algae biorefinery : concepts
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schmid-staiger@igb.fraunhofer.de
Dr. Ulrike Schmid-Staiger
National German Workshop on Biorefineries15th September 2009, Worms
Algae Biorefinery - Concepts
schmid-staiger@igb.fraunhofer.de
Microalgae - microscopic small „plants“
Ubiquitous - seawaterfreshwatersoilair
� About 40.000 different algae in marine water sytems
� Algae are consumed bymankind for thousand of years
� 40-50 Gigatons of carbon arefixed by marine algae everyyear
schmid-staiger@igb.fraunhofer.de
Algae biomass– a sustainable renewable resource for fine chemicals and energy
Advantages of using microalgae as renewable resource
� Growth rate is 5 to 10 times higher compared to plants
� Essential for growth are sunlight, CO 2, and anorganicnutrients like nitrogen and phosphorous
� Carbon dioxide emitted from combustion processes can be used as a source of carbon for algal growth (1 kg of dry algal biomass requiring about 1.8 kg of CO 2).
� Microalgae can be cultivated in seawater or brackish water on non-arable land, and do not compete for resources with conventional agriculture.
� Microalgae biomass can be harvested during all seasons.
� The biomass is homogenous and free of lignocellulose.
schmid-staiger@igb.fraunhofer.de
Lipids
Main components of microalgaeAlgae
Proteins
• high contentup to 50% of dry weight in growing cultures
• all 20 amino acids
Carbo-hydrates
• storage productsά-(1-4)-glucans ß-(1-3)-glucans, fructanssugars, glycerol
• only very low cellulose content
storage lipids
• mainly TAGs
• up to 50% of DW
• with solvents extractable fromwet biomass
• recovery by pressing out the dry and ruptured biomass
valuable Compounds
• pigments
• antioxidants
• fatty acids
• vitamins
• anti-fungal, -microbial -viral toxinssterolsMAAs
membrane lipids
• different lipid classes
• up to 40% of total lipids are PUFA
• solubilised by solventextraction of wet biomass, then transesterification
schmid-staiger@igb.fraunhofer.de
Valuable compounds from microalgae
Pigments / Carotenoidsß-Carotene
AstaxanthinLuteinZeaxanthinCanthaxanthinChlorophyllPhycocyaninPhycoerythrinFucoxanthin
Fatty acids (PUFAs) DHA (C22:6)EPA (C20:5) ARA (C20:4) GAL (C18:3)
VitaminsA, B1, B6, B12, C, EBiotineRiboflavinNicotinic acidPantothenateFolic acid
AntioxidantsCatalasesPolyphenolsSuperoxid DismutaseTocopherols
Other / PharmaceuticalsAntifungalAntimicrobialAntiviralToxinsAmino acids, ProteinsSterolsMAAs as light protectant
schmid-staiger@igb.fraunhofer.de
Utilization of microalgae biomass
Lipids
Proteins
Carbo-hydrates
valuable Compounds
BioenergyBiofuels
Feed
Chemical Building Blocks
AquaculturePoultry breeding
Fatty acids/lipidsPigmentsVitaminsAntioxidantsNutraceuticals
Bifunctional building blocksacidsalcohols
DieselKeroseneMethaneSyngas
Productionin closed PBR
Harvestand
Processingdewateringdrying
Algae biomassfractionation
Food
Feed
Food
Cosmetics
schmid-staiger@igb.fraunhofer.de
Sustainable Algae-based Processes
CHP-Plant
Microalgae Cultivation
Lignocellulose freeAlgae Biomass
Solar Energy
NutrientsN , P, Mg, K
CO2
Wet BiomassConcentrating
Methane electr. Energy thermal Energy
Biogas Technology
Input Output
• Carbohydrates
• Proteins
• Lipids, PUFAs
• Antioxidants
• Pigments
• Silicates
• Micronutrients (Fe, Zn, Mg)
Production DSP
Residual Biomass
Operating Power Drying
Extraction
Recycling
schmid-staiger@igb.fraunhofer.de
Comparison between different cultivation systems
highhighlowBiomass concentration
lowhighhighEnergy demand per kg biomass produced
highhighlowVolumetric productivity
highhighlowCost to scale-up
highhighlowSterility
low
Low-high
excellent
excellent
Flat panel airlift reactors
excellentFairly goodLight efficiency
highlowOxygen accumulation
Low-highPoorGas transfer
excellentNoneTemperature control
Tubular reactorsRaceway pondsSystem
Net energy production is possible !
schmid-staiger@igb.fraunhofer.de
static mixer
main targeted flow
deep-drawn PVC half-shellsincluding the static mixers
�High productivity by a sophisticated system of static
mixers resulting in efficient light distribution to all algal
cells and low shear forces effecting to the algal cells
�Low production cost of the reactor by construction of
plastics
�High scalability and modularity
�Low energy consumption for inter-mixing due to airlift-
driven intermixing
�A pure photoautotrophic production process
- Low requirements of energy as sunlight as main energy
source can be used
�Provides the possibility to grow all kind of algae with high
productivity at high biomass concentration
Characteristics of the Flat Panel Airlift Reactor
schmid-staiger@igb.fraunhofer.de
Scale-up Step to a Pilot Plant
� Link of several reactor modules (with a volume of 180 litre each) and joint operation outdoors
� Production of algal products in the range of several hundred kilograms.
