Isolation, Identification and Characteristics of a Zn-resisting Bacterium, Sphingomonas sp. DX-T3-03

Abstract:

A strain of resistance to zinc with high concentration, named DX-T3-03, was isolated from the metal-polluted sediment of soils around Dexing copper mine. Basing on morphology, biochemical and physiological characterization, DX-T3-03 was characterized as Sphingomonas sp.. A phylogenetic tree was constructed with the published 16S rRNA sequences of relative bacteria species. In the phylogenetic tree, the DX-T3-03 strain has the closest relative to Sphingomonas aquatilis strain JSS-7 with 99% sequence homeology. The optimum growth conditions of DX-T3-03 strain were temperature of 35°C, pH of 6.7, rotating rate of 150 r/min. It could resist zinc of 25 mmol/L or above and be able to grow in a variety of single and combined heavy metals (Cu 70 mg/L, Cd 300 mg/L, Pb 400 mg/L, Ni 60 mg/L).

Key words:Heavy metals, Zinc resistance, Identification, 16S rRNA