Repository of Research and Investigative Information

Repository of Research and Investigative Information

Ahvaz Jundishapur University of Medical Sciences

Isolation and Identification of Chromium (VI)-Resistant Bacteria From Soltan Abad River Sediments (Shiraz-Iran)

Kafilzadeh, Farshid and Saberifard, Shima (2016) Isolation and Identification of Chromium (VI)-Resistant Bacteria From Soltan Abad River Sediments (Shiraz-Iran). Jundishapur Journal of Health Sciences. ISSN 2252-0627


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Background: Chromium (Cr) is an important heavy metal widely used in industries. It is one of the seventeen chemicals with the highest danger to human health according to the United States environmental protection agency (USEPA). Objectives: The aim of this study was to isolate and identify Cr (VI)-resistant bacteria from Soltan Abad River sediments (Shiraz-Iran) and evaluate their potential for the detoxification of Cr (VI) to Cr (III) under environmental conditions. Materials and Methods: Bacterial isolates were identified on the basis of colony morphology, Gram staining, and biochemical tests using standard microbiological methods. The minimum inhibitory concentrations (MICs) of chromium were determined by the broth agar dilution method. Cr (VI) reduction assay was determined by measuring the absorbance of the purple complex of Cr (VI) with 1,5-diphenylcarbazide. The growth of Cr (VI)-resistant bacteria was determined at different concentrations of Cr (VI). Finally, the effects of temperature and pH on the growth of selected bacteria and Cr (VI) reduction were investigated using an Luria-Bertani (LB) medium containing 50 mg/L Cr (VI). Results: The results indicated that Pseudomonas aeruginosa and Serratia marcescens were the most resistant bacteria with MICs of 200 and 150 mg/L, respectively. Both bacteria completely reduced 25 and 50 mg/L of Cr (VI) in 36 hours and 48 hours, respectively. The growth rate of both bacteria decreased with increases in the Cr (VI) concentration, and the chromate reduction was directly correlated with the growth of the bacteria. These bacteria were capable of reducing Cr (VI) at a wide range of temperatures (25 to 45°C) and pH levels (5 to 9). The optimum medium conditions for Cr (VI) reduction and the growth of the isolates were temperatures between 30 and 40°C and a pH of 7.0 to 8.0. Conclusions: P. aeruginosa and S. marcescens can be good candidates for the detoxification of Cr (VI) in Soltan Abad River.

Item Type: Article
Keywords: Keywords: Chromium (VI); Resistant Bacteria; Minimum Inhibitory Concentration; Pseudomonas aeruginosa; Serratia marcescens
Subjects: Q Science > QR Microbiology
Divisions: Faculty of Medicine, Health and Life Sciences > School of Medicine
Depositing User: آقای بهرام سوسنی غریب وند
Date Deposited: 10 Mar 2018 04:32
Last Modified: 10 Mar 2018 04:32

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