ABSTRACT

This research work was conducted to access the antibacterial activity of Bacillus species isolated from agricultural sites in two different communities (Umudike and Ndoru in Ikwuano local government area) in Abia State of Nigeria. The antibacterial activities of the isolated Bacillus spp was tested against three different bacterial strains (Staphylococcus aureus, micrococcus spp, Escherichia coli) by agar well diffusion method and incubated for 24hrs at 370C. The Research Results shows that most strains possess significant antibacterial potentials mostly against S. aureus and micrococcus sp but less activity against the Gram negative E. coli. Thereafter, Further investigations was carried out to determine the optimum growth conditions for these Bacillus species for maximum antibiotic production. Optimum activity was achieved using nutrient broth culture at different optimization conditions (temperatures; 300C., 370C. and 450C.   incubation time; 24hrs,48hrs and 72hrs and pH; 6, 7, 8), The medium was then centrifuged at 10,000rpm for 20minutes to get the cell free supernatant and a Bacitracin assay done on nutrient agar plates by measuring the diameter zones of inhibition in millimeters(mm) against the test organisms being used. And the highest zone of inhibition for incubation temperature was observed, (24mm) against Micrococcus spp at 370C, (27mm) at 72hrs incubation period and (24mm) at pH8, antibacterial activity was also produced maximally against S. aureus at optimized temperature, incubation time and pH as (18mm, 20mm and 14mm) respectively and zero effect was seen on E. coli. Therefore, antimicrobial compounds from these Bacillus species can be good candidates for future antibiotics production. Further screening for antimicrobial agents should be carried out in search of novel therapeutic compounds. 

TABLE OF CONTENTS

Title page I

Certification II

Dedication III

Acknowledgement IV

Table of content V

List of Tables VIII

Abstract IX

 CHAPTER ONE

1.1 Introduction 1

CHAPTER  TWO

2.0 Literature Review 4

 2.1 Bacillus and its Taxanomy 4

2.1.1 Bacillus Cereus Group 4

2.1.2 Bacillus Subtilis Group 7

2.2 The Nature Of Bacillus Endospore 8

2.3  Bacillus Endospore Formation Process 8

2.4 Structure, Biosynthesis And Mechanism Of Action Of Bacitracin 10

2.4.1 Structure Of Bacitracin 10

2.4.2  Biosynthesis Of Bacitracin 11 

2.4.3 Mechanism Of Action Of Bacitracin 11

2.5  Antimicrobial Spectrum Of Bacitracin 11

2.6  Uses Of Bacitracin 12

CHAPTER THREE

3.0     Materials And Methods 13

3.1     The Study Area 13

3.2     Soil Sample Collection 13

3.3 Sample Preparation 14

3.4 Sterility 14

3.5 Preparation Of Culture Media 14

3.7 Collection And Confirmation Of Test Isolates 15

3.7.1 Colonial Morphology 15

3.7.2 Gram Staining 15

3.7.3 Motility Test 15

3.7.4 Biochemical Test 16

3.8 Preliminary Screening For Bacitracin Producing Bacillus Spp 18

3.9 Optimization Of Conditions For Bacitracin Production 18

3.9.1 Optimization For Incubation Temperature 19

3.9.2 Optimization For Time Of Incubation 19

3.9.3 Optimization For pH Of Incubation 19

3.10 Presentation And Analysis Of Data 19

CHAPTER FOUR

4.0 Results 20

4.1 Results Presentation 20

CHAPTER FIVE

5.0 Discussion, Conclusion And Recommendation 28

5.1 Discussion  28

5.2 Conclusion 29

5.3 Recommendations 30

REFERENCES

LIST OF TABLES

Table 1: Sample collection sites 22 

Table 2: Morphological and biochemical characteristics of isolates 23

Table 3: Preliminary screening for bacitracin 24

Table 4:  Antimicrobial effect of crude extracts of Bacitracin against E. coli,

 S. aureus and Micrococcus spp at optimized incubation temperature 25

Table 5:  Antimicrobial effect of crude extracts of Bacitracin against E. coli,

 S. aureus and Micrococcus spp at various incubation periods 26

Table 6: Antimicrobial effect of crude extracts of Bacitracin against E. coli,

 S. aureus and Micrococcus spp at various optimized pH 27