Isolation and identification of Chromium-Resistant bacteria from the Soltan Abad River, Shiraz-Iran

Pollutants such as heavy metals that can have destructive effects on the environment can have great impacts on the ecosystem that are directly toxic to living organisms, especially human.. Removing heavy metals requires advanced and expensive technology. Therefore, bioremediation using heavy metal-resistant microorganisms can be a cheaper solution. The aim of this study was to isolate and identify of chrome-resistant bacteria in water and sediments of the Soltan Abad River located in Shiraz.
During two consecutive seasons of the year (spring and summer 2013), the spectrum of resistance of these bacteria was determined by measuring the minimum inhibitory concentration of growth (MIC), growth kinetics, antibiotic tests, detect the high resistance bacteria and determine the resistant bacterial species using PCR.
The mean logarithmic number of bacteria in presence chromium (chromium-resistant bacteria) was much lower than the mean logarithmic number of bacteria in the control medium. Also, after purification of bacteria and Gram staining and other biochemical differential tests, the percentage of gram negative bacteria (66.5%) was higher than gram positive bacteria (33.5).
The results showed that at the sampling stations, depending on the pollutants level, different percentages of bacteria can be isolated. These native microorganisms can be used for bioremediation of chromium.