Caffè Scientifico
Sezione di Oceanografia
ALGAL BIOMASS AND RENEWABLE ENERGY:
CO2 EFFECTS ON GROWTH AND LIPID COMPOSITION
OF MICROALGAE
Federica Cerino
gruppo MaB – Biologia Marina
27 maggio 2014
Energy-Environment
80% OF GLOBAL ENERGY DEMAND IS PRODUCED FROM FOSSIL FUEL
[CO2] = from 326 ppm (1970) to 395 ppm (2013)
Kyoto
Protocol
(1997)
Doha
Conference
Horizon 2020:
-20% CO2
+20% energy efficiency
+20% renewable energy
Biomass
Organic material, animal or vegetal
• Heat
• Electricity
•
•
•
•
•
Biogas
Bioethanol
Biohydrogen
Pure vegetal oil
Biodiesel
Biodiesel
Mixture of fatty acyd alkyl esters, obtained from
vegetable oils and animal fats
TRANSESTERIFICATION
triglycerides
alcohol
glycerol
fatty acid alkyl esters
ADVANTAGES:
- closed carbon cycle
- highly biodegradable
- renewable
- minimal toxicity
- it can be used in existing diesel engines with little or no modification
Biodiesel
1st generation (edible)
•
•
•
•
•
•
corn
sugar cane
sunflower
rapeseed
soybeans
palm oil
2nd generation (nonedible)
•
•
•
•
•
•
•
•
•
jatropha
mahua
jojoba oil
tobacco seed
salmon oil
sea mango
waste cooking oil
restaurant grease
animal fats
3th generation
• microalgae
Microalgae
Microalgae are prokaryotic and eukaryotic photosynthetic organisms
They are present in all earth ecosystem (aquatic and terrestrial) and live
in a wide range of environmental conditions
They reproduce themselves using photosynthesis to convert sun energy
into chemical energy
They are responsible for about half of the global net primary production
They have a high efficiency in the CO2 fixation
It is estimated that more than 50,000 species exist, but only around
30,000 have been studied and analysed (Richmond, 2004)
Microalgae
Easy to cultivate
Tolerate sub-optimal
conditions
High growth rates and
productivity
Require much less
land area
High oil content
High oil yield
Microalgae
Plant source
Seed oil content
(% oil by WT in
biomass)
Oil yield
(L oil/ha year)
Land use
(m2 year/kg
biodiesel)
Biodiesel productivity
(kg biodiesel/ha year)
Corn/Maize (Zea mays L.)
44
172
66
152
Hemp (Cannabis sativa L.)
33
363
31
321
Soybean (Glycine max L.)
18
636
18
562
Jatropha (Jatropha curcas L.)
28
741
15
656
Camelina (Camelina sativa L.)
42
915
12
809
Canola/Rapeseed (Brassica napus L.)
41
974
12
862
Sunflower (Helianthus annuus L.)
40
1070
11
946
Castor (Ricinus communis)
48
1307
9
1156
Palm oil (Elaeis guineensis)
36
5366
2
4747
Microalgae (low oil content)
30
58,700
0.2
51,927
Microalgae (medium oil content)
50
97,800
0.1
86,515
Microalgae (high oil content)
70
136,900
0.1
121,104
Mata et al., 2010
Microalgae - Biodiesel
growth medium/nutrient concentration
light
temperature
pH
air/CO2
Mata et al., 2010
Microalgae - Biodiesel
CRESCITA
fatty acids (%)
40
30
20
10
0
control
medium/2 medium/4
LIPID
CONTENT
mineral
N/4
fatty acid composition (%)
100
BIOMASS
80
60
40
20
0
control
medium/2 medium/4
saturated
monounsaturated
N/4
mineral
polyunsaturated
Aim
To analyze the answers of two microalgae to different
CO2 concentrations
CELL GROWTH
LIPID CONTENT
Chlorella vulgaris
Pleurochrysis cf. pseudoroscoffensis
Material & Methods
air
gas mixer
illumination
pH controller
CO2
• 2 cylindrical photobioreactors, in
plexiglass
• 20 L max volume
• photoperiod controller
• pH controller
• gas-mixer
