1/12/2016

1

Optimizing Saccharification and Yield in Lignin-Modified plants

Stanford, November 2-3, 2016

Wout BoerjanDepartment of Plant Systems Biology

VIB-UGentTechnologiepark 9279052 Gent, Belgium

woboe@psb.vib-ugent.be

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/

1/12/2016

2

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

1/12/2016

3

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

1/12/2016

4

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

1/12/2016

5

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)

1/12/2016

6

cse residual transcript level

cse growth phenotype

1/12/2016

7

cse cell wall phenotype

cse deposits less lignin

cse lignin is rich in H units

1/12/2016

8

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

1/12/2016

9

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

1/12/2016

10

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)

1/12/2016

11

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

1/12/2016

12

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

1/12/2016

13

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

…..

1/12/2016

14

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

1/12/2016

15

… 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

1/12/2016

16

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