I'm trying to find MIC values of ZnO however iIm unable to understand how it is calculated as zinc oxide doesn't dissolve in any solvent. In the case of disc diffusion method how to prepare disc of different concentration?
The disc diffusion method is not recommended. You can try a mixture of many concentrations of ZnO with specifiic culture media in Petri dishes or in tubes inoculated with the microorganism test. For each variant you must detect the microbial growth.