Sustainable Algal Biofuels
Richard Sayre
•
•
•
•
Director, ERAC Institute for
Renewable Fuels
Director, Center for Advanced
Biofuel Systems (DOE-EFRC)
Scientific Director, National
Alli
Alliance
ffor Ad
Advanced
d Bi
Biofuels
f l
and Bioproducts (DOE Algal
Biofuels Consortium)
y
Inc.
CTO,, Phycal
Biofuels from Microalgae
R
id growth
th rate
t
Rapid
Unlike plants, all cells are photosynthetic
4 50%
4‐50% Lipid biomass
High photosynthetic efficiency
Double biomass in 6-12 hours
High oil content
4-50%
4 50% non-polar
non polar lipids
All biomass harvested
100%
Harvest interval
24/7; not seasonally, so reduces risk
Sustainable
Capture CO2
50‐90%
Other biomass
Other biomass
Use waste water and nutrients
No direct competition with food
High
biomass
Top
p oil p
producers :
High biomass; high oil production
•Chlorella sps.
• Amphora sps.
High oil
content
• Neochloris
• Ankistrodesmus
• Tetraselmis
• Nanochloropsis sps.
sps
J. App. Phycol. 21 (2009): 493
Three business models for making algal biofuels
T it
Trait
A t t
Autotrophic
hi
H t
Heterotrophic
t
hi
H b id
Hybrid
Companies
Sapphire
Solazyme
Phycal,
General
Dynamics
CO2 capture
Yes
No
Yes
Nutrient
deprivation
Yes
No
No
Sugar
utilization
No
Yes
Yes
C it l costs
Capital
t
L
Low
Hi h
High
I t
Intermediate
di t
Oil production
rate
Low
High
Intermediate
Co-product
C
d t
production
rate
L
Low
High
Hi
h
($?)
L
Low
Projected
cost for oil
($/gallon)
$2
$8
(co-product
offset ?)
$2
Phycal: Getting to $1 - $2 per gallon
Process
First Gen Process
Future Process
$4/gallon (~$160/bbl)
$1‐2/gallon (~$40‐80/bbl)
Location
Hawaii
Southeast US
Plant Size
50 Mgpy
250 Mgpy
g y
Algal System
“Indigenous” algae
g
g
Transgenic, biosecure
g
,
algae
g
Sugar System
Natural Cassava
Genetic Cassava
Open pond
Open pond w/ CI
AQX
Phycal Olexal™ w/ CI
Microfiltration
Dewatering Array, or other lower‐cost method
Refinery or fermentation
Refinery or fermentation
Digest to methane
Gasify to hydrogen
N/A
/
Pyrolyze
l
li i
lignin or refinery technology
fi
h l
Cost target
Growth System
Extraction
Primary Dewatering
CO2 source
Resid. Biomass
Aromatics
i
5
Enhancing the Biology:
Energy
gy capture,
p
conversion, and accumulation
Capture
55% losses
Conversion
30-40% losses
Accumulation
4-6% gain
Phycal value – added traits
Algaculture in open ponds
INPUT TRAITS:
‐ Stress tolerance
‐ Photosynthesis enhancement
‐ Metabolic engineering
Metabolic engineering
‐ Nutrient use efficiency
Fermentation to produce algal oil.
Purification and refinement of oil.
OUTPUT TRAITS:
‐ Carbon use flexibility
‐ Selectivity of oil species
Co product synthesis
‐ Co‐product synthesis
7
Phycal transgenic technology roadmap
Transformation Technology
• Improved Expression vectors
• Homologous recombination
• Novel gene identification
Abiotic Stress
• Temperature
• pH
• Nutrients
• Salinity
• Light
Photosynthetic Efficiency
Photosynthetic
Efficiency
• Light Harvesting Complex alteration
• CO2 capture
• Bottleneck enzymes
Bottleneck enzymes
• Bottleneck electron transfer
Biomass
• Proteins
• Carbohydrates
• Pigments
• Nutriceutical
Heteroboost™
• Xylose Utilization
• Arabinose Utilization Utilization
• Sucrose Utilization
Biosecurity
• Chemical Approach
pp
• Cell Ablation Approach
Lipid Yield & Structure
• Push, Pull, Store
Push Pull Store
• Alternative FA content
Secretion
• Fatty acids
Fatty acids
• Alkanes
Crop Protection
Crop
Protection
• Virus
• Bacteria
• Competitive algae
• Grazers
• Additives
8
Choosing the right algae:
GMO constraints
• Use non‐toxic, food‐grade algal strains (e.g., Chlorella)
• Use non‐sexual, eukaryotic strains to reduce likelihood of horizontal gene transfer
• Unlike biofuel production strains, most environmentally disruptive algal species have slow growth rates, reduced nutrient uptake rates, and compete poorly at high light*
• Engineer desirable pond production traits into algae that reduce Engineer desirable pond production traits into algae that reduce
fitness in the wild
• Reducing light harvesting antennae size increases photosynthetic efficiency and growth in well‐mixed ponds but reduces fitness in the wild due to less effective competition for d
f
h
ld d
l
ff
f
light (reduced shading of competitors) and reduced ability to harvest light at low intensities (survival at bottom of water column).
)
• Elimination of bicarbonate pumps in high CO2 environment of pond reduces energy cellular demands but also reduces ability to capture inorganic carbon in the wild
• Introduce terminator gene technologies into GMO algae that are I t d
t
i t
t h l i i t GMO l
th t
repressed in the pond but de‐repressed in wild
* Sunda, W.G., E. Graneli & C.J. Gobler. 2006. Positive feedback and the development and persistence of ecosystem disruptive algal blooms.
J. Phycol. 42:963–974.
Biomass yield versus pond depth has a
log-linear relationship
LHC+
Log (Bio
L
omass Y
Yield)
1.1
Mix
LHC• Unlike LHC+, mixed
antennae and LHC- strains
have a positive relationship
between yield and pond
depth.
R² = 0.93
1
0.9
• Negative relationship
between depth and yield for
LHC is
LHC+
i presumably
bl due
d to
t
self shading or NPQ losses .
R² = 0.95
R² = 0.83
0.8
• Optimal
p
pond
p
depth
p for
yield/volume is ~10 cm
0.7
5
10
15
20
Pond Depth
cm
25
30
-log
log I/Io = length
εc