ABSTRACT

Fermentation of sugar derived from enzymatic hydrolysis of inexpensive wood particles and sawdust (waste) is an economical and efficient method for bioethanol production. Sawdust and wood particles contains high amount of cellulose which needs to be broken down to simple sugar (glucose) that can be fermented to produce ethanol. Trichoderma viride with high enzymatic (cellulase) activity was used to hydrolyse the mechanically processed wood particles and sawdust and allowed to hydrolyse for 5 to 7 days after which the presence of reducing sugar was determined using Fehling's and Anthrone method. The determined sugar content, 6.87% was optimized to 23.90% by adding sugar. After optimization, the hydrolysate was inoculated with Saccharomyces cerevisiae isolated from palm wine and left to ferment for 7 days. During the fermentation, changes in temperature, pH, titratable acidity, sugar content, specific gravity, biomass and ethanol yield were monitored. The temperature fluctuated between 29⁰C and 30⁰C with pH decreasing from 5.8 to 4.1 generating a biomass yield of 1.98g/L. The sugar content reduced from 23.90% to 3.83% and 10.16% ethanol was obtained at the end of the fermentation. The results proved that wood particles and sawdust are potential substrates for production of ethanol. Extending the days of fermentation could lead to a higher ethanol yield.

TABLE OF CONTENTS

Title page                                                                                                                       i

Certification                                                                                                                         ii                    

Dedication                                                                                                                           iii

Acknowledgements                                                                                                             iv

Table of contents                                                                                                                 v

List of Tables                                                                                                                      vi

List of Figures                                                                                                                    vii

Abstract                                                                                                                             viii

CHAPTER ONE

1.1 Introduction 1

1.2 Aim and objectives 2

CHAPTER TWO

2.0 Literature Review 3

2.1 Ethanol 3

2.1.1 Properties of ethanol 4

2.1.2 Uses of ethanol 4

2.1.3 Adverse effects 5

2.2 Ethanol production 6

2.2.1 Ethanol from lignocellulosic materials 6

2.2.2 Cellulosic ethanol 8

2.2.3 Cellulose 8

2.2.4 Properties of cellulose 8

2.5 Cellulase

Cellulase producing microorganisms

Enzymatic hydrolysis

Cellulose hydrolysis and glucose fermentation

Simultaneous Saccharification and Fermentation (SSF)

Fermentation

Palm wine yeast

Microbial biomass

3.0 CHAPTER THREE

Materials and methods

14

3.1 Collection of materials 14

3.2 Sample and media preparation 14

3.3 Enzymatic hydrolysis 14

3.4 Determination of specific gravity 15

3.5 Determination of sugar 15

3.6 Determination of titratable acidity 16

3.7 Glucose optimization 16

3.8.1 Isolation of palm wine yeast 16

3.8.2 Fermentation 17

3.8.3

3.9 Measurement of parameters

Distillation 17

18

CHAPTER FOUR

Results 19

CHAPTER FIVE

5.1 Discussion 32

5.2 Conclusion 33

5.3 Recommendation 34

REFERENCES