This document discusses the potential for cassava breeding to improve its use for bioethanol production. It notes that cassava breeding has successfully increased fresh root and dry matter yields. There is now a need to breed for stable dry matter contents. The document also discusses novel cassava traits being explored, such as waxy starches and small starch granules, that could reduce ethanol production costs. Finally, it examines how interactions between root quality traits and processing methods can maximize economic and environmental benefits through analyzing the best germplasm for different conversion processes.

2. Cassava breeding potential for
bioethanol
Becerra López-Lavalle, L.A. , Dufour, D.,
Sánchez, T. and H. Ceballos

3. Outline
• Introduction
• High, stable and reliable productivity
• Novel traits
• Processing methods X root quality interactions
• Perspectives

4. Outline
• Introduction
• High, stable and reliable productivity
• Novel traits
• Processing methods X root quality interactions
• Perspectives

5. Cassava origin
Low Soil Fertility
Flooded land
Slopped Land
Degraded Soils

6. Cassava modern production
Sub-humid environment Acid –Soil environment
Near Hanoi, Vietnam Guan-Xi Province, China
19’000,000 hectares

7. Cassava modern production
Sub-humid environment Acid –Soil environment
Near Hanoi, Vietnam Guan-Xi Province, China
19’000,000 hectares
233,000 Tonnes

8. Main uses of Cassava
Fresh - boiled
Cassava leaves Fufu
Farinha - Gari
Human consumption

9. Main uses of Cassava
Chicken factory
Near Hanoi, Vietnam Pressed cake
Dry chips for animal feed
Animal feedstock

10. Main uses of Cassava
Bio-Ethanol
Fried-Chips Goren-Krupuk
Starch
Industrial use of Cassava

11. Tropical/Sub-tropical crop
Main cassava production regions in the world

12. Outline
• Introduction
• High, stable and reliable productivity
• Novel traits
• Processing methods X root quality interactions
• Perspectives

13. Crop Potential
Breeding successfully increased
fresh-root (FR) productivity & dry-
matter (DM) content. We now need
STABLE -DM contents
SM 1433-4
South-China 5
84 t/ha FR in a 9.5 ha commercial field
(~25 t/ha DM)

14. Crop Potential
Fresh root yield
(t/ha)
Dry matter
content
(%)
Dry matter yield
(t/ha)
SM 2775-2 53.8 32.1 17.3
SM 2775-4 35.3 35.9 12.7
SM 2775-2 37.3 30.7 11.5
SM 2775-4 27.1 36.9 10.0
At two location: Codazzi (Cesar) and Barrancas (Guajira)
At five location: Patalito, Sto Thomas & Molinero (Atlantico), La Union
(Sucre) and Chinu (Cordoba)
The case of “watery” roots for ethanol

15. Crop Potential
Fresh root yield
(t/ha)
Dry matter
content
(%)
Dry matter yield
(t/ha)
SM 2775-2 53.8 32.1 17.3
SM 2775-4 35.3 35.9 12.7
SM 2775-2 37.3 30.7 11.5
SM 2775-4 27.1 36.9 10.0
At two location: Codazzi (Cesar) and Barrancas (Guajira)
At five location: Patalito, Sto Thomas & Molinero (Atlantico), La Union
(Sucre) and Chinu (Cordoba)
The case of “watery” roots for ethanol
High Dry Matter content does not
seems critical to ethanol production

16. Outline
• Introduction
• High, stable and reliable productivity
• Novel traits
• Processing methods X root quality interactions
• Perspectives

17. Cassava “Novel” traits
Amylose-free (“waxy”)
starch mutation
•Amylose is difficult to
degrade
•Amylose-free starch
should cost less to
convert into ethanol

18. Cassava “Novel” traits

19. Less amylose = more ethanol

20. Less amylose =
more ethanol

21. Cassava “Novel” traits
Fermentability:
assess their potential in bio-ethanol, bio-plastics,
sweeteners

22. CM 523-7
Rayong 60
NEP
WAXY
Without enzyme
With enzyme0
50
100
150
200
250
300
350
400
Clone
Total ethanol
(ml ethanol /
kg starch)
Cassava starch fermentation: with and without starch
4 1/3 days
Total ethanol
(mL/Kg of starch)

23. Small granule/high amylose
NormalStarchSmallgranuleStarch

24. Small granule/high amylose
NormalStarchSmallgranuleStarch
• A small granule and a rough surface
facilitate the action of enzymes (less
consumption of enzymes, lower costs of
conversion).
• But higher amylose content would
increase costs….

