Reduction of Hexavalent Chromium by Viable Cells of Chromium Resistant Bacteria Isolated from Chromite Mining Environment

Table 3

Effect of metal ions on chromate reduction by viable cells of Arthrobacter sp. SUK 1201.

Incubation, hr	% Cr(VI) reduced
	Metal ions, 100 µM
	Control (-Additional metal ions)	Cu(II)	Ni(II)	Co(II)	Mn(II)	Zn(II)
12	46.2 ± 1.8	81.4 ± 3.2	44.1 ± 2.6	53.0 ± 2.0	54.1 ± 0.6	48.0 ± 0.4
24	60.2 ± 2.6	100 ± 0.8	53.0 ± 1.6	57.0 ± 0.8	60.0 ± 1.6	57.0 ± 1.9
48	100 ± 0.6	100 ± 0.2	66.0 ± 2.6	74.0 ± 1.0	60.0 ± 0.6	63.4 ± 2.4

(Cr(VI) reduction was carried out in V. B. broth containing 100 µM Cr(VI). The initial cell density was maintained at cells/mL. Separately sterilized metal solutions were added to V. B. broth at equimolar (100 µM) level of Cr(VI).
Incubation: 48 h at 25°C under continuous shaking (120 rpm). Residual Cr(VI) was estimated by usual diphenylcarbazide method. Results represent mean of triplicate experiments ± standard error).