1Ogbonna, J. C., 1Ndubuisi I. A., 2Murata, Y., 2Omae, H.1Department of Microbiology, University of Nigeria, Nsukka

2 Japan International Centre for Agricultural Sciences

Production of Ethanol from Cassava Processing Wastes in Nigeria

Top ten cassava producers in the world

(2013)

Country Production (t/year)

Nigeria 47,406,770

Thailand 30,227,542

Indonesia 23,936,920

Brazil 21,484,218

Angola 16,411,674

Ghana 15,989,940

DR Congo 14,611,911

Viet Nam 9,757,681

Cambodia 7,572,344

India 7,236,600

Total world production = 268,000,000

Production of fresh cassava tubers in Nigeria

Year tonnes

2007 43,410,000

2008 44,582,000

2009 36,822,248

2010 42,533,180

2011 46,190,248

2012 50,950,292

2013 47,406,770

2014 56.328,480

2015 57,643,271

2016 57,134,478

Source: FAOSTAT

Major products from cassava in Nigeria

Garri

Fufu

Cassava Flour

Cassava starch

Garri

Fufu

Cassava flour

Cassava starch

Family/cottage processors

Wastes are scattered and

used for animal feed

Many cassava flour and cassava

starch companies. Many with

capacity of more than 5 t/day

and generate average of 495kg

wastes per tonne

These wastes can be economically

converted to bio-ethanol

Cassava Processing Wastes

Peels 250-300 kg/t

Dust 30 kg/t

Fibers 20~40 kg

Cassava flour

Cassava starch

Peels 250~300 kg/t

Pulp 400 kg/t

Partially decayed and infested parts are also good

substrate for bio-ethanol production

In order to develop a process for efficient conversion

of the cassava processing wastes to ethanol, we:

1. Screened for thermo-tolerant strains of yeast

2. Optimized their ethanol production from cassava

processed wastes in flask cultures

3. Produced ethanol from the wastes using a 5-L jar

fermentor

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

P83 S67 P27 P71 S26 S65 S2 S86 S1 P5

Eth

an

ol

con

cen

tra

tio

n (

%)

Isolates

42°C

45°C

Ethanol production by the 10 best isolates from

Nigeria at 42°C and 45°C.

Kluyveromyces marxianus.KC544512

Kluyveromyces marxianus.KF646170

Isolate11

Kluyveromyces marxianus.JQ425346

Kluyveromyces marxianus.KC544513

12 34

Kluyveromyces marxianus.KP132325

Kluyveromyces marxianus.KP132326

Kluyveromyces marxianus.KR089884

Kluyveromyces marxianus.KR089890

Kluyveromyces marxianus.KP132326(2)

Kluyveromyces marxianus.KM279376

Kluyveromyces marxianus.KM279377

Kluyveromyces marxianus.KM279378

14 5

Kluyveromyces marxianus.KR150710

Kluyveromyces marxianus.KR150711

Pichia kudriavzevii.KJ706460

Pichia kudriavzevii.JQ726607

Pichia kudriavzevii.KJ706301

Pichia kudriavzevii.KJ706937

Pichia kudriavzevii.KJ706619

S26

S27

Achromobacter xylosoxidans.JN585718

70

70

66

35

99

44

18

17

8

67

90

69

56

100

42

48

0.2

Phylogenetic tree for the isolates

0

1

2

3

4

5

30 40 42Et

han

ol (

%v/

v)Temperature

Cassava peel

Cassava pulp

Effect of temperature on simultaneous

saccharification and ethanol production from

cassava pulp and peel.

0

1

2

3

4

5

6

pH3 pH4 pH5 pH6 pH7Et

han

ol (

%)

pH values

Effects of pH on the maximum ethanol

concentration produced from 20%

cassava pulp.

0

1

2

3

4

5

6

7

YEAST

EXTRACT

PEPTONE MALT

EXTRACT

AMMONIA

NITRATE

UREA SODIUM

NITRATE

CONTROL

PULP

PEEL

Effect of nitrogen source on ethanol production from cassava pulp and peel

Nitrogen source

Eth

an

ol

con

cen

trati

on

(g/l

)

0

1

2

3

4

5

0 24 48 72E

tha

no

l (%

)

Time (h)

Cpeel

Cpulp

Time courses of ethanol production from

20% cassava peel and pulp in flask cules

012345678

0 7 24 48 72

Eth

an

ol

(%)

Time (h)

Fermentation of Cassava pulp using a 5 L jar fermentor

Large scale Re-distillation,

Rectification and

Dehydration Company

Petroleum Refinery Industry

Gasohol

Gasoline Retailers

99.5% Ethanol

40~60% Ethanol

Small scale

ethanol production

Companies

Yeast seed

culture

Companies

Crude

enzyme

companies

Crude

amylase

Yeast paste

or broth

Cassava peels/pulp

Small scale cassava processors

Industrial cluster model for commercial fuel ethanol production

In Nigeria

57 MT

Cassava

tubers

Processed

rotten

Peel

pulp

(495kg/t) Wastes

28.22 MT

60%

(16.93 MT)40%

(11.29 MT)

2.032 x 109 L

Ethanol

(180L/t)

Garri

Fufu

Flour

Starch

Animal feed

Organic manure

Summary

ConclusionAccording to National Bureau of Statistics, Nigeria

consumed 54.3 million liters of PMS daily within the first

quarter of 2017. This requires 5,430,000 L of ethanol per

day to make E10 gasohol (90% gasoline with 10%

ethanol), amounting to 1,981,950,000 liters of ethanol per

year. This can be supplied by converting wastes from

40% of the annual 57 million tones of cassava to ethanol.

Currently, Nigerian local refineries are producing only

about 8 million liters of PMS per day. This requires only

800,000 liters of ethanol per day (292,000,000 L per

annum) and can be supplied by converting wastes from

only 5.84% of cassava produced in Nigeria.

THANKSI hereby express my gratitude to IRENA for

inviting me to participate in this meeting and

thank all of you for listening.