A review of whole cell wall NMR by the direct-dissolution of biomass
Abstract
To fully realize the potential of lignocellulosic biomass as a renewable resource for the production of fuels, chemicals, and materials, an improved understanding of the chemical and molecular structures within biomass and how those structures are formed during biosynthesis and transformed during (thermochemical and biological) conversion must be developed. This effort will require analytical techniques which are not only in-depth, rapid, and cost-effective, but also leave native cell wall features intact. Whole plant cell wall nuclear magnetic resonance (NMR) analysis facilitates unparalleled structural characterization of lignocellulosic biomass without causing (or with minimal) structural modification. The objective of this review is to summarize research pertaining to solution- or gel-state whole plant cell wall NMR analysis of biomass, demonstrating the capability of NMR to delineate the structural features and transformations of biomass. In particular, this review will focus on the application of a two-dimensional solution-state NMR technique and perdeuterated ionic liquid based organic electrolyte solvents for the direct dissolution and analysis of biomass. Furthermore, we believe this type of analysis will be critical to advancing biofuel research, improving bioprocessing methodology, and enhancing plant bioengineering efforts.
- Authors:
-
- Dept. of Energy (DOE) Bioenergy Science Center (BESC) (United States); Washington Univ., St. Louis, MO (United States)
- Georgia Inst. of Technology, Atlanta, GA (United States)
- Washington Univ., St. Louis, MO (United States)
- Dept. of Energy (DOE) Bioenergy Science Center (BESC) (United States); Georgia Inst. of Technology, Atlanta, GA (United States); Univ. of Tennessee, Knoxville, TN (United States)
- Publication Date:
- Research Org.:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). BioEnergy Science Center (BESC)
- Sponsoring Org.:
- USDOE Office of Science (SC)
- OSTI Identifier:
- 1266000
- Alternate Identifier(s):
- OSTI ID: 1327727
- Grant/Contract Number:
- AC05-00OR22725
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Green Chemistry
- Additional Journal Information:
- Journal Volume: 18; Journal Issue: 3; Journal ID: ISSN 1463-9262
- Publisher:
- Royal Society of Chemistry
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 09 BIOMASS FUELS
Citation Formats
Foston, Marcus B., Samuel, Reichel, He, Jian, and Ragauskas, Arthur J. A review of whole cell wall NMR by the direct-dissolution of biomass. United States: N. p., 2016.
Web. doi:10.1039/C5GC02828K.
Foston, Marcus B., Samuel, Reichel, He, Jian, & Ragauskas, Arthur J. A review of whole cell wall NMR by the direct-dissolution of biomass. United States. https://doi.org/10.1039/C5GC02828K
Foston, Marcus B., Samuel, Reichel, He, Jian, and Ragauskas, Arthur J. Tue .
"A review of whole cell wall NMR by the direct-dissolution of biomass". United States. https://doi.org/10.1039/C5GC02828K. https://www.osti.gov/servlets/purl/1266000.
@article{osti_1266000,
title = {A review of whole cell wall NMR by the direct-dissolution of biomass},
author = {Foston, Marcus B. and Samuel, Reichel and He, Jian and Ragauskas, Arthur J.},
abstractNote = {To fully realize the potential of lignocellulosic biomass as a renewable resource for the production of fuels, chemicals, and materials, an improved understanding of the chemical and molecular structures within biomass and how those structures are formed during biosynthesis and transformed during (thermochemical and biological) conversion must be developed. This effort will require analytical techniques which are not only in-depth, rapid, and cost-effective, but also leave native cell wall features intact. Whole plant cell wall nuclear magnetic resonance (NMR) analysis facilitates unparalleled structural characterization of lignocellulosic biomass without causing (or with minimal) structural modification. The objective of this review is to summarize research pertaining to solution- or gel-state whole plant cell wall NMR analysis of biomass, demonstrating the capability of NMR to delineate the structural features and transformations of biomass. In particular, this review will focus on the application of a two-dimensional solution-state NMR technique and perdeuterated ionic liquid based organic electrolyte solvents for the direct dissolution and analysis of biomass. Furthermore, we believe this type of analysis will be critical to advancing biofuel research, improving bioprocessing methodology, and enhancing plant bioengineering efforts.},
doi = {10.1039/C5GC02828K},
journal = {Green Chemistry},
number = 3,
volume = 18,
place = {United States},
year = {Tue Jan 19 00:00:00 EST 2016},
month = {Tue Jan 19 00:00:00 EST 2016}
}
Web of Science
Works referenced in this record:
The Path Forward for Biofuels and Biomaterials
journal, January 2006
- Ragauskas, Arthur J.; Williams, Charlotte K.; Davison, Brian H.
