 1.1 in the leaf. Hydrothermal and dilute acid pretreatments predominantly reduced xylan content, while the ionic liquid (IL) pretreatment targeted AIL reduction. The amount of glucan converted into glucose after 26 h of pre-saccharification was highest after IL pretreatment (42% in culm and 63.5% in leaf) compared to the other pretreatments. Additionally, glucan conversion in leaf tissues was approximately 1.5-fold of that in culm tissues. Percent glucan conversion varied between genotypes but there was no genotype that was superior to all others across the pretreatment groups. Path analysis revealed that S/G ratio, AIL and xylan had the strongest negative associations with percent glucan conversion, while ASL and glucan content had strong positive influences. CONCLUSION To improve saccharification efficiency of lignocellulosic biomass, breeders should focus on reducing S/G ratio, xylan and AIL content and increasing ASL and glucan content. This will be key for the development of sugarcane varieties for bioenergy uses.
Collapse
Affiliation(s)
- K. Hodgson-Kratky
- Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Brisbane, QLD 4072 Australia
| | - G. Papa
- Joint BioEnergy Institute, Emeryville, CA 94608 USA
- Advanced Biofuels and Bioproducts Process Development Unit, Emeryville, CA 94608 USA
| | - A. Rodriguez
- Joint BioEnergy Institute, Emeryville, CA 94608 USA
- Sandia National Laboratories, Livermore, CA 94550 USA
| | - V. Stavila
- Sandia National Laboratories, Livermore, CA 94550 USA
| | - B. Simmons
- Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Brisbane, QLD 4072 Australia
- Joint BioEnergy Institute, Emeryville, CA 94608 USA
| | - F. Botha
- Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Brisbane, QLD 4072 Australia
- Sugar Research Australia, Brisbane, QLD 4068 Australia
| | - A. Furtado
- Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Brisbane, QLD 4072 Australia
| | - R. Henry
- Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Brisbane, QLD 4072 Australia
| |
Collapse
|
120
|
Wang H, Pu Y, Ragauskas A, Yang B. From lignin to valuable products-strategies, challenges, and prospects. BIORESOURCE TECHNOLOGY 2019; 271:449-461. [PMID: 30266464 DOI: 10.1016/j.biortech.2018.09.072] [Citation(s) in RCA: 245] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 09/13/2018] [Accepted: 09/14/2018] [Indexed: 05/24/2023]
Abstract
The exploration of effective approaches for the valorization of lignin to valuable products attracts broad interests of a growing scientific community. By fully unlocking the potential of the world's most abundant resource of bio-aromatics, it could improve the profitability and carbon efficiency of the entire biorefinery process, thus accelerate the replacement of fossil resources with bioresources in our society. The successful realization of this goal depends on the development of technologies to overcome the following challenges, including: 1) efficient biomass pretreatment and lignin separation technologies that overcomes its diverse structure and complex chemistry challenges to obtain high purity lignin; 2) advanced chemical analysis for precise quantitative characterization of the lignin in chemical transformation processes; 3) novel approaches for conversion of biomass-derived lignin to valuable products. This review summarizes the latest cutting-edge innovations of lignin chemical valorization with the focus on the aforementioned three key aspects.
Collapse
Affiliation(s)
- Hongliang Wang
- Bioproducts, Sciences, and Engineering Laboratory, Department of Biological Systems Engineering, Washington State University, Richland, WA 99354, USA; Center of Biomass Engineering/College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China
| | - Yunqiao Pu
- Center for Bioenergy Innovation, Joint Institute of Biological Science, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Arthur Ragauskas
- Center for Bioenergy Innovation, Joint Institute of Biological Science, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA; Department of Chemical and Biomolecular Engineering & Department of Forestry, Wildlife and Fisheries, Center for Renewable Carbon, University of Tennessee, Knoxville, TN, USA
| | - Bin Yang
- Bioproducts, Sciences, and Engineering Laboratory, Department of Biological Systems Engineering, Washington State University, Richland, WA 99354, USA; Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA.
| |
Collapse
|
121
|
Piqueras S, Füchtner S, Rocha de Oliveira R, Gómez-Sánchez A, Jelavić S, Keplinger T, de Juan A, Thygesen LG. Understanding the Formation of Heartwood in Larch Using Synchrotron Infrared Imaging Combined With Multivariate Analysis and Atomic Force Microscope Infrared Spectroscopy. FRONTIERS IN PLANT SCIENCE 2019; 10:1701. [PMID: 32117328 PMCID: PMC7008386 DOI: 10.3389/fpls.2019.01701] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 12/03/2019] [Indexed: 05/03/2023]
Abstract
Formation of extractive-rich heartwood is a process in live trees that make them and the wood obtained from them more resistant to fungal degradation. Despite the importance of this natural mechanism, little is known about the deposition pathways and cellular level distribution of extractives. Here we follow heartwood formation in Larix gmelinii var. Japonica by use of synchrotron infrared images analyzed by the unmixing method Multivariate Curve Resolution - Alternating Least Squares (MCR-ALS). A subset of the specimens was also analyzed using atomic force microscopy infrared spectroscopy. The main spectral changes observed in the transition zone when going from sapwood to heartwood was a decrease in the intensity of a peak at approximately 1660 cm-1 and an increase in a peak at approximately 1640 cm-1. There are several possible interpretations of this observation. One possibility that is supported by the MCR-ALS unmixing is that heartwood formation in larch is a type II or Juglans-type of heartwood formation, where phenolic precursors to extractives accumulate in the sapwood rays. They are then oxidized and/or condensed in the transition zone and spread to the neighboring cells in the heartwood.
