Development of Cellulosic Biofuels

1
Development of Cellulosic Biofuels
Chris Somerville Energy Biosciences Institute UC
Berkeley, LBL, University of Illinois
2
Current and predicted energy useCurrent use 13 TW
Global Primary Energy Supply by Fuel
2002
2030
- excludes traditional biomass Source IEA
2004 Jim Breson
3
Potential of carbon-free energy sources
TW
1000000
100000
10000
1000
100
10
?
1
0.1
Nuclear
Hydro
Wind
Geothermal
Solar
Current use
Tides currents
From Basic Research Needs for Solar Energy
Utilization, DOE 2005
4
Combustion of biomass can provide carbon neutral
energy
Sunlight
CO2
Photosynthesis
Combustion
Polysaccharides
(Storage)
Work
5
Combustion of biomass can provide carbon neutral
energy
Sunlight
CO2
CO2
Tilling Land conversion Fertilizer Transportation
Processing
Photosynthesis
Combustion
Biomass
Work
But it depends on how the biomass is produced and
processed
6
Effect of land use change on soil carbon
Guo Gifford, Global Change Biology 8,345
7
Indirect land use concept

• Assertions

• Assumptions

• Diversion of land from feed to fuel production
  shifts production of food to other land
• Some of the other land may be undeveloped
• Use of undeveloped land causes large CO2
  emissions from burning and soil emissions

• Demand for feed is inelastic
• Demand is not satisfied by substitution
• General equilibrium models are meaningful
• Economic elasticities for intensification, and
  extensification are known
• Land use is driven by economics

8
Limited potential of biodiesel
160
140
120
100
Billion gallons
80
60
40
20
0
Current biodiesel
Capacity
US Diesel
US Fuel
65 biodiesel companies in operation, 50 in
construction 2006
9
Vision of an algal fuel facility
http//www.solixbiofuels.com/html/home.html
10
Overview of Brazil sugarcane

• 2007-08 harvest 528 MMT
• 8 M Ha planted by 2008
• 20 B liters ethanol, 2007
• 80-120 T/Ha
• 6400 L ethanol/Ha
• 333 mills, 200 planned
• Plantings last 5 y, cut one per year
• Large mill
• 22,000 tons/day
• 1500 truck loads/day

11
US Biofuel Production has Expanded Rapidly
AS OF March 2006
In operation
Under construction
Proposed
12
Corn prices (Chicago Board of Trade)
13
US Corn exports are projected to increase
http//www.ers.usda.gov/briefing/Baseline/crops.ht
m
14
Agricultural land use has declined
http//www.ers.usda.gov/briefing/Baseline/crops.ht
m
15
Renewable Fuel Standard(Energy Independence and
Security Act of 2007)
40
Biodiesel
35
General Advanced
Cellulosic Advanced
30
Conventional
Previous RFS
Advanced
25
20
Biofuel Volume (billion gallons)
15
10
5
0
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
Year
16
Responsible Biofuels

• No conversion of undeveloped land
• No erosion, runoff, nitrous oxide emissions
• Net GHG benefits based on full lifecycle
  accounting
• No effect on food production

17
US Biomass inventory 1.3 billion tons
Wheat straw
26 B gals

Corn stover
6.1
Soy
19.9
6.2
Crop residues
7.6
Grains
5.2
Manure
4.1
Urban waste
2.9
Perennial crops
35.2
Forest
12.8
From Billion ton Vision, DOE USDA 2005
18
High yield decreases transportation and land costs
500,000 gal/day scenario
Richard Hamilton, Ceres
19
Potential bioenergy crops tested in the US
From Lewandowski et al., Biomass Bioenergy
25,335
20
Perennials have little or no erosion
Corn
Soybeans
Perennial herbaceous
Short rotation wood
0
10
20
30
40
50
Tonnes/HA/y of soil loss
From Oliveira et al in Jones and Walsh (eds)
Miscanthus for Energy and Fibre, 2001
21
An energy crop
Yield of 26.5 tons/acre observed by Young
colleagues in Illinois, without irrigation
Courtesy of Steve Long et al
22
Switchgrass and Miscanthus at Illinois
60
50
Mg/Ha
40
30
20
10
0
2004
2005
2006
mean
Heaton, Dohleman and Long, Climate Change Biology
2008
23
Locations of European Miscanthus Trials
From Clifton-Brown et al in Jones and Walsh
(eds) Miscanthus for Energy and Fibre, 2001
24
Harvesting Miscanthus
http//bioenergy.ornl.gov/gallery/index.html
25
Response of Miscanthus to nitrogen fertilizer
20
N0
N60
15
N120
10
Yield (t/HA)
5
0
93
94
95
96
97
98
99
0
1
2
3
4
5
6
Year
Christian, Riche Yates Ind. Crops Prod. (2008)
26
Some priority research topics

• How much pest and pathogen tolerance (or other
  traits) is there and how to genotype for it?
• Molecular basis for self-incompatibility and how
  to control it for breeding purposes?
• What is the mechanistic basis for low nitrogen
  response in some grasses?