- Science, Vol. 311, Issue 5760, p. 484-489
Ester linkages between lignin and glucuronoxylan in a lignin-carbohydrate complex from beech (Fagus crenata) wood
journal, January 1988
- Takahashi, N.; Koshijima, T.
- Wood Science and Technology, Vol. 22, Issue 3
Biomass Recalcitrance: Engineering Plants and Enzymes for Biofuels Production
journal, February 2007
- Himmel, M. E.; Ding, S.-Y.; Johnson, D. K.
- Science, Vol. 315, Issue 5813, p. 804-807
Selective, Nickel-Catalyzed Hydrogenolysis of Aryl Ethers
journal, April 2011
- Sergeev, A. G.; Hartwig, J. F.
- Science, Vol. 332, Issue 6028, p. 439-443
Lignin-based carbon fibers for composite fiber applications
journal, January 2002
- Kadla, J.F; Kubo, S; Venditti, R.A
- Carbon, Vol. 40, Issue 15, p. 2913-2920
Bio-fuels from thermochemical conversion of renewable resources: A review
journal, February 2008
- Goyal, H. B.; Seal, Diptendu; Saxena, R. C.
- Renewable and Sustainable Energy Reviews, Vol. 12, Issue 2
Biomass Characterization: Recent Progress in Understanding Biomass Recalcitrance
journal, August 2012
- Foston, Marcus; Ragauskas, Arthur J.
- Industrial Biotechnology, Vol. 8, Issue 4
Methods in Lignin Chemistry
book, January 1992
- Timell, T. E.; Lin, Stephen Y.; Dence, Carlton W.
- Springer Series in Wood Science
Elucidation of Lignin Structure through Degradative Methods: Comparison of Modified DFRC and Thioacidolysis
journal, June 2003
- Holtman, Kevin M.; Chang, Hou-Min; Jameel, Hasan
- Journal of Agricultural and Food Chemistry, Vol. 51, Issue 12
Recent Advances in Characterization of Lignin Polymer by Solution-State Nuclear Magnetic Resonance (NMR) Methodology
journal, January 2013
- Wen, Jia-Long; Sun, Shao-Long; Xue, Bai-Liang
- Materials, Vol. 6, Issue 1
Hydrothermal Carbon from Biomass: Structural Differences between Hydrothermal and Pyrolyzed Carbons via 13 C Solid State NMR
journal, December 2011
- Falco, Camillo; Perez Caballero, Fernando; Babonneau, Florence
- Langmuir, Vol. 27, Issue 23
Solution-State NMR of Lignocellulosic Biomass
journal, June 2011
- Lu, Fachuang; Ralph, John
- Journal of Biobased Materials and Bioenergy, Vol. 5, Issue 2
Solvents applied in the field of cellulose chemistry: a mini review
journal, June 2005
- Heinze, Thomas; Koschella, Andreas
- Polímeros, Vol. 15, Issue 2
Dissolution of Cellose with Ionic Liquids
journal, May 2002
- Swatloski, Richard P.; Spear, Scott K.; Holbrey, John D.
- Journal of the American Chemical Society, Vol. 124, Issue 18, p. 4974-4975
Ionic Liquids and Their Interaction with Cellulose
journal, December 2009
- Pinkert, André; Marsh, Kenneth N.; Pang, Shusheng
- Chemical Reviews, Vol. 109, Issue 12
Synthesis of Transportation Fuels from Biomass: Chemistry, Catalysts, and Engineering
journal, September 2006
- Huber, George W.; Iborra, Sara; Corma, Avelino
- Chemical Reviews, Vol. 106, Issue 9, p. 4044-4098
Can ionic liquids dissolve wood? Processing and analysis of lignocellulosic materials with 1-n-butyl-3-methylimidazolium chloride
journal, January 2007
- Fort, Diego A.; Remsing, Richard C.; Swatloski, Richard P.