25. Waxy
Small granules
StarchViscosity(5%)
0
200
400
600
800
1000
1200
0 5 10 15 20
Temperature (minutes)
Viscosity(cP)
0
20
40
60
80
100
Small granule/high amylose
RVA Amylogram

26. Starch-less mutation
Source:
L. Carvalho
EMBRAPA
Brazil

27. Outline
• Introduction
• High, stable and reliable productivity
• Novel traits
• Processing methods X root quality interactions
• Perspectives

28. Bio-ethanol production
Ethanol factory in Thai Nguan near Khon Kaen (Thailand)

29. Bio-ethanol production
Ethanol factory in Thai Nguan near Khon Kaen (Thailand)
5.27 kg of fresh root produce one liter of ethanol
1.4 – 1.5 bath / kg fresh root
25 bath / lt of ethanol produced

30. Fermentation
Distillation &
dehydration
Ethanol
SugarcaneSugarcane juices
Ethanol from corn or cassava is
more expensive because starch
need to be degraded to the
equivalent of sugar cane juices
Boiler
Maize or Cassava
Starch degradationLiquefaction & saccharification

31. Slurrytank
Sorce of
satrch
Grinding
Jet cooker
>100 °C
(5-8’)
Secondary
Liquefaction
(95 °C – 90’)
Thermo-stable
Alpha-amylase
(Liquefacction)
Glucoamylase
(Saccharification) Fermentation
Saccharification
60°C(8-10horas)
Yeasts
Solids
Distillation&
dehydration
Storage
tank

32. Slurrytank
Sorce of
satrch
Grinding
Jet cooker
>100 °C
(5-8’)
Secondary
Liquefaction
(95 °C – 90’)
Thermo-stable
Alpha-amylase
(Liquefacction)
Glucoamylase
(Saccharification) Fermentation
Saccharification
60°C(8-10horas)
Yeasts
Solids
Distillation&
dehydration
Storage
tank
New enzymes
Liquefaction + saccharification

33. Slurrytank
Sorce of
satrch
Grinding
Fermentation
Solids
Distillation&
dehydration
Storage
tank
Saccharification
60°C(8-10horas)
Yeasts
New enzymes
Liquefaction + saccharification
New enzymes
+ yeasts
Liquefaction + saccharification
+ fermentation

34. Solids
Distillation&
dehydration
Storage
tank

35. Medium throughput fermenters

36. 0
20
40
60
80
100
0 10 20 30 40 50 60
Time (minutes)
HidrolisisIndex(%)
Digestion rate of different cassava starches
(1.0 ml of pacreatic α-amilase)
pH 6.9 at 37°C
~80%
~30%

37. 0
20
40
60
80
0 10 20 30 40 50 60
Time (minutes)
Hidrolisisindex(%)
~60%
~30%
Digestion rate of different cassava starches
(0.5 ml of StargenTM 2)
pH 4.0 at 37°C

38. Root processing vs. quality
• Starch degrading enzymes and yeast are being improved.
• The process to convert starch into ethanol constantly changes.
• As in maize, there are genetic differences in cassava for ethanol
production (small starch granule).
• We are in a unique position to analyze the best germplasm –
processing method to maximize economic benefit and reduce
negative impact on the environment.
• What is the potential of “sugary” cassava?

39. Outline
• Introduction
• High, stable and reliable productivity
• Novel traits
• Processing methods X root quality interactions
• Perspectives

40. Cassava Bio-ethanol perspective
• Cassava is a competitive raw material for
bio-ethanol production in Asia (Thailand,
China, Vietnam, Indonesia?, Australia?)
• A large % of the ethanol production cost is
constitute by the enzyme and yeast.
• Advances in microbiology and enzymology
can significantly reduce ethanol production
cost from starches

41. Cassava Bio-ethanol prespective
• There are clones with low dry matter
content but maximum productivity per
hectare that can now be used in ethanol
production
• Different mutants could reduce costs of
conversion from root to ethanol (including
“sugary”?)

42. Energy crops: farms of 1-100 ha
Sweet potato Sweet sorghum
Cassava Banana
Sugar cane
Coffee residues
Small rural communities
Micro-plants
1.000 – 2.000 lt/day
5 – 10 t crop/day
< – 1 ha crop/day
Central Plant (dehydration)
Transport
Ethanol
(99,5%)
Ethanol
(50%)

43. Cassava Bio-ethanol perspective
• For ethanol production a key issue is the
continuous supply of feedstock all year
round.
• Processing of fresh roots (low dry matter?) at
harvest time and dried chips during off-
season is one potential alternative.

44. Cassava Bio-ethanol perspective
• Combining feedstock from different crops.
For instance, cassava/sweet-sorghum has
proved advantageous.
• We need to further analyze the by-products
and their potential use for animal feeding.

45. Thank you