� Net energy production is possible, due to reduction of energy demand with scale-up
64 MJ/kg TS 24 MJ/kg TS
21,6 MJ/kg TS
schmid-staiger@igb.fraunhofer.de11
0
20
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60
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120
140
160
Energieaufwand / Energy demand (MJ/kg DW)
Raceway Rohrreaktorhorizontal,gepumpt*
Rohrreaktorhelical,
gepumpt*
Rohrreaktorvertikal,
gepumpt**
Flat PanelReaktor, Uni
Almeria*
FPA , Subitecderzeit §
FPA , Subitec,Ziel §
Comparison of the energy input per kg DW of different production systems
schmid-staiger@igb.fraunhofer.de
Sustainable Algae-based Processes
CHP-Plant
Microalgae Cultivation
Lignocellulose freeAlgae Biomass
Solar Energy
NutrientsN , P, Mg, K
CO2
Wet BiomassConcentrating
Methaneelectr. Energy thermal Energy
Biogas Technology
Input Output
• Carbohydrates
• Proteins
• Lipids, PUFAs
• Antioxidants
• Pigments
• Silicates
• Micronutrients(Fe, Zn, Mg)
Production DSP
Residual Biomass
Operating Power Drying
Extraction
schmid-staiger@igb.fraunhofer.de
Growth and Biomass Productivity in FPA-Reactors exemplary of Phaeodactylum tricornutum
� High biomass productivity at even high biomass concentrations due to efficient intermixing
� Dependency of biomass productivity of relative light intensity per cell
� Optimum biomass yield at relatively low light availability (g DW produced per mole of photons E).
Phaeodactylum tric.: Growth in FPA-Reaktor
0
5
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25
30
10 15 20 25 30
time
DW
(g/l)
0
400
800
1200
Ligh
t int
ensi
ty
(µE
m-2
s-1
)
0,0
0,4
0,8
1,2
1,6
0 5 10 15 20 25
biomass concentration (g DW l -1)
Pro
d. (g
DW
l-1
d-1)
0,0
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0,8
1,2
1,6
0,0 0,1 0,2 0,3 0,4 0,5
rel. light availability (E g DW -1d-1)P
rod.
(g
DW
l-1
d-1
); Y
light
(g
DW
/E)
Y light (g DW/E)
schmid-staiger@igb.fraunhofer.de
Production of storage products in microalgae
Growing algal cells
N- and P-limitationvaluable
compound
proteins
carbohydrates
lipids
pigments
Carbohydrates as energy storage product
valuable compound
proteins
carbohydrates
lipidspigments
valuable compound
proteinscarbohydrates
lipids
pigments
Lipids as energy storage product
schmid-staiger@igb.fraunhofer.de
Energetic use: Microalgal lipid production
���� Microalgal lipid production depends strongly on available light per cell
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0 2 4 6 8 10
time (d)
lipid
s (
% o
f dry
wei
ght)
Nanno.o. Nanno.l Chl.v. Nanno.o2
0
1
2
3
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0 0,2 0,4 0,6 0,8 1 1,2rel. light availability (E g DW -1*d-1 )
Lipi
d in
crea
se p
er d
ay (
%)
Optimized production
schmid-staiger@igb.fraunhofer.de
Fatty acid composition
Chlorella vulg. - Wachstumsphase
C14:0
C16:0
C18:1n9cC18:2n6c
C20:0
C16:1n7
C18:0
Gesamtlipidgehalt 9 % der TS
Chlorella vulg. - Lipidphase
C14:0C16:0
C18:1n9c
C18:2n6c
C20:0
C18:0
C16:1n7
Ölsäure
Total lipid content 45% of DW
Main fatty acid: C18:1 oleic acid
Total lipid content 9 % of DW
Growth phase Lipid phase
schmid-staiger@igb.fraunhofer.de
Downstream Processing
Algaeproduction Cell harvest Drying Cell disruption
Extraction /Purification Products
Process line
1
2
3
Separation
Filtration
Precipitation
Flotation
Spray drying
Superheatedsteam
High pressurehomogenizer
Ball mill
Fast expansion
from drybiomass
Fluid extractionorg. solventsl / H2O
Supercritical fluidsscCO2
Fluid extractionorg. solventsl / H2O
from wetbiomass
hydrophilic
• Proteins• Starch• Glycerine• Vitamins• Micronutrients
lipophilic
• Oils• Fatty acids (PUFA)• Carotenoids• Steroids
Residual biomass
FhG1
Slide 17
FhG1 Th e challenge foralgal biomass harvesting is to take the very low cell densityand concentrate it to a point where lipid extraction ispossible (as much as 1000X) using the lowest possible costand process options. Th erefore, energy-intensive processessuch as centrifugation may be feasible for high-valueproducts but are far too costly in an integrated systemproducing lower-value products, such as algal oils forbiofuels applications.Fraunhofer Gesellschaft, 12-09-2009
