GENETIC MANIPULATION OF GENES FOR ENVIRONMENTAL BIOREMEDIATION AND CONSTRUCTION OF STRAINS WITH MULTIPLE ENVIRONMENT BIOREMEDIATION PROPERTIES

Fouad M., Qureshi (2005) GENETIC MANIPULATION OF GENES FOR ENVIRONMENTAL BIOREMEDIATION AND CONSTRUCTION OF STRAINS WITH MULTIPLE ENVIRONMENT BIOREMEDIATION PROPERTIES. Doctoral thesis, University of Karachi.

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Abstract

Environmental bioremediation, the science of control of pollution by the use of biological means, has no parallel in terms of elimination of waste, selectivity, and efficiency, especially where the pollutant is a xenobiotic. In general, it can be used either for sequestration or detoxification or degradation of the pollutant. An indigenous bacterial strain, Bacillus licheniformis CMG370, was discovered to be degrading the pesticide cypermethrin in addition to being capable of utilizing a number of monoaromatics and pesticides. Biodegradation of cypermethrin was analyzed by TLC and GC/MS. Another bacterium Enterobacter sp. CMG371 was found to be tolerating high levels of the heavy metal nickel. Insertional inactivation of genes. by transposon mutagenesis located this genetic determinant of nickel resistance in CMG371 on a 7.33 kb Clal fragment of the chromosomal DNA. It was determined by cloning that these genes could be successfully expressed in E. coli host. Since, it had been reported in literature that bioremediation processes are adversely affected and even inhibited by co-contamination of organic pollutants with heavy metals, the nickel resistance genetic determinant of CMG371 was used to transform nickel sensitive CMG370 in order to allow it to resist the lethal and toxic effects of nickel. This was achieved by cloning the 7.33 kb ClaI nickel resistance genes in a shuttle vector, pBCX, which was used to transform the cypermethrin degrading Bacillus licheniformis CMG370 resulting in the formation of the genetically engineered strain Bacillus licheniformis CMG382, which was found and confirmed by TLC and GC/MS analyses to be degrading cypermethrin in the presence of nickel. In order to study the application of these strains for bioremediation, four bioreactors were constructed. Two bioreactors, one having Serratia sp. N 14 and the other having bacterial consortium as a biofilm on quartz sand grains were constructed and demonstrated to remove cobalt from industrial effluent. Since quartz sand was found to be sequestering the metal, another bioreactor having biofilm of Pseudomonas aeruginosa CMG 156 on custom fashioned PVC cylinders was constructed. It demonstrated removal of copper from synthetic effluent that was confirmed by X-ray microanalysis. The fourth bioreactor was constructed by immobilizing the GMO Bacillus licheniformis CMG382 in agar cubes and it was evaluated for degradation of cypennethrin in a synthetic effluent co-contaminated with nickel by TLC and GC/MS. Successful degradation of cypermethrin in presence of nickel in the bioreactor demonstrated the potential of Bacillus licheniformis CMG382 for bioremediation.

Item Type: Thesis (Doctoral)
Uncontrolled Keywords: genetic manipulation, genes, environmental bioremediation, control of pollution, xenobiotic pollutant, bacillus licheniformis, cypermethrin, enterobacter sp, pesticide biodegradation
Subjects: R Medicine > RZ Other systems of medicine
Depositing User: Muhammad Khan Khan
Date Deposited: 02 Sep 2016 09:35
Last Modified: 02 Sep 2016 09:35
URI: http://eprints.hec.gov.pk/id/eprint/863

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