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.

The cost of neomycin production may be significantly decreased by using inexpensive carbon substrates like agricultural residues. However, scarce information can be found in the literature about the utilization of cellulosic and lignocellulosic residues for obtaining neomycin. Usually agricultural residues producing various toxic compounds to the atmosphere; so, as an interesting alternative to the utilization of agricultural wastes (as apple pomace, cotton seed meal, soy bean powder and wheat bran) for simultaneous neomycin production. The highest neomycin production (2765 µg/g substrate) was achieved with apple pomace in solid-state fermentation. The optimization of physical parameters such as inoculum size, substrate particle size, incubation temperature, initial pH, initial moisture level, incubation period and chemical parameters such as additional carbon and nitrogen sources were studied for the production of neomycin in solid-state fermentation using Streptomyces fradiae NCIM 2418. The optimum values of the critical components determined for the maximum neomycin production were inoculum size 2×106 CFU/g initial dry substrate, substrate particle size 1.2 mm, incubation temperature 30oC, initial pH 8, initial moisture level 70%, fructose (1% w/v), (NH4)2HPO4 (1% w/v), L-glutamine (1%w/v) and incubation period day 10. An overall 2.6-fold improvement in neomycin production was achieved due to optimization.