schmid-staiger@igb.fraunhofer.de
Sustainable Algae-based Processes
CHP-Plant
Microalgae Cultivation
Lignocellulose freeAlgae Biomass
Solar Energy
NutrientsN , P, Mg, K
CO2
Wet BiomassConcentrating
Methaneelectr. Energy thermal Energy
Biogas Technology
Input Output
• Carbohydrates
• Proteins
• Lipids, PUFAs
• Antioxidants
• Pigments
• Silicates
• Micronutrients(Fe, Zn, Mg)
Production DSP
Waste Biomass
Operating Power Drying
Extraction
schmid-staiger@igb.fraunhofer.de
Downstream processes of microalgae: Eicosapentaenoic acid (EPA)
• part of the membrane lipids of algal chloroplasts• occurs as one of the fatty acids of the monogalactosyldiglycerides
� cell disruption� preextraction of the monogalactosyldiglyceride necessary
• only fatty acid ethyl esters or free fatty acids can be extracted by use of scCO2
� transesterification of the monogalactosyldiglyceride
monogalactosyldiglyceride Fatty acid ethyl ester
+ +
EthanolEPA
Gly
cero
l
Gly
cero
l
Lipase/
Alkali-catalyst EPA
Fatty acidFatty acid
schmid-staiger@igb.fraunhofer.de
Vorlagebehälter
scCO2 SourcescCO 2-Extraction
Extraction with scCO 2
Expansion
EPA
EtOH
Extraction (2. steps)
1h, RT
Lipase/KOH
Trans-esterification/ Saponification
Centrifugation(filtration)
Preextraction withtransesterification
Downstream processes of microalgae: Eicosapentaenoic acid (EPA)
Algaecultivation
schmid-staiger@igb.fraunhofer.de
Downstream processes of microalgae: Astaxanthin
Vorlagebehälter
scCO2 SourcescCO 2-Extraction
Extraction with scCO 2
Expansion
Astaxanthinoil
Drying and grindingAlgaecultivation
Drying Grinding
schmid-staiger@igb.fraunhofer.de
Energy conversion processes from microalgae
schmid-staiger@igb.fraunhofer.de
Schematic process of biodiesel production
schmid-staiger@igb.fraunhofer.de
Sustainable Algae-based Processes
CHP-Plant
Microalgae Cultivation
Lignocellulose freeAlgae Biomass
Solar Energy
NutrientsN , P, Mg, K
CO2
Wet Biomass Concentrating
Methane electr. Energy thermal Energy
Biogas Technology
Input Output
• Carbohydrates
• Proteins
• Lipids, PUFAs
• Antioxidants
• Pigments
• Silicates
• Micronutrients (Fe, Zn, Mg)
Production DSP
Residual Biomass
Operating Power Drying
Extraction
Recycling
schmid-staiger@igb.fraunhofer.de
Outlook: Integrated process for mass and energy based utilization of microalgae
Products: pigmentsω-3-fatty acidsvitamins
residual biomass
digestion /codigestion
CO2
NH4, PO4
recycling
1,85 kg CO2 are fixed per kg algal biomass produced
CHPS
Algal biomassH2O
CO2
O2 CH2O
Calvin-ZyklusLichtreaktionen
ATP+NADPH+H+
ADP+ Pi
+NADP+
Energie
8 MJ electricity
12 MJ heatper m³ biogas
Biogas
organic wastes
schmid-staiger@igb.fraunhofer.de
Demands to Microalgal Biorefinery Processes
• Energy efficient algae biomass production process
high rate of photosynthesis, photobioreactor, CO2-utilization, net energy
balance
• Product recovery
solvents (which and quantity)
extraction from wet biomass, avoiding energy intensive drying steps
• Residual biomass utilization
free of lignocellulose, conversion to biogas by anaerobic digestion,
• Recycling of nutrients
CO2, nitrogen, phosphate
• Water use
quantity and quality
schmid-staiger@igb.fraunhofer.de
Thank you for your attention
Ulrike Schmid-Staiger, Ph.D.Fraunhofer IGBNobelstr. 1270569 StuttgartTel. +49-(0)711-970 4111Email: schmid-staiger@igb.fraunhofer.de
schmid-staiger@igb.fraunhofer.de
Downstream processes of microalgae: Eicosapentaenoic acid (EPA)
• preextraction with EtOH
• wet Biomass shows betterresults than dried biomass
• only 2 extraction steps arenecessary
27,4
77,6
12,7
5,3
9,6
0,0
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2% dried biomass 2% wet biomass
Yie
ld [%
]
3. extraction2. extraction1. extraction
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