ABSTRACT

This study was aimed at investigating and exploring indigenous soil microflora for antimicrobial production. 12 soil samples were collected, serially diluted and spread plated on Tryptone soy agar and Sabouraud dextrose agar plates. 18 isolates were recovered from the soil samples. Agar disc diffusion method was used to check the antagonistic activity of the resulting isolates against four test bacteria (Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Enterococcus faecalis ATCC 7080, and Salmonella typhi). Inhibition zones obtained from the isolates showed that Isolate A2 was active against Staphylococcus aureus (14mm) while another isolate C2 produced a zone of 10mm against Salmonella typhi. Among Gram negative bacteria E. coli was least susceptible as none of the isolates could inhibit its growth. The isolated organisms were in the genera Micrococcus and Bacillus. Development of new antibacterial agents with activity against multi-drug resistant bacteria is therefore perceived as a critical public health need.

TABLE OF CONTENTS

Title page i

Certification ii

Dedication iii

Acknowledgements iv

Table of contents v

List of Tables vii

Abstract viii

CHAPTER ONE

1.1 Introduction 1

1.2 Aims and Objectives 4

CHAPTER TWO

2.1 LITERATURE REVIEW 5

2.1.1 Soil Bacteria 5

2.1.2 Soil Actinomycete 6

2.1.3 Soil Fungi 8

2.1.4 Soil Antibiotic 9

2.1.5 Soil pH and Alkalinity 10

CHAPTER THREE

Materials and Methods

3.1 Sample Collection 14

3.2 Isolation of Soil Microorganisms 14

3.3 Purification of isolates 15

3.4 Preparation of inoculum of test organisms 15

3.5 Preparation of inoculum of each isolates 15

3.6 Characterization and Identification of isolates 16

3.6.1 Gram staining 16

3.7 Biochemical tests 16

3.7.1 Catalase test

3.7.2 Indole test 16

3.7.3 Citrate utilization test  17

3.7.4 Hydrogen sulphide (H2S) Production test    17

3.7.5 Starch Hydrolysis 17

CHPATER FOUR

4.0 RESULTS 18

CHAPTER FIVE

5.1 Discussion 22

5.2 Conclusion 24

References    26