Agro-energy
g
gy feedstock: Miscanthus



1
Miscanthus x giganteus
 Sterile hybrid propagated though rhizomes
Bulk sample harvested in Germany Air dried and
stored in freezer
Composite sample being used for all analyses
Biomass to Bioethanol
Agro-energy
g
gy feedstock: Miscanthus

Perennial crop
Grows to 11-14 ft in height/year

High biomass yields
C4 grass with high rate of carbon fixation
14 – 17 tons/acre
t
/
((up tto 27 ttons/acre
/
iin ttrials)
i l )
Crop stands survive 25-30 years without
significant loss in biomass yields

2
Presently used in Europe for power and heat
generation
ti
Biomass to Bioethanol
Moisture and Ash content

Moisture content of air dried
Miscanthus sawdust (6 mm)
4 6%
4.6%

Ash content
Measured
Me
ed b
by ramped
mped he
heating
ting to 525
°C in a muffle furnace
2 2%
2.2%
Higher than Loblolly pine (0.2 %) &
sweetgum (0.8
(0 8 %)
3
Biomass to Bioethanol
Elemental analysis
y
Measured on 0.05 mm ground samples using elemental micro analyzer
60.0
50.0
Miscanthus
Sweetgum
Loblolly Pine
Wt.%
40.0
30.0
20.0
10 0
10.0
0.0
C
4
H
O
Biomass to Bioethanol
N
Inorganic
g
elements
Analyzed in 6 mm ground samples
 Acid digestion followed by ICP-emission
spectroscopy
 Coulometric method for total halogen (Cl+Br+I)

5
Biomass to Bioethanol
Inorganic
g
elements
380.0
360.0
340 0
340.0
320.0
Miscanthus
Sweetgum
L.Pine
300.0
Co
ontent (mg/Kg)) o.d. weight
280.0
260.0
240.0
220.0
200 0
200.0
180.0
160.0
140.0
120.0
100.0
80.0
60 0
60.0
40.0
20.0
0.0
Ba
6
Cu
Fe
Na
Biomass to Bioethanol
P
Si
Inorganic
g
elements
2000.0
Conte
ent (mg/Kg ove
en dried weig
ght)
1750.0
Miscanthus
Sweetgum
L.Pine
1500.0
1250.0
1000.0
750 0
750.0
500.0
250.0
0.0
Ca
7
K
Mg
S
Biomass to Bioethanol
Mn
Cl+Br+I
Extractives
Solvent-soluble, non-volatile
material
 Extracted with dichloromethane
 Characterized using GC-MS
 Extractives content:

Condenser
Sample
1.0 %
 2.9 % for Loblolly pine
 0.4 % for Sweetgum
Water soluble extractives (important
for grassy biomass)
 3.6 %
8
Biomass to Bioethanol
Solvent
Dichloromethane extractives composition
400.0
microgra
ams/g o.d. weight
350.0
300.0
Miscanthus
Sweetgum
L.Pine
250 0
250.0
200.0
150.0
100.0
50.0
9
Biomass to Bioethanol
at
ic
Li
gn
in
/A
ro
m
ol
s
er
St
no
ls
lk
a
A
in
es
R
C
ar
bo
xy
lic
ac
ac
id
s
id
s
0.0
10
9,
12
Biomass to Bioethanol
ic
er
ol
er
ol
as
t
Si
to
st
ig
m
d
er
ol
ac
i
no
l
id
20 0
20.0
St
et
sa
Er
go
st
ab
ie
ac
o
ac
d
O
ro
ct
ca
no
ic
O
ad
e
ac
i
d
d
d
ac
i
ac
i
ac
i
micrograms//gram o.d. mis
scanthus
120.0
eh
yd
ct
ca
di
en
oi
c
ic
ic
ic
ca
no
ca
no
ca
no
ad
e
ad
e
O
ct
D
-O
H
ex
ad
e
tra
de
Pe
nt
Te
Dichloromethane Extractives : Miscanthus
OH
100.0
80.0
C2H 5
60.0
40.0
COOH
HO
0.0
Water soluble extractives: Miscanthus
Compound
Amount (µg/g Miscanthus)
Alpha-L-Galactopyranose
p
py
40.24
Alpha-D-Arabinopyranose
52.81
Xylitol
512.22
D Gl
D-Glucose
30 12
30.12
p-hydroxyl cinnamic acid
1145.21
D-Mannitol
1358.42
Mannose
105.84
O
CH2OH
O
OH
OH
OH
Mannitol
OH
Xylitol
OH
OH
HO
OH
O
OH
HO
OH
OH
OH
M
Mannose
Gl
Glucose
A bi
Arabinopyranose
P-hydroxyl cinnamic acid
11
Biomass to Bioethanol
Acid soluble and insoluble lignin
g

