Microbial Degradation of Endosulfan by Newly Isolated Strain, Klebsiella pneumoniae KE-1

다국어 초록 (Multilingual Abstract)

For bioremediation of toxic endosulfan, endosulfan-degradation bacteria, which do not form toxic endosulfan sulfate, were isolated from various soil samples using endosulfan as sole carbon and energy source. Among the several isolated bacteria, strain KE-1, which was identified as Klebsiella pneumoniae by physiological and 16S rDNA sequence analysis, showed superior endosulfan degradation activity. Analysis of culture pH, growth and endosulfan and its metabolites demonstrated that KE-1 biologically degrades 8.72 ㎍-endosulfan ㎖-1 day-1 when incubated with 93.9 ㎍ ㎖-1 endosulfan for 10 days without formation of toxic endosulfan sulfate. And then, free sulfate concentration in the culture rapidly increased from 240.3 ㎍ ㎖-1 to 275 ㎍ ㎖-1.
During endosulfan degradation by K. pneumoniae KE-1, also observed that several polypeptides were specifically induced with endosulfan, as shown by the band around 66 kDa and the bands at 45, 29, 97.4 kDa. Among the polypeptides, expression of band around 66 kDa showed a good correlation with endosulfan degradation activity and it was regulated by sulfur ion.
Our results suggest that Klebsiella pneumoniae KE-1 degraded endosulfan by a non-oxidative pathway and the potential of strain KE-1 as a biocatalyst for endosulfan bioremediation.

목차 (Table of Contents)

• CONTENTS
• LIST OF TABLES AND FIGURES = v
• INTRODUCTION = 1
• MATERIALS AND METHODS = 3
• Media and chemicals = 3
• Isolation of endosulfan degraders = 3
• Assay of endosulfan metabolites and free sulfate = 4
• Identification of endosulfan degrader = 5
• CharacterizationofendosulfandegradationbyKlebsiellapneumoniaeKE-1 = 6
• Degradation of endosulfan by K. pneumoniae KE-1 = 6
• Response of K. pneumoniae KE-1 to sulfate free and sulfate contained = 7
• Preparation of cell extract = 7
• SDS-PAGE = 8
• RESULTS = 8
• Screening of endosulfan degradation that did not produce
• endosulfan sulfate = 8
• Identification of strain KE-1 = 11
• Characterization of endosulfan degradation by K. pneumoniae KE-1 = 13
• Degradation of endosulfan by K. pneumoniae KE-1 = 15
• Effect of sulfur sources on endosulfan degradation = 18
• Regulation of endosulfan degradation proteins by sulfate = 22
• DISCUSSIONS = 24
• KOREAN SUMMARY = 27
• ENGLISH SUMMARY = 29
• REFERENCES = 31