Collapse
Affiliation(s)
- Sara Piqueras
- Biomass Science and Technology Group, Department of Geosciences and Natural Resource Management, University of Copenhagen, Frederiksberg, Denmark
- *Correspondence: Sara Piqueras,
| | - Sophie Füchtner
- Biomass Science and Technology Group, Department of Geosciences and Natural Resource Management, University of Copenhagen, Frederiksberg, Denmark
| | | | - Adrián Gómez-Sánchez
- Chemometrics Group, Department of Analytical Chemistry, University of Barcelona, Barcelona, Spain
| | - Stanislav Jelavić
- Nano-Science Center, Department of Chemistry, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
- Section for GeoGenetics, Faculty of Health and Medical Sciences, Globe Institute, University of Copenhagen, Copenhagen, Denmark
| | - Tobias Keplinger
- Wood Material Science Group, Department of Construction, Environment and Geomatics, Institute for Building Materials (IfB), ETH Zürich, Zürich, Switzerland
- WoodTec Group, Cellulose & Wood Materials, EMPA, Dübendorf, Switzerland
| | - Anna de Juan
- Chemometrics Group, Department of Analytical Chemistry, University of Barcelona, Barcelona, Spain
| | - Lisbeth Garbrecht Thygesen
- Biomass Science and Technology Group, Department of Geosciences and Natural Resource Management, University of Copenhagen, Frederiksberg, Denmark
| |
Collapse
|
122
|
Dekker RFH, Queiroz EAIF, Cunha MAA, Barbosa-Dekker AM. Botryosphaeran – A Fungal Exopolysaccharide of the (1→3)(1→6)-β-D-Glucan Kind: Structure and Biological Functions. BIOLOGICALLY-INSPIRED SYSTEMS 2019. [DOI: 10.1007/978-3-030-12919-4_11] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
|
123
|
Lambert E, Aguié-Béghin V, Dessaint D, Foulon L, Chabbert B, Paës G, Molinari M. Real Time and Quantitative Imaging of Lignocellulosic Films Hydrolysis by Atomic Force Microscopy Reveals Lignin Recalcitrance at Nanoscale. Biomacromolecules 2018; 20:515-527. [DOI: 10.1021/acs.biomac.8b01539] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Eléonore Lambert
- LRN EA 4682, Université de Reims Champagne-Ardenne, 51685 Reims, France
| | | | - Delphine Dessaint
- FARE Laboratory, INRA, Université de Reims Champagne-Ardenne, 51100, Reims, France
| | - Laurence Foulon
- FARE Laboratory, INRA, Université de Reims Champagne-Ardenne, 51100, Reims, France
| | - Brigitte Chabbert
- FARE Laboratory, INRA, Université de Reims Champagne-Ardenne, 51100, Reims, France
| | - Gabriel Paës
- FARE Laboratory, INRA, Université de Reims Champagne-Ardenne, 51100, Reims, France
| | - Michaël Molinari
- LRN EA 4682, Université de Reims Champagne-Ardenne, 51685 Reims, France
| |
Collapse
|
124
|
Jain L, Kurmi AK, Agrawal D. Feasibility studies with lignin blocking additives in enhancing saccharification and cellulase recovery: Mutant UV-8 of T. verruculosus IIPC 324 a case study. Enzyme Microb Technol 2018; 118:44-49. [DOI: 10.1016/j.enzmictec.2018.07.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 06/19/2018] [Accepted: 07/12/2018] [Indexed: 01/13/2023]
|
125
|
Djajadi DT, Pihlajaniemi V, Rahikainen J, Kruus K, Meyer AS. Cellulases adsorb reversibly on biomass lignin. Biotechnol Bioeng 2018; 115:2869-2880. [PMID: 30132790 PMCID: PMC6282830 DOI: 10.1002/bit.26820] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 07/30/2018] [Accepted: 08/13/2018] [Indexed: 12/14/2022]
Abstract
Adsorption of cellulases onto lignin is considered a major factor in retarding enzymatic cellulose degradation of lignocellulosic biomass. However, the adsorption mechanisms and kinetics are not well understood for individual types of cellulases. This study examines the binding affinity, kinetics of adsorption, and competition of four monocomponent cellulases of Trichoderma reesei during adsorption onto lignin.
TrCel7A,
TrCel6A,
TrCel7B, and
TrCel5A were radiolabeled for adsorption experiments on lignin‐rich residues (LRRs) isolated from hydrothermally pretreated spruce (L‐HPS) and wheat straw (L‐HPWS), respectively. On the basis of adsorption isotherms fitted to the Langmuir model, the ranking of binding affinities was
TrCel5A >
TrCel6A >
TrCel7B >
TrCel7A on both types of LRRs. The enzymes had a higher affinity to the L‐HPS than to the L‐HPWS. Adsorption experiments with dilution after 1 and 24 hr and kinetic modeling were performed to quantify any irreversible binding over time. Models with reversible binding parameters fitted well and can explain the results obtained. The adsorption constants obtained from the reversible models agreed with the fitted Langmuir isotherms and suggested that reversible adsorption–desorption existed at equilibrium. Competitive binding experiments showed that individual types of cellulases competed for binding sites on the lignin and the adsorption data fitted the Langmuir adsorption model. Overall, the data strongly indicate that the adsorption of cellulases onto lignin is reversible and the findings have implications for the development of more efficient cellulose degrading enzymes.
Collapse
Affiliation(s)
- Demi T Djajadi
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Kongens Lyngby, Denmark
| | | | | | | | - Anne S Meyer
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Kongens Lyngby, Denmark
| |
Collapse
|
126
|
Tarasov D, Leitch M, Fatehi P. Lignin-carbohydrate complexes: properties, applications, analyses, and methods of extraction: a review. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:269. [PMID: 30288174 PMCID: PMC6162904 DOI: 10.1186/s13068-018-1262-1] [Citation(s) in RCA: 143] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 09/19/2018] [Indexed: 05/06/2023]
Abstract
The complexity of lignin and hemicellulose segmentation has been known since the middle of the ninetieth century. Studies confirmed that all lignin units in coniferous species and 47-66% of lignin moieties in deciduous species are bound to hemicelluloses or cellulose molecules in lignin-carbohydrate complexes (LCC). Different types and proportions of lignin and polysaccharides present in biomass lead to the formation of LCC with a great variety of compositions and structures. The nature and amount of LCC linkages and lignin substructures affect the efficiency of pulping, hydrolysis, and digestibility of biomass. This review paper discusses the structures, compositions, and properties of LCC present in biomass and in the products obtained via pretreating biomass. Methods for extracting, fractionating, and analyzing LCC of biomass, pulp, and spent pulping liquors are critically reviewed. The main perspectives and challenges associated with these technologies are extensively discussed. LCC could be extracted from biomass following varied methods, among which dimethyl sulfoxide or dioxane (Björkman's) and acetic acid (LCC-AcOH) processes are the most widely applied. The oxidation and methylation treatments of LCC materials elucidate the locations and frequency of binding sites of hemicelluloses to lignin. The two-dimensional nuclear magnetic resonance analysis allows the identification of the structure and the quantity of lignin-carbohydrate bonds involved in LCC. LCC application seems promising in medicine due to its high anti-HIV, anti-herpes, and anti-microbial activity. In addition, LCC was successfully employed as a precursor for the preparation of spherical biocarriers.
Collapse
Affiliation(s)
- Dmitry Tarasov
- Chemical Engineering Department, Lakehead University, 955 Oliver Road, Thunder Bay, ON P7B 5E1 Canada
- Natural Resource Management Faculty, Lakehead University, 955 Oliver Road, Thunder Bay, ON P7B 5E1 Canada
| | - Mathew Leitch
- Natural Resource Management Faculty, Lakehead University, 955 Oliver Road, Thunder Bay, ON P7B 5E1 Canada
| | - Pedram Fatehi
- Chemical Engineering Department, Lakehead University, 955 Oliver Road, Thunder Bay, ON P7B 5E1 Canada
| |
Collapse
|
127
|
Faraji M, Fonseca LL, Escamilla-Treviño L, Barros-Rios J, Engle NL, Yang ZK, Tschaplinski TJ, Dixon RA, Voit EO. A dynamic model of lignin biosynthesis in Brachypodium distachyon. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:253. [PMID: 30250505 PMCID: PMC6145374 DOI: 10.1186/s13068-018-1241-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 08/27/2018] [Indexed: 05/31/2023]
Abstract
BACKGROUND Lignin is a crucial molecule for terrestrial plants, as it offers structural support and permits the transport of water over long distances. The hardness of lignin reduces plant digestibility by cattle and sheep; it also makes inedible plant materials recalcitrant toward the enzymatic fermentation of cellulose, which is a potentially valuable substrate for sustainable biofuels. Targeted attempts to change the amount or composition of lignin in relevant plant species have been hampered by the fact that the lignin biosynthetic pathway is difficult to understand, because it uses several enzymes for the same substrates, is regulated in an ill-characterized manner, may operate in different locations within cells, and contains metabolic channels, which the plant may use to funnel initial substrates into specific monolignols. RESULTS We propose a dynamic mathematical model that integrates various datasets and other information regarding the lignin pathway in Brachypodium distachyon and permits explanations for some counterintuitive observations. The model predicts the lignin composition and label distribution in a BdPTAL knockdown strain, with results that are quite similar to experimental data. CONCLUSION Given the present scarcity of available data, the model resulting from our analysis is presumably not final. However, it offers proof of concept for how one may design integrative pathway models of this type, which are necessary tools for predicting the consequences of genomic or other alterations toward plants with lignin features that are more desirable than in their wild-type counterparts.
