Copper biosorption by Bacillus pumilus OQ931870 and Bacillus subtilis OQ931871 isolated from Wadi Nakheil, Red Sea, Egypt
Amal W. Danial, Fatma M. Dardir
Abstract
Abstract Background Despite being necessary, copper is a toxic heavy metal that, at high concentrations, harms the life system. The parameters that affect the bioreduction and biosorption of copper are highly copper-resistant bacteria. Results In this work, the ability of the bacterial biomass, isolated from black shale, Wadi Nakheil, Red Sea, Egypt, for Cu 2+ attachment, was investigated. Two Cu 2+ resistance Bacillus species were isolated; Bacillus pumilus OQ931870 and Bacillus subtilis OQ931871. The most tolerant bacterial isolate to Cu 2+ was B. pumilus . Different factors on Cu 2+ biosorption were analyzed to estimate the maximum conditions for Cu biosorption. The q max for Cu 2+ by B. pumilus and B. subtilis determined from the Langmuir adsorption isotherm was 11.876 and 19.88 mg. g −1 , respectively. According to r 2 , the biosorption equilibrium isotherms close-fitting with Langmuir and Freundlich model isotherm. Temkin isotherm fitted better to the equilibrium data of B. pumilus and B. subtilis adsorption. Additionally, the Dubinin-Radushkevich (D-R) isotherm suggested that adsorption mechanism of Cu 2+ is predominately physisorption. Conclusion Therefore, the present work indicated that the biomass of two bacterial strains is an effective adsorbent for Cu 2+ removal from aqueous solutions.