Abstract

HEAVY METAL LEACHING BY A NOVEL Aspergillus sp. ISOLATED FROM A POLLUTED SITE

Nilika Bhattacharya*, Apala Pal, Preeti Khan, Moumita Basu , Sohini Chakraborty,Nayanika Sengupta and Dr. Arup Kumar Mitra

Abstract

In this investigation, a polluted soil from a metal industry of Kharagpur was collected; serially diluted and plated in a microbiological media. The organism isolated was found to be the blue green mould Aspergillus sp. Atomic absorption specificity analysis of soil shows maximum presence of Cu (7.47mg/kg) and Fe (61495.21mg/kg) and the organism also shows appreciable tolerance to heavy metals. This heavy metal stress also brought about certain morphological variations, percentage shrinkage in vesicular size with respect to control is 30.23%, 66.00%, 27.30% for Fe-750ppm, Fe-1000ppm and Cu-10ppm respectively , but the size of conidia remained invariant. On the basis of precipitates collected from the culture tube, the change of oxidation state from 2-3 for both the metals was observed. Accordingly Cu and Fe dependent oxidases of the organism was estimated. Iron Oxidase showed an increase by 0.20u/mg of total protein in presence of Fe and copper dependent oxidase showed an increase by 0.25u/mg of total protein in presence of Cu. Phase contrast microscopy distinctly proved the morphological modification. Hence we propose that the fungus not only is tolerant to Cu and Fe but also removes it from the cyclical pool to reservoir pool having adequate potential for biomining.

Keywords: Aspergillus sp., Metal Tolerance , Morphological variation , Enzyme Assay, hase Contrast Microscopy.