African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5210

Full Length Research Paper

Isolation, characterization and fingerprinting of some chlorpyrifos- degrading bacterial strains isolated from Egyptian pesticides-polluted soils

Nabil S. Awad1,2*, Hussein H. Sabit1, Salah E. M. Abo-Aba1,3, Reda A.  Bayoumi4
1Faculty of Biotechnology, Misr University for Science and Technology, Egypt. 2College of Medicine, Biotechnology and Genetic Engineering Unit, Taif University, Taif, Kingdom Saudi Arabia. 3Department of Biological Sciences, Faculty of Science, King Abdul-Aziz University, Jeddah, Saudi Arabia. 4Department of Biotechnology, Faculty of Science, Taif University, Taif (El-Khorma), Kingdom Saudi Arabia.
Email: [email protected], [email protected]

  •  Accepted: 23 June 2011
  •  Published: 16 September 2011


Five bacterial isolates (B-CP5- B-CP6 - B-CP7- B-CP8- B-CP9) were isolated from pesticides- contaminated soil in Egypt. The capability of these isolates to degrade chlorpyrifos was investigated using enrichment mineral salt (MS) medium containing chlorpyrifos. Two different PCR-based techniques, RAPD-PCR and PCR-RFLP for amplified16S rRNA fragment were used to conduct genetic fingerprinting and obtain specific molecular markers for the studied isolates. The isolates exhibited substantial growth in mineral salt medium supplemented with 100-300 mg/L chlorpyrifos as a sole source of carbon and energy. Based on their morphological, cultural and biochemical characters, the isolates have been identified as Pseudomonas stuzeri, Enterobacter aerogenes, Pseudomonas pseudoalcaligenes, Pseudomonas maltophila andPseudomonas vesicularis respectively. Pseudomonas stuzeri was the most potent degrader strain. Five specific markers for this strain were determined. The highest genetic similarity was observed between CP8 and CP7 (66%), while the lowest genetic similarity was detected between CP8 and CP6 (37%). All isolates had the same pattern after digestion of 16S rRNA amplified fragment with two restriction enzymes (EcoRI and AluI) except Enterobacter aerogenes, which generate two monomorphic bands at 420 and 130 bp, respectively. In conclusion, the strain Pseudomonas stuzeri could be used to clean up the areas contaminated with Chlorpyrifos. Obtained molecular markers might be used for identifying and tracking the most potent bacterial isolate. The used PCR techniques represent a powerful tool and could be used for rapid typing of this strain.


Key words: Pesticide, chlorpyrifos, biodegradation, 16S rRNA, RAPD-PCR,Pseudomonas sp.