ABSTRACT

Streptomyces species was isolated from soil samples using spread plate method on Streptomyces agar while Streptomyces broth was used for fermentation and optimization. The varied culture conditions evaluated were pH, Mineral salt concentration, speed of agitation and nutritional components tested were Carbon and Nitrogen sources. The production of antimicrobial metabolite was authenticated by antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa. Amongst the carbon sources, maximum production of antimicrobial metabolite was observed with the medium containing Galactose anhydride evident by high inhibition zone of 32mm and 23mm (Staphylococcus aureus and Pseudomonas aeruginosa) respectively. This was followed closely by the medium incorporated with glycerol and glucose. Maximum productivity of antimicrobial metabolite was also achieved with the medium containing malt extracts evident with an inhibition zone of 30mm and 27mm for Staphylococcus aureus and Pseudomonas aeruginosa. This was also followed by the medium containing yeast extract. For pH, maximum metabolite production was attained in the medium adjusted to 10, with an inhibition zone of 30mm and 33mm for Staphylococcus aureus and Pseudomonas aeruginosa respectively, which was closely followed by pH 9.  For the medium incorporated with additional mineral salts, best metabolite production was obtained at a concentration of 0.30mol/ml evident by an inhibition diameter of 30mm and 27mm for the respective test organisms. Best antimicrobial metabolite production was also observed with the medium whose agitation speed was 250rpm. This gave an inhibition diameter of 26mm and 23mm respectively against the test organisms. Finally, for better productivity of antimicrobial metabolite by Streptomyces species, carbon source such as Galactose anhydride, Nitrogen source such as malt extract, mineral concentration of 0.30mol/ml, pH of 10 and agitation speed of 250rpm, should be used.

TABLE OF CONTENTS

Certification ii

Dedication iii

Acknowledgements iv

Table of Contents v

List of Tables viii

List of Figures ix

Abstract x

Chapter One

1.0. Introduction 1

1.1 Aim 3

1.2 Objective 4

Chapter Two

2.0 Literature review 5

2.1 Antimicrobial metabolites produced by Streptomyces species 5

2.1.1 History 5

2.1.2 Synthesis 6

2.1.3 Composition 6

2.1.4 Spectrum of activity 7

2.1.5 Mechanism of action 7

2.1.6 Clinical uses 8

2.2. Streptomycetes 9

2.2.1 Habitat and reproduction 12

2.2.2 Genome 14

2.2.3 Ecology 14

2.2.4. Streptomyces as human pathogens 16

Chapter Three

3.0 Materials and method 17

3.1 Collection of samples 17

3.2 Sterilization of apparatuses and equipment 17

3.3. Preparation of culture and fermentative media 17

3.4. Isolation of Streptomyces 18

3.5 Test organisms used in screening 18

3.6 Confirmation of the test isolates 18

3.7. Antimicrobial metabolites extraction 18

3.8. Antimicrobial screening of the metabolites 19

3.9. Determination of the effect of varied nutritional requirements on metabolite

            Production 19

3.9.1. Carbon sources 19

3.9.2. Nitrogen sources 19

3.10. Determination of the effect of varied culture condition on metabolite production. 20

3.10.1.   pH 20

3.10.2. Sodium chloride concentration 20

3.10.3. Speed of agitation 20

Chapter Four

4.0. Results 29

Chapter Five

5.0. Discussion and Conclusion 30

5.1. Discussion 32

5.2. Conclusion 33

REFERENCE 37

APPENDIX