Collapse
Affiliation(s)
- Mojdeh Faraji
- The Wallace H. Coulter, Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 950 Atlantic Drive, Atlanta, GA 30332-2000 USA
- BioEnergy Sciences Center (BESC), Oak Ridge National Lab, Oak Ridge, TN USA
| | - Luis L. Fonseca
- The Wallace H. Coulter, Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 950 Atlantic Drive, Atlanta, GA 30332-2000 USA
- BioEnergy Sciences Center (BESC), Oak Ridge National Lab, Oak Ridge, TN USA
| | - Luis Escamilla-Treviño
- BioEnergy Sciences Center (BESC), Oak Ridge National Lab, Oak Ridge, TN USA
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, 1155 Union Circle #305220, Denton, TX 76203-5017 USA
| | - Jaime Barros-Rios
- BioEnergy Sciences Center (BESC), Oak Ridge National Lab, Oak Ridge, TN USA
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, 1155 Union Circle #305220, Denton, TX 76203-5017 USA
| | - Nancy L. Engle
- BioEnergy Sciences Center (BESC), Oak Ridge National Lab, Oak Ridge, TN USA
- Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 USA
| | - Zamin K. Yang
- BioEnergy Sciences Center (BESC), Oak Ridge National Lab, Oak Ridge, TN USA
- Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 USA
| | - Timothy J. Tschaplinski
- BioEnergy Sciences Center (BESC), Oak Ridge National Lab, Oak Ridge, TN USA
- Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 USA
| | - Richard A. Dixon
- BioEnergy Sciences Center (BESC), Oak Ridge National Lab, Oak Ridge, TN USA
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, 1155 Union Circle #305220, Denton, TX 76203-5017 USA
| | - Eberhard O. Voit
- The Wallace H. Coulter, Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 950 Atlantic Drive, Atlanta, GA 30332-2000 USA
- BioEnergy Sciences Center (BESC), Oak Ridge National Lab, Oak Ridge, TN USA
| |
Collapse
|
128
|
Satlewal A, Agrawal R, Bhagia S, Sangoro J, Ragauskas AJ. Natural deep eutectic solvents for lignocellulosic biomass pretreatment: Recent developments, challenges and novel opportunities. Biotechnol Adv 2018; 36:2032-2050. [PMID: 30193965 DOI: 10.1016/j.biotechadv.2018.08.009] [Citation(s) in RCA: 137] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 07/09/2018] [Accepted: 08/26/2018] [Indexed: 12/26/2022]
Abstract
Conversion of lignocellulosic biomass to fuels and chemicals has attracted immense research and development around the world. Lowering recalcitrance of biomass in a cost-effective manner is a challenge to commercialize biomass-based technologies. Deep eutectic solvents (DESs) are new 'green' solvents that have a high potential for biomass processing because of their low cost, low toxicity, biodegradability, easy recycling and reuse. This article discusses the properties of DESs and recent advances in their application for lignocellulosic biomass processing. The effectiveness of DESs in hydrolyzing lignin-carbohydrate complexes, removing lignin/hemicellulose from biomass as well as their effect on biomass deconstruction, crystallinity and enzymatic digestibility have been discussed. Moreover, this review presents recent findings on the compatibility of natural DESs with enzymes and microorganisms.
Collapse
Affiliation(s)
- Alok Satlewal
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, USA; Joint Institute for Biological Sciences, Biosciences Division, Oak Ridge National Laboratory (ORNL), TN 37831, USA; Department of Bioenergy, DBT-IOC Centre for Advanced Bioenergy Research, Research and Development Centre, Indian Oil Corporation Ltd, Faridabad, Haryana 121007, India
| | - Ruchi Agrawal
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, USA; Department of Bioenergy, DBT-IOC Centre for Advanced Bioenergy Research, Research and Development Centre, Indian Oil Corporation Ltd, Faridabad, Haryana 121007, India
| | - Samarthya Bhagia
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, USA.
| | - Joshua Sangoro
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, USA.
| | - Arthur J Ragauskas
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, USA; Joint Institute for Biological Sciences, Biosciences Division, Oak Ridge National Laboratory (ORNL), TN 37831, USA; Department of Forestry, Wildlife, and Fisheries, Center for Renewable Carbon, University of Tennessee, Institute of Agriculture, Knoxville, TN 37996, USA.
| |
Collapse
|
129
|
Goacher RE, Braham EJ, Michienzi CL, Flick RM, Yakunin AF, Master ER. Direct analysis by time-of-flight secondary ion mass spectrometry reveals action of bacterial laccase-mediator systems on both hardwood and softwood samples. PHYSIOLOGIA PLANTARUM 2018; 164:5-16. [PMID: 29286544 DOI: 10.1111/ppl.12688] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Revised: 12/20/2017] [Accepted: 12/26/2017] [Indexed: 06/07/2023]
Abstract
The modification and degradation of lignin play a vital role in carbon cycling as well as production of biofuels and bioproducts. The possibility of using bacterial laccases for the oxidation of lignin offers a route to utilize existing industrial protein expression techniques. However, bacterial laccases are most frequently studied on small model compounds that do not capture the complexity of lignocellulosic materials. This work studied the action of laccases from Bacillus subtilis and Salmonella typhimurium (EC 1.10.3.2) on ground wood samples from yellow birch (Betula alleghaniensis) and red spruce (Picea rubens). The ability of bacterial laccases to modify wood can be facilitated by small molecule mediators. Herein, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), gallic acid and sinapic acid mediators were tested. Direct analysis of the wood samples was achieved by time-of-flight secondary ion mass spectrometry (ToF-SIMS), a surface sensitive mass spectrometry technique that has characteristic peaks for H, G and S lignin. The action of the bacterial laccases on both wood samples was demonstrated and revealed a strong mediator influence. The ABTS mediator led to delignification, evident in an overall increase of polysaccharide peaks in the residual solid, along with equal loss of G and S-lignin peaks. The gallic acid mediator demonstrated minimal laccase activity. Meanwhile, the sinapic acid mediator altered the S/G peak ratio consistent with mediator attaching to the wood solids. The current investigation demonstrates the action of bacterial laccase-mediator systems directly on woody materials, and the potential of using ToF-SIMS to uncover the fundamental and applied role of bacterial enzymes in lignocellulose conversion.
