The main role of this lysozyme is in digestion. Has antibacterial activity against the Gram-positive bacterium P.cerevisiae and the Gram-negative bacteria E.coli and V.vulnificus. Shows some chitinase activity but no isopeptidase activity. 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. Activity decreased by 80% by addition of 0.01 M calcium, zinc or magnesium. Activity only decreased by 17% by addition of ammonium, and by 2% by addition of sodium. Retains more than 90% of its maximum activity between pH 5.4 and 6.4 in the ionic strength range of I=0.005-0.01. In buffers of I=0.005 more than 75% of maximum activity is retained between pH 5.3 and 7.5. In buffers of I=0.02 more than 75% of maximum activity is retained between pH 5.3 and 6.5. Optimum temperature is 55 degrees Celsius. No decrease in activity was detected after incubation at 30 degrees Celsius for 30 minutes. No activity could be detected after incubation at 90 degrees Celsius for 30 minutes or 100 degrees Celsius for 10 minutes. Expressed in the epithelia of the basophil cells in the digestive tubules, but not in the epithelial cells lining the digestive ducts and stomach. Expressed at a much lower level in the style sac-midgut tissues. No expression detected in mantle, gills, labial palps or hemocytes. Belongs to the glycosyl hydrolase 22 family. Type-I lysozyme subfamily.