The Conversion of Biomass
Biofuels
Since the dawn of civilization humans have
relied on plants for survival. Even today plants
influence almost everything we do either
directly or indirectly. They are the only source
of food, fuels, shelter, clothes and medicines.
Plants are the natural reservoir of chemical
compounds and are designated as the best
natural chemists.

 the term Biofuel covers
solid biomass,
liquid fuels
 biogases
Plants as Sources of Petroleum
Like Substances
Gopher plant: grows wild in California: 25 barrels of crude oil per hectare
Copaifera multijuga: found in Brazil: produces almost pure diesel fuel
Jojoba: 50% oil by weight: resembles sperm whale oil: doesn’t go rancid
The Energy Problem
• How will society meet
growing energy
demands in a
sustainable manner?
• Fossil-fuels currently
supply ~80% of world
energy demand.
Biofuels as an Alternative
• Biofuels are not THE answer to
sustainable energy, but biofuels may be
part of the answer
• Biofuels may offer advantages over fossil
fuels, but the magnitude of these
advantages depends on how a biofuel
crop is grown and converted into a usable
fuel
Analysis of Alternative Biofuels
 First-generation' or conventional biofuels are biofuels
made from sugar, starch, and vegetable oil.
 Second-generation biofuel implementation from non-food
crops. These include waste biomass, the stalks of wheat, corn,
wood, and special-energy-or-biomass crops (e.g. Miscanthus)
Third generation biofuel is Algae fuel, also called oilgae, is a
biofuel from algae
Technology Progression
Synthetic Biorefinery
Gasification
Direct Synthesis?
Corn
Algae
Cellulosic Bioethanol
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Biogas
Direct combustion
Pyrolysis: Involves high
temperatures (500900°C), low oxygen
Main ingredient is
methane.
Can be produced by
human, animal, and
agricultural wastes.
Biogas is isolated by the
use of methane digesters.
Ethanol/ Biodiesel Fuels
• Fermentation
• esterification
• Ethanol can be
produced by
fermenting certain
plants
• Biodiesel is produced
by using left over food
products such as
– Vegetable oil
– Animal fats
Biomass to
Fuel
Conversions
Results:
Alcohol (Ethanol)
Biogas (Methane)
Syngas
Gasoline (Biocrude)
Diesel Fuel (Plant Oil)
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Produced domestically, from renewable resources
Ethanol is grain alcohol produced by corn and other crops
Blended with gasoline to make fuels
Ethanol blended gasoline is becoming more readily
available and more cost efficient to consumer
• The most common types of ethanol gas are: E10, which is
10% ethanol and 90% unleaded gasoline, appropriate for
any make or model of any engine, and E85 which is 85%
ethanol and 15% gasoline, must have flex-fuel engine to
use…
• Ethanol contains oxygen, so it burns cleaner and prevents
gunky build up of automotive engines.
Why Ethanol?
Multiple Issues, One Answer
– Cheaper fuel for consumers
– More energy security & diversified sources
– Higher farm incomes & rural employment
– Significant carbon emission reduction
– Faster GDP growth, Lower Imports & energy prices
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Process of conversion to ethanol
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5.
Grind crops into fine powder, remainder is used to feed livestock
powder is mixed with water and alpha-amylase, an enzyme that
helps break the starch into smaller particles. The resulting mash is
cooked at 120 to 150 degrees to liquefy the starch and reduce
bacteria levels, and then heated to 225 degrees to help break the
starch down further.
mash is removed from the cookers and cooled. Then a second
enzyme, glucoamylase, is added to help convert the liquid starch
into a sugar that can be fermented.
The mash is mixed with yeast, which changes the sugar to
ethanol and carbon dioxide. It takes about 48 hours for the mash
to ferment.
Mixture is heated again to isolate ethanol, ethanol the condenses
to its liquid form
Saccharomyces cerevisiae
• Well known
microorganism:
– Used for
making wine,
beer, bread etc.
• Easy to use in
the lab
Bioreactor
F
Gin
X: biomass
G: glucose
E: ethanol
V: volume
X
G
E
V
F: Glucose feed rate
Gin: Inlet substrate
concentration
A simplified scheme for the processing of biomass into ethanol.
