Oxidative Delignification Chemistry - American Chemical Society

Chapter 16

Cell Wall Degradation of Spruce, Poplar, and Wheat Straw by MnO/Oxalate: An Overview 2

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Downloaded by UNIV OF GUELPH LIBRARY on September 17, 2012 | http://pubs.acs.org Publication Date: March 26, 2001 | doi: 10.1021/bk-2001-0785.ch016

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Bernard Kurek , Bonnie R. Hames , Christelle Lequart , Katia Ruel , Brigitte Pollet , Catherine Lapierre , François Gaudard , and Bernard Monties 5

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Unité de Physico-chimie et Biotechnologie des Polymères, Laboratoire de Biochimie des Macromolécules Végétales, Institut National de la Recherche Agronomique (INRA), 2 esplanade Roland Garros, 51686 Reims, France (email: [email protected]) Center for Renewable Chemical Technologies and Materials, National Renewable Energy Laboratory, 1617 Cole Boulevard, Denver, CO, 80401-3393 Unité de Physico-chimie et Biotechnologie des Polymères, Laboratoire de Fractionnement Enzymatique, INRA, Moulin de la Housse, BP 1039, 51687 Reims, France Centre d'Etudes et de Recherche sur les Macromolécules Végétales, Centre National de la Recherche Scientifique, domaine universitaire, BP53X, 38041 Grenoble, France Laboratoire de Biochimie (INRA), Institut National Agronomique de Paris-Grignon, 78850 Thiverval-Grignon, France 2

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Manganese dioxide and oxalate are two components commonly found in wood during its microbial decay. The degradation of cell wall from wheat straw, spruce and poplar sawdust by the association of MnO and oxalate is reviewed here. The Mn 2

oxidants formed are shown to modify the properties of the

wood cell wall at the molecular but also ultrastructural levels. Marked reductions in the contents of ether linked Guaiacyl and Syringyl monomers, but also of the main dimers composing the lignins are observed in all samples after MnO /oxalate oxidation. The Mn oxidants also slightly modify polysaccharides, but in spruce only and probably at the level of hemicellulose. Finally, the cell wall architecture is altered by MnO /oxalate, in a specific manner depending on the plant considered. 2

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© 2001 American Chemical Society

In Oxidative Delignification Chemistry; Argyropoulos, D.; ACS Symposium Series; American Chemical Society: Washington, DC, 2001.

273 Introduction Wood-destroying fungi accumulate large amounts of transition metals during decay (I ,2) and black Mn0 deposits are frequently observed on fibers in severely deligmfied wood (3, 4). They also produce significant levels of oxalic acid during the process, which can sometimes acidify wood down to pH 2 (5, 6). However, the role of manganese(IV) as M n 0 species in microbial degradation and the reasons for oxalate accumulation in woods remain hypothetical (2, 7, 8). We have recently shown that the solubilization of M n 0 by oxalate at pH=2,5 leads to the production of Mn chelates capable of oxidizing lignin within wheat straw, poplar and spruce cell wall (9, 10, 11 ,12). We therefore proposed that M n 0 and related Mn(IV) species could indeed be actively involved in the degradation of lignocellulose when associated with oxalates, in complement to the well described enzymatic processes. Still, such a mechanism and the possible cooperations between abiotic and enzyme systems are not demonstrated to occur in the natural environment, but all elements are in place within wood to promote this phenomenon. This paper reviews the results on the ability of the Μη/oxalate oxidative system to selectively modify lignocellulosic matrixes. Specific degradation pattern of lignin, cellulose and hemicelluloses were evidenced in wheat straw, poplar and spruce wood under the same experimental conditions, and ultrastructural modifications pointed out the importance of the supramolecular organization of cell wall on its degradation. 2

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Experimental Plant material and substrates

Wheat straw (Triticum aestivum ψ.) was harvested by hand at foil maturity and air dried. Internodes were separated, collected and reduced into ~2mm particle size. Extractive free poplar wood sawdust (Populus trichocarpa, cv Fridzi Pauley) and spruce wood (Picea abies) sawdust was used throughout the study. Permethylation of in situ lignin in wheat straw was carried out by diazomethane generated from Diazald® (Sigma Aldrich) (13). Before oxidation a short four-minute ball milling was applied on the sample in order to reduce heterogeneity between particle size (10).

