Test chemicals and media
The stock solution of arsenic and other heavy metals was prepared by dissolving heavy metal salts (1,000 mg L−1) in Milli-Q water and filter sterilized through 22-µm filter (Axiva). For arsenate (V) Sodium arsenate dibasic heptahydrate (Na2HAsO4·7H2O), and for arsenite (III) Sodium (meta)arsenite (NaAsO2) salts were used. Beside these, salts like Cadmium chloride (CdCl2), cobaltous nitrate hexahydrate (Co(NO3)2.6H2O), copper chloride (CuCl2), potassium dichromate (K2Cr2O7), lead nitrate (Pb(NO3)2), nickel sulphate hexahydrate (NiSO4.6H2O), and zinc sulphate heptahydrate (ZnSO4.7H2O) were used to prepared stock solution of respective heavy metal. Working test metal solution (20 mg L−1) was prepared by diluting the prepared concentrated stock solution. All the glasswares were acid washed with 10% nitric acid before use to avoid binding of metals. All the chemicals and culture media were of analytical grade and obtained from Himedia, Merck, Sigma, and BioRad.