ABSTRACT

Lactic Acid Bacteria play key roles in the fermentation of maize to akamu. The lactic acid bacterial species associated with the local fermentation of maize were isolated, characterized and identified. The isolation of the lactic acid bacteria was done by culturing of the sample after serial dilution on MRS agar for 24hrs at 37oC. The isolates obtained were subcultured on a nutrient agar to obtain a pure culture of the lactic acid bacteria. The occurrences of the lactic acid bacteria were determined. The characterization and identification of the lactic acid bacteria was achieved by the different biochemical tests that were carried out such as the, sugar fermentation, catalase. The morphology, gram reaction and colony features were also investigated. The 12 samples showed high microbial load which ranged from 1.8×106cfu/ml to 2.8×106cfu/ml. A total of 43 lactic acid bacteria were isolated which comprised of Lactobacillus spp (12), Streptococcus spp (9), Lactococcus spp (7), Pediococcus spp (8) and Leuconostoc spp (7). Lactobacillus spp had 100% occurrence in the 12 samples. Lactic acid bacteria are essential bacteria responsible for the fermentation of maize to akamu.

TABLE OF CONTENTS

Title page i

Certification ii

Dedication iii

Acknowledgements iv

Table of contents vi

List of tables vii

Abstract viii

CHAPTER ONE

1.0 Introduction 1

1.1 Food fermentation 1

1.2 Akamu 2

1.3 Aim 3

1.4 Objectives 3

CHAPTER TWO

2.0 Literature review 4

2.1 Lactic acid bacteria 4

2.2 Physiology and morphology 6

2.3 General description of lactic acid bacteria 8

2.4 Applications of lactic acid bacteria 9

2.5 Cereal 12

2.6 Maize 13

2.6.1 Distribution 14

2.6.2 Nutritional Value and Health Benefits 14

2.6.3 Medicinal Value 15

2.6.4 Economic Importance 15

CHAPTER THREE

3.0 Materials and methods 16

3.1 Sources of material 16

3.2 Sample preparation 16

3.3 Preparation of media for bacteria isolation 16

3.4 Enumeration of bacteria from locally fermented maize  16

3.5 Isolation of microorganism 17

3.6 Characterization of bacteria isolates 17

3.6.1 Colony features of bacteria isolates 17

3.6.2 Microscopic Feature 17

3.6.3    Biochemical Tests for Identification of Bacteria 18

3.7      Identification of isolates 19

CHAPTER FOUR

4.0 Results 20

CHAPTER FIVE

5.0 Discussion 25

5.1 Conclusion 25

REFERENCES