Journal of Pure and Applied MicrobiologyVol. 6 No. 1

Assessment of Chromium Resistant Bacteria Isolated from Tannery Waste Contaminated Soil in the Region of Fez (Morocco): A Statistical Approach

Hanane Sayel, Wifak Bahafid, Nezha Tahiri Joutey, Khalid Derraz and Naima El Ghachtouli*

Microbial Biotechnology Laboratory, Faculty of Sciences and Technology, Sidi Mohammed Ben Abdellah University, Fez, Morocco.

Received on 15 April 2011 and accepted on 27 May 2011

 

ABSTRACT

The environmental risk of chromium pollution is pronounced in soils adjacent to tannery effluents. The influence of contamination by chromium on the diversity of soil microorganisms was investigated in Sebou-Fez system. Soil samples obtained from five sites of the same area were analyzed for chromium contamination. A group of 35 chromium-resistant bacteria were isolated. A negative correlation between soil microbial population and chromium content was observed. These isolates displayed different degrees of resistance to chromium, approximately 77.14% of these isolates showed an MIC value of 400- 600 mg/L Cr(VI). A large number of the cultures reduced >20% Cr(VI) during growth ( 57.1%). Three of the culture showed >80% chromate reduction (about of 8.57% of the total). These strains were tested for their ability to tolerate zinc, mercury, lead, cobalt, copper, and nickel in their growth medium. A large number of the cultures tolered 1500, 2000, and 2000 mg/L Zn, Ni, and Pb, respectively. Some strains can be exploited for bioremediation of hexavalent chromium containing wastes, since it seems to have the potential to reduce the toxic hexavalent form of chromium to its non toxic trivalent form.

Keywords : Bioremediation, Microbial population, Chromium, Heavy metal resistance, Cr(VI) reduction.