Collapse
Affiliation(s)
- Robyn E Goacher
- Department of Biochemistry, Chemistry and Physics, Niagara University, 5795 Lewiston Road, Lewiston, NY, 14109, USA
| | - Erick J Braham
- Department of Biochemistry, Chemistry and Physics, Niagara University, 5795 Lewiston Road, Lewiston, NY, 14109, USA
- Department of Chemistry, Texas A&M University, 580 Ross Street, College Station, TX, 77843, USA
| | - Courtney L Michienzi
- Department of Biochemistry, Chemistry and Physics, Niagara University, 5795 Lewiston Road, Lewiston, NY, 14109, USA
| | - Robert M Flick
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
| | - Alexander F Yakunin
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
| | - Emma R Master
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada
- Department of Bioproducts and Biosystems, Aalto University, FI-00076 Aalto, Kemistintie 1, Espoo, Finland
| |
Collapse
|
130
|
Jung S, Trajano HL, Yoo CG, Foston MB, Hu F, Tolbert AK, Wyman CE, Ragauskas AJ. Topochemical Understanding of Lignin Distribution During Hydrothermal Flowthrough Pretreatment. ChemistrySelect 2018. [DOI: 10.1002/slct.201801837] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Seokwon Jung
- School of Chemistry and Biochemistry; Georgia Institute of Technology, Atlanta; GA 30332 USA
- BioEnergy Science Center & Center for Bioenergy Innovation; Oak Ridge National Laboratory, Oak Ridge; TN 37831 USA
| | - Heather L. Trajano
- BioEnergy Science Center & Center for Bioenergy Innovation; Oak Ridge National Laboratory, Oak Ridge; TN 37831 USA
- Department of Chemical & Environmental Engineering; Center for Environmental Research and Technology University of California, Riverside; CA 92521 USA
- Department of Chemical and Biological Engineering; University of British Columbia Vancouver, British Columbia, V6T 1Z3; Canada
| | - Chang Geun Yoo
- BioEnergy Science Center & Center for Bioenergy Innovation; Oak Ridge National Laboratory, Oak Ridge; TN 37831 USA
- UT-ORNL Joint Institute for Biological Science; Oak Ridge National Laboratory, Oak Ridge; TN 37831 USA
| | - Marcus B. Foston
- BioEnergy Science Center & Center for Bioenergy Innovation; Oak Ridge National Laboratory, Oak Ridge; TN 37831 USA
- Department of Energy; Environmental & Chemical Engineering Washington University, Saint Louis; MO 63130 USA
| | - Fan Hu
- School of Chemistry and Biochemistry; Georgia Institute of Technology, Atlanta; GA 30332 USA
- BioEnergy Science Center & Center for Bioenergy Innovation; Oak Ridge National Laboratory, Oak Ridge; TN 37831 USA
| | - Allison K. Tolbert
- School of Chemistry and Biochemistry; Georgia Institute of Technology, Atlanta; GA 30332 USA
- BioEnergy Science Center & Center for Bioenergy Innovation; Oak Ridge National Laboratory, Oak Ridge; TN 37831 USA
| | - Charles E. Wyman
- BioEnergy Science Center & Center for Bioenergy Innovation; Oak Ridge National Laboratory, Oak Ridge; TN 37831 USA
- Department of Chemical & Environmental Engineering; Center for Environmental Research and Technology University of California, Riverside; CA 92521 USA
| | - Arthur J. Ragauskas
- School of Chemistry and Biochemistry; Georgia Institute of Technology, Atlanta; GA 30332 USA
- BioEnergy Science Center & Center for Bioenergy Innovation; Oak Ridge National Laboratory, Oak Ridge; TN 37831 USA
- UT-ORNL Joint Institute for Biological Science; Oak Ridge National Laboratory, Oak Ridge; TN 37831 USA
- Department of Chemical and Biomolecular Engineering & Department of Forestry, Wildlife; Fisheries University of Tennessee, Knoxville; TN 37996 USA
| |
Collapse
|
131
|
Catalytic Strategies Towards Lignin-Derived Chemicals. Top Curr Chem (Cham) 2018; 376:36. [PMID: 30151801 DOI: 10.1007/s41061-018-0214-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 08/10/2018] [Indexed: 12/16/2022]
Abstract
Lignin valorization represents a crucial, yet underexploited component in current lignocellulosic biorefineries. An alluring opportunity is the selective depolymerization of lignin towards chemicals. Although challenged by lignin's recalcitrant nature, several successful (catalytic) strategies have emerged. This review provides an overview of different approaches to cope with detrimental lignin structural alterations at an early stage of the biorefinery process, thus enabling effective routes towards lignin-derived chemicals. A first general strategy is to isolate lignin with a better preserved native-like structure and therefore an increased amenability towards depolymerization in a subsequent step. Both mild process conditions as well as active stabilization methods will be discussed. An alternative is the simultaneous depolymerization-stabilization of native lignin towards stable lignin monomers. This approach requires a fast and efficient stabilization of reactive lignin intermediates in order to minimize lignin repolymerization and maximize the envisioned production of chemicals. Finally, the obtained lignin-derived compounds can serve as a platform towards a broad range of bio-based products. Their implementation will improve the sustainability of the chemical industry, but equally important will generate opportunities towards product innovations based on unique biobased chemical structures.
Collapse
|
132
|
Suseela V, Tharayil N. Decoupling the direct and indirect effects of climate on plant litter decomposition: Accounting for stress-induced modifications in plant chemistry. GLOBAL CHANGE BIOLOGY 2018; 24:1428-1451. [PMID: 28986956 DOI: 10.1111/gcb.13923] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 07/16/2017] [Indexed: 06/07/2023]
Abstract
Decomposition of plant litter is a fundamental ecosystem process that can act as a feedback to climate change by simultaneously influencing both the productivity of ecosystems and the flux of carbon dioxide from the soil. The influence of climate on decomposition from a postsenescence perspective is relatively well known; in particular, climate is known to regulate the rate of litter decomposition via its direct influence on the reaction kinetics and microbial physiology on processes downstream of tissue senescence. Climate can alter plant metabolism during the formative stage of tissues and could shape the final chemical composition of plant litter that is available for decomposition, and thus indirectly influence decomposition; however, these indirect effects are relatively poorly understood. Climatic stress disrupts cellular homeostasis in plants and results in the reprogramming of primary and secondary metabolic pathways, which leads to changes in the quantity, composition, and organization of small molecules and recalcitrant heteropolymers, including lignins, tannins, suberins, and cuticle within the plant tissue matrix. Furthermore, by regulating metabolism during tissue senescence, climate influences the resorption of nutrients from senescing tissues. Thus, the final chemical composition of plant litter that forms the substrate of decomposition is a combined product of presenescence physiological processes through the production and resorption of metabolites. The changes in quantity, composition, and localization of the molecular construct of the litter could enhance or hinder tissue decomposition and soil nutrient cycling by altering the recalcitrance of the lignocellulose matrix, the composition of microbial communities, and the activity of microbial exo-enzymes via various complexation reactions. Also, the climate-induced changes in the molecular composition of litter could differentially influence litter decomposition and soil nutrient cycling. Compared with temperate ecosystems, the indirect effects of climate on litter decomposition in the tropics are not well understood, which underscores the need to conduct additional studies in tropical biomes. We also emphasize the need to focus on how climatic stress affects the root chemistry as roots contribute significantly to biogeochemical cycling, and on utilizing more robust analytical approaches to capture the molecular composition of tissue matrix that fuel microbial metabolism.
