Biosorption of Ni (II) by bacillus sp. isolated from desert-maranjab soil

Abstract

The objective of this research was to isolate microorganisms which produce uptake of nickel ions, from soils in Desert-Maranjab. In this study various soil samples were collected in Desert Maranjab and were cultured on nutrient agar and saboroud dextrose agar and the patent isolates were purified. Twenty soil samples were collected from various areas of Desert Maranjab, Iran .Initial screening of a total of 40 bacterial isolates at pH 5, resulted in the selection of one isolate with maximum uptake capacity of nickel ions 0.71 mmol.g-1 dry weights. A contact time of 10 min was sufficient to reach equilibrium. It was tentatively identified as Bacillus sp according to morphological and biochemical properties and named strain AEJ-89.This Bacillus sp gram positive bacteria were used to investigate the biosorption of Ni ions. In the next step the effects of some ecological parameters (temperature, pH, kinetics and isotherm were studied on the biosorption. The results obtained showed that the optimized conditions for the uptake nickel ions were as follow: Temperature 25ºC, pH= 7.8 - 7.2, and carbon sources (glucose and lactose 10 g / l). The equilibrium time was about 5 min and the adsorption equilibrium data were well described by the Langmuir`s equation.