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Evaluation of second generation biofuels production from native halophytes by chemical-characterization of Salicornia sinus-persica Ayah Alassali, Iwona Cybulska, Mette H. Thomsen
[email protected], phone: +971 28500121
Thursday, December 19, 2013 Version 1
2
Contents
• Introduction
– Masdar Institute and SBRC
– The importance of halophytes for desert areas
• Study objectives
• Methodology
– Sugar content
– Extent glucan to glucose convertibility
• Results
– Wet fractionation results
– Sugar content analysis for juice
– Juice fermentability
– Sugar content analysis for pulp
– Fibers fermentability
• Conclusions
Thursday, December 19, 2013
3
Introduction
Thursday, December 19, 2013
Masdar Institute
The Masdar Institute of Science and Technology (Masdar Institute) is a graduate level, research-oriented university which is focused on alternative energy, sustainability, and the environment.
4
Introduction
SBRC
• The Sustainable Bioenergy Research Consortium was established by the Masdar Institute of Science and Technology.
• The SBRC is focused on research in sustainable biofuels and biomaterials derived from the conversion of plant oils and biomass.
Thursday, December 19, 2013
6
Introduction
• Abu Dhabi exemplifies a coastal desert, where seawater could be used for salt-tolerant crops (halophytes) cultivation.
• The produced halophyte biomass could be utilized in feed, food and/or energy production, depending on its chemical composition.
• In this study the UAE native halophyte Salicornia sinus-persica was studied for its potential to be used as a feedstock for green biorefinery.
Thursday, December 19, 2013
8
Methodology
Washed Salicornia
Unwashed Salicornia
Juicing Fibers
Juice
Sugar monomer composition analysis by HPLC
Weak acid hydrolysis Fresh untreated juice
Strong acid hydrolysis Dry matter and ash
content analysis
Dry matter and ash
content analysis
Sugar analysis
9
Methodology
Extent glucan to glucose convertibility
Thursday, December 19, 2013
Juice
Autoclaved at 121 ˚C, 20 min.
Fresh/ no-pretreatment SSF
SSF conditions: cellulases (Novozymes) was used, with a pre-hydrolysis time of 2 hours
at 50 C with intensive shaking (120 rpm) prior to addition of S. cerevisiae at 32C for 7
days.
Fibers Mildly pretreated at 121 ˚C, 30 and 60 min.
Fresh/ no-pretreatment
Hydrothermal pretreatment
SSF
10
Results
Wet fractionation/ DM and ash content
DM (%) Ash (%) of the DM
22.42 97.89
Thursday, December 19, 2013
Fresh biomass
76.78%
18.19%
Juice
Fibers
DM (%) Ash (%) of the DM 38.88 19.18
DM (%) Ash (%) of the DM 13.53 61.12
11
Results
Fresh juice vs. acid hydrolyzed juice cellulose and inhibitors content
Thursday, December 19, 2013
•Washing had no effect on sugar composition
•Acid hydrolysis increases pentose content
•Total sugar content of the juice is approx. 1-1.5% (comparable to
other green biomasses such as grass and clover)
0
1
2
3
4
5
6
7
Unwashed-fresh juice Unwashed-WAH Washed-freshjuice Washed-WAH
Co
nce
ntr
atio
n (
g/L)
Glucose
Xylose
Arabinose
Acetic acid
Ethanol
12
Results
Juice fermentation
Thursday, December 19, 2013
-1
0
1
2
3
4
5
6
7
8
-3 17 37 57 77 97 117 137 157 177
Co
nce
ntr
atio
n (
g/L
)
Time (hours)
Glucose
Xylose
Arabinose
Ethanol
Lactic acid
Acetic acid
Formic acid
Fermentation of fresh juice of Salicornia sinus-persica with S. cerevisiae
13
Results
Juice fermentation
Thursday, December 19, 2013
0
20
40
60
80
100
120
-3 47 97 147 197
Eth
ano
l yie
ld (
%)
Time (h)
14
Results
Autoclaved (121 ˚C for 20 minutes) vs. fresh Juice fermentation
Thursday, December 19, 2013
0
1
2
3
4
5
6
Co
nce
ntr
atio
n (
g/L
)
Lactic acid
Formic acid
Acetic acid
Ethanol
Furfural
15
Results
Fiber’s sugar content after strong acid hydrolysis of fresh biomass
Thursday, December 19, 2013
0
2
4
6
8
10
12
14
Fibers of washed biomass Fibers of unwashed biomass
Co
nte
nt
(g/1
00
gDM
)
Glucose
Xylose
Arabinose
16
Results Sugar content after mild pretreatment of the fibers at 121 ˚C for 30 and 60 min.
Thursday, December 19, 2013
0
5
10
15
20
25
30-W 30-Un 60-W 60-Un
con
cen
trat
ion
(g/
10
0 g
DM
)
Glucose
Xylose
Arabinose
• The monomeric sugars were concentrated
• Pretreatment duration did not influence the sugar concentration
17
Results
Thursday, December 19, 2013
0
10
20
30
40
50
60
70
80
90
121°C, 30-min,hydrolyzate
121°C, 30-min, water(diluted)
121°C, 60-min,hydrolyzate
121°C, 60-min, water(diluted)
Eth
ano
l yie
ld (
% o
f th
e t
he
ore
tica
l)
Ethanol yield in SSF of pretreated pulp from wet fractionation of Salicornia sinus-persica after mild pretreatment.
18
Results
Fiber’s sugar content – w/wo pretreatment
Thursday, December 19, 2013
0
5
10
15
20
25
30
35
Fresh Pretreated @ 121˚C Pretreated @ 150 ˚C Pretreated @ 170 ˚C
con
ten
t (g
/10
0gD
M)
Lactose
Glucose
Xylose
Galactose
Fructose
Ash
19
Results
Ethanol yields after SSF of fresh and pretreated fibers
Thursday, December 19, 2013
-
10.00
20.00
30.00
40.00
50.00
60.00
70.00
80.00
90.00
100.00
Fresh Treated @121, 10minutes
Treated @150, 10minutes
Treated @170, 10minutes
Eth
ano
l yie
ls (
% t
o t
he
th
eo
reti
cal e
than
ol c
on
ten
t)
• Low severity factors
• Ethanol yield can reach up to 86% when treated at 170 ˚C for 10 minutes
20
Conclusion
Thursday, December 19, 2013
• Fresh Salicornia sinus-perica contains more than 70% of water. For such green biomass direct fractionation and fermentation can be advantageous. This allows for water preservation and the ability to run at lower dry matter in the fermentation step.
• High yield per hectares (green biomass yield up to 50 tons/ha/year) and possibility of harvesting several times per year.
• Biomass washing does not significantly enhance juice/fibers fermentation.
• Juice autoclaving does not enhance the ethanol fermentation, however minimize inhibitor s’ formation.
• Juice fermentation can obtain up to 100% yield of ethanol (based on theoretical yields).
• Fibers free sugars content increase with increasing the pretreatment temperature, however the possibility of producing inhibitors increases as well.