Isolation and Characterization of Pseudomonas sp. Cr13 and Its Application in Removal of Heavy Metal Chromium.

The purpose of this study was to elaborate the characteristics of Pseudomonas sp. Cr13, including physiological and biochemical characteristics, optimization of growth conditions, minimum inhibitory concentration of Cr6+ and resistance to other heavy metals, removal efficiency of Cr6+, and antibiotics sensitivity. A strain Pseudomonas sp. Cr13 was screened from mine-contaminated soils, which could tolerate high concentration of Cr6+ (up to 250 mg l-1) and Cd2+ (50 mg l-1). The optimum pH, NaCl concentration, and temperature for growth were 6, 10% NaCl, and 30 °C, respectively. The removal efficiency of Cr6+ by strain Pseudomonas sp. Cr13 was studied. The removal efficiency of Cr6+ decreased with the increased concentration of Cr6+. Under the optimal conditions, the maximum of the removal rate can reach up to 94.26% in contaminated soils. In addition, antibiotics sensitivity of this strain was investigated. It was found that this strain was sensitive to nine types of antibiotics, which would lay a good foundation for the choice of selective marker in genetic engineering modification of this strain. The results in this article would lay a good foundation for the bioremediation of heavy metals pollution in the future. Pseudomonas sp. Cr13 can tolerate high concentration of Cr6+ and partially remove Cr6+, which make Cr13 an attractive option for the bioremediation of heavy metal chromium (Cr). Our findings suggest that Pseudomonas sp. Cr13 is a potential bacterium with the ability of bioremediation of heavy metal Cr.