15-AlgaeBiorefineryWorms0909

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Dr. Ulrike Schmid-Staiger

National German Workshop on Biorefineries

15th September 2009, Worms

Algae Biorefinery - Concepts



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Microalgae - microscopic small „plants“

Ubiquitous - seawaterfreshwatersoilair

About 40.000 different algae in

marine water sytems

Algae are consumed by

mankind for thousand of years

40-50 Gigatons of carbon arefixed by marine algae every

year



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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, CO2, and anorganic

nutrients 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 CO2).

Microalgae can be cultivated in seawater or brackish wateron 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.



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Lipids

Main components of microalgae

Algae

Proteins

• high contentup to 50% ofdry weight ingrowing

cultures

• all 20 aminoacids

Carbo-hydrates

• storage productsά-(1-4)-glucansß-(1-3)-glucans,fructans

sugars, glycerol

• only very lowcellulose content

storage lipids

• mainly TAGs

• up to 50% of DW

• with solventsextractable from

wet biomass

• recovery by

pressing out thedry and rupturedbiomass

valuableCompounds

• 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 solvent

extraction of wetbiomass, thentransesterification



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Valuable compounds from microalgae

Pigments / Carotenoids

ß-CaroteneAstaxanthinLuteinZeaxanthinCanthaxanthin

ChlorophyllPhycocyaninPhycoerythrinFucoxanthin

Fatty acids (PUFAs)DHA (C22:6)EPA (C20:5)ARA (C20:4)GAL (C18:3)

VitaminsA, B1, B6, B12, C, EBiotineRiboflavinNicotinic acidPantothenate

Folic acid

AntioxidantsCatalasesPolyphenolsSuperoxid Dismutase

Tocopherols

Other / PharmaceuticalsAntifungal

AntimicrobialAntiviral

Toxins

Amino acids, ProteinsSterolsMAAs as light protectant



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Utilization of microalgae biomass

Lipids

Proteins

Carbo-hydrates

valuableCompounds

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



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Sustainable Algae-based Processes

CHP-Plant

MicroalgaeCultivation

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

Recycling



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Comparison between different cultivation systems

highhighlowBiomass concentration

lowhighhighEnergy demand per kgbiomass 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 !



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static mixermain targeted flow

deep-drawn PVC half-shellsincluding the static mixers

High productivity by a sophisticated system of staticmixers 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



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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



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11

0

20

40

60

80

100

120

140

160

Energieaufwand / Energy

demand (MJ/kg DW)

Raceway Rohrreaktor

horizontal,

gepumpt*

Rohrreaktor

helical,

gepumpt*

Rohrreaktor

vertikal,

gepumpt**

Flat Panel

Reaktor, Uni

Almeria*

FPA , Subitec

derzeit §

FPA , Subitec,

Ziel §

Comparison of the energy input per kg DW of different production systems



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CHP-Plant



Solar Energy


CO2



thermal Energy

Biogas Technology

Input Output

• Carbohydrates

• Proteins

• Lipids, PUFAs

• Antioxidants

• Pigments

• Silicates


Production DSP

Residual Biomass


Extraction



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Growth and Biomass Productivity in FPA-Reactors exemplary of

Phaeodactylum tricornutum

High biomass productivity at even high biomassconcentrations due to efficient intermixing

Dependency of biomass productivity of relative lightintensity 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

D W ( g

/ l )

0

400

800

1200

L i g h t i n t e

n s i t y

( µ E 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

)

P r o d

. ( g D W 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 r o d . ( g D W

l - 1 d - 1 ) ; Y l i g h t

( g D W / E )

Ylight

(g DW/E)



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Production of storage products in microalgae

Growing algal cells

N- and P-limitation

valuable

compound

proteins

carbohydrate

s

lipids

pigments

Carbohydrates as energy storage product

valuable

compound

proteins

carbohydrates

lipidspigments

valuablecompound

proteins

carbohydrates

lipids

pigments

Lipids as energy storage product



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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)

l i p i

d s

( % o

f d r y w e i g h t )

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 1,2

rel. light availability (E g DW-1*d-1 )

L i p

i d i n c r e a s e p e r d a y

( % )

Optimized production



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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



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Downstream Processing

Algaeproduction Cell harvest Drying Cell disruption

Extraction /

Purification Products

Process line

1

2

3

Separation

Filtration

Precipitation

Flotation

Spray drying

Superheatedsteam

High pressure

homogenizer

Ball mill

Fast expansion

from drybiomass

Fluid extraction

org. solventsl / H2O

Supercritical fluidsscCO2

Fluid extractionorg. solventsl / H2O

from wetbiomass

hydrophilic

• Proteins

• Starch• Glycerine

• Vitamins

• Micronutrients

lipophilic

• Oils

• Fatty acids (PUFA)

• Carotenoids• Steroids

Residualbiomass

FhG1



Slide 17

FhG1 Th e challenge foralgal biomass harvesting is to take the very low cell density

and 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



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CHP-Plant



Solar Energy


CO2



thermal Energy

Biogas Technology

Input Output

• Carbohydrates

• Proteins

• Lipids, PUFAs

• Antioxidants

• Pigments

• Silicates


Production DSP

Waste Biomass


Extraction



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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

+ +Ethanol

EPA

G l y c e r o l

G l y c e r o l

Lipase/

Alkali-catalyst EPAFatty acid

Fatty acid



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r

scCO2 SourcescCO2-Extraction

Extraction with scCO2

Expansion

EPA

EtOH

Extraction

(2. steps)1h, RT

Lipase/KOH

Trans-esterification/Saponification

Centrifugation

(filtration)

Preextraction withtransesterification


Algaecultivation



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Downstream processes of microalgae: Astaxanthin

r

scCO2 SourcescCO2-Extraction

Extraction with scCO2

Expansion

Astaxanthinoil

Drying and grindingAlgae

cultivation

Drying Grinding



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Energy conversion processes from microalgae



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Schematic process of biodiesel production



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CHP-Plant



Solar Energy


CO2



thermal Energy

Biogas Technology

Input Output

• Carbohydrates

• Proteins

• Lipids, PUFAs

• Antioxidants

• Pigments

• Silicates


Production DSP

Residual Biomass


Extraction

Recycling



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Outlook: Integrated process for mass and energy based utilization of

microalgae

Products: pigments

ω-3-fatty acids

vitamins

residual biomass

digestion / codigestion

CO2

NH4, PO4

recycling

1,85 kg CO2 are fixedper kg algal biomassproduced

CHPS

Algal biomassH2O

CO2

O2CH2O

Calvin-

ZyklusLichtreaktionen

ATP+NADPH+H+

ADP+ Pi

+NADP+

Energie

8 MJ electricity

12 MJ heatper m³ biogas

Biogas

organic wastes



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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 utilizationfree of lignocellulose, conversion to biogas by anaerobic digestion,

• Recycling of nutrients

CO2, nitrogen, phosphate

• Water use

quantity and quality



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Thank you for your attention

Ulrike Schmid-Staiger, Ph.D.Fraunhofer IGB

Nobelstr. 12

70569 StuttgartTel. +49-(0)711-970 4111

Email: [email protected]



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• 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

Y i e l d [ % ]

3. extraction2. extraction1. extraction

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15-AlgaeBiorefineryWorms0909