Question

Why does lysozyme cannot affects gram negative bacterial cell wall

Answer 1

If lysozyme has the ability to attack the binding between NAG and NAM, it should be able to do that during all growth phases. But some bacteria (Gram-positive) become resistant to lysozyme in the stationary phase.

Could the reason be a modification of the peptidoglycan during the stationary phase, which make the bacteria resistant to lysozyme?

Answer 2

Bacterial cell walls contain a layer of peptidoglycan, which is the specific site that lysozyme targets. The peptidoglycan layervcontains alternating molecules called N- acetylglycosamine and N- acetylmuramic acid...  For this reason,  lysozyme canmore readily destroy gram  positive bacteria than gram negative bacteria.