Has antibacterial activity against Gram-positive bacteria. No activity against S.aureus. 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. Optimally active at acid pH. Belongs to the glycosyl hydrolase 25 family.