Reduction of Chromium-VI by Chromium Resistant Lactobacilli: A Prospective Bacterium for Bioremediation

Chromium is a toxic heavy metal, which primarily exists in two inorganic forms, Cr (VI) and Cr (III). Highly soluble hexavalent chromium is carcinogenic due to its oxidizing nature. It is well established that the intestinal bacteria including Lactobacilli have regulatory effect on intestinal homeos...

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Bibliographic Details
Published inToxicology international Vol. 19; no. 1; pp. 25 - 30
Main Authors Mishra, Ritesh, Sinha, Vartika, Kannan, Ambrose, Upreti, Raj K
Format Journal Article
LanguageEnglish
Published India Medknow Publications and Media Pvt. Ltd 01.01.2012
Medknow Publications & Media Pvt. Ltd
Medknow Publications & Media Pvt Ltd
Subjects
Antibiotics
Bacteria
Bioremediation
Chromium
Environmental aspects
Environmental protection
Enzymes
Lactobacillus
Metals
Microbiology
Original
United States
lactobacilli
chromate reductase
Bioremediation
hexavalent chromium
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Summary:Chromium is a toxic heavy metal, which primarily exists in two inorganic forms, Cr (VI) and Cr (III). Highly soluble hexavalent chromium is carcinogenic due to its oxidizing nature. It is well established that the intestinal bacteria including Lactobacilli have regulatory effect on intestinal homeostasis and a breakdown in the relationship between intestinal cells and bacteria results in the manifestation of gastrointestinal (GI) disorders. In this study Cr (VI) resistance was developed in Lactobacillus strains and the reduction of Cr (VI) was evaluated. All resistant strains showed similarities with their respective normal strains and did not acquire resistance to various antibiotics. A complete bacterial reduction of 32ppm Cr (VI) was observed within 6 to 8 hours. The presence of chromate reducing enzyme have also been established following the partial purification (2 to 5 fold) and characterization of chromate reductase in Lactobacillus strains. The chromate reductase of our strains showed optimum activity at pH 6.0 and 30°C. To our knowledge; these strains are fast in Cr (VI) reduction than any other known bacteria. The results suggest that chromate- resistant Lactobacillus strains would be useful for chromium detoxification from GI-tract as well as for bioremediation of hexavalent chromium from contaminated environment.
ISSN:0971-6580
0976-5131
DOI:10.4103/0971-6580.94512