Bio-Absorption of Lead by Isolated Bacteria from Petrochemical Waste water

Subject Areas : environmental management

Bita Karim Salmani ¹ , Mohammad Ali Amozegar ² , Javad Hamedi ³

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Received: 2008-02-09 Accepted : 2008-10-24 Published : 2011-06-22

Keywords: Lead, Bacillus sp, Petrochemical wastewater, Bio-absorption,

Abstract :

Bio-absorption is presented as an alternative to traditional physicochemical means for removing toxic metals from ground water and wastewater. In this research 99 bacterial strains were isolated from three wastewater samples from one of Iran petrochemical industries. Examination of these isolated for Pb2+ tolerance were carried out by using PYT agar medium containing different concentrations of      Pb (NO3)2  from 4 to 15 mM. The isolated KAH1, KAH2 and KAH3, had tolerance to Pb 15, 6.5 and 6.5 mM respectively. These high tolerant strains were selected and their ability of lead bio-absorption, were investigated by atomic absorption spectrophotometer. The highest ability was observed in the strain KAH1 and this strain decreased Pb concentration from 80 mg/l to 44.4 and 48.2 mg/l after 48 and 96 hours incubation, respectively. The results of the experiments showed that bio-absorption was affected by the initial pH of the medium, initial metal ion and exposure time. According to the morphological, physiological and biochemical characterizations of the strain with that of valid strains, the strain was tentatively identified as Bacillus sp. strain KAH1. The maximum Lead bio-absorption capacity of KAH1 isolate was determined to be 48.25 mg/g (97.67%) at pH 4.0 with 150 mg/l concentration in 4 hours equilibrium time