What are the reagents that can be used to kill bacterial cells in a culture or culture-supernatant without affecting the proteins (and other biomolecules) secreted by the bacteria?
I can recommend a mixture of penicillin-streptomycin to kill bacteria without destroying the structure of extracellular proteins in a supernatant or liquid culture. This mixture will have bactericidal effect for Gram positive and Gram negative bacteria. Alternatively, you can filter your liquid culture or supernatant using a 0.45 micron syringe filter.
Thanks Sinan Bayram , I was thinking if NaN3 could also be used. (However, I thought 0.22 micron instead of 0.45 micron needs to be used to get rid of bacterial cells).