Pilot plant for the anaerobic fermentation of biomass into
mixed alcohol fuel by a mixture of microorganisms.
Flex Fuel Vehicles (FFV)
Little incremental cost to produce & low risk
Consumer choice: use EITHER ethanol or gasoline
Easy switchover for automobile manufacturers
Fully compatible with Hybrid cars
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Can Rapid Adoption of FFV Happen?
Brazil: FFV Market Share of Light Vehicle Sales
4% in Mar’03
50% in May’05
70% in Dec’05
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Energy Crops: Sugar Cane
Sugar cane: very high productivity per acre. Use bagasse and
sugar cane residues (sugar cane waste). Bagasse to energy
plants: 7% of Hawaiian energy
(Mauritius)
Bagasse
Energy Crops: Corn
• ~ 2 billion gallons of corn
ethanol produced in the U.S.
annually.
• Producing ethanol from corn
requires almost as much energy
to produce as it yields.
• Corn is a major food crop—
producing ethanol from corn
reduces its availability for food
and inflate prices.
Benefits of Corn & Sugar Cane
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Most Popular
Improves wildlife habitat
Reduced green house gases
High sugar content
Bagasse from sugarcane is also a good source of sugar
Problems with Corn Sugar Cane
• Less Efficient
• producing corn ethanol requires about as much energy
to produce as it yields
• Since corn and sugar cane are major food crops,
production of ethanol could decrease their amount of
available for food & inflate prices
• Grows very
successfully
• seems to be potentially
more promising then
corn, due to less
waste… the whole plant
is used to produce
ethanol, not just a part.
Needs very little energy
to grow
Benefits of Switchgrass
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Reduces soil erosion
Improves wildlife habitat
Can be co-produced for animal feed
Durable
Moisture efficient
Low Maintenance
High Yield
High energy conversion & Efficiency
Can grow in harsher areas
Decreases wind flow
Less water; less fertilizer; less pesticide
Reduced green house gases
Problems with Switchgrass
• Requires a large energy input to process into
ethanol
• Requires a huge increase in industrialized
farming
• Could provoke farmers to grow switchgrass
instead of other crops
Energy Crops: Miscanthus
1 years growth without replanting!
10-30 tons/acre
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Algae are photosynthetic
organisms
CO2 + H2O + Light Energy  Biomass
Algae very diverse: microscopic to giant kelp
Efficient, rapid growth, can double biomass in a day
Produce 50% of oxygen but are less than 1% of all plant
biomass
Few species have been studied for biofuel potential
Chlorophyceae
Dinophyceae
Bacillariophyceae
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ALGAE BIOFUEL –SUBSTITUE FOR FOOD RELIANCE CROPS; REDUCED
GLOBAL WARMING & LOWERED ENVIRONMENTAL IMPACTS
• Algae requires CO2 for growth therefore fuel is carbon neutral
• Possible integration to achieve low-cost CO2 sequestration
and nutrient remediation
• Uses all nutrients, minimizing eutrophication
• Biodegradable, so minimal issues with accidental spills /leaks
• Uses underutilized land, e.g. deserts
• Yields >10x those for land plants so much less land is needed
• Can grow in salt, or brackish water
• Can produce high yields of
– Lipids for biodiesel
– starch / polysaccharides for ethanol
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Advantages of Ethanol Blends: Emissions
•E85
•Low Evaporative emissions (Lower RVP)
•Expected Low Permeation emissions in FFV’s
•Low Nox in modern vehicles with oxygen sensors
•Zero sulphur, low carbon monoxide, particulate & toxic emissions
•E6 (low ethanol blends)
•Low Nox in modern vehicles with oxygen sensors (higher in older
vehicles)
•Increased RVP and increased VOC’s (and hence ozone formation)
•Increased permeation emissions in older vehicles
•Reduced CO emissions
…but
•Reduced permeation emissions ( thicker hoses & plastics) in newer
vehicles
•California Low Emissions Vehicle II program reduces permeation and
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evaporative emissions (part of 2007 Federal Law)
Technology Improvements
• Bioengineering
• Enzymes
• Plant engineering
• Process & Process Yields
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Process Cost
Pre-treatment
Co-production of chemicals
Process Yield gals/ ton
Consolidated bioprocessing
• Energy crops
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Miscanthus
Switch grass
Poplar
Willow
• Recent trends
• Synthetic Biology
• Nanotechnology
• Thermochemical
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Biodiesel
Biodiesel is an ecofriendly clean alternative diesel fuel
produced from the plant sources. Large numbers of
plants synthesize oils in their seeds. They may be edible
or non-edible type. These natural oils when processed
chemically (Reacted with alcohols to produce esters)
show striking similarities to petroleum derived diesel
and are called biodiesel.
