Biodegradation of the metallic carcinogen hexavalent chromium Cr(VI) by an indigenously isolated bacterial strain

Abstract

Background:Hexavalent chromium [Cr(VI)], a potential mutagen and carcinogen, is regularly introduced into the environment through diverse anthropogenic activities, including electroplating, leather tanning, and pigment manufacturing. Human exposure to this toxic metal ion not only causes potential human health hazards but also affects other life forms. The World Health Organization, the International Agency for Research on Cancer, and the Environmental Protection Agency have determined that Cr(VI) compounds are known human carcinogens. The Sukinda valley in Jajpur District, Orissa, is known for its deposit of chromite ore, producing nearly 98% of the chromite ore in India and one of the prime open cast chromite ore mines in the world (CES, Orissa Newsletter).Materials and Methods:Our investigation involved microbial remediation of Cr(VI) without producing any byproduct. Bacterial cultures tolerating high concentrations of Cr were isolated from the soil sample collected from the chromite-contaminated sites of Sukinda, and their bioaccumulation properties were investigated. Strains capable of growing at 250 mg/L Cr(VI) were considered as Cr resistant.Results:The experimental investigation showed the maximum specific Cr uptake at pH 7 and temperature 30°C. At about 50 mg/L initial Cr(VI) concentrations, uptake of the selected potential strain exceeded 98% within 12 h of incubation. The bacterial isolate was identified by 16S rRNA sequencing as Brevebacterium casei.Conclusion:Results indicated promising approach for microbial remediation of effluents containing elevated levels of Cr(VI).

Bio-reduction of Cr(VI) by exopolysaccharides (EPS) from indigenous bacterial species of Sukinda chromite mine, India

“…The concentration of total chromium and hexavalent chromium in Sukinda mine sludge was found to be 9.64 and 1.56 mg/l, respectively. Das and Mishra (2010) has reported a similar total chromium concentration range of 9 ± 12 mg/g of soil. In order to emphasize the application potential of this Bioreduction study with respect to natural conditions prevailing at Sukinda mine site, a related concentration of 10 mg/l was selected for this study.…”

“…Chromium tolerant bacteria capable of reduction of hexavalent chromium have been reported from chromium polluted Sukinda environment (Das and Mishra 2010;Dhal et al 2010). Isolation of indigenous bacteria from the sludge of Sukinda mine would be apt to perform in situ remediation as they are site specific and tolerant to Cr(VI).…”

Human Health Risk Assessment of Chromium in Drinking Water: A Case Study of Sukinda Chromite Mine, Odisha, India

“…Chromium (Cr) is one of the most important metal used in various industrial process like tannery, electroplating, chemical, dyes and paint, steel alloy and glass manufacturing (Das and Mishra 2010). Due to excessive demand, the total production of Cr has increased in the last few years and according to estimate it was increased to 3.74 million tons in 2011 from 3.4 million tons in 2009 (IBM 2012).…”

Meteorology drives ambient air quality in a valley: a case of Sukinda chromite mine, one among the ten most polluted areas in the world

“…1, IBM 2013). The chromite ore belt at Sukinda is spread over an area of approximately 200 km 2 in Jajpur district of Odisha, India and is a well-known chromite hub in the world (Das and Mishra 2010). In India, most of the mining operations are done by opencast method.…”