Carbon and nitrogen are good for bacteria and I am not sure if we can replace them.

@ Kuebra, I think you may try to grow bacteria using only dipotassium phosphate, magnesium sulphate, calcium chloride, sodium chloride and ferric chloride with agar powder. But it is really difficult to grow bacteria without carbon and nitrogen supply. Although some bacteria can grow without added carbon source. They exhibit an "autotrophic metabolism" and fix carbon in the form of CO2.

you can use M9 minimal medium and prepare it using following recipe.

https://www.aatbio.com/resources/buffer-preparations-and-recipes/m9-salts

and add your sources of Carbon and Nitrogen

Good luck