optimizing saccharificationand yield in lignin-modified plants...pal4 1/12/2016 5 g units s units...
TRANSCRIPT
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Optimizing Saccharification and Yield in Lignin-Modified plants
Stanford, November 2-3, 2016
Wout BoerjanDepartment of Plant Systems Biology
VIB-UGentTechnologiepark 9279052 Gent, Belgium
Plants capture CO2 and energy while growing
-> plants are a renewable resource for liquid fuels
and bio-based materials
https://www.pinterest.com/northamericanen/biomass/
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Lignin polymer Polymerised glucose
Lignocellulose to fermentable sugars
Wood = 75% sugar
Outline of presentation
1. Lignin amount determines biomass processing
2. CSE is a new gene of the lignin biosynthetic pathway
3. Can the yield penalty be overcome?
4. Translational research in poplar
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G units S units
Arabidopsis is a model for biofuel crops
wild type
ccr1-6
Van Acker et al., 2013, Biotech for Biofuels
Saccharification of stems of lignin mutants
Before saccharification After saccharification
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Outline of presentation
1. Lignin amount determines biomass processing
2. CSE is a new gene of the lignin biosynthetic pathway
3. Can the yield penalty be overcome?
4. Translational research in poplar
G units S units
Lignin biosynthesis gene discovery
PAL1
PAL2
PAL3
PAL4
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G units S units
PAL1
PAL2
PAL3
PAL4
Lignin biosynthesis gene discovery
Correlation network (transcripts+metabolites)
highly
lignifying
tissue
Vanholme et al., Plant Cell (2012)
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cse residual transcript level
cse growth phenotype
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cse cell wall phenotype
cse deposits less lignin
cse lignin is rich in H units
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G units S unitsH units
cse deposits less lignin
cse lignin is rich in H units
G units S units
Caffeoyl shikimate accumulates in cse mutants
H units
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G units S units
CSE converts caffeoyl shikimate into caffeic acid
H units
Vanholme et al., Science (2013)
80% cellulose to glucose conversion in cse mutants,
without pretreatment
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Outline of presentation
1. Lignin amount determines biomass processing
2. CSE is a new gene of the lignin biosynthetic pathway
3. Can the yield penalty be overcome?
4. Translational research in poplar
How to overcome the vessel-collapse of cse mutants?
-> restore CSE gene expression in vessels only
Fibers
Vessels
WT cse-2
Petersen et al., Biotechnology for Biofuels (2012)
Vargas et al., Biotechnology for Biofuels (2016)
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Vessel phenotype cse-2 proVND:CSE
WT cse-2
cse-2 proVND7:CSE cse-2 proVND6:CSE
Vargas et al., Biotechnology for Biofuels (2016)
collapsed
restored
partially
restored
Biomass is largely restored by expressing CSE
under control of proVND7
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Lignin amount remains low upon vessel-specific
complementation
Lignin amount
Lig
nin
/Ce
ll w
all
(%)
a
b,cb b,c c c
Saccharification remains high upon vessel-specific
complementation while yield is restored
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Outline of presentation
1. Lignin amount determines biomass processing
2. CSE is a new gene of the lignin biosynthetic pathway
3. Can the yield penalty be overcome?
4. Translational research in poplar
Translational research:
from models to biomass crops to the biorefinery
Bio-based products
Liquid biofuels
Bioplastics
Cosmetics
…..
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H lignin
G lignin S lignin
Down-regulation of CCR in poplar
Line n lignin cellulose hemicellulose
WT 6 20.65 ± 0.22 48.22 ± 0.69 30.72 ± 0.69
FS3 5 16.75 ± 0.16 56.55 ± 0.49 23.19 ± 0.70
FS40 5 16.64 ± 0.18 57.07 ± 0.81 24.10 ± 0.44
-20% +17% -23%
Leplé et al., Plant Cell 2007
Wild type
Transgenic (>200%)
CCR defective -> 2-fold more glucose released from stems
Van Acker et al., PNAS (2014)
CCR down-regulated poplar wood is easier to
saccharify
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… the most protected forest in the world…
Simultaneous Saccharification and Fermentation
Higher ethanol yield/g wood1-year old wood
Van Acker et al., PNAS (2014)
0%0%
0%
+57%
When taken
into account
the biomass
yield penalty
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General conclusions
1. CSE is a new gene of the lignin biosynthetic pathway that can be
used to overcome cell wall recalcitrance
-> 4 fold higher cellulose-to-glucose conversion without
pretreatment
2. The yield penalty associated with CSE-deficiency can be
overcome by vessel-specific complementation using proVND7
3. Field trials are an essential step in translating research from the
lab to the field
Claire Halpin
Katarzyna Rataj
Yuguo Xiao
Lydia Welsh
Christopher McClellan
Gordon G. Simpson
Bioenergy and Bio-aromatics
Group @VIB
Ruben Vanholme
Rebecca Van Acker
Wannes Voorend
Joanna Cross
Marina de Lyro Soriano Saleme
Véronique Storme
Igor Cesarino
Lívia Vargas
Lisa Sundin
Geert Goeminne
Pedro Araujo
Bart Ivens
Kris Morreel
Bartel Vanholme
Marc Van Montagu
Hoon Kim
Cliff Foster
Nicolas Santoro
John RalphUGent
Wim Soetaert
Dirk Aerts
Kathleen Piens
INRA France
Gilles Pilate
Jean-Charles Leplé
Frédéric Légée
Catherine Lapierre