Optimizing Saccharificationand Yield in Lignin-Modified plants

Transcription

1 Optimizing Saccharificationand Yield in Lignin-Modified plants Stanford, November 2-3, 2016 Wout Boerjan Department of Plant Systems Biology VIB-UGent Technologiepark Gent, Belgium Plants capture CO 2 and energy while growing -> plants are a renewable resource for liquid fuels and bio-based materials 1

2 Lignocellulose to fermentable sugars Wood = 75% sugar Lignin polymer Polymerised glucose Outline of presentation 1. Lignin amount determines biomass processing 2. CSEis a new gene of the lignin biosynthetic pathway 3. Can the yield penalty be overcome? 4. Translational research in poplar 2

3 Arabidopsis is a model for biofuel crops G units S units Saccharification of stems of lignin mutants Before saccharification After saccharification wild type ccr1-6 Van Acker et al., 2013, Biotech for Biofuels 3

4 Outline of presentation 1. Lignin amount determines biomass processing 2. CSEis a new gene of the lignin biosynthetic pathway 3. Can the yield penalty be overcome? 4. Translational research in poplar PAL1 PAL2 PAL3 PAL4 Lignin biosynthesis gene discovery G units S units 4

5 Lignin biosynthesis gene discovery PAL1 PAL2 PAL3 PAL4 G units S units Correlation network(transcripts+metabolites) highly lignifying tissue Vanholme et al., Plant Cell (2012) 5

6 cse residual transcript level cse growth phenotype 6

7 cse cell wall phenotype cse deposits less lignin cseligninis richin H units 7

8 cse deposits less lignin cseligninis richin H units H units G units S units Caffeoyl shikimate accumulates in cse mutants H units G units S units 8

9 CSE converts caffeoyl shikimate into caffeic acid H units G units S units 80% cellulose to glucose conversion in csemutants, without pretreatment Vanholme et al., Science(2013) 9

10 Outline of presentation 1. Lignin amount determines biomass processing 2. CSEis a new gene of the lignin biosynthetic pathway 3. Can the yield penalty be overcome? 4. Translational research in poplar How toovercomethe vessel-collapseof csemutants? -> 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) 10

11 Vessel phenotype cse-2 provnd:cse collapsed restored WT cse-2 cse-2 provnd7:cse cse-2 provnd6:cse partially restored Vargas et al., Biotechnology for Biofuels (2016) Biomass is largely restored by expressing CSE undercontrol of provnd7 11

12 Lignin amount remains low upon vessel-specific complementation a Lignin amount Lignin/Cell wall (%) b b,c b,c c c Saccharification remains high upon vessel-specific complementation while yield is restored 12

13 Outline of presentation 1. Lignin amount determines biomass processing 2. CSEis 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.. 13

14 Down-regulation of CCR in poplar Line n lignin cellulose hemicellulose WT ± ± ±0.69 FS ± ± ±0.70 FS ± ± ± % H lignin +17% -23% Lepléet al., Plant Cell 2007 G lignin S lignin CCR down-regulated poplar wood is easier to saccharify Transgenic (>200%) Wild type CCR defective -> 2-fold more glucose released from stems Van Acker et al., PNAS (2014) 14

15 the most protected forest in the world Simultaneous Saccharification and Fermentation Higher ethanol yield/g wood 1-year old wood +57% When taken into account the biomass yield penalty 0% 0% 0% Van Acker et al., PNAS (2014) 15

16 General conclusions 1. CSEis 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 Bioenergy and Bio-aromatics 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 UGent Wim Soetaert Dirk Aerts Kathleen Piens INRA France Gilles Pilate Jean-Charles Leplé Frédéric Légée Catherine Lapierre John Ralph Hoon Kim Cliff Foster Nicolas Santoro Claire Halpin Katarzyna Rataj Yuguo Xiao Lydia Welsh Christopher McClellan Gordon G. Simpson 16