- Green Chemistry, Vol. 9, Issue 1, p. 63-69
Ionic Liquid as a Green Solvent for Lignin
journal, April 2007
- Pu, Yunqiao; Jiang, Nan; Ragauskas, Arthur J.
- Journal of Wood Chemistry and Technology, Vol. 27, Issue 1
Dissolution of Wood in Ionic Liquids
journal, October 2007
- Kilpeläinen, Ilkka; Xie, Haibo; King, Alistair
- Journal of Agricultural and Food Chemistry, Vol. 55, Issue 22
Lignin solubility in non-imidazolium ionic liquids: Lignin solubility in non-imidazolium ILs
journal, August 2014
- Glas, Daan; Van Doorslaer, Charlie; Depuydt, Daphne
- Journal of Chemical Technology & Biotechnology, Vol. 90, Issue 10
On the solubility of wood in non-derivatising ionic liquids
journal, January 2013
- Kyllönen, Lasse; Parviainen, Arno; Deb, Somdatta
- Green Chemistry, Vol. 15, Issue 9
Perdeuterated pyridinium molten salt (ionic liquid) for direct dissolution and NMR analysis of plant cell walls
journal, January 2009
- Jiang, Nan; Pu, Yunqiao; Samuel, Reichel
- Green Chemistry, Vol. 11, Issue 11
Rapid Determination of Lignin Content via Direct Dissolution and 1H NMR Analysis of Plant Cell Walls
journal, September 2010
- Jiang, Nan; Pu, Yunqiao; Ragauskas, Arthur J.
- ChemSusChem, Vol. 3, Issue 11
Comparing the Recalcitrance of Eucalyptus, Pine, and Switchgrass Using Ionic Liquid and Dilute Acid Pretreatments
journal, May 2012
- Li, Chenlin; Sun, Lan; Simmons, Blake A.
- BioEnergy Research, Vol. 6, Issue 1
Topochemical and morphological characterization of wood cell wall treated with the ionic liquid, 1-ethylpyridinium bromide
journal, January 2015
- Kanbayashi, Toru; Miyafuji, Hisashi
- Planta, Vol. 242, Issue 3
Solution-State 2D NMR Spectroscopy of Plant Cell Walls Enabled by a Dimethylsulfoxide- d 6 /1-Ethyl-3-methylimidazolium Acetate Solvent
journal, March 2013
- Cheng, Kun; Sorek, Hagit; Zimmermann, Herbert
- Analytical Chemistry, Vol. 85, Issue 6
Non-degradative dissolution and acetylation of ball-milled plant cell walls: high-resolution solution-state NMR
journal, August 2003
- Lu, Fachuang; Ralph, John
- The Plant Journal, Vol. 35, Issue 4
Dissolution and Gelation of Cellulose in TBAF/DMSO Solutions: The Roles of Fluoride Ions and Water
journal, September 2009
- Östlund, Åsa; Lundberg, Dan; Nordstierna, Lars
- Biomacromolecules, Vol. 10, Issue 9
Short Note: Rapid NMR Method for Determination of Threo: Erythro Ratios in Lignin Model Compounds
journal, January 1985
- Ralph, John; Wilkins, Alistair L.
- Holzforschung, Vol. 39, Issue 6, p. 341-344
Evidence for Increased Steric Compression in Anti Compared to Syn Lignin Model Quinone Methides
journal, March 1990
- Ede, Richard M.; Main, Lyndsay; Ralph, John
- Journal of Wood Chemistry and Technology, Vol. 10, Issue 1
Lignin–feruloyl ester cross-links in grasses. Part 2. Model compound syntheses
journal, January 1992
- Ralph, John; Helm, Richard F.; Quideau, Stéphane
- J. Chem. Soc., Perkin Trans. 1, Issue 21
1H NMR of acetylated β-ether/β-ether lignin model trimers
journal, April 1993
- Ralph, John
- Magnetic Resonance in Chemistry, Vol. 31, Issue 4
Preparation of synthetic lignins with superior NMR characteristics via isotopically labeled monolignols
journal, January 1998
- Ralph, John; Zhang, Yingsheng; M. Ede, Richard
- Journal of the Chemical Society, Perkin Transactions 1, Issue 16
Assignment of 2D TOCSY Spectra of Lignins: the Role of Lignin Model Compounds
journal, April 1996
- Ede, Richard M.; Ralph, John
- Magnetic Resonance in Chemistry, Vol. 34, Issue 4
NMR Studies on the Occurrence of Spirodienone Structures in Lignins
journal, April 2006
- Zhang, Liming; Gellerstedt, Göran; Ralph, John
- Journal of Wood Chemistry and Technology, Vol. 26, Issue 1
Lignin-hydroxycinnamyl model compounds related to forage cell wall structure. 1. Ether-linked structures
journal, November 1992
- Helm, Richard F.; Ralph, John.
