Abstract
Fungal strains; resistant to Chromium (Cr) and tannic acid were isolated from tannery effluents and rDNA gene sequentially identified as Aspergillus niveus MCC 1318, Aspergillus flavus MCC 1317 and Aspergillus niger MCC 1316. The minimum inhibitory concentration (MIC) of the reported isolates ranged up to 200 ppm and 5% for Cr and tannic acid, respectively. Theoretical optimization of the various physiochemical parameters for the removal of Cr and tannic acid was supported using Plackett–Burman design and response surface methodology (RSM). A. niveus, A. niger and, A. flavus were able to remove 80%, 82% and 88% Cr and the residual tannic acid was found to be 20%, 27%, 25% respectively. A hike of 10% was found in the removal Cr in case of novel fungal consortia of A. niger, A. flavus and A. niveus. Enhanced biodegradation (4%–9%) of tannic acid was also observed in the presence of fungal consortia. Bioremediation efficiency of individual fungal strains for other heavy metals such as Zn, Pb, Cd and Ni was observed to be 55%, 68%, 41% and 69% respectively for A. niveus, 60%, 59%, 59% and 50% respectively for A. niger and 63%, 52%, 68% and 58% for A. flavus. An incomparable removal of Zn, Pb, Cd and Ni was observed in the case of fungal consortia i.e. 80%, 70%, 80% and 75% respectively. Fourier transform infrared spectroscopy (FTIR) unveil the adsorption phenomena by revealing the interactions of adsorbed Cr with methyl and methylene groups, secondary amides, phosphate groups present in the fungal media.
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•12 fungal strains have been isolated from the contaminated samples of chromium (Cr(VI)).•Screening and scrutinization divulges FS3 and FS5 isolates to be the most tolerant fungi against the higher concentrations of tested heavy metal.•The maximum value of Cr(VI) uptake and % removal by A. flavus and A. fumigatus stood at 5.65±0.34 mg/g; 74.15±1.48% and 5.90±0.71 mg/g; 74.41±2.02% respectively.