ABSTRACT

In this work, the production of Citric acid by Aspergillus niger using plantain and banana peels were allowed to ferment for 7 days and the physical changes were observed.  Physical changes of banana peels showed that pH decreased from 6.5 to 2.5, while the total titrable acidity increased from 0.074% to 1.28%. The biomass increased from 64mg/L to 330mg/L. the total solid decreased from 16.86% to 9.96%. The percentage of Citric acid yielded at the end of the fermentation was increased from 0.172% to 1.304%. While the physical changes of plantain peel showed that pH decreased from 6.5 to 2.4, while the total titrable acidity increased from 0.06% to 1.24%. The biomass increased from 61mg/L to 298mg/L. The percentage of Citric acid yielded at the end of fermentation was increased from 0.156% to 1.273%. The total solid decreased from 18.32% to 93%. The properties listed above were studied during the fermentation period indicates the changes that occurred at each particular day of fermentation starting from day 1 to day 7. This work has shown that banana and plantain peel serve as a potential substrates for the production of citric acid by Aspergillus niger and its utilization will facilitate large scale production of this commercially valuable organic acid.

TABLE OF CONTENT

Certification ii

Dedication iii

Acknowledgement iv

Table of Content Lists of Tables vi

List of Figures vii

Abstract viii

CHAPTER ONE

1.0 Introduction 1 

1.1 Historical Development. 2

1.2 Microorganism 3              

 1.3 Substrates 4

1.4 Uses 5

1.5 Application of Citric Acid 6

CHAPTER TWO

2.0 Literature Review 7 

2.1 Ecology 8 

2.2 Taxonomy 9 

2.3 Banana 11

2.4 Plantain 12

CHAPTER THREE

3.0 Materials and Method 18

3.1 Collection of Banana and Plantain Fruits 18

3.2 Sampling 18

3.3 Sterilization 18

3.4 Production of Citric Acid 18

3.5 Citric Acid Determination 19

3.6 Biomass Determination 19

3.7 Determination of pH 19

3.8 Determination of Total Solid 20

3.9 Determination of Total Titrable Acidity 20

3.10 Determination of Sugar Content 21

3.10.1 Lactophenol Cotton Blue Staining 22

CHAPTER FOUR

4.0 Results 23

CHAPTER FIVE

5.0 Discussion and Conclusion 29

5.1 Discussion 29

5.2 Conclusion 30

5.3 Recommendation 30

References