Isolation Of Antibiotic Producing Microorganisms From Soil Samples From Ohokobe Ndume

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