Zinc oxide (ZnO) has broad applications in various areas. Green synthesis is an alternative to conventional physical and chemical methods. Green synthesis of nanoparticles is gaining importance due to its cost-effectiveness, reduction of toxic chemicals and extensive antimicrobial activity. Herein, we have discovered synthesis of zinc oxide nanoparticles (ZnONPs) using agro waste materials like sheep and goat faecal matter as a reducing agent. Synthesized ZnONPs were evaluated for their purity, particle size, morphological structure, using UV-visible spectroscopy, Fourier transforms infrared spectroscopy, X-ray diffraction and scanning electron microscope analysis. However, nanoparticles gain low crystallite size, they seemed to be uneven structures like spongy like and flower shaped particles. Obtained nanoparticles exhibit good antimicrobial activity and minimum inhibitory concentration against Salmonella typhimurium and Bacillus subtilis. Agro-waste based green synthesized ZnONPs possess small sized particles, enhances the good antimicrobial effect. This research leads to develop a new way of cost-effective synthesis and reducing usage of chemicals in further studies.

BACKGROUND: Accumulation of industrial dyes in wastewater creates not only environmental problems, but also medical and aesthetic problems. Removal of synthetic dyes from contaminated hot textile industrial discharge is a fundamental issue. Herein, the microbial decolorization of azo dyes amaranth RI and fast red E was studied. The decolorization process was studied in terms of various physicochemical and analytical parameters.RESULTS: The azo dye decolorization efficiency was improved with beef extract and maltose as nitrogen and carbon sources, respectively. At 55 °C, Geobacillus thermoleovorans KNG 112 showed the maximum decolorization for both amaranth RI and fast red E at pH 7 and 8, respectively. Fourier transform infrared spectral analysis revealed the formation of amide, nitrosamine, aromatic and carbonyl compounds, alkyne, alkane, alcohol and alkyl halide groups after dye decolorization. Mixed dye (amaranth RI and fast red E) decolorization resulted in formation of various alkyl acetals, amines (nitrosamines, secondary and tertiary amines) azo groups and alkyl chloride. Furthermore, phytotoxic effect of azo dyes on the germination of fenugreek and green gram showed no inhibitory effects; however, more and rapid germination compared to the control group was observed.CONCLUSIONS: The results lead to the conclusion that the optimization of G. thermoleovorans KNG 112 for removal of azo dyes could have applications in decontamination of hot industrial discharges.

No abstract