چکیده (انگلیسی):

An analysis of wastewater samples collected from different industrial regions ofEgypt demonstrated dangerously high levels of nickel (0.27–31.50 mg L−1), chromium(1.50–7.41 mg L−1) and zinc (1.91–9.74 mg L−1) in the effluents. Alarmingly, these heavy metalsare among the most toxic knownones to humans and wildlife. Sixty-nine Actinomycete iso-lates derived from contaminated sites were evaluated under single, binary, and ternarysystems for their biosorption capacity for Ni2+, Cr6+and Zn2+from aqueous solutions. Theresults of the study identified isolates MORSY1948 and MORSY2014 as the most activebiosorbents. Phenotypic and chemotypic characterization along with molecular phyloge-netic evidence confirmed that the two strains are members of the Nocardiopsis and Nocardiagenera, respectively. The results also proved that for both the strains, heavy metal reductionwas more efficient with dead rather than live biomass. The affinity of the dead biomass ofMORSY1948 strain for Ni2+, Cr6+and Zn2+under the optimized pH conditions of 7, 8 and7, respectively at 40◦C temperature with 0.3% biosorbent dosage was found to be as fol-lows: Ni2+(87.90%) > Zn2+(84.15%) > Cr6+(63.75%). However, the dead biomass of MORSY2014strain under conditions of pH 8 and 50◦C temperature with 0.3% biosorbent dose exhibitedthe highest affinity which was as follows: Cr6+(95.22%) > Ni2+(93.53%) > Zn2+(90.37%). Allheavy metals under study were found to be removed from aqueous solutions in entiretywhen the sorbent dosage was increased to 0.4%.© 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. This isan open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).