Abstract:A chitinase-producing bacteria, isolated from sea water, was identified as Aeromonas hydrophila. The characteristics of purified chitinase from fermented broth by ammonium sulfate fractionation and dialysis were studied. Its optimal pH value and temperature were 7.0 and 45 ℃, respectively, using colloid chitin as substrate. The chitinase showed high thermal stability, with a residue activity of 50% remained after incubation of the enzyme in water for 12 h at 40 ℃. Metal ions had different effects on the chitinase activity which could be improved by Mg2+, but obviously inhibited by Cu2+ and Al3+. Its Michaelis constant Km in the hydrolysis of chitin was 29.15 g/L, indicating that the chitinase possessed high substrate affinity.
