| Summary: | The present study investigates the hexavalent chromium detoxification potential of a fungal species (PS-12) isolated from tannery wastewater. The isolated fungus strongly tolerates 600 mg/L concentration of Cr (0.61±0.03) and was identified as Talaromyces pinophillus by ITS region sequencing. The reduction study was carried out in Erlenmeyer flasks comprising potato dextrose broth amended with different concentrations of Cr+6. PS-12 showed efficient reduction at various temperatures (20°C to 40°C) and pH (5 to 9) in the presence of heavy metals (As, Cd, Cu, Mn, Ni and Pb) and metabolic inhibitors (phenol, NaN3, EDTA). Further, the isolated fungus exhibits excellent biochemical, non-enzymatic and enzymatic antioxidant responses under Cr stress. The maximum reduction of Cr+6 to Cr+3 was found at pH 7 and 50 mg/L concentration with 5.30 ± 0.38 mg/g accumulation in dried biomass. The scanning electron microscopy exposed the bioaccumulation/ biosorption phenomenon as the presence of globular protrusions (smooth hyphae), tightly aggregated and dense structures. The energy dispersive spectroscopy (EDS) and x-ray photoelectron spectroscopic analysis (XPS) revealed the adsorption and precipitation of Cr+3 on the surface of Talaromyces pinophillus mycelium. Furthermore, the participation of the protein-linked functional groups in the complexion of Cr+3 was revealed by the Fourier-transform infrared spectroscopic (FTIR) analysis. The fungus Talaromyces pinophillus exhibited excellent Cr+6 reduction ability with ample biomass production at various stress conditions like temperature, pH, and initial metal ion conditions, presence of other HMs as well as metabolic inhibitors. However, reduction ability was recorded higher in the presence of electron donors. A range of fungal species have been studied for the reduction of Cr+6. Morever, this is the first study that reports the Cr+6 detoxification potential of the newly isolated fungus Talaromyces pinophillus.
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