ABSTRACT

In this work, dry and wet peels derived from watermelon waste as alternative substrate for Single Cell Protein production from Saccharomyces cerevisiae (from palm wine), Aspergillus niger and Saccharomyces cerevisiae (from baker’s yeast) were investigated. Submerged method was employed to culture them in batches. A glucose solution (monosaccharide) was used as a control for the experiment. Batch 1 represent 4-day culture of the three microorganisms grown on dry, wet and control substrates respectively. Batch 1 gave rise to the following biomass in grams; for palm wine yeast – 0.10, 0.08 and 0.07; for baker’s yeast; 0.15, 0.35 and 0.32; for A. niger – 0.24, 0.30 and 0.21. Batch II represent 6-day culture of the microorganisms grown on dry, wet and control substrates respectively giving rise to the following biomass yield in grams; for palm wine yeast; 0.14, 0.35 and 0.15; for baker’s yeast – 0.33, 0.45 and 0.41; for A. niger – 0.26, 0.43 and 0.28. Batch III represent 8-day culture of the microorganisms grown on dry, wet and control substrates respectively which gave rise to the following biomass yield; for palm wine yeast – 0.10, 0.15 and 0.08; for baker’s yeast – 0.32, 0.43 and 0.29; A. niger – 0.13, 0.32 and 0.25. Nutritional compositions of the raw dry and wet watermelon waste prior to their use as substrates were determined. Proximate composition of the fungal biomass was also determined. Present investigation revealed that baker’s yeast grown on the wet watermelon substrate cultured for 6-day produced the highest quantity of single cell protein, suggesting that wet watermelon peel is more suitable for the production of SCP. The findings from this study support the need for SCP production from cheap, inexpensive agro-waste materials.

TABLE OF CONTENTS

Certification   .           .           .           .           .           .           .           .           .           .           i

Declaration    .           .           .           .           .           .           .           .           .           .           ii

Dedication      .           .           .           .           .           .           .           .           .           .           iii

Acknowledgement     .           .           .           .           .           .           .           .           .           iv

Table of contents       .           .           .           .           .           .           .           .           .           v

List of Tables and Figures   .           .           .           .           .           .           .           .           vii

Abstract         .           .           .           .           .           .           .           .           .           .           viii

CHAPTER ONE                                                            

1.0       Introduction .           .           .           .           .           .           .           .           .           1

1.1       Fungi .           .           .           .           .           .           .           .           .           .           2

1.2       Botany of Watermelon [Citrullus lanatus (Thumb.) Matsum

and Nakai]     .           .           .           .           .           .           .           .           .           3

1.3       Aims and Objectives             .           .           .           .           .           .           .           4

1.4       Justification   .           .           .           .           .           .           .           .           .           4         

CHAPTER TWO

2.0       Literature Review     .           .           .           .           .           .           .           .           6

2.1       Choice of Microorganism for SCP Production      .           .           .           .           8

2.2       Potential Substrates for Single Cell Protein Production .           .           .           11

2.3       Cultivation Methods in SCP Production    .           .           .           .           .           12

2.4       Nutritional Value of SCP     .           .           .           .           .           .           .           15

2.5       The Biotechnology of SCP Production       .           .           .           .           .           16

2.5.1    The Biochemistry and Physiology of Biomass Production           .           .           16

2.5.2    Process Design and Control             .           .           .           .           .           .           18

2.6       The Economics of SCP Production and Marketing          .           .           .           20

2.7       Drawbacks of Single Cell Protein Technology       .           .           .           .           20

2.8       Future Prospects       .           .           .           .           .           .           .           .           22

CHAPTER THREE

3.0       Materials and Methods        .           .           .           .           .           .           .           23

3.1       Collection of the Plant Material      .           .           .           .           .           .           23       

3.2       Preparation of the Plant Sample     .           .           .           .           .           .           23

3.2.1    Dry Sample    .           .           .           .           .           .           .           .           .           23

3.2.2    Wet Sample   .           .           .           .           .           .           .           .           .           23

3. 3      Preparation of Watermelon Extracts         .           .           .           .           .           23

3.4       Microorganisms Used           .           .           .           .           .           .           .           25

3.5       Analysis of the Raw Substrate         .           .           .           .           .           .           25

3.6       Production and Harvesting of Single Cell Protein (SCP) .           .           .           25

3.7       Analysis of Fungal Biomass and Procedures for

Proximate Composition        .           .           .           .           .           .           .           26

3.7.1    Moisture Content      .           .           .           .           .           .           .           .           26

3.7.2    Determination of Ash Content        .           .           .           .           .           .           26

3.7.3    Determination of Crude Fat Content (Dry Extraction)    .           .           .           27

3.7.4    Determination of Crude Fat Content (Wet Extraction)   .           .           .           28

3.7.5    Determination of Crude Protein     .           .           .           .           .           .           28

3.8       Procedure for Total Sugar using Anthrone Reagent        .           .           .           29

CHAPTER FOUR

4.0       Results            .           .           .           .           .           .           .           .           .           31

CHAPTER FIVE

5.0       Discussion and Conclusion .           .           .           .           .           .           .           40

5.1       Discussion      .           .           .           .           .           .           .           .           .           40

5.2       Conclusion     .           .           .           .           .           .           .           .           .           42

REFERENCES         .           .           .           .           .           .           .           .           .           43