Collapse
Affiliation(s)
- Vidya Suseela
- Department of Plant & Environmental Sciences, Clemson University, Clemson, SC, USA
| | - Nishanth Tharayil
- Department of Plant & Environmental Sciences, Clemson University, Clemson, SC, USA
| |
Collapse
|
133
|
Cui S, Wada S, Tobimatsu Y, Takeda Y, Saucet SB, Takano T, Umezawa T, Shirasu K, Yoshida S. Host lignin composition affects haustorium induction in the parasitic plants Phtheirospermum japonicum and Striga hermonthica. THE NEW PHYTOLOGIST 2018; 218:710-723. [PMID: 29498051 DOI: 10.1111/nph.15033] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 01/08/2018] [Indexed: 05/24/2023]
Abstract
Parasitic plants in the family Orobanchaceae are destructive weeds of agriculture worldwide. The haustorium, an essential parasitic organ used by these plants to penetrate host tissues, is induced by host-derived phenolic compounds called haustorium-inducing factors (HIFs). The origin of HIFs remains unknown, although the structures of lignin monomers resemble that of HIFs. Lignin is a natural phenylpropanoid polymer, commonly found in secondary cell walls of vascular plants. We therefore investigated the possibility that HIFs are derived from host lignin. Various lignin-related phenolics, quinones and lignin polymers, together with nonhost and host plants that have different lignin compositions, were tested for their haustorium-inducing activity in two Orobanchaceae species, a facultative parasite, Phtheirospermum japonicum, and an obligate parasite, Striga hermonthica. Lignin-related compounds induced haustoria in P. japonicum and S. hermonthica with different specificities. High concentrations of lignin polymers induced haustorium formation. Treatment with laccase, a lignin degradation enzyme, promoted haustorium formation at low concentrations. The distinct lignin compositions of the host and nonhost plants affected haustorium induction, correlating with the response of the different parasitic plants to specific types of lignin-related compounds. Our study provides valuable insights into the important roles of lignin biosynthesis and degradation in the production of HIFs.
Collapse
Affiliation(s)
- Songkui Cui
- Graduate School of Biological Science, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara, 630-0192, Japan
- Institute for Research Initiatives, Division for Research Strategy, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara, 630-0192, Japan
- RIKEN Center for Sustainable Resource Science, 1-7-22 Suehirocho, Tsurumi, Yokohama, 230-0045, Japan
| | - Syogo Wada
- Graduate School of Biological Science, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara, 630-0192, Japan
| | - Yuki Tobimatsu
- Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Yuri Takeda
- Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Simon B Saucet
- RIKEN Center for Sustainable Resource Science, 1-7-22 Suehirocho, Tsurumi, Yokohama, 230-0045, Japan
| | - Toshiyuki Takano
- Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Toshiaki Umezawa
- Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
- Research Unit for Development and Global Sustainability, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Ken Shirasu
- RIKEN Center for Sustainable Resource Science, 1-7-22 Suehirocho, Tsurumi, Yokohama, 230-0045, Japan
- Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo, 113-0033, Japan
| | - Satoko Yoshida
- Graduate School of Biological Science, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara, 630-0192, Japan
- Institute for Research Initiatives, Division for Research Strategy, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara, 630-0192, Japan
- RIKEN Center for Sustainable Resource Science, 1-7-22 Suehirocho, Tsurumi, Yokohama, 230-0045, Japan
| |
Collapse
|
134
|
Carlos C, Fan H, Currie CR. Substrate Shift Reveals Roles for Members of Bacterial Consortia in Degradation of Plant Cell Wall Polymers. Front Microbiol 2018; 9:364. [PMID: 29545786 PMCID: PMC5839234 DOI: 10.3389/fmicb.2018.00364] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 02/15/2018] [Indexed: 01/05/2023] Open
Abstract
Deconstructing the intricate matrix of cellulose, hemicellulose, and lignin poses a major challenge in biofuel production. In diverse environments in nature, some microbial communities, are able to overcome plant biomass recalcitrance. Identifying key degraders of each component of plant cell wall can help improve biological degradation of plant feedstock. Here, we sequenced the metagenome of lignocellulose-adapted microbial consortia sub-cultured on xylan and alkali lignin media. We observed a drastic shift on community composition after sub-culturing, independently of the original consortia. Proteobacteria relative abundance increased after growth in alkali lignin medium, while Bacteroidetes abundance increased after growth in xylan medium. At the genus level, Pseudomonas was more abundant in the communities growing on alkali lignin, Sphingobacterium in the communities growing on xylan and Cellulomonas abundance was the highest in the original microbial consortia. We also observed functional convergence of microbial communities after incubation in alkali lignin, due to an enrichment of genes involved in benzoate degradation and catechol ortho-cleavage pathways. Our results represent an important step toward the elucidation of key members of microbial communities on lignocellulose degradation and may aide the design of novel lignocellulolytic microbial consortia that are able to efficiently degrade plant cell wall polymers.
Collapse
Affiliation(s)
- Camila Carlos
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, United States.,U.S. Department of Energy, Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States
| | - Huan Fan
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, United States
| | - Cameron R Currie
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, United States.,U.S. Department of Energy, Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, United States
| |
Collapse
|
135
|
Hu Z, Zhang G, Muhammad A, Samad RA, Wang Y, Walton JD, He Y, Peng L, Wang L. Genetic loci simultaneously controlling lignin monomers and biomass digestibility of rice straw. Sci Rep 2018; 8:3636. [PMID: 29483532 PMCID: PMC5827516 DOI: 10.1038/s41598-018-21741-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 02/07/2018] [Indexed: 12/23/2022] Open
Abstract
Lignin content and composition are crucial factors affecting biomass digestibility. Exploring the genetic loci simultaneously affecting lignin-relevant traits and biomass digestibility is a precondition for lignin genetic manipulation towards energy crop breeding. In this study, a high-throughput platform was employed to assay the lignin content, lignin composition and biomass enzymatic digestibility of a rice recombinant inbred line population. Correlation analysis indicated that the absolute content of lignin monomers rather than lignin content had negative effects on biomass saccharification, whereas the relative content of p-hydroxyphenyl unit and the molar ratio of p-hydroxyphenyl unit to guaiacyl unit exhibited positive roles. Eight QTL clusters were identified and four of them affecting both lignin composition and biomass digestibility. The additive effects of clustered QTL revealed consistent relationships between lignin-relevant traits and biomass digestibility. Pyramiding rice lines containing the above four positive alleles for increasing biomass digestibility were selected and showed comparable lignin content, decreased syringyl or guaiacyl unit and increased molar percentage of p-hydroxyphenyl unit, the molar ratio of p-hydroxyphenyl unit to guaiacyl unit and sugar releases. More importantly, the lodging resistance and eating/cooking quality of pyramiding lines were not sacrificed, indicating the QTL information could be applied to select desirable energy rice lines.
