Isolation, characterization and toxicity of a malachite green degradation bacterial strain

Abstract:

[Objective] An efficient malachite green degradation bacterial strain was isolated from the actived sludge sample collected from wastewater-treating system of dye manufacturer, and the toxicity of malachite green before and after decolorization was contrasted through some methods. [Methods] A decolor bacteria was isolated by dilution plating procedure and was then identified by scanning electron microscope (SEM) and 16S rRNA gene analysis. The toxicity of malachite green before and after decolorization was evaluated through biological toxicity tests using Chlorella and Vicia faba as test material. [Results] The strain separated from the wastewater-treating system of dye manufacturer was identified as Klebsiella sp. JD on the basis of 16S rRNA gene analysis. Klebsiella sp. JD biochemical colony which was gray and viscous shows a regular circle shape. With the touch of inoculation loop, the colony was draw into wire easily and the wire had a smooth surface. By comparing with the growth rate and inhibiting rate of Chlorella, the MCN‰ and PI of Vicia faba, it could be found that the toxicity of malachite green decreased after decolorization. [Conclusion] A malachite green degradation bacterial strain is isolated in this research. The efficient strain can reduce the toxicity of dye, which has a practical significance in the remediation of dye contaminated water.