Cadmium-induced oxidative stress tolerance in cadmium resistant Aspergillus foetidus: its possible role in cadmium bioremediation.
Toxic effects of cadmium (Cd) were examined on a cadmium-resistant strain of Aspergillus foetidus isolated from wastewater. The Cd removal potential was analyzed. The results indicated that the strain could tolerate up to 25 mM and 63 mM Cd in liquid and solid Czapek-Dox media, respectively. It efficiently removed Cd from liquid growth media and industrial wastewater by mycelial biosorption. The strain produced oxalic acid for the purpose of Cd bioleaching as confirmed by the presence of cadmium oxalate crystals on the mycelial surface. Intracellular proline contents and the antioxidative enzyme activities increased up to a certain level to detoxify the overproduced free radicals. These data indicate that the strain has inherent mechanisms to grow in Cd contaminated environment, tolerate high Cd doses and high Cd uptake potential which are pre-requisite for acting as a suitable candidate for Cd bioremediation.
Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, India.
Shatarupa
S
Chakraborty
Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, India. Electronic address: abhi_biochem81@yahoo.in.
Abhishek
A
Mukherjee
Department of Zoology, University of Kalyani, Kalyani 741235, India.
Anisur Rahman
AR
Khuda-Bukhsh
Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, India.
Tapan Kumar
TK
Das
D001230:Aspergillus / Q000737:chemistry / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002104:Cadmium / Q000378:metabolism* / Q000633:toxicity*; D004785:Environmental Pollutants / Q000378:metabolism / Q000633:toxicity; D004789:Enzyme Activation / Q000187:drug effects; D005656:Fungal Proteins / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D018384:Oxidative Stress / Q000187:drug effects*; D010088:Oxidoreductases / Q000378:metabolism; D011392:Proline / Q000032:analysis; D013052:Spectrometry, X-Ray Emission; D013438:Sulfhydryl Compounds / Q000032:analysis
D004785:Environmental Pollutants; D005656:Fungal Proteins; D013438:Sulfhydryl Compounds; D002104:Cadmium; D011392:Proline; D010088:Oxidoreductases
Antioxidative enzymes; Aspergillus foetidus; Bioremediation; Lipid peroxidation; Oxidative stress; Thiol