- Journal of Agricultural and Food Chemistry, Vol. 40, Issue 11
Lignin-hydroxycinnamoyl model compounds related to forage cell wall structure. 2. Ester-linked structures
journal, April 1993
- Helm, Richard F.; Ralph, John.
- Journal of Agricultural and Food Chemistry, Vol. 41, Issue 4
NMR Studies of Lignins. 1. Signals Due to Protons in Formyl Groups.
journal, January 1977
- Lundquist, Knut; Olsson, Tomas; Boll, Per M.
- Acta Chemica Scandinavica, Vol. 31b
NMR Studies of Lignins. 3. 1H NMR Spectroscopic Data for Lignin Model Compounds.
journal, January 1979
- Lundquist, Knut; Mannervik, Bengt; Nordfors, Kerstin
- Acta Chemica Scandinavica, Vol. 33b
NMR Studies of Lignins. 5. Investigation of Non-derivatized Spruce and Birch Lignin by 1H NMR Spectroscopy.
journal, January 1981
- Lundquist, Knut; Parker, Vernon D.; Rømming, C.
- Acta Chemica Scandinavica, Vol. 35b
On the Occurrence of β-1 Structures in Lignins
journal, January 1987
- Lundquist, Knut
- Journal of Wood Chemistry and Technology, Vol. 7, Issue 2
Quantitative 13C NMR Analysis of Kraft Lignins.
journal, January 1987
- Gellerstedt, Göran; Robert, Danielle; Parker, Vernon D.
- Acta Chemica Scandinavica, Vol. 41b
Identification of Lignin and Polysaccharide Modifications in Populus Wood by Chemometric Analysis of 2D NMR Spectra from Dissolved Cell Walls
journal, September 2009
- Hedenström, Mattias; Wiklund-Lindström, Susanne; Öman, Tommy
- Molecular Plant, Vol. 2, Issue 5
Solution-state 2D NMR of Ball-milled Plant Cell Wall Gels in DMSO-d 6
journal, March 2008
- Kim, Hoon; Ralph, John; Akiyama, Takuya
- BioEnergy Research, Vol. 1, Issue 1, p. 56-66
Unveiling the Structural Heterogeneity of Bamboo Lignin by In Situ HSQC NMR Technique
journal, June 2012
- Wen, Jia-Long; Xue, Bai-Liang; Xu, Feng
- BioEnergy Research, Vol. 5, Issue 4
Heteronuclear Single-Quantum Coherence Nuclear Magnetic Resonance (HSQC NMR) Characterization of Acetylated Fir (Abies sachallnensis MAST) Wood Regenerated from Ionic Liquid
journal, May 2011
- Qu, Chen; Kishimoto, Takao; Kishino, Masanori
- Journal of Agricultural and Food Chemistry, Vol. 59, Issue 10
Dissolution and acetylation of ball-milled birch (Betula platyphylla) and bamboo (Phyllostachys nigra) in the ionic liquid [Bmim]Cl for HSQC NMR analysis
journal, July 2012
- Qu, Chen; Kishimoto, Takao; Ogita, Shinjiro
- Holzforschung, Vol. 66, Issue 5
Characterization of nonderivatized plant cell walls using high-resolution solution-state NMR spectroscopy
journal, June 2008
- Yelle, Daniel J.; Ralph, John; Frihart, Charles R.
