Khafagi, I., Dewedar, A., Rashad, A., Abo-Seda, A. (2012). Competence of Agrobacterium rhizogenes to accumulate heavy metals and toxicity of cadmium and copper to Agrobacterium strains. test, 7(1), 57-67.
Ishrak Khafagi; Ahmed Dewedar; Alaa Rashad; Akram Abo-Seda. "Competence of Agrobacterium rhizogenes to accumulate heavy metals and toxicity of cadmium and copper to Agrobacterium strains". test, 7, 1, 2012, 57-67.
Khafagi, I., Dewedar, A., Rashad, A., Abo-Seda, A. (2012). 'Competence of Agrobacterium rhizogenes to accumulate heavy metals and toxicity of cadmium and copper to Agrobacterium strains', test, 7(1), pp. 57-67.
Khafagi, I., Dewedar, A., Rashad, A., Abo-Seda, A. Competence of Agrobacterium rhizogenes to accumulate heavy metals and toxicity of cadmium and copper to Agrobacterium strains. test, 2012; 7(1): 57-67.

Competence of Agrobacterium rhizogenes to accumulate heavy metals and toxicity of cadmium and copper to Agrobacterium strains

Catrina: The International Journal of Environmental Sciences
Article 8, Volume 7, Issue 1, 2012, Pages 57-67    PDF (285.17 K)
Document Type: Original Article
Authors
Ishrak Khafagi* 1; Ahmed Dewedar1; Alaa Rashad1; Akram Abo-Seda2
1Botany Department, Faculty of Science, Suez Canal University, Ismailia, Egypt.
2Botany Department, Faculty of Science, Suez Canal University, Suez, Egypt.
Abstract
Heavy metals cannot be degraded through various treatments. Bioaccumulation and bioaugmentation
of heavy metals by food chain could damage normal physiological activity of higher organisms and
threat human life. Heavy metals are very toxic even at low concentration (1.0 – 10 μg/ l) and their
toxicity can last for a long time in nature. Short-deep treatment beds constructed at Abo-Attwa,
Experimental Station, Ismailia, Egypt were efficient in the removal of organic matter, BOD and COD
from primary treated influent by 50%, 66 % and 68 %, respectively. Also, the treatment beds were
efficient in the removal of 93 – 98 % of the heavy metals Cu, Pb, Zn, Ni and Cd from influent. Eight
Agrobacterium strains, three A. rhizogenes and five A. tumefaciens, were isolated and characterized
from naturally-occurring microbial flora proximate domestic wastewater of Abo-Attwa Experimental
Station, Ismailia, Egypt. The Agrobacterium strains were able to accumulate lead, zinc and nickel at
varying rates. On the other hand, copper and cadmium were toxic to all Agrobacterium strains tested.
The toxicity order of various heavy metals to Agrobacterium strains tested was Cd> Cu> Zn> Ni> Pb.
The three A. rhizogenes strains accumulated higher amounts of Zn and Ni than A. tumefaciens strains.
Induction of some tolerant Agrobacterium strains via growth adaptation in the presence of progressive
high concentration of Cd and Cu was achieved. A. rhizogenes strain A8 was superior in adaptation and
survival as tolerant strain to both cadmium (Cd) and copper (Cu) on growing in Nutrient Broth
containing elevated concentrations 1, 3, 10 and 30 μg/ l of both metals. The A. rhizogenes strains A1
and A7 efficiently accumulated 90 % more Cd than non-adapted Agrobacterium cells when grown at
10μg/l. Furthermore, The A. rhizogenes strains A1, A7 and A8 accumulating 90 % , 75 % and 80 %
respectively more Cu than non-adapted Agrobacterium cells when grown at 10μg/l. The
bioaccumulation efficiency % of the A. rhizogenes strains A1 and A7 was 40 %for accumulating 30μg/l
of the toxic metal cadmium (Cd). The potential role of Agrobacterium in the bioremediation of heavy
metals was also considered.
Keywords
Agrobacterium; Bioaccumulation, Biological treatment beds, Heavy metals; tolerant
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