27
Private forests are extensive
Alig Butler (2004)USDA Forest Service
PNW-GTR-613
28
Land Usage
AMBIO 23,198 (Total Land surface 13,000 M Ha)
29
gtgtA billion acres of agricultural land have been
abandoned
Campbell et al., Env. Sci. Technol. (2008)
42,5791
30
Species of interest outside USA

• Jatropha curcas
• Spartina sp.
• Leucaena leucocephala
• Pongamia pinnata
• Copaifera langsdorfii

31
Annual precipitation
32
Limiting factors for global NPP
Baldocchi et al. 2004 SCOPE 62
33
Summary of Syngas-Liquids Processes
Richard Bain, NREL
34
Steps in cellulosic ethanol production
From Breaking the Biological Barriers to
Cellulosic Ethanol
35
Dilute acid schematics 1-6
Aden et al (2002) NREL/TP-510-32438
Prehydrolysis
Feed handling
Solid-liquid separation
Lime addition
Saccharification and fermentation
Seed production
36
Dilute acid schematics 7-12
Aden et al (2002) NREL/TP-510-32438
Beer distillation
Rectification distillation
Ethanol dehydration
Evaporation
Anaerobic digestion
Lignin separation and recycle
37
Dilute acid schematics 13-18
Aden et al (2002) NREL/TP-510-32438
Aerobic digestion
Storage
Combustion and turbogenerator
Boiler feed drying
Boiler feed water adjuvants
Boiler feed water preparation
38
Dilute acid schematics 19-21
Aden et al (2002) NREL/TP-510-32438
Cooling water
Process water
Sterile water
39
Plants are mostly composed of sugars
3 nm
Section of a pine board
Polymerized glucose
40
Effect of lignin content on enzymatic recovery of
sugars from Miscanthus
D Vrije et al (2002) Int J Hydrogen Energy
27,1381
Ralph, Ralph Landucchi http//ars.usda.gov/Servi
ces/docs.htm?docid10491
41
Some lignin is linked to hemicellulose
Lignin
Cellulose Hemicellulose
Harris Stone in Biomass Recalcitrance, pp 75
ed M Himmel, Blackwell (2008)
42
At least 1000 genes are implicated in
polysaccharide synthesis and modification
379 glycosidases transglycosidases (32
families)
425 glycosyltransferases ( 38 families)
34 polysacharide lyases
110 esterases
http//afmb.cnrs-mrs.fr/CAZY/
43
Enzymatic hydrolysis of cellulose is slow
Skopec, Himmel, Matthews, Brady Protein
Engineering 16, 1005
44
Accessory proteins stimulate activityof
cellulases and chitinases
Eijsink et al, Trends Biotechnol 26,228
45
Possible routes to improved catalysts

• Explore the enzyme systems used by termites (and
  ruminants) for digesting lignocellulosic material
• Compost heaps and forest floors are poorly
  explored
• In vitro protein engineering of promising enzymes
• Develop synthetic organic catalysts (for
  polysaccharides and lignin)

46
Comparison of carbohydrate-active enzymes in
Postia placenta vs other fungi
Family 1 carbohydrate binding modules
P. placenta T reesei P. chrysosporium
endo-glycanases
exocellobiohydrolases
endo-xylanase
cellulose binding endoglucanases
Martinez et al PNAS 106,1954
47
Saccharification Fermentation

Fermentation Yield Cost Impact
2.40
70
2.10
Minimum Ethanol Selling Price (/gal)
92
1.80
1.50
95
1.33
1.28
1.23
1.20
glucose only
add 85 xylose
add 85 arabinose
all other sugars
85
NREL
48
Fermentation of all sugars is essential
Jeffries Shi Adv Bioch Eng 65,118
49
Engineered yeast 424A(LNH-ST) utilizes xylose
Sedak and Ho, Appl Biochem Biotechnol
113-116403-16, 2004
50
Routes to potential fuels
Fortman et al, Trends Biotechnology 26,375
51
Steps in cellulosic ethanol production
From Breaking the Biological Barriers to
Cellulosic Ethanol
52
Conversion of sugar to alkanes
Huber et al., (2005) Science 308,1446
53
US Cellulosic ethanol plants under development
54
The Future?
http//genomicsgtl.energy.gov/biofuels/index.shtml