- Magnetic Resonance in Chemistry, Vol. 46, Issue 6
Whole plant cell wall characterization using solution-state 2D NMR
journal, August 2012
- Mansfield, Shawn D.; Kim, Hoon; Lu, Fachuang
- Nature Protocols, Vol. 7, Issue 9
Solution-state 2D NMR of ball-milled plant cell wall gels in DMSO-d6/pyridine-d5
journal, January 2010
- Kim, Hoon; Ralph, John
- Org. Biomol. Chem., Vol. 8, Issue 3
A gel-state 2D-NMR method for plant cell wall profiling and analysis: a model study with the amorphous cellulose and xylan from ball-milled cotton linters
journal, January 2014
- Kim, Hoon; Ralph, John
- RSC Adv., Vol. 4, Issue 15
A polymer of caffeyl alcohol in plant seeds
journal, January 2012
- Chen, F.; Tobimatsu, Y.; Havkin-Frenkel, D.
- Proceedings of the National Academy of Sciences, Vol. 109, Issue 5
Changes in the Structure of the Cellulose Fiber Wall during Dilute Acid Pretreatment in Populus Studied by 1 H and 2 H NMR
journal, October 2010
- Foston, Marcus; Ragauskas, Arthur J.
- Energy & Fuels, Vol. 24, Issue 10
A comprehensive discussion of HSQC and HMQC pulse sequences
journal, January 2004
- Mandal, Pravat K.; Majumdar, Ananya
- Concepts in Magnetic Resonance, Vol. 20A, Issue 1
Quantitative 2D HSQC NMR determination of polymer structures by selecting suitable internal standard references
journal, January 2007
- Zhang, Liming; Gellerstedt, Göran
- Magnetic Resonance in Chemistry, Vol. 45, Issue 1
Quantitative 2D HSQC (Q-HSQC) via Suppression of J -Dependence of Polarization Transfer in NMR Spectroscopy: Application to Wood Lignin
journal, April 2003
- Heikkinen, Sami; Toikka, Merja M.; Karhunen, Pirkko T.
- Journal of the American Chemical Society, Vol. 125, Issue 14
Elucidation of Lignin Structure by Quantitative 2D NMR
journal, June 2011
- Sette, Marco; Wechselberger, Rainer; Crestini, Claudia
- Chemistry - A European Journal, Vol. 17, Issue 34
HSQC (heteronuclear single quantum coherence) 13C–1H correlation spectra of whole biomass in perdeuterated pyridinium chloride–DMSO system: An effective tool for evaluating pretreatment
journal, September 2011
- Samuel, Reichel; Foston, Marcus; Jaing, Nan
- Fuel, Vol. 90, Issue 9
Structural changes in switchgrass lignin and hemicelluloses during pretreatments by NMR analysis
journal, November 2011
- Samuel, Reichel; Foston, Marcus; Jiang, Nan
- Polymer Degradation and Stability, Vol. 96, Issue 11
High-resolution 13C NMR studies of cellulose and cellulose oligomers in ionic liquid solutions
journal, January 2005
- Moulthrop, Jason S.; Swatloski, Richard P.; Moyna, Guillermo
- Chemical Communications, Issue 12
1H NMR analysis of cellulose dissolved in non-deuterated ionic liquids
journal, May 2014
- Kuroda, Kosuke; Kunimura, Haruhito; Fukaya, Yukinobu
- Cellulose, Vol. 21, Issue 4
1 H NMR Evaluation of Polar and Nondeuterated Ionic Liquids for Selective Extraction of Cellulose and Xylan from Wheat Bran
journal, July 2014
- Kuroda, Kosuke; Kunimura, Haruhito; Fukaya, Yukinobu
- ACS Sustainable Chemistry & Engineering, Vol. 2, Issue 9
Chemical, ultrastructural and supramolecular analysis of tension wood in Populus tremula x alba as a model substrate for reduced recalcitrance
journal, January 2011
- Foston, Marcus; Hubbell, Christopher A.; Samuel, Reichel
- Energy & Environmental Science, Vol. 4, Issue 12
Structural characterization of alkaline hydrogen peroxide pretreated grasses exhibiting diverse lignin phenotypes
journal, January 2012
- Li, Muyang; Foster, Cliff; Kelkar, Shantanu
- Biotechnology for Biofuels, Vol. 5, Issue 1
Deuterium incorporation in biomass cell wall components by NMR analysis
journal, January 2012
- Foston, Marcus B.; McGaughey, Joseph; O'Neill, Hugh
- The Analyst, Vol. 137, Issue 5
The effect of deuteration on the structure of bacterial cellulose
journal, June 2013
- Bali, Garima; Foston, Marcus B.; O’Neill, Hugh M.
