lignin biomass recalcitrane

LIGNIN

A Twenty-first Century Challenge

Isroi (http://isroi.com)

BIOMASS RECALCITRANE

http://isroi.wordpress.com/

Cell Wall Model: Cellulose, Hemicellulose and Lignin

Pseudocolor SEM micrograph of lignin redeposited on cellulose (10,000X).

www.nrel.gov/.../technology.cfm/tech=18

http://www.nrel.gov/basic_sciences/technology.cfm/tech=18

Lignin:

• Nature’s second abundant organic substances

• Product of phenylpropanoid pathway

• Lignin – monolignol/lignin-forming pathway steps evolved during transition (evolution) of plants from the water habitat to the land habitat.

Plant evolution

LIGNIN: Moleculer Basis and role in plant adaptation

Diagram showing changes in cell wall

composition during the course of

evolution.

Sarkar P et al. J. Exp. Bot. 2009;60:3615-3635

© The Author [2009]. Published by Oxford University Press [on behalf of the Society for Experimental Biology]. All rights

reserved. For Permissions, please e-mail: [email protected]

Sarkar P et al. J. Exp. Bot. 2009;60:3615-3635

Figure 3. Phylogenetic tree

showing the distribution of

lignin monomer composition

across major lineages. *, S-

units are only found in cell

cultures of Ginkgo, not in wood

(Novo Uzal et al., 2009). **,

Lignin-like structures are

reported in some mosses and

green algae, but the presence of

real lignin in these nonvascular

species remains questionable;

red algae have been barely

studied (Weng et al., 2008b;

Martone et al., 2009).

Vanholme R. et.al. Plant Physiol. 2010:153:895-905

Copyright © 2010. © 2010 American Society of Plant Biologists. All rights reserved.

LIGNIN: Moleculer Basis and role in plant adaptation

Red Seaweed

Like many land plants, this red seaweed produces lignin, a primary component of wood. (Credit: Kathy Ann Miller)

http://www.science20.com/news_releases/biofuels_research_makes_a_plant_evolution_discovery

Selaginela

Selaginela

http://esciencenews.com/

Both lignin and cellulose are found in the rigid cell walls of the xylem cells (those that conduct water) in the primitive plant, Selaginella. (Credit: Zina Deretsky, National Science Foundation; Selaginella cross section SEM by Jing-Ke Weng, Clint Chapple, Purdue University; Lignin structure from Wout Bergjan, John Ralph, Marie Baucher (Annual Review of Plant Biology, Vol. 54:519-546, June 2003); Cellulose structure from http://www.chusa.jussieu.fr/disc/bio_cell/)

Fossil Ginkgo leaves from the Jurassic of England. Some 160 million years ago.

Modern Ginkgo leaves.

Corn Stover

Wood

http://siteresources.worldbank.org

Softwood Hardwood

• Larger, longer cells • Water transported by cells

• Contains large-diameter vessels • Water transported by these vessels

Lignin: Major monolignols of lignins.

Hatfield R., Vermerris W. Plant Physiol. 2001:126:1351-1357

H-unit P-hydroxyphenyl

G-unit guaiacyl

S-unit syringyl

Lignin: Major monolignols of lignins.

(A) Monolignol esters 30-32 found in grasses.

(D) Several dominant substructures present in native lignins.

Lignin Structure:

Freudenbrerg (1965)

Brunow et al. 1998

Lignin Structure:

Lignin Structure:

Lignin Biosynthesis Pathway

Lignin Pathway Evolution

Humphreys, J. M., C. C. S. Chapple. 2002. Rewriting the lignin roadmap. Plant Bio. 5, 224–229.

http://cellwall.genomics.purdue.edu/downloads/pathway2002.pdf








Vascular Plant Diversification and Lignification


Pinus taeda

Medicago sativa

Loblolly pine (Pinus taeda)

Tamarack (Larix laricina) Ebony (Diospyros ebenum)

Douglas fir

compression

normal

Black cottonwood

tension

normal

Monilignol Biosynthesis

7.3.2


7.3.3


7.3.4


7.3.5


7.3.6


7.3.7


7.3.8


http://aob.oxfordjournals.org/content/91/6/673/F3.expansion


Inherent Shortcomings in lignin analyses: a critical juncture and the urgent need

Lignin Isolation Procedure:

• Strong acid (sulphite pulping proceses) • Strong alkaline (kraft pulping) • Milled wood lignin • Björkman lignin

Figure 2. Representation of a lignin polymer from poplar, as predicted from NMR-based lignin

analysis (adapted from Stewart et al., 2009).



Lignin Structure: Lignin subunit and lignin structural analyses by NMR spectroscopy

Quantification of lignin amounts, lignin degradation protocols, and synthetic dehydropolymerizates

• Klason Lignin Various non-lignin componens, such as tannins, was determined

• Acetyl bromide • Thioglycolic acid

Modulation of monolignol pathway and peroxidase enzymatic step

Lignin, a key component of plant cell walls, is normally synthesized from three simple monolignols (top). The hydroxyl group (OH), shown in red, must remain unmodified for these precursors to link up. Liu's team created a novel enzyme (green "ribbon" structure) that can methylate this specific hydroxyl group. This enzyme may therefore lead to ways to interfere with lignin biosynthesis in plants to make them easier to break down for biofuels.

Chang-Jun Liu

Native Lignin Macromolecular Configuration

Freudenbrerg (1965)

1965

Lignin Structure: 1970s-1980s

Adler (1977)

Lignin Structure:

Lignin Structure:

Partial structure of a hypothetical lignin molecule from European beech (Fagus sylvatica ). The phenylpropanoid units that make up lignin are not linked in a simple, repeating way. The lignin of beech contains units derived from coniferyl alcohol, sinapyl alcohol, and para-coumaryl alcohol in the approximate ratio 100:70:7 and is typical of angiosperm lignin. Gymnosperm lignin contains relatively fewer sinapyl alcohol units. (After Nimz 1974.)

Brunow et al. 1998

Lignin Structure: 1990s and 2000s

Figure 2. Representation of a lignin polymer from poplar, as predicted from NMR-based lignin

analysis (adapted from Stewart et al., 2009).



Lignin Structure: Lignin subunit and lignin structural analyses by NMR spectroscopy

Future Outlook

Future Outlook

1. Monolignol transport to the cell/wall 2. Lignin initiation sites 3. Lignin Primary Sequences/New Chemistries 4. Re-oxidation of the growing lignin chains 5. Monolignol radical and lignin primary chain

interactions, proposed template polymerization, and lignin association

6. Transcriptional control of individual cell wall formation processes, biomechanics, and biodegradation of plant cell walls.

Thanks You

Biomass Recalcitrance

Alkali nitrobenzene oxidation/thioacidolysis/permanganate oxidation degradation procedures

lignin biomass recalcitrane

Education

based lignin

plant cell

lignin structural

plant physiol

plant bio

plant biologists

lignin roadmap

lignin polymer