Open AccessReduction of chromium-vi by chromium resistant lactobacilli: A prospective bacterium for bioremediation
Author(s) -
Ritesh Mishra,
Vartika Sinha,
A. Kannan,
Raj K. Upreti
Publication year - 2012
Publication title -
toxicology international/indian journal of toxicology
Language(s) - English
Resource type - Journals
eISSN - 0976-5131
pISSN - 0971-6580
DOI - 10.4103/0971-6580.94512
Subject(s) - hexavalent chromium , chromate conversion coating , chromium , bioremediation , bacteria , chemistry , microbiology and biotechnology , lactobacillus , detoxification (alternative medicine) , potassium chromate , food science , biology , medicine , alternative medicine , organic chemistry , pathology , genetics
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.