Collapse
Affiliation(s)
- Zhen Hu
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan, China
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Guifen Zhang
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan, China
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Ali Muhammad
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan, China
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Rana Abdul Samad
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan, China
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Youmei Wang
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan, China
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Jonathan D Walton
- Department of Energy Plant Research Laboratory and DOE Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, 48824, USA
| | - Yuqing He
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Liangcai Peng
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan, China
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Lingqiang Wang
- Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan, China.
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China.
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China.
| |
Collapse
|
136
|
Głazowska S, Baldwin L, Mravec J, Bukh C, Hansen TH, Jensen MM, Fangel JU, Willats WGT, Glasius M, Felby C, Schjoerring JK. The impact of silicon on cell wall composition and enzymatic saccharification of Brachypodium distachyon. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:171. [PMID: 29951115 PMCID: PMC6009033 DOI: 10.1186/s13068-018-1166-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 06/08/2018] [Indexed: 05/20/2023]
Abstract
BACKGROUND Plants and in particular grasses benefit from a high uptake of silicon (Si) which improves their growth and productivity by alleviating adverse effects of biotic and abiotic stress. However, the silicon present in plant tissues may have a negative impact on the processing and degradation of lignocellulosic biomass. Solutions to reduce the silicon content either by biomass engineering or development of downstream separation methods are therefore targeted. Different cell wall components have been proposed to interact with the silica pool in plant shoots, but the understanding of the underlying processes is still limited. RESULTS In the present study, we have characterized silicon deposition and cell wall composition in Brachypodium distachyon wild-type and low-silicon 1 (Bdlsi1-1) mutant plants. Our analyses included different organs and plant developmental stages. In the mutant defective in silicon uptake, low silicon availability favoured deposition of this element in the amorphous form or bound to cell wall polymers rather than as silicified structures. Several alterations in non-cellulosic polysaccharides and lignin were recorded in the mutant plants, indicating differences in the types of linkages and in the three-dimensional organization of the cell wall network. Enzymatic saccharification assays showed that straw from mutant plants was marginally more degradable following a 190 °C hydrothermal pretreatment, while there were no differences without or after a 120 °C hydrothermal pretreatment. CONCLUSIONS We conclude that silicon affects the composition of plant cell walls, mostly by altering linkages of non-cellulosic polymers and lignin. The modifications of the cell wall network and the reduced silicon concentration appear to have little or no implications on biomass recalcitrance to enzymatic saccharification.
Collapse
Affiliation(s)
- Sylwia Głazowska
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Laetitia Baldwin
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Jozef Mravec
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Christian Bukh
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Thomas Hesselhøj Hansen
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Mads Mørk Jensen
- Department of Chemistry and INANO, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Jonatan U. Fangel
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - William G. T. Willats
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Marianne Glasius
- Department of Chemistry and INANO, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Claus Felby
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg, Denmark
| | - Jan Kofod Schjoerring
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| |
Collapse
|
137
|
Rydahl MG, Hansen AR, Kračun SK, Mravec J. Report on the Current Inventory of the Toolbox for Plant Cell Wall Analysis: Proteinaceous and Small Molecular Probes. FRONTIERS IN PLANT SCIENCE 2018; 9:581. [PMID: 29774041 PMCID: PMC5943554 DOI: 10.3389/fpls.2018.00581] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 04/13/2018] [Indexed: 05/18/2023]
Abstract
Plant cell walls are highly complex structures composed of diverse classes of polysaccharides, proteoglycans, and polyphenolics, which have numerous roles throughout the life of a plant. Significant research efforts aim to understand the biology of this cellular organelle and to facilitate cell-wall-based industrial applications. To accomplish this, researchers need to be provided with a variety of sensitive and specific detection methods for separate cell wall components, and their various molecular characteristics in vitro as well as in situ. Cell wall component-directed molecular detection probes (in short: cell wall probes, CWPs) are an essential asset to the plant glycobiology toolbox. To date, a relatively large set of CWPs has been produced-mainly consisting of monoclonal antibodies, carbohydrate-binding modules, synthetic antibodies produced by phage display, and small molecular probes. In this review, we summarize the state-of-the-art knowledge about these CWPs; their classification and their advantages and disadvantages in different applications. In particular, we elaborate on the recent advances in non-conventional approaches to the generation of novel CWPs, and identify the remaining gaps in terms of target recognition. This report also highlights the addition of new "compartments" to the probing toolbox, which is filled with novel chemical biology tools, such as metabolic labeling reagents and oligosaccharide conjugates. In the end, we also forecast future developments in this dynamic field.
Collapse
Affiliation(s)
- Maja G. Rydahl
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Aleksander R. Hansen
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Stjepan K. Kračun
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
- GlycoSpot IVS, Frederiksberg, Denmark
| | - Jozef Mravec
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
- *Correspondence: Jozef Mravec
| |
Collapse
|
138
|
Herbaut M, Zoghlami A, Paës G. Dynamical assessment of fluorescent probes mobility in poplar cell walls reveals nanopores govern saccharification. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:271. [PMID: 30305844 PMCID: PMC6169017 DOI: 10.1186/s13068-018-1267-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 09/20/2018] [Indexed: 05/15/2023]
Abstract
BACKGROUND Improving lignocellulolytic enzymes' diffusion and accessibility to their substrate in the plant cell walls is recognised as a critical issue for optimising saccharification. Although many chemical features are considered as detrimental to saccharification, enzymes' dynamics within the cell walls remains poorly explored and understood. To address this issue, poplar fragments were submitted to hot water and ionic liquid pretreatments selected for their contrasted effects on both the structure and composition of lignocellulose. In addition to chemical composition and porosity analyses, the diffusion of polyethylene glycol probes of different sizes was measured at three different time points during the saccharification. RESULTS Probes' diffusion was mainly affected by probes size and pretreatments but only slightly by saccharification time. This means that, despite the removal of polysaccharides during saccharification, diffusion of probes was not improved since they became hindered by changes in lignin conformation, whose relative amount increased over time. Porosity measurements showed that probes' diffusion was highly correlated with the amount of pores having a diameter at least five times the size of the probes. Testing the relationship with saccharification demonstrated that accessibility of 1.3-1.7-nm radius probes measured by FRAP on non-hydrolysed samples was highly correlated with poplar digestibility together with the measurement of initial porosity on the range 5-20 nm. CONCLUSION Mobility measurements performed before hydrolysis can serve to explain and even predict saccharification with accuracy. The discrepancy observed between probes' size and pores' diameters to explain accessibility is likely due to biomass features such as lignin content and composition that prevent probes' diffusion through non-specific interactions probably leading to pores' entanglements.
