An <i>ex-situ</i> and <i>in vitro</i> approach towards the bioremediation of carcinogenic hexavalent chromium

Abstract

Chromium, ranking the second most among toxic heavy metal pollutants in the world, causing respiratory, cardiovascular and renal problems in human beings is under study herein. We examined the biological remediation of the carcinogenic Cr (VI) polluted soils by indigenous yeast isolates. The total element analysis of the treated sample was determined by Energy Dispersion X-ray Micro Analysis (EDXMA). The sample under study was observed to have a high concentration of 458.29 mgKg^-1 Cr (VI), determined by Atomic Absorption Spectroscopy (AAS) and DPC analysis. The most tolerant isolate designated as CSR was used for <i>in vitro</i> and <i>ex-situ</i> bioremediation studies of Cr (VI). The isolate achieved significant bioremediation of 86% <i>in vitro</i> and 75.12% in <i>ex-situ</i> method. The optimal conditions for <i>in vitro</i> bioremediation were found to be 28 °C and a pH of 6. The ITS1, 5.8S rRNA and D1, D2 domain of LSU rRNA gene characterization of the isolate CSR illustrated that it belongs to Ustilago genera. The isolate was deposited in NCBI GenBank as <i>Ustilago sp.</i> CSR (KY284846). Although, <i>Ustilago</i> is generally a pathogenic fungus, our study opens up the scope of using <i>Ustilago</i> spp. for bioremediation of the carcinogenic heavy metal Chromium.