Chemicals

Activated Mn0 (85% ; particle size -coumaric acids

b/

Ferulic acid a/ esterified etherified 14.110.6 14.6±1.9 0.42 10.9 4.5 12.0

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/>-Coumaric acid Etherified Esterified 4.010.5 21.910.5 13.6 3.2 3.9 20.1

control sample Oxidized - condition C Oxidized - condition D in ^mohslg sample ; incubated in oxalate ; datafromref (9); deviations to mean < 15%. c/

c/

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b/

c /

However, no free phenolic acids have been detected in the reaction media (data not shown, (9)). It is likely that oxidized cinnamates may be retained within the cell wall, probably through overreaction with lignin, forming new structures which escape to classical chemical analyses. In this respect, ferulic acid was shown to be readily polymerized by Mn0 /oxalate in condition Β ((9); data not shown). 2


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Conclusions The different studies presented here demonstrated the degradative action of the abiotic oxidative system composed of M n 0 and oxalate on wood and graminacea. The modifications at the level of cell wall ultrastructure, the strong modifications in the lignin bonding pattern in each plant considered, the specific alteration of cinnamic acids in wheat straw and the slight but significant degradation of hemicelluloses in spruce wood confirm that abiotic Mn chelates are able to modify the supramolecular organisation of the cell wall matrixes, and some of the particular interactions existing between the constitutive polymers. Thus, Mn0 and oxalate could be part of an efficient system that pretreats lignocellulosic material before or during microbial and/or enzymatic attack of cell walls. However, further studies are required in order to demonstrate the existence of such a mechanism in situ and in vivo, possibly controlled by or coordinated with the action of ligninolytic microorganisms.


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References 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.

Illman, B. L.; Meinholtz, D. C.; Highley, T. L. Biodeter. Res. 1989, 2, 485496. Jellison, J.; Connolly, J.; Goodell, B.; Doyle, B.; Illman, Β.; Fekete, F.; Ostrofsky, A. Int. Biodeter. Biodeg. 1997, 39, 165-179. Blanchette, R. A. Phytopathology 1984, 74, 725-730. Barrasa, J.; Gonzalez, A. E.; Martinez, A. T. Holzforschung 1992, 46, 1-8. Micales, J. A. Material und Organismen 1995, 29, 159-176. Dutton, M . V.; Evans, C. S.; Atkey, P. T.; Wood, D. A. Appl. Microbiol. Biotechnol. 1993, 39, 5-10. Roy, B., P.; Paice, M . G.; Archibald, F. S. J. Biol. Chem. 1994, 269, 1974519750. Shimada, M.; Ma, D.-B.; Akamatsu, Y.; Hattori, T. FEMS Microbiol. Rev. 1994, 13, 285-296. Lequart, C.; Kurek, B.; Debeire, P.; Monties, B. J. Agric. Food Chem. 1998, 46, 3868-3874. Hames, B. R.; Kurek, B.; Pollet, B.; Lapierre, C.; Monties, B. J. Agric. Food Chem. 1998, 46, 5362-5367. Lequart, C.; Ruel, K.; Lapierre, C.; Pollet, B.; Kurek, B. J. Biotechnol. 2000, in press. Kurek, B.; Gaudard, F. J. Agric. Food Chem. 2000, in press. Lapierre, C.; Monties, B.; Rolando., C. Holzforschung 1988, 42, 409-411.



285 14. Roland, J. C.; Vian, B. Electron microscopy of plant cell; Hall, J. L. and Hawes, C., Ed.; Acadamic press: London, 1991, pp 2-66. 15. Effland, M . J. TAPPI 1977, 60, 143-144. 16. Lapierre, C.; Pollet, B.; Rolando, C. Res. Chem. Interm. 1995, 21, 397-412. 17. Blakeney, A. B.; Harris, P. J.; Henry, R. J.; Stone, B. A. Carbohyd. Res. 1983, 113, 291-299. 18. Scalbert, Α.; Monties, B.; Lallemand, J. Y.; Guitet, E.; Rolando, C. Phytochemistry 1985, 24, 1359-1362. 19. Joseleau, J. P.; Ruel, K. Biotechnology in the pulp and paper industry; Kuwahara, M . and Shimada, M., Ed.; UNI Publisher CO Ltd: Kyoto, 1992, pp 195-202. 20. Fengel, D.; Wegener, G. Wood; ISBN 3-11-008481-3 ed.; Walter de Gruyter: Berlin, New-York, 1983. 21. Fatiadi, A. J. Synthesis (Stuttgart) 1976, 65, 65-104. 22. Lapierre, C.; Rolando, C. Holzforschung 1988, 42, 1-4. 23. Martinez-Inigo, M.-J.; Kurek, B. Holzforschung 1997, 51, 543-548. 24. Kurek, B.; Monties, B. Enzyme Microb. Technol. 1994, 16, 125-130. 25. Lam, T. T. T.; Iiyama, K.; Stone, B. Microbial and plant opportunities to improve lignocellulose utilization by ruminants; Akin, D. E., Ljundahl, L. G., Wilson, J. R. and Harris, P. J., Ed.; Elsevier: New York, 1990 pp 43-69


Oxidative Delignification Chemistry - American Chemical Society

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