Collapse
Affiliation(s)
- Mickaël Herbaut
- Fractionation of AgroResources and Environment (FARE) Laboratory, INRA, University of Reims Champagne-Ardenne, Reims, France
| | - Aya Zoghlami
- Fractionation of AgroResources and Environment (FARE) Laboratory, INRA, University of Reims Champagne-Ardenne, Reims, France
| | - Gabriel Paës
- Fractionation of AgroResources and Environment (FARE) Laboratory, INRA, University of Reims Champagne-Ardenne, Reims, France
| |
Collapse
|
139
|
Djajadi DT, Jensen MM, Oliveira M, Jensen A, Thygesen LG, Pinelo M, Glasius M, Jørgensen H, Meyer AS. Lignin from hydrothermally pretreated grass biomass retards enzymatic cellulose degradation by acting as a physical barrier rather than by inducing nonproductive adsorption of enzymes. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:85. [PMID: 29619081 PMCID: PMC5880018 DOI: 10.1186/s13068-018-1085-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Accepted: 03/17/2018] [Indexed: 05/03/2023]
Abstract
BACKGROUND Lignin is known to hinder efficient enzymatic conversion of lignocellulose in biorefining processes. In particular, nonproductive adsorption of cellulases onto lignin is considered a key mechanism to explain how lignin retards enzymatic cellulose conversion in extended reactions. RESULTS Lignin-rich residues (LRRs) were prepared via extensive enzymatic cellulose degradation of corn stover (Zea mays subsp. mays L.), Miscanthus × giganteus stalks (MS) and wheat straw (Triticum aestivum L.) (WS) samples that each had been hydrothermally pretreated at three severity factors (log R0) of 3.65, 3.83 and 3.97. The LRRs had different residual carbohydrate levels-the highest in MS; the lowest in WS. The residual carbohydrate was not traceable at the surface of the LRRs particles by ATR-FTIR analysis. The chemical properties of the lignin in the LRRs varied across the three types of biomass, but monolignols composition was not affected by the severity factor. When pure cellulose was added to a mixture of LRRs and a commercial cellulolytic enzyme preparation, the rate and extent of glucose release were unaffected by the presence of LRRs regardless of biomass type and severity factor, despite adsorption of the enzymes to the LRRs. Since the surface of the LRRs particles were covered by lignin, the data suggest that the retardation of enzymatic cellulose degradation during extended reaction on lignocellulosic substrates is due to physical blockage of the access of enzymes to the cellulose caused by the gradual accumulation of lignin at the surface of the biomass particles rather than by nonproductive enzyme adsorption. CONCLUSIONS The study suggests that lignin from hydrothermally pretreated grass biomass retards enzymatic cellulose degradation by acting as a physical barrier blocking the access of enzymes to cellulose rather than by inducing retardation through nonproductive adsorption of enzymes.
Collapse
Affiliation(s)
- Demi T. Djajadi
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads Building 229, 2800 Kongens Lyngby, Denmark
| | - Mads M. Jensen
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Marlene Oliveira
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads Building 229, 2800 Kongens Lyngby, Denmark
| | - Anders Jensen
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg C, Denmark
| | - Lisbeth G. Thygesen
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg C, Denmark
| | - Manuel Pinelo
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads Building 229, 2800 Kongens Lyngby, Denmark
| | - Marianne Glasius
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Henning Jørgensen
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads Building 229, 2800 Kongens Lyngby, Denmark
- Present Address: Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Anne S. Meyer
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads Building 229, 2800 Kongens Lyngby, Denmark
| |
Collapse
|
140
|
Herbaut M, Zoghlami A, Habrant A, Falourd X, Foucat L, Chabbert B, Paës G. Multimodal analysis of pretreated biomass species highlights generic markers of lignocellulose recalcitrance. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:52. [PMID: 29492107 PMCID: PMC5828075 DOI: 10.1186/s13068-018-1053-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 02/14/2018] [Indexed: 05/21/2023]
Abstract
BACKGROUND Biomass recalcitrance to enzymatic hydrolysis has been assigned to several structural and chemical factors. However, their relative importance remains challenging to evaluate. Three representative biomass species (wheat straw, poplar and miscanthus) were submitted to four standard pretreatments (dilute acid, hot water, ionic liquid and sodium chlorite) in order to generate a set of contrasted samples. A large array of techniques, including wet chemistry analysis, porosity measurements using NMR spectroscopy, electron and fluorescence microscopy, were used in order to determine possible generic factors of biomass recalcitrance. RESULTS The pretreatment conditions selected allowed obtaining samples displaying different susceptibility to enzymatic hydrolysis (from 3 up to 98% of the initial glucose content released after 96 h of saccharification). Generic correlation coefficients were calculated between the measured chemical and structural features and the final saccharification rates. Increases in porosity displayed overall strong positive correlations with saccharification efficiency, but different porosity ranges were concerned depending on the considered biomass. Lignin-related factors displayed highly negative coefficients for all biomasses. Lignin content, which is likely involved in the correlations observed for porosity, was less detrimental to enzymatic hydrolysis than lignin composition. Lignin influence was highlighted by the strong negative correlation with fluorescence intensity which mainly originates from monolignols in mature tissues. CONCLUSIONS Our results provide a better understanding of the factors responsible for biomass recalcitrance that can reasonably be considered as generic. The correlations with specific porosity ranges are biomass species-dependent, meaning that enzymes cocktails with fitted enzyme size are likely to be needed to optimise saccharification depending on the biomass origin. Lignin composition, which probably influences its structure, is the most important parameter to overcome to enhance enzymes access to the polysaccharides. Accordingly, fluorescence intensity was found to be a rapid and simple method to assess recalcitrance after pretreatment.
Collapse
Affiliation(s)
- Mickaël Herbaut
- Fractionation of AgroResources and Environment (FARE) Laboratory, INRA, University of Reims Champagne-Ardenne, Reims, France
| | - Aya Zoghlami
- Fractionation of AgroResources and Environment (FARE) Laboratory, INRA, University of Reims Champagne-Ardenne, Reims, France
| | - Anouck Habrant
- Fractionation of AgroResources and Environment (FARE) Laboratory, INRA, University of Reims Champagne-Ardenne, Reims, France
| | - Xavier Falourd
- Biopolymères Interactions Assemblages (BIA) Laboratory, INRA, Nantes, France
| | - Loïc Foucat
- Biopolymères Interactions Assemblages (BIA) Laboratory, INRA, Nantes, France
| | - Brigitte Chabbert
- Fractionation of AgroResources and Environment (FARE) Laboratory, INRA, University of Reims Champagne-Ardenne, Reims, France
| | - Gabriel Paës
- Fractionation of AgroResources and Environment (FARE) Laboratory, INRA, University of Reims Champagne-Ardenne, Reims, France
| |
Collapse
|
141
|
Gilna P, Lynd LR, Mohnen D, Davis MF, Davison BH. Progress in understanding and overcoming biomass recalcitrance: a BioEnergy Science Center (BESC) perspective. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:285. [PMID: 29213324 PMCID: PMC5707806 DOI: 10.1186/s13068-017-0971-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 11/15/2017] [Indexed: 06/07/2023]
Abstract
The DOE BioEnergy Science Center has operated as a virtual center with multiple partners for a decade targeting overcoming biomass recalcitrance. BESC has redefined biomass recalcitrance from an observable phenotype to a better understood and manipulatable fundamental and operational property. These manipulations are the result of deeper biological understanding and can be combined with other advanced biotechnology improvements in biomass conversion to improve bioenergy processes and markets. This article provides an overview of key accomplishments in overcoming recalcitrance via better plants, better microbes, and better tools and combinations. A perspective on the aspects of successful center operation is presented.
