Confuzzled26

Hello fellow scientists, I have been having a slight problem with protein solubility, when i overexpress my protein of interest (14kda) using LB (luria bertani) broth, my protein is soluble and i am able to purify however when i do the same overexpression using minimal media (M9) the protein is insoluble, what kind of variations either to the media or growth conditions would anyone recommend in order to get this protein soluble, i plan to do NMR to resolve the full protein structure, any feedback would be most appreciated!