Required for cell separation during growth. Hydrolysis of (1->4)-beta-linkages between N-acetylmuramic acid and N-acetyl-D-glucosamine residues in a peptidoglycan and between N-acetyl-D-glucosamine residues in chitodextrins. The LysM domains are thought to be involved in peptidoglycan binding. Belongs to the glycosyl hydrolase 73 family.