Optimization of Chromate Reduction by Whole Cells of <i>Arthrobacter</i> sp. SUK 1205 Isolated from Metalliferous Chromite Mine Environment

Abstract

<i>Arthrobacter</i> sp. SUK 1205 isolated from metalliferous chromite mine environment of Orissa, India showed wide degree of tolerance to heavy metals including Cr(VI), variety of antibiotics and was also capable of reducing Cr(VI) during growth. Freshly grown whole cells of this bacterium were evaluated for chromate reduction under batch culture using Vogel Bonner (V. B.) broth as the base. Cells of SUK 1205 were capable of completely reducing 100 μM Cr(VI) in V. B. broth within 48 h of incubation. Reduction of chromate increased with increase in cell density which attained maximum at 10<sup>10</sup> cells/ml, however, reverse was the phenomenon when the concentration of Cr(VI) increased gradually. Glycerol, glycine and glucose promoted chromate reduction efficiency of the cells when used as electron donors. Optimum pH and temperature were found to be 7.0 and 35°C respectively. The process of reduction was inhibited by Ni(II), Mn(II), Zn(II) and Co(II), but Cu(II) and Fe(III) was promotive in nature. On the other hand, 2, 4-dinitrophenol was found to be neither promotive nor inhibitory for the reduction process, but carbonyl cyanide-m-chloro phenyl hydrazone, sodium azide, sodium fluoride and N,N,-dicyclohexyl carboiimide were inhibitory. Cells of SUK 1205 when permeabilized with toluene, triton X-100 and tween 80 showed an enhancement of the process and thereby indicated that reduction of Cr(VI) was mainly associated with soluble component of the cells. <i>Arthrobacter</i> sp. SUK 1205, therefore, showed great promise for use in Cr(VI) detoxification under a wide range of environmental conditions

Biosorption of Hexavalent Chromium by Pseudomonas aeruginosa Strain ANSC: Equilibria Isothermic, Kinetic and Thermodynamic Studies

“…Under 300 mg/L of chromate, P. aeruginosa ANSC removed nearly all residual chromate (96.03 %) by 120 h of incubation. Under 400, 500 and 600 mg/L of chromate, however, P. aeruginosa ANSC evidenced a steady increase towards removal of Cr(VI), with the bacterium recording the least percentage Cr(VI) removal of 41.53% under 600mg/L of chromate at 120 h. Similar outcomes were reported by Dey and Paul [10] using whole cells of Arthrobacter sp. SUK 1205 isolated from metalliferous chromite mine.…”

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

“…Such promoting effect of DNP has also been reported in Burkholderia cepacia [40] and Staphylococcus gallinarum [11] and Arthrobacter sp. SUK 1205 [27]. Further, it has been pointed out that DNP, being an uncoupler, might have accelerated the respiratory chain linked electron transport mechanism [40].…”

“…SUK 1201 cells reduced 100 M Cr(VI) in 48 h when the initial cell concentration was maintained at 10 9 cells/mL; however, with 10 fold increase in cell density, 100 M Cr(VI) was completely reduced in 30 h. Increase in cell density stimulated Cr(VI) reduction process (Table 2) as has been reported with Bacillus sphaericus AND 303 [28], Pseudomonas CRB5 [29], Ochrobactrum intermedium SDCr-5 [30], Lysinibacillus fusiformis ZC1 [25], and Arthrobacter sp. SUK 1205 [27].…”

“…Glycerol, acetate, and peptone as electron donors could have completely reduced the added Cr(VI) in 24 h, while glycine and yeast extract appeared to be less efficient electron donors for reducing Cr(VI). Likewise, chromate reducing organisms are reported to utilize a variety of organic compounds as electron donors for Cr(VI) reduction [27,31]. Whole cells of Arthrobacter sp.…”

“…KSUCr9a [37,38], and Arthrobacter sp. SUK 1205 [27]. The function of Cu(II) is either related to electron transport protection or to act as an electron redox centre, in some cases, as a shuttle for electrons between protein subunits [7,24,39].…”