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Dr. Ulrike Schmid-Staiger
National German Workshop on Biorefineries15th September 2009, Worms
Algae Biorefinery - Concepts
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
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.
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
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
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
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
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 !
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
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
0
20
40
60
80
100
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
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
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
10
15
20
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
0,4
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)
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
Energetic use: Microalgal lipid production
���� Microalgal lipid production depends strongly on available light per cell
0
10
20
30
40
50
60
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
4
5
6
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
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
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
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
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
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
Downstream processes of microalgae: Astaxanthin
Vorlagebehälter
scCO2 SourcescCO 2-Extraction
Extraction with scCO 2
Expansion
Astaxanthinoil
Drying and grindingAlgaecultivation
Drying Grinding
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
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
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
Thank you for your attention
Ulrike Schmid-Staiger, Ph.D.Fraunhofer IGBNobelstr. 1270569 StuttgartTel. +49-(0)711-970 4111Email: [email protected]
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
0
10
20
30
40
50
60
70
80
90
100
2% dried biomass 2% wet biomass
Yie
ld [%
]
3. extraction2. extraction1. extraction
