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Title of Thesis

Salma Raihan
Institute/University/Department Details
Department of Genetics/ University of Karachi
Number of Pages
Keywords (Extracted from title, table of contents and abstract of thesis)
bacterial resistance, cadmium, nickel, environmental pollution, multiple resistant bacteria, heavy metals, p. aeruginosa, e. coli, moraxello, bacillus, enterococcuis, industrial wastes, chemical wastes, bioreactors

Consideration of controlling environmental pollution has concentrated on the possibility of using multiple resistant bacteria for removal of heavy metals from polluted effluent or sediments through a form of bioaccumulation that would follow the different mechanisms of resistance. For this purpose thirteen metallotolerant bacteria designated as CMG51 to CMG64 were isolated from effluent of local industries that include P. aeruginosa, E. coli, Moraxello, Bacillus and Enterococcuis species. Selection of isolates were based on their high resistance to cadmium and nickel. All the isolates showed effect of pH, temperature, and growth media on metal resistance. Similarly metal concentration also showed a direct effected on colonial and cellular morphology as well as a growth retarding effect of metal salts was also observed. Studies on the mechanism of metal resistance showed that different mechanisms operate in different isolates. On the basis of these studies one of the isolates CMG52 showed the involvement of permeability barrier ie 11 metal resistance. and of thirteen, four isolates CMG58, CMG59, CMG61, and CMG64 harbored low molecular weight plasmids that was confirmed by curing, conjugation, and transformation to involve in metal resistance. Plasmid hearing isolates showed higher protein content when grown in presence of metal salts. Likewise, qualitative analysis showed presence of additional protein band in presence or plasmid whereas no additional band was observed in cured derivatives when grown in subinhibitory concentration of metal salts. Variations in molecular weights of protein suggested the possibility that these metallotolerant proteins might be adopted version of some pre-existing proteins. To have the practical application of the following study, lab. scale bioreactors were constructed by developing the biofilms of MGG4 on locally available support materials and successfully used for cadmium removal.

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3670.65 KB
S. No. Chapter Title of the Chapters Page Size (KB)
1 0 Contents
381.81 KB
2 1 Literature Review 1
677.14 KB
  1.1 Sources Of Industrial Wastes (Heavy Metals) 1
  1.2 Production Of Chemical Wastes In Pakistan 5
  1.3 Effects Of Heavy Metals On Living Organisms 10
  1.4 Use Of Heavy Metals As Essential Nutrients 15
  1.5 Resistance To Heavy Metals 16
  1.6 Mechanisms Used By Microorganisms For Metal Removal 25
  1.7 Biological Treatment For Better Environment 37
  1.8 Use Of Immobilized Cell Technology Fro Removal Of Toxic Heavy Metals 39
  1.9 Cell Systems Required Fro Immobilization 42
  1.10 Methods Of Immobilization 43
  1.11 Types Of Bioreactors 48
  1.12 Advantages Of Membrane Reactors 53
3 2 Materials And Methods 55
444.98 KB
  2.1 Microbiology 55
  2.2 Genetic Studies 62
  2.3 Analytical Studies 75
  2.4 Protein Estimation 81
  2.5 Practical Application: Immobilization Of Cmg64, Pseudomonas Aeruginosa , For Cadmium Removal 87
4 3 Results 96
1669.35 KB
  3.1 Microbiology 99
  3.2 Genetics Studies 138
  3.3 Analytical Studies 152
  3.4 Practical Application Of Present Study 171
5 4 Discussion 196-211
183.51 KB
6 5 Findings And Conclusions 212-215
52.95 KB
7 6 Bibliography 216-262
528.46 KB
8 7 Appendices 263-275
83.29 KB