Chromium (III) Biosorption of Deinococcus radiodurans and Its Vitreoscilla Haemoglobin (vgb) Gene-Transferred Recombinants

Objectives: This study used Deinococcus radiodurans, which is extremely resistant to oxidative damage, genotoxic chemicals, high levels of ionising and ultraviolet radiation and drying, and its Vitreoscilla haemoglobin (vgb) gene-cloned recombinant with the vgb− recombinant strain as a control. In addition to the conditions wherein bacteria have an optimum Cr (III) biosorption capacity, the contribution of the vgb gene to the biosorption ability of the bacteria has been investigated by providing the organism with a more oxygenic environment. Methods: Bacteria were produced and metal stock solution was prepared. To determine the Cr (III) removal capacities of wild and recombinant D. radiodurans strains, the residual metal concentration in aqueous media at the beginning and after biosorption was determined in Atomic Absorption Spectrophotometer. Some optimal conditions were created for the biosorption conditions to occur. Conclusions: The optimisation tests showed that Cr (III) reached the highest biosorption capacity within 15 minutes at a metal concentration of 2,000 ppm, 30 °C, pH 5.0 and 150 rpm stirring speed in all the three bacteria. The vgb gene had no significant contribution to the biosorption capacity.