Material & Methods
Chlorella (green algae)
Chlorophyceae
•
•
Generally unicellular
and colonial, but also
pluricellular
Abundant in freshwater
environments
Chlorella vulgaris
•
•
Highly resistant
Easily cultivable with a high growth rate
Used for:
• CO2 sequestration
• Wastewater depuration
• Nutritional supplement
• Applications in human health
Material & Methods
air
gas mixer
illumination
Chlorella (green algae)
CO2
cellular growth
• cell abundances
• growth rate
• duplication time
• maximum concentration
lipid content
• total lipid content
• fatty acid composition
pH controller
control
CO2 1%
T=20 ± 1°C
L:D=12:12
light=250-300 µE m-2s-1
Results
Chlorella (green algae)
CO2
10 6 cells ml -1
C
45
40
35
30
25
20
15
10
5
0
0 1 2 3 4 5 6 7 8 9 1011121314151617181920212223
day
Max= 36 · 106 cell ml-1
µ= 1.17 d-1
T2= 14
Max= 32 · 106 cell ml-1
µ= 1.38 d-1
T2= 12
Results
Chlorella (green algae)
fatty acids (%)
100
80
60
40
20
0
C
CO2
100%
fatty acid composition
fatty acid composition
100%
80%
60%
40%
20%
0%
C
saturated
monounsaturated
CO2
polyunsaturated
80%
60%
40%
20%
0%
C
CO2
C16
C18
C20
C16:1 cis9
C18:1 cis9
C18:1n7
C18:2 cis9,12
C18:3 cis9,12,15
Material & Methods
Pleurochrysis (coccolithophore)
Coccolithophores (Prymnesiophyceae)
• calcareous nanophytoplankton
• with external calcite (CaCO3) plates (coccoliths)
covering their surface
Play key roles in:
• marine ecosystem as primary producers
• marine biogeochemistry as producers of organic
carbon, carbonate and dimethylsulphide
Pleurochrysis cf. pseudoroscoffensis
• marine species isolated in the
Gulf of Trieste
10 µm
5 µm
Material & Methods
air
gas mixer
illumination
Pleurochrysis (coccolithophore)
CO2
cellular growth
• cell abundances
• growth rate
• duplication time
• maximum concentration
lipid content
• total lipid content
• fatty acid composition
morphometric analysis
pH controller
• cellular size
• coccolith size
chemical parameters
control
CO2 1%
CO2 2%
• nutrients
• POC/PIC/PTN
• pH
Results
Pleurochrysis (coccolithophore)
500
400
400
-1
500
300
200
p <0.05
100
0
0
1
2
3
4
5
day
6
7
8
9
CO2 2%
pH= 8.1 ± 0.4
3
3
pH= 7.5 ± 0.2
10 cells ml
-1
pH= 8.4 ± 0.3
10 cells ml
CO2
C
CO2 1%
pH= 7.1 ± 0.1
300
200
100
0
0
1
2
3
4
5
day
6
7
8
9
Max= 2.86 · 105 cell ml-1 Max= 4.32 · 105 cell ml-1
µ= 0.86 d-1
µ= 1.01 d-1
T2= 19
T2= 16
Max= 2.71 · 105 cell ml-1 Max= 3.85 · 105 cell ml-1
µ= 0.82 d-1
µ= 1.06 d-1
T2= 20
T2= 16
Results
3500
-1
PTN (µmol l )
2500
2000
1500
2500
2000
1500
1000
1000
500
500
0
3500
0
3500
3000
3000
-1
2500
2000
1500
2500
2000
1500
500
500
0
14000
0
14000
12000
12000
-1
POC (µmol l )
1000
10000
8000
6000
4000
10000
8000
6000
4000
2000
0
CO2 2%
3000
1000
POC (µmol l )
-1
3000
Pleurochrysis (coccolithophore)
3500
PIC (µmol l )
-1
PIC (µmol l )
-1
PTN (µmol l )
CO2 1%
CO2
C
2000
0
1
2
3 4
5
day
6
7
8
9
0
0
1
2
3 4
5
day
6
7
8
9
Results
Pleurochrysis (coccolithophore)
CO2 1%
CO2
C
14
14
C A1
C A2
CO2 A1
CO2 A2
10
8
6
4
0
9d
3.0
3.0
CL
CW
CO2 L
2.0
1.5
1.0
0.5
5h
CL
CO2 W
coccolith size (µm)
2.5
3d
7d
4
0
8d
CO2 A2
6
0
3d
day
CO2 A1
8
2
5h
C A2
10
2
0
C A1
12
cell size (µm)
cell size (µm)
12
coccolith size (µm)
CO2 2%
CW
day
CO2 L
2.5
2.0
1.5
1.0
0.5
0.0
0.0
3d
day
9d
2d
6d
day
CO2 W
Results
Pleurochrysis (coccolithophore)
CO2 1%
10 µm
C
10 µm
CO2 2%
CO2