Biodiesel is an ecofriendly biodegradable, clean
alternative renewable, low cost, nontoxic fuel produced
from the plant Jatropha curcas. It contains more
oxygen, no petroleum, essentially free of sulphur &
aromatics, cleaner burn at higher temperature and will
reduce green house gas emission. It can be used directly
or blended with petroleum diesel to run the machinery.
 Why non edible oils instead of easily available
edible oils are used for this purpose?
deficiency in edible oil production and plants
producing non edible oil may be the only material
of choice for production of biodiesel.
Azadirachta (Neem)
Calophyllum (Undi)
Pongamia (Karanj)
Jatropha curcas (Bharenda)
Of the above Jatropha curcas is considered most
potential source as nonedible biodiesel producing
plant in our country because it can be grown on
almost any soil type found in our country
Biofuel Plant
Jatropha curcas
Four Year Old
Eucalyptus:
Hawaii
Eucalyptus: produce high amounts
Of biomass under drier conditions
Than hemp. Very hardy species.
Lignin and biofuel production
• Lignin has negative impacts on biofuel prodution
– lignin impedes access of hydrolytic enzymes to wall
polysaccharides
– lignin adsorbs hydrolytic enzymes
– lignin interferes with pretreatment processes
– lignin degradation products inhibit fermentation
– lignin is not fermentable (but its energy can be utilized)
• Lignin is essential for plant viability; all the genes ar known
• Can reducing lignin content, composition, and tissue specificity
improve biomass quality? Plants seem to tolerate substantial
lignin modification.
Lignin modification may decrease the need for pretreatment
How can biotechnology help with biofuel production?
Changing the plant:
greater yield (photosynthesis) domestication of partially
domesticated plants (e.g. architecture, making plants more
easily harvested)
Changing the biomass components for easier processing:
ratio of cellulose to lignin; structure of lignin; structure of
cellulose; incorporating cellulase; new triglycerides that yield
better biodiesel.
Selecting new microorganisms (Synthetic genomics):
efficiency of pentose fermentation; combining cellulose
hydrolysis and fermentation; new fermentation end-products
insoluble in water.
Producing better enzymes:
gene shuffling technologies
Are Biofuels Cost Competitive?
• In 2005, neither biofuel was cost-competitive with
petroleum – but as petroleum prices increased the
gap closed
• Ethanol:
– Estimated ethanol production cost in 2005 was
$0.46 per gasoline energy equivalent L
– Wholesale gasoline prices averaged $0.44/L in
2005
• Soy biodiesel
– Estimated soybean biodiesel production cost in
2005 was $0.55 per diesel EEL,
– Diesel wholesale prices averaged $0.46/L in 2005
• Recent price effects unfavorable for biofuels:
– Lower fossil-fuel prices
– Higher corn prices
Advantages of Biofuels
– Reduce our dependence on imported energy
– Decrease carbon dioxide emissions
– Strengthen farm economy & create new jobs
Positive Environmental effects of
ethanol and biodiesel
Greenhouse
gasses
reduced by both
relative to
gasoline and
diesel
combustion
Adverse Environmental effects
• Fertilizer use
• Pesticide application
Toward better biofuels:
1) Biomass feedstock producible with low
inputs (e.g., fuel, fertilizers, and pesticides)
2) Producible on land with low agricultural
value
3) Conversion of feedstock into biofuels
should require low net energy inputs
Ultimately, the world will obtain most of its
food, fuel, fiber, chemical feedstocks,
and some of its pharmaceuticals from
genetically altered vegetation and trees."