Klason lignin
 Acid insoluble lignin isolated using NREL methods
 Extractive free (40 mesh) sample hydrolyzed using 72 % H2SO4

Acid soluble lignin
 Measured using UV-vis spectrophotometer
 Calculated from absorption at 205 nm

Pretreatment effluents
 pH adjusted by the addition of 72 % H2SO4 and autoclaved at 121
°C for
f 1 hour
h
 Solution filtered and lignin content measured as the sum of solid
residue ((Klason lignin)
g ) and soluble lignin
g
measured with UV.
12
Biomass to Bioethanol
Lignin
g
content and composition
Klason lignin
Miscanthus: 25 %
Loblolly pine: 29 %
Sweetgum: 26 %
 CH OH
2
CH2OH
CH2OH
 CH
CH
CH
 CH
1
CH
1
CH
1
6
4
13
3
4
OCH3 CH3O
OH
OH
Guaiacyl
SW x
HW x
Grass x
Biomass to Bioethanol
6
2
5
3
5
Acid
A
id soluble
l bl lilignin
i
Miscanthus: 1.1 %
Loblolly pine: 0.5 %
Sweetgum: 2.6
26%
6
2
OCH3
2
3
5
4
OH
Syringyl
p-Coumaryl
x
x
x
x
x
Carbohydrate
y
analysis
y




40 mesh extractive free wood
Hydrolyzed with 72 % H2SO4
Diluted to 3% H2SO4 and autoclaved at
121°C
121
C for 1 hour
For pretreatment effluents
p adjusted
pH
j
byy the addition of 72 %H2SO4
Autoclaved at 121 °C for 1 hour
Filtered and filtrate used for sugar analysis

14
Sugars
S
ga s meas
measured
ed using
sing HPLC with
ith
pulsed amperometric detector
Biomass to Bioethanol
Carbohydrate
y
profile
60.0
OH
55.0
O
HO
OH
OH
%d
dry weight o
of carbohyd
drates
00
50.0
OH
45.0
40 0
40.0
Miscanthus
Sweetgum
L.Pine
35.0
30 0
30.0
O
OH
25.0
CH2OH
OH
OH
O
OH
OH
OH
20.0
15.0
CH2OH
O
OH
HO
O
10.0
5.0
OH
OH
OH
OH
OH
HO
OH
0.0
A bi
Arabinose
15
G l t
Galactose
Gl
Glucose
X l
Xylose
Biomass to Bioethanol
M
Mannose
OH
Summary:
y Miscanthus composition

Higher ash content than sweetgum or pine
Hi h contents
Higher
t t off P,
P K,
K Si and
d halides
h lid
Dichloromethane extractives mostly carboxylic
acids,
d alkanols
lk
l and
d sterols
l
 Water extractives mostly derived from
carbohydrates
 26 % total lignin content

Lower than woody biomass feedstocks

Carbohydrates are mostly glucose and xylose
Xylose content highest among the three feedstocks
16
Biomass to Bioethanol