Use of Amaranth as Feedstock for Bioethanol Production

Energy Postgraduate Conference 2013

Nqobile Xaba

MSc student

North-West University

Background

• Biomass is considered one of the viable renewable energy resource.• Due to implications brought by the use of fossil derived fuels

(elevation of greenhouse gases)• Biomass based fuels include bioethanol and biodiesel• Advantages of biofuels: wide availability, less impact on the

environment, biodegradable.• Concerns: food vs. fuel, Use of protected land for biomass production,

Depleting local water supplies, Cost of technology manufacturing and maintenance.

• Lignocellulose as a "perfect" feedstock to address the above concerns

1. Balat, M. 2011. Production of Bioethanol from Lignocellulose Materials via the Biochemical Pathway: A Review. Energy Conversion and Management, 52:858-875.2. Srirangan, K., Akawi, L., Moo-Young, M. & Chou, C.P. 2012. Towards Sustainable Production of Clean Energy Carriers from Biomass Resource. Applied Energy.

Pretreatmentenzymes

yeastbacteria

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Aims and Objectives

AimThe aim of the project is to show the viability of amaranth as a sustainable feedstock for large scale bioethanol production in South Africa

Objectives• Develop method to convert cellulose and hemicellulose from

amaranth lignocellulose into fermentable sugars• Investigate the effect of parameters such as time, power and

concentration of base on the pentose and hexose sugar yield during microwave pretreatment and hydrolysis

• Investigate the conversion of fermentable pentose and hexose sugars liberated from amaranth lignocellulose to ethanol using suitable micro-organisms

• Develop method to remove lignin from amaranth lignocellulose to be used for other bio-energy applications

• Compare the use of a conventional microwave to that of an industrial microwave when used for pretreatment and hydrolysis of lignocellulose material from amaranth 3

GrainSmall ( 0.9 – 1.7 mm diameterWhite, gold, brown and pinkComposition: protein (13.1 – 21%), fat (5.6 -10.9%), starch (48-69%), fibre (3.1-5.0%), ash (2.5-4.4%)

Feedstock

LeavesComposition: protein (15 %), Fat (7%), total carbohydrates(63%), Fiber (2.9 %), ash (2.6 %)Contains vitamins A, K, B6, C, riboflavin and folate, and also high in minerals (Ca, Fe, Mg, P, K, Zn, Cu, Mn)

DescriptionGrain amaranth; C4 plant; Drought tolerant; Colour: maroon or crimson; Height: 1.5 m – 3 m

ClassificationOrder: CaryophyllalesFamily: AmaranthaceaeSub-family: AmaranthoideaeGenus: AmaranthusSpecies: Amaranthus Cruentus

CompositionMoisture (6.23-6.71 %), protein (13.2-17.6 %dmN × 6.25), fats (6.3-8.1%), fibre (3.4-5.3 %), ash (2.8-3.6 %)

1. Teutonico, R.A. & Knorr, D. 1985. AMARANTH: Composition, properties, and applications of a rediscovered food crop. Ecological Agriculture Projects.2. Mlakar, S.G., Turinek, M., Jakop, M., Bavec, M. & Bavec, F. 2010. Grain Amaranth as an Alternative and Perspective Crop in Temperate Climate. Journal of Geography, 5 (1):135-145.3. South Africa Department of Agriculture forestry & fisheries. 2010. Amaranthus Production Guideline. Retrieved 17 March 2012. from http://www.nda.agric.za/docs/Brochures/Amaranthus.pdf 4

Base: KOH, NaOH, Ca(OH)2

Concentration: 1, 2, 3, 5 % (w/v) Power: 100, 180, 300 W Time: 5-25 minutes Biomass loading (5%, 3%, 1% (w/v) )

Cellulase enzymes: Celluclast (0.24 mL/g) Novozyme (0.25 mL/g) Tween 80 (1.25 g/L) 0.05 M trisodium citrate Buffer in 10 g/L sodium azide pH 4.8 , 50 OC, 150 rpm, 48 h

Saccharomyces Cerevisiae30 OC, 120 rpm, 24-48 h

Liquid fraction•HPLC: Sugar monomers and total reduced sugars; Bioethanol

•UV: lignin, cell growth

•Solid Residue: FTIR, SEM

Reduced sugars

Solid residue

Bioethanol

AmaranthAcid hydrolysis1. 70% H2SO4 (3mL), digest

for 2 h2. Dilute to 87 mL and

auctoclave at 121 oC for 1 h

MicrowavePretreatment

Enzymatic hydrolysis Fermentation Analysis

Separated into stem and roots, washed, dried, milled (<1 cm)

Multiwave PRO microwavePower: 100-1000 WTime: 5 – 20 minPressure: 60 barvs

Domestic microwave Method5

Conclusion

• Composition analysis of amaranthus cruentus showed that amaranth is a viable feedstock for bioethanol production

• Alkaline pretreatment showed that Ca(OH)2 is a proper base to use for high total sugar yields

• Increasing the power of the microwave increases total sugar yields and time does not affect concentration of sugars at low power (100W)

• The structural analysis (FTIR) of the biomass residue showed that these bases have an effect on removal of lignin

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Acknowledgements

• My supervisor Prof. S. Marx for support and guidance

• Dr I. Chiyandzu and Mr C. Schabort for their assistance

• Mr G. van Rensburg for assistance in the laboratory

• Mrs E. De Koker for administrative assistance

• Dr A. Jordan for SEM analysis

• The biofuels group for support

• The National Research Foundation and North West University for funding.

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References

1. Balat, M. 2011. Production of Bioethanol from Lignocellulose Materials via the Biochemical Pathway: A Review. Energy Conversion and Management, 52:858-875.

2. Srirangan, K., Akawi, L., Moo-Young, M. & Chou, C.P. 2012. Towards Sustainable Production of Clean Energy Carriers from Biomass Resource. Applied Energy.

3. Teutonico, R.A. & Knorr, D. 1985. AMARANTH: Composition, properties, and applications of a rediscovered food crop. Ecological Agriculture Projects.

4. Mlakar, S.G., Turinek, M., Jakop, M., Bavec, M. & Bavec, F. 2010. Grain Amaranth as an Alternative and Perspective Crop in Temperate Climate. Journal of Geography, 5 (1):135-145.

5. South Africa Department of Agriculture forestry & fisheries. 2010. Amaranthus Production Guideline. Retrieved 17 March 2012. from http://www.nda.agric.za/docs/Brochures/Amaranthus.pdf 10

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Thank you