Study of Thermostable Chitinase Enzymes from Indonesian Bacillus K29-14

Thermophilic microorganisms capable of producing chitinase enzymes were screened from samples collected from several crater and geothermal areas. The chitinolytic microorganisms were grown in a selective medium containing colloidal chitin. The Bacillus K29-14 isolate was found to exhibit the highest chitinase and chitin deacetylase activities. When grown in a chitin-containing medium, the isolate produced extracellular chitinase after 24 h of incubation. The optimum temperature and pH for the chitinase were $55^\circ{C}$ and pH 7, respectively, while those for the chitin deacetylase were $55^\circ{C}$ and pH 8, respectively. The thermostable chitinase and chitin deacetylase also retained 80- 90% of their activity after incubation for 5 h at $70^\circ{C}$. The divalent cations $CoCl_2\;and\;NiCl_2$, increased the chitinase activity, while $ZnCl_2$, inhibited the enzyme. The chitin deacetylase was also activated by the presence of $MgCl_2$ and inhibited by $MnCl_2,\;NiCl_2,\;and\;CaCl_2$. A zymogram analysis revealed several forms of chitinase, with a 67 kDa form being the major enzyme.