Bioremediation Of Hexavalent Chromium Research Articles

Bioremediation of hexavalent chromium contaminated water in fixed-film upflow reactors - a south african first

Bioremediation of hexavalent chromium contaminated water in fixed-film upflow reactors - a south african first

Bioremediation of Hexavalent Chromium and Tannic Acid in Synthetic Tannery Wastewater Using Free and Calcium Alginate–Immobilized Spores and Mycelia of Aspergillus niger and Aspergillus parasiticus

ABSTRACT The bioremediation of chromate and tannic acid in synthetic tannery wastewater was studied in a batch culture system using free and immobilized spores and mycelia of A. niger and A. parasiticus. Significant (p< .001) decreases in total dissolved solids (TDS), biochemical oxygen demand (BOD), chemical oxygen demand (COD), Cr(VI), and tannic acid concentrations were observed in cultures of both fungi after 96 h of growth. The A. niger culture medium had significantly lower TDS (p< .001), BOD, and tannic acid concentration (p< .05) compared to that of A. parasiticus. Immobilization of both spores and mycelia of the two fungi on Ca-alginate resulted in significantly (p< .05–.001) lower residual Cr(VI) concentrations within 24 h hydraulic retention time (HRT). Chromate removal increased significantly (p< .05) as the number of beads of immobilized spore/mycelia increased from 10 to 100; the increase in Cr(VI) removal ranging from 40.3% to 47.9% with 10 beads and 97.4% to 98.6% with 100 beads. Similarly, tannic acid removal by spores and mycelia of the fungi was significantly (p< .05) enhanced by immobilization. Repeated use of the alginate entrapped spores/mycelia of both fungi up to 3 cycles of 72-h HRT showed no significant change in their ability to carryout Cr(VI) removal.

Bioremediation of hexavalent chromium in soil microcosms

Pseudomonas mendocina when added in soil microcosms could immobilize 100 μg (2 mM) chromate/g soil in 8 h by converting it into trivalent form. The chromate-contaminated soils, after microbiological treatment, supported growth of wheat seedlings without exerting any toxic effects. The method is potentially useful in the bioremediation of chromate-contaminated sites. © Rapid Science Ltd. 1998

Study on Hexavalent Chromium Reduction by Chromium Resistant Bacterial Isolates of Sukinda Mining Area

Rapid industrialization coupled with explosive development of chemical and mining industries has not only resulted in global deterioration of the environmental quality but also has drawn attention of scientists for an effective measure to control environmental pollution. Sukinda in the district of Jajpur, Orissa has drawn worldwide attention as one of the most polluted area with chromium due to chromate rich. In the present experiment, attempt has made to detoxify Cr (VI) by chromium resistant bacterial isolates of Sukinda mining area. Random soil and water samples were collected aseptically from four different sites of the mining area and physiochemical parameters of the samples were estimated. Out of the twelve, four chromium resistant bacterial isolates viz., Micrococcus luteus, Pseudomonas putida, Serratia marcescens and Acinetobacter calcoaceticus tolerated hexavalent chromium beyond 500 ppm and selected for reduction. Among all, Acinetobacter calcoaceticus shown highest amount of hexavalent chromium reduction of 67.14% incubated at 30°C for 24 hr at pH 7. Then Acinetobacter calcoaceticus was selected for parametric studies and observed to exhibit highest reduction i.e., 70.53% potential at pH 8.0, temperature 30°C/24 hr. Therefore, Acinetobacter calcoaceticus may be use in the bioremediation of hexavalent chromium toxicity.DOI: 10.3126/on.v8i1.4313