سال انتشار: ۱۳۸۸

محل انتشار: اولین کنفرانس بین المللی تصفیه فاضلاب و بازیافت آب، فناوری ها و یافته های نو

تعداد صفحات: ۷

نویسنده(ها):

R Nayeri – Department of Microbiology, Faculty of Science, Islamic Azad University, Branch of Sciences and Researches, P.O.Box 14515/775, Tehran, Iran
N Ghaemi – Department of Biotechnology, Faculty of Science, University of Tehran, Tehran, Iran
A Noohi – Department of Microbiology, Faculty of Science, Islamic Azad University, Branch of Sciences and Researches, P.O.Box 14515/775, Tehran, Iran

چکیده:

Lead is present in different types of industrial effluents, being responsible for environmental pollution. The bacterial strains used in the present study, isolated from wastewaters of industrial centers in Qom and Qazvin. The tolerance to lead was determined by the agar dilution method on modified-Luria Bertani Agar medium containing of 5 Mm concentration method. After this stage, about 29 different bacterial isolates resistant to lead, were identified. Then, a particular method (Pümpel et al., 1995) was employed. The test is based on the visualization and interpretation of the lead distribution between agar and colonies by chemical precipitation with hydrogen sulfide. Ten isolates were selected, which consisted of four Gram-negative and six Gram-positive bacteria. Biosorption capacities of dried biomass of these bacteria were investigated by using an Atomic Absorption Spectrophotometer. At experimental conditions including: initial lead concentration 500 ppm, temperature 30ºC, pH 5, contact time 24 h and agitation rate 150 rpm, the maximum metal biosorption capacities was observed by two of the bacteria which were Gram-positive and Gram-negative bacterium with biosorption values 162.8 mg/gdw and 125.6 mg/gdw, respectively. The binding capacities for lead were investigated by using nonliving cells (heat dried or autoclaved) and living cells.