RETRACTED: Identification of a New Microalgal Strain From Chromite Mine Wastes for Detoxification of Hexavalent Chromium for Sustainable Crop Growth

Abstract

Sukinda chromium mine is well known for its chromium (Cr) reserve in India. It accounts for 97% of Cr production in the country. The open cast mining results in the seepage and accumulation of chromium in the nearby paddy fields through soil runoff. Deposition of high concentrations of toxic Cr6+ adversely affected the growth and productivity of rice plants. It was studied that Cr6+ toxicity can be counteracted by the microbes especially algae. Hence, an attempt has been made for the exploration of an indigenous micro-algal strain for the detoxification of Cr6+ in the rice fields. Three different micro-algal strains were isolated from the waterlogged regions of the mine waste area and tested against Cr6+. The average concentration of Cr6+ in the soils of rice fields and its surrounding regions was estimated around 40ppm. In vitro study was conducted to determine the optimal growth parameters for the growth of the algal strains. The concentration of total chromium availability was determined by using ICP-OES (Inductively coupled plasma atomic emission spectroscopy. It showed that all the algal-stains were able to detoxify Cr6+, but the best result (89.63%) was observed in one strain ‘SM3’. SEM-EDX study also showed that there was no Cr adsorbed on the surface of the algal strain. Raman Spectroscopy study confirmed the reduction of Cr6+ to Cr3+ in algal strain. The strain was identified as Fischerella sp. (Accession no. MK422171) through morphological and molecular characterization. This algal strain can be used for the bioremediation of chromium contaminated crop fields.