African Journal of
Biotechnology

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12481

Full Length Research Paper

Cadmium resisting bacteria in Alexandria Eastern Harbor (Egypt) and optimization of cadmium bioaccumulation by Vibrio harveyi

Hanan Abd-Elnaby, Gehan M. Abou-Elela and Nermeen A. El-Sersy*
National Institute of Oceanography and Fisheries, Microbiology laboratory, Marine Environment Division, Alanfushy Quit Bay, Alexandria, Egypt.
Email: [email protected]

  •  Accepted: 14 February 2011
  •  Published: 25 April 2011

Abstract

Cadmium resisting bacteria (CRB) were present in all water and sediments (samples) collected from Alexandria Eastern Harbor, Egypt. The occurrences of CRB in sediments samples were higher than in water samples and reached up to 77.22% of total counts. Five isolates were selected to be the most resistant to cadmium with minimal inhibitory concentration of 60 ppm. The most potent isolate that accumulates a maximum Cd2+ concentration of 23.3 mg Cd2+/ g dry cells wasidentified as Vibrio harveyi. Medium components affecting metal removal by V. harveyi were explored based on the application of Plackett-Burman design. The growth of V. harveyi in the optimized culture conditions, recorded cadmium biosorption of 1.52 fold increase. Immobilized living cells of V. harveyi on hazelnut shells increased the uptake of cadmium to 49.35 mg Cd2+/g dry cells and removal efficiency up to 84%. Transmission electron microscope study confirmed the accumulation of Cd2+ by V. harveyi cells.

 

Key words: Cadmium resisting bacteria, Vibrio harveyi, bioaccumulation, Plackett-Burman design.