European Journal of Biomedical and Pharmaceutical Sciences

CHARACTERIZATION OF CADMIUM BIOREMEDIATION AND PLANT GROWTH PROMOTION ACTIVITIES OF LEUCOBACTER SP. KUCD3 ISOLATED FROM INDUSTRIAL BELT OF KALYANI, WEST BENGAL, INDIA

Abhishek Paul and Bejoysekhar Datta*

ABSTRACT

Exploitation of cadmium (Cd) resistance mechanism of microorganisms can be a potential eco-friendly measure to remediate cadmium pollution. In this investigation a cadmium tolerant (500 mg/L) bacterium designated as KUCd3 was isolated from industrial waste collected at Kalyani, West Bengal, India and was identified as Leucobacter sp. based on molecular and biochemical tests. Cd removal activity by the isolate was found to be a cell biomass dependent process as it increased along with active cell mass generation and became maximum (66.3%) at stationary phase of its growth. Physiological factors such as pH and salinity, initial Cd concentration and other heavy metals like nickel and zinc influenced its Cd removal activity considerably. Transmission electron microscopy, energy dispersive X-ray spectroscopy and cell fractionation study revealed that intercellular bioaccumulation of Cd around the cell envelop of the growing bacterial population was the major bioremediation mechanism of the isolate. It removed up to 60.18% of Cd from Cd amended sewage water in presence of natural microflora. The isolate produced substantial amount of indole acetic acid (105 µg/mL) in presence of tryptophan. It could successfully colonize in the rhizosphere soil of mustard plant (Brassica sp.) and promote its growth both under normal and Cd supplemented conditions. Application of the isolate as seed inoculant could reduce Cd uptake (43.32% in shoots and 54.55% in root) by the plant. So, Leucobacter sp. KUCd3 can be considered as a potential Cd bioremediation agent for Cd contaminated sewage water and agricultural field.

Keywords: Bioremediation, Cadmium, Plant growth promotion, Leucobacter; Mustard.