Collapse
Affiliation(s)
- Paul Gilna
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Biosciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Bldg. 1505, Rm. 100A, Oak Ridge, TN 37831-6037 USA
| | - Lee R. Lynd
- Biosciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Bldg. 1505, Rm. 100A, Oak Ridge, TN 37831-6037 USA
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755 USA
| | - Debra Mohnen
- Biosciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Bldg. 1505, Rm. 100A, Oak Ridge, TN 37831-6037 USA
- Complex Carbohydrate Research Center and Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602 USA
| | - Mark F. Davis
- Biosciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Bldg. 1505, Rm. 100A, Oak Ridge, TN 37831-6037 USA
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Brian H. Davison
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Biosciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Bldg. 1505, Rm. 100A, Oak Ridge, TN 37831-6037 USA
| |
Collapse
|
142
|
Li X, Zheng Y. Lignin-enzyme interaction: Mechanism, mitigation approach, modeling, and research prospects. Biotechnol Adv 2017; 35:466-489. [DOI: 10.1016/j.biotechadv.2017.03.010] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 02/19/2017] [Accepted: 03/23/2017] [Indexed: 01/23/2023]
|
143
|
Weigand L, Mostame S, Brandt-Talbot A, Welton T, Hallett JP. Effect of pretreatment severity on the cellulose and lignin isolated from Salix using ionoSolv pretreatment. Faraday Discuss 2017; 202:331-349. [DOI: 10.1039/c7fd00059f] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The ionoSolv pretreatment is a new technique employing protic low-cost ionic liquids and has previously been applied to successfully fractionate switchgrass and the grass Miscanthus giganteus. This study investigates the effect of using the protic ionic liquid solution [N2220][HSO4]80% with two different acid/base ratios (1.02 and 0.98) at 120, 150 and 170 °C on the pretreatment outcome of the hardwood willow. The ionic liquid solution was able to fractionate willow, and a pulp and lignin fraction were recovered after treatment. The pretreatment success was determined via enzymatic hydrolysis of the pulp, which showed that the ionoSolv pretreatment was able to increase enzymatic glucose yields compared to untreated willow biomass. The pretreatment produced a cellulose-rich pulp with high hemicellulose and lignin removal. The pulp composition and glucose yield after saccharification were greatly influenced by the acidity of the ionic liquid solution, temperature and pretreatment time. The extracted lignin was analysed via 2-D HSQC NMR spectroscopy and GPC to investigate the changes in the lignin structure induced by the pretreatment severity. The lignin structure (in terms of inter-unit linkages and S/G ratio) and molecular weight varied significantly depending on the pretreatment conditions used.
Collapse
Affiliation(s)
- Lisa Weigand
- Department of Chemical Engineering
- Imperial College London
- SW7 2AZ London
- UK
| | - Shahrokh Mostame
- Department of Chemical Engineering
- Imperial College London
- SW7 2AZ London
- UK
| | | | - Tom Welton
- Department of Chemistry
- Imperial College London
- London
- UK
| | - Jason P. Hallett
- Department of Chemical Engineering
- Imperial College London
- SW7 2AZ London
- UK
| |
Collapse
|
144
|
Li M, Cao S, Meng X, Studer M, Wyman CE, Ragauskas AJ, Pu Y. The effect of liquid hot water pretreatment on the chemical-structural alteration and the reduced recalcitrance in poplar. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:237. [PMID: 29213308 PMCID: PMC5707831 DOI: 10.1186/s13068-017-0926-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 10/06/2017] [Indexed: 05/12/2023]
Abstract
BACKGROUND Hydrothermal pretreatment using liquid hot water (LHW) is capable of substantially reducing the cell wall recalcitrance of lignocellulosic biomass. It enhances the saccharification of polysaccharides, particularly cellulose, into glucose with relatively low capital required. Due to the close association with biomass recalcitrance, the structural change of the components of lignocellulosic materials during the pretreatment is crucial to understand pretreatment chemistry and advance the bio-economy. Although the LHW pretreatment has been extensively applied and studied, the molecular structural alteration during pretreatment and its significance to reduced recalcitrance have not been well understood. RESULTS We investigated the effects of LHW pretreatment with different severity factors (log R0) on the structural changes of fast-grown poplar (Populus trichocarpa). With the severity factor ranging from 3.6 to 4.2, LHW pretreatment resulted in a substantial xylan solubilization by 50-77% (w/w, dry matter). The molecular weights of the remained hemicellulose in pretreated solids also have been significantly reduced by 63-75% corresponding to LHW severity factor from 3.6 to 4.2. In addition, LHW had a considerable impact on the cellulose structure. The cellulose crystallinity increased 6-9%, whereas its degree of polymerization decreased 35-65% after pretreatment. We found that the pretreatment severity had an empirical linear correlation with the xylan solubilization (R2 = 0.98, r = + 0.99), hemicellulose molecular weight reduction (R2 = 0.97, r = - 0.96 and R2 = 0.93, r = - 0.98 for number-average and weight-average degree of polymerization, respectively), and cellulose crystallinity index increase (R2 = 0.98, r = + 0.99). The LHW pretreatment also resulted in small changes in lignin structure such as decrease of β-O-4' ether linkages and removal of cinnamyl alcohol end group and acetyl group, while the S/G ratio of lignin in LHW pretreated poplar residue remained no significant change compared with the untreated poplar. CONCLUSIONS This study revealed that the solubilization of xylan, the reduction of hemicellulose molecular weights and cellulose degree of polymerization, and the cleavage of alkyl-aryl ether bonds in lignin resulted from LHW pretreatment are critical factors associated with reduced cell wall recalcitrance. The chemical-structural changes of the three major components, cellulose, lignin, and hemicellulose, during LHW pretreatment provide useful and fundamental information of factors governing feedstock recalcitrance during hydrothermal pretreatment.
Collapse
Affiliation(s)
- Mi Li
- BioEnergy Science Center (BESC), Oak Ridge, USA
- Biosciences Division, ORNL, Oak Ridge, TN USA
| | - Shilin Cao
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA USA
- Present Address: College of Material Engineering, Fujian Agriculture and Forestry University, Fuzhou, People’s Republic of China
| | - Xianzhi Meng
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN USA
| | - Michael Studer
- BioEnergy Science Center (BESC), Oak Ridge, USA
- College of Engineering - Center for Environmental Research and Technology (CE-CERT), Bourns College of Engineering, University of California, Riverside, CA USA
- Present Address: Laboratory for Bioenergy and Biochemicals, School of Agricultural, Forest and Food Sciences, Bern University of Applied Sciences, Bern, Switzerland
| | - Charles E. Wyman
- BioEnergy Science Center (BESC), Oak Ridge, USA
- College of Engineering - Center for Environmental Research and Technology (CE-CERT), Bourns College of Engineering, University of California, Riverside, CA USA
| | - Arthur J. Ragauskas
- BioEnergy Science Center (BESC), Oak Ridge, USA
- Biosciences Division, ORNL, Oak Ridge, TN USA
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN USA
- Department of Forestry, Wildlife, and Fisheries, Center for Renewable Carbon, University of Tennessee Institute of Agriculture, Knoxville, TN USA
| | - Yunqiao Pu
- BioEnergy Science Center (BESC), Oak Ridge, USA
- Biosciences Division, ORNL, Oak Ridge, TN USA
| |
Collapse
|