10 µm
10 µm
Results
Pleurochrysis (coccolithophore)
CO2 1%
CO2 2%
20
total lipid content (%)
total lipid content (%)
20
15
10
5
15
10
0
0
C
CO2 1%
100
90
80
70
60
50
40
30
20
10
0
C
fatty acid composition (%)
fatty acid composition (%)
5
C
saturated
C16
100
90
80
70
60
50
40
30
20
10
0
CO2 1%
monounsaturated
C17
polyunsaturated
C18
CO2 2%
C
saturated
C16
CO2 1%
monounsaturated
C17
polyunsaturated
C18
C20
C22
C24
C20
C22
C24
C16:1 cis9
C18:1 cis9
C20:1 w 9
C16:1 cis9
C18:1 cis9
C20:1 w 9
C22:1 w 9
C18:2 cis9,12
C18:3 cis 9,12,15
C22:1 w 9
C18:2 cis9,12
C18:3 cis 9,12,15
Conclusions
Chlorella (green algae)
• higher growth rate
• higher number of divisions per day
• higher lipid content
Potential utilization in biodiesel production
Pleurochrysis (coccolithophore)
In both experiments (1 and 2% CO2):
•
•
•
•
biomass increase
higher growth rate
higher number of division per day
slight effect on morphology
In the experiment with CO2 2%, the maximum of biomass was
reached earlier
Potential utilization in CO2 removal
Perspectives
•
To test other species and strains
•
To search for the best growth conditions to have higher lipid
synthesis and higher cell growth
•
To test the effects of other culture conditions (light, salinity,
nutrients, temperature)
•
To test the combined effects of several different factors to analyze
their eventual sinergy in the lipid production
Perspectives
wastewater
Biodiesel
light
CO2
Lipids
Cosmetic
nutrients
Animal feed
HARVESTING
PROCESSING
Proteins
Nutritional supplement
Ethanol
BIOREFINERY
Carbohydrates
THANK YOU
Si ringraziano per la collaborazione:
- Cinzia Comici
- Martina Kralj
- Gianmarco Ingrosso
- Ana Karuza
- Cinzia Fabbro
- Cinzia De Vittor
- Michele Giani
- Prof. Bogoni, UNITS
- Prof. Procida, UNITS
- Dott. Urbani, UNITS
Parte di questo studio è inserito nel progetto CO2 Monitor
Results
Pleurochrysis (coccolithophore)
CO2
C
CO2 1%
800
800
600
400
200
P-PO 4 (µmol L )
0 1 2 3 4
5
day
600
400
200
0
6 7 8 9
50
50
40
40
P-PO 4 (µmol L-1)
-1
0
-1
N-NO3 (µmol L -1)
1000
N-NO3 (µmol L )
1000
30
20
10
0
0 1 2 3 4
5
day
6 7 8 9
CO2 2%
0 1 2 3 4
5
6 7 8 9
5
6 7 8 9
day
30
20
10
0
0 1 2 3 4
day
Perspectives
la produzione di biodiesel da microalghe
non è ancora una realtà commercialmente significativa
 abbattimento dei costi relativi alla somministrazione di nutrienti, tramite il trattamento delle
acque reflue e l’utilizzo dei nutrienti in esse presenti
 abbattimento dei costi relativi alla somministrazione di CO2, tramite il recupero e utilizzo dei
gas di scarico industriali come fonte della CO2 necessaria alla crescita
 abbattimento del dispendio idrico necessario al mantenimento delle colture tramite riciclo dei
mezzi
 miglioramento delle tecniche per il processamento della biomassa, soprattutto per quanto
riguarda la fase di raccolta
 applicazione di tecniche di ingegneria genetica per incrementare l’efficienza fotosintetica e
quindi il rendimento della biomassa, il miglioramento del tasso di crescita, del contenuto in olio,
e della tolleranza alla temperatura
 risoluzione del problema dell’applicazione su larga scala dei risultati ottenuti in laboratorio
(scaling-up); allestimento di impianti pilota su larga scala da cui ottenere dati che possano essere
usati per valutazioni di fattibilità economica