- Carbohydrate Research, Vol. 374
13C cell wall enrichment and ionic liquid NMR analysis: progress towards a high-throughput detailed chemical analysis of the whole plant cell wall
journal, January 2012
- Foston, Marcus; Samuel, Reichel; Ragauskas, Arthur J.
- The Analyst, Vol. 137, Issue 17
Comprehensive Signal Assignment of 13 C-Labeled Lignocellulose Using Multidimensional Solution NMR and 13 C Chemical Shift Comparison with Solid-State NMR
journal, September 2013
- Komatsu, Takanori; Kikuchi, Jun
- Analytical Chemistry, Vol. 85, Issue 18
Hydrophobic Interactions Determining Functionalized Lignocellulose Solubility in Dialkylimidazolium Chlorides, as Probed by 31 P NMR
journal, February 2009
- King, Alistair W. T.; Kilpeläinen, Ilkka; Heikkinen, Sami
- Biomacromolecules, Vol. 10, Issue 2
In Situ Determination of Lignin Phenolics and Wood Solubility in Imidazolium Chlorides Using 31 P NMR
journal, September 2009
- King, Alistair W. T.; Zoia, Luca; Filpponen, Ilari
- Journal of Agricultural and Food Chemistry, Vol. 57, Issue 18
Quantitative 31P NMR analysis of solid wood offers an insight into the acetylation of its components
journal, November 2014
- Sadeghifar, Hasan; Dickerson, James P.; Argyropoulos, Dimitris S.
- Carbohydrate Polymers, Vol. 113
Heterobimetallic complexes CpNiCo(CO)2(PPh3)(PhC2C6H4-R -p): their synthesis, electrochemistry and ESR
journal, November 1991
- Sun, Shou-Heng; Meng, Qing-Jin; Zhu, Hui-Zhen
- Chinese Journal of Chemistry, Vol. 9, Issue 6
Plant cell wall profiling by fast maximum likelihood reconstruction (FMLR) and region-of-interest (ROI) segmentation of solution-state 2D 1H–13C NMR spectra
journal, January 2013
- Chylla, Roger A.; Van Acker, Rebecca; Kim, Hoon
- Biotechnology for Biofuels, Vol. 6, Issue 1
Works referencing / citing this record:
Novel Synthesis of Immobilized Brønsted‐ Acidic Ionic Liquid: Application in Lignin Depolymerization
journal, May 2018
- Singh, Sandip K.; Dhepe, Paresh L.
- ChemistrySelect, Vol. 3, Issue 19
Opportunities of Ionic Liquids for Lignin Utilization from Biorefinery
journal, July 2018
- Zhu, Xinyun; Peng, Chang; Chen, Huaxin
- ChemistrySelect, Vol. 3, Issue 27
Chemical and thermal properties of precipitates made from hydrolysate of spruce wood chips
journal, May 2019
- Tarasov, Dmitry; Leitch, Mathew; Fatehi, Pedram
- Wood Science and Technology, Vol. 53, Issue 4
Dimethyl sulfoxide assisted dissolution of cellulose in 1-ethyl-3-methylimidazoium acetate: small angle neutron scattering and rheological studies
journal, January 2019
- Yang, Mingkun; Zhao, Wenwen; Wang, Shizeng
- Cellulose, Vol. 26, Issue 4
Formic-Acid-Induced using Recyclable-Ionic Liquids as Catalysts for Lignin Conversion into Aromatic Co-Products
journal, November 2019
- Singh, Sandip K.; Dhepe, Paresh L.
- Waste and Biomass Valorization, Vol. 11, Issue 11
Ionic liquids catalyzed lignin liquefaction: mechanistic studies using TPO-MS, FT-IR, RAMAN and 1D, 2D-HSQC/NOSEY NMR
journal, January 2016
- Singh, Sandip K.; Dhepe, Paresh L.
- Green Chemistry, Vol. 18, Issue 14
Hyperpolarised NMR to follow water proton transport through membrane channels via exchange with biomolecules
journal, January 2018
- Nastasa, Viorel; Stavarache, Cristina; Hanganu, Anamaria
- Faraday Discussions, Vol. 209