Biochemical Characterization of Amaranthus Cell Wall as a Lignocellulosic Biomass Resource in biorenewable

Energy Production

Andre Salazar

Olga A. Zabotina

Biochemistry Department

Iowa State University

Amaranthus – Biomass Resource

• Amaranthus – Food Production ◦ Agricultural seed ◦ Environmentally tolerant and adaptable

• Amaranthus – Energy Production ◦ Plant cellulose and monosaccharides◦ Lignocellulosic ethanol

• Amaranthus – Potential Economic Impact ◦ Sustainable Supplement to grain production

Research Objective

• Hypothesis ◦ Amaranthus is a viable biomass resource for lignocellulosic

ethanol production in comparison with plant resources under evaluation.

• Objectives ◦ Determine biochemical carbohydrate properties of Amaranthus

cell wall ◦ Compare Amaranthus to other plants proposed as biomass

resources in lignocellulosic ethanol production ◦ Improve Amaranthus biomass model with the inclusion of cell

wall biochemical properties

Experimental Information

• Plants ◦ Amaranthus cruentus – DB98246 ◦ Amaranthus hypochondriacus – PI558499

• Plots ◦ Single row (each plant) – 20 ft long, 5 ft apart

• Biochemical Analysis ◦ Plant – Stem diameter and height, and mass ◦ Cell Wall – Cellulose, lignin, monosaccharides

• Data Statistical Analysis ◦ Mean Comparison – Anova ◦ Covariance Comparison – Correlation

Field and Sample Data

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Stem Diameter (4 wks) Stem Height (4 wks) Stem Diameter (8 wks) Stem Height (8 wks)

cm

A. cruentus (Field) A. cruentus (Sample)

A. hypochondriacus (Field) A. hypochondriacus (Sample)

Plant Stem Properties

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100.0

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Stem Diameter (4 wks) Stem Diameter (8wks) Stem Height (4 wks) Stem Height (8 wks)

cm

A. cruentus A. hypochondriacus

Plant Mass Results

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400.0

600.0

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Stem Mass (4 wks) Stem Mass (8wks) Leaf Mass (4 wks) Leaf Mass (8 wks)

gm

A. cruentus A. hypochondriacus

Plant Dry Mass Results

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Plant Dry Mass (4 wks) Plant Dry Mass (8 wks) Cell Wall Dry Mass (4 wks) Cell Wall Dry Mass (8 wks)

Per

cen

t T

ota

l Mas

s

A. cruentus A. hypochondriacus

Cellulose and Lignin

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A. cruentus A. hypochondriacus M. sinensis Switchgrass Maize Stover

Per

cen

t M

ass

/ mg

Dry

Cel

l Wal

l

Cellulose Lignin

Percent Total Monosaccharide Molecular Mass

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20.00

40.00

60.00

80.00

A. cruentus A. hypochondriacus M. sinensis Switchgrass Maize Stover

Per

cen

t / m

g D

ry C

ell W

all

Glucose Xylose Galactose

Summary

• Amaranthus Plants ◦ Stem and Leaf measurements – No significant difference ◦ Plant dry and cell wall mass – No significant difference ◦ Cellulose and lignin – No significant difference ◦ Xylose – A. hypochondricus > A. cruentus

• Biomass Plant Comparison ◦ Cellulose – No significant difference ◦ Lignin – M. sinesis > switchgrass > Amaranthus ◦ Glucose – Maize > M. sinesis, switchgrass , Amaranthus ◦ Xylose – Switchgrass > M. sinesis, Maize > Amaranthus ◦ Galactose – Amaranthus > M. sinesis, Maize, switchgrass

• Correlation – Plant measurement to mass

Conclusions

• Amaranthus Plants ◦ No significant difference ◦ Xylose content

• Biomass resource ◦ Amaranthus comparable to other resources

• Cellulose – Equivalent content • Lignin – Less content • Monosaccharide – Equivalent to Maize stover

Additional Research

• Amaranthus◦ Analyze cell wall biochemical properties at 16 wks ◦ Evaluate results for correlations ◦ Evaluate data fit into biomass model