Hydrolyzes laminarin majorily to glucose (G1), laminaribiose (L2), laminaritriose (L3), laminaritetraose (L4) and laminaripentaose (L5). Hydrolyzes laminarioligosaccharides L3, L4, L5 and laminarihexaose (L6) to G1, L2 and L3. Hardly hydrolyzes L2. Does not hydrolyze lichenan, pustulan, carboxymethyl cellulose, locust bean gum or soluble starch. Hydrolysis of (1->3)-beta-D-glucosidic linkages in (1->3)-beta-D-glucans. Ca(2+) does not affect the enzyme activity nor the thermostability. Other cations, such as Mg(2+), Mn(2+), Cu(2+), Zn(2+), Ag(+) or Hg(2+) do not cause any serious adverse effect on the activity. Also no significant change in the activity in response to the addition of 1 mM EDTA. Optimum pH is 6.0. More than 80% of its maximal activity is maintained at pH 5.5-6.5. Optimum temperature is 50 degrees Celsius. Retains 20% of the maximal activity after incubation at 60 degrees Celsius for 30 min. Retains approximately 15% of the maximal activity at the temperature below 15 degrees Celsius. Belongs to the glycosyl hydrolase 16 family.