Biowastes-derived enzyme-powered zinc oxide and titanium oxide nanomaterials synthesis for anticancer and eco-friendly photocatalytic activity

Abstract

Biowastes derived enzyme powered zinc oxide (ZnO) and titanium oxide (TiO2) nanomaterials were prepared using a soft-chemical method and their photocatalytic dye degradation efficiencies against toxic Methylene Blue (MB - cationic) and Methyl Orange (MO-anionic) dyes were studied. The enzymes prevalent in certain biowastes (vegetable wastes and fruit peels) are derived through eco-friendly fermentation process and used for nanomaterial synthesis. The enzyme quantitative assay confirmed the presence of the enzymes viz., protease, peroxidase, cellulase, amylase and lipase in the synthesized nanopowders. The photocatalytic results showed the enhanced combined effect of the semiconductor photocatalyst (ZnO and TiO2) and the bio-catalyst (enzymes). The efficiency of the resultant photocatalysts: ZnO - 95% (60 min) and TiO2 99% (60 min). The XRD results confirm the crystallized form of enzymes in the nanomaterial. The desirable morphological changes caused by the enzyme coupling with semiconductor was evidenced from SEM images. The study showed that the synthesized material (enzyme powered ZnO and TiO2) are desirable candidates for environmentally friendly, biocompatible photocatalysis for toxic dyes degradation. The cytotoxicity studies revealed that the material may effectively destroy the lung cancer A-549 cells. The half maximal inhibitory concentration (IC50) values of enzyme powered ZnO and TiO2 are 51.75 ± 0.05 μg/mL and 52.25 ± 0.05 μg/mL, respectively. Thus, the biowastes derived enzyme powered ZnO and TiO2 can be considered as promising materials for cost-effective dye degradation and anticancer activities.