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 contai 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°C and pH 7, respectively, while those for the chitin deacetylase were 55°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°C. The divalent cations CoCl₂ and NiCl₂ increased the chitinase activity, while ZnCl₂ inhibited the enzyme. The chitin deacetylase was also activated by the presence of MgCl₂ and inhibited by MnCl₂, NiCl₂, and CaCl₂. A zymogram analysis revealed several forms of chitinase, with a 67 kDa form being the major enzyme.