Journal of Biotechnology & Biomaterials
Open Access

Abstract

The anthropogenic uses and applications of chromium have increased rapidly since the industrial revolution. Chromium exists in a wide range of valency states from -4 to +6 with the hexavalent species (Cr6+) predominant in natural aquifers and its trivalent counterpart (Cr3+) prevailing in the municipal and industrial wastewater. Apart from its toxicity, Cr6+ is also highly soluble and thus mobile and biologically available in the ecosystems. Because of its persistence in the environment, anthropogenic release of Cr6+ executes extravagant toxicity and behemoth threat. The bacterial species are able to grow in the toxic conditions and are generally assumed to be tolerant or resistant to chromium. Pseudomonas sp. was the first hexavalent chromium remediating microorganism to be indentified from waste water. A number of chromiumresistant microorganisms were subsequently isolated such as B. cereus, B. subtilis, P. aeruginosa, P. ambigua, P. fluorescens, E. coli, Achromobacter eurydice, Micrococcus roseus, Enterobacter cloacae, Desulfovibrio desulfuricans and D. vulgaris. Bacillus coagulans isolated from electroplating industry was capable of reducing Cr (VI) by using soluble enzyme and utilizing malate as external electron donor. The sulfate reducing bacteria have the ability to reduce chromium in the soil. Several strains of Brevibacterium sp. was isolated from industrial wastewater had ability to reduce Cr (VI) at various concentrations. Fungus acts as bio-absorptive material to remove hexavalent chromium. Biosorption mechanism is done by two methods-metabolism dependent and non-metabolism dependent. Fungal strains of Aspergillus sp., Penicillium sp., Fusarium sp., Pichia sp. etc., are also capable for chromium bioremediation in environment. The application of microorganisms to detoxifying metals has been tested in a number of systems but the viability and metabolic activity of cells are still the major limiting factors affecting the detoxification efficiency of the cellular biomass and enzymes involved. Genetically engineered microorganisms have higher activities in transforming and remediating heavy metals like chromium. However, the risk of releasing such organisms into the environment is still under investigation.

Biography

Email: sayan_evs@yahoo.co.in sayan.evs@gmail.com