Light driven Aspergillus niger-ZnS nanobiohybrids for degradation of methyl orange

Inorganic-microbial hybrid systems have potential to be sustainable, efficient and versatile chemical synthesis platforms by integrating the light-harvesting properties of semiconductors with microbial cells. Here, we demonstrate light-driven photocatalytic semiconducting Aspergillus niger cells-ZnS nanoparticles for enhanced removal of the dye methyl orange. Chemically synthesized ZnS nanoparticles exhibited a zinc blende pattern in X-ray diffraction, had a dimension of 20-90 nm with a band gap (E-bg) of 3.4 eV at 1.83 x 10(18) photons/second. Biologically synthesized ZnS nanoparticles of 40-90 nm showed a hexagonal pattern in the X-ray powder diffraction spectra with an E-bg 3.7 eV at 1.68 x 10(18) photons/second. At a methyl orange (MO) concentration of 100 mg/L, dosage of 0.5 x 105 mol catalyst and pH 4, a 97.5% and 98% removal efficiency of MO was achieved in 90 min and 60 min for, respectively, chemically and biologically synthesized ZnS nanobiohybrids in the presence of UV-A light. The major degradation products of photocatalysis for chemically synthesized ZnS nanobiohybrids were naphtholate (C10H7O m/z 143) and hydroquinone (C(9)H(5 )m/z 113). For the biologically synthesized ZnS nanobiohybrids, the degradation products were hydroquinone (C9H5 m/z 113) and 2-phenylphenol (C12H10O m/z 170).

Automated summary

Inorganic-microbial hybrid systems integrate the light-harvesting properties of semiconductors with microbial cells to create sustainable, efficient, and versatile chemical synthesis platforms. This study demonstrates the use of light-driven photocatalytic semiconducting Aspergillus niger cells-ZnS nanoparticles for enhanced removal of the dye methyl orange.