Possesses lytic activity against M.lysodeikticus and several fish pathogenic bacteria. 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. Optimum pH is 6.0. Optimum temperature is 25 degrees Celsius. Ubiquitous. Belongs to the glycosyl hydrolase 23 family.