Bioconversion potential of sorghum crude grains to ethanol: A case study

Muhammad NasidiPhD research student

School of Contemporary SciencesUniversity of Abertay Dundee

Principal Supervisor: Prof. G Walker

Introduction

Sorghum bicolor (L.) Moench is a C-4 cereal crop that grows well under varied temp and rainfall regimes.

It is the 2nd most important cereal crop in Africa and the 5th world wide (FAO 2008).

The grains come in different shapes and sizes and may contain condensed tannin (ICRISAT 2004).

The crude grains comprised husks, awn, spikelet, rachis and pubescence materials (USAID, 2009)

Courtesy: CIAD, Nigeria

....Intro. Contd.

.....background contd.

Pests/diseases attack accounts for over 10% of annual sorghum production loss in Nigeria (USAID, 2009; Codex, 2012).

Quelea birds invaded farmSorghum grain head

Courtesy: www.google.com

In Africa & Asia, over $130 million loss in income is recorded by farmers annually due to sorghum head smut attack (Yago et. al., 2011).

An estimated 200,000t of post-harvest sorghum grains are loss to smut/fungi infection annually in Nigeria; due to poor storage facilities (USAID, 2009; Ismail, et. al., 2010).

Examples of sorghum production loss sources;

Why bioethanol in this study?

Bioethanol is a petrol additive/substitute for use as automotive fuel (Defra, 2006).

Nigeria sets a voluntary target of achieving self-sufficiency in domestic E-10 fuel supply by 2020 (NBPI, 2007).

This represents a potential demand of 1.3billion litres of bio-ethanol for transport, in addition to the 3.75 billion litres ethanol gel demand for cooking (NBPI, 2007; FMARD

2011).

Currently over 90% of ethanol consumed in Nigeria is imported (NNPC, 2010)

Source: googleimage.com

Research background The SSV2, KSV8 and KSV3 sorghum cultivars are among the most favourable cultivated varieties in Nigeria, because of their suitability as food, animal feeds, and malting/brewing feedstock source (USAID, 2009; Ofor, et. al., 2009; Hussein et. al., 2009; FMARD, 2011).

(Galadima et al 2011; Imam and Capareda 2011; Nasidi et al 2010; FMARD, 2012).

Degraded and/or spoilt sorghum grains are usually fed to livestock in Nigeria. This practice is considered to have serious health consequences to livestock and possibly humans wellbeing in Nigeria (NAERLS, 2008; Hussaini et al 2009; Etuk, et. al., 2012).

Research Aim & Objectives

AIMThis work aimed to investigate the potential for bioconversion of crude/degraded sorghum grains to ethanol.

OBJECTIVES To investigate possible potential for utilisation of degraded/spoilt sorghum grains as fuel alcohol feedstock.

To specifically investigate saccharification and fermentation performance of SSV2, KSV8 and KSV3 sorghum crude grains.

SSV2 head

KSV3 head

KSV8 head

Materials and Methods

Fermentation with S. cerevisiae and Pichia yeast sp.

Results discussions

S/no Item SSV2 KSV8 KSV3

1 Ash 2.81 ±0.10 1.31 ±0.03 2.25 ±0.07

2 Lignin 15.10 ±0.13 11.58 ±0.04 13.96 ±0.13

3 Starch 63.64 ±1.67 66.87 ±1.34 72.42 ±1.86

4 Crude protein 15.57 ±0.52 14.31 ±0.41 16.38 ±0.47

Table 1: Composition of SSV2, KSV8 & KSV3 sorghum cultivars (g/100g db)

... Results contd.

Sorghum crude grains Pasting profile

.... Fermentation results.

ANKOMRF CPU

ANKOMRF module

ANKOMRF monitor

Keyboard

Shaking incubator

Fermentation progress was monitored through cumulative CO2 gas pressure (psi) measurements by ANKOM® system.

ANKOMRF module

ANKOMRF SYSTEM

ANKOMRF glass bottle

Fermentation graphs

*Data are mean of 2 replicates

*Data are mean of 2 replicates

...fermentation graphs

*Data are mean of 2 replicates

*Data are mean of 2 replicates

Conclusions.

Final ethanol yield obtained for the crude grains of SSV2, KSV8 and KSV3 sorghum cultivars in this study were 401l/t, 423l/t and 443l/t respectively.

These results compared well with the 460-480l/t alcohol yields reported for de-husked and malted sound grains of SSV2, KSV8 and KSV3 sorghum cultivars (Agu, 1995; Agu, et. al., 2006; Ogbonna, 2011; Okolo, et. al., 2012; Aregbesola, et. al,. 2012).

These results suggest residual/degraded sorghum grains from fields invaded by pests or post-harvest grain storage facilities attacked by rodents may be considered potential feedstock source for bioethanol production.

Future Work Sorghum grains severely infected by smut/mold diseases could be investigated to evaluate their fermentation performance potentials.

Acknowledgement

I would like to express my sincere appreciation to; My generous sponsor, PTDF (Nigeria).

My supervisory team: Prof. G Walker, Dr Y Deeni and Dr D Blackwood.

Mall Idris (NIHORT, Kano, Nigeria).

Dr A Reg (SWRI, Edinburgh).

Thank you for Thank you for listeninglistening

Source: googleimage.com