Isolation and Characterization of Chitinase from Marine Bacteria

Abstract

A marine bacterium, which can produce an extracellular chitinase, was isolated and identified. The counts of the chitinolytic bacteria in six marine animals ranged from 3.3x10⁴ to 2.3x10⁶ CFU/g, which accounted for 22.03 % of the total bacterial count. Ninety-nine isolates were found to produce chitinase. The isolate SH1.13 produced the highest activity of chitinase and was identified as Bacillus circulans. The initial pH and temperature for growth and chitinase production were 7.0 and 37 °C, respectively, for 48 hrs. The optimum pH and temperature of the enzyme reaction were 4.0 and 37 °C, respectively. The chitinase was stable at pH 4.0 and from 20 to 40 °C. After purification by 90 % ammonium sulfate precipitation followed by Sephacryl S-200 HR chromatography, only one protein peak was obtained. The final specific activity of chitinase was 0.48 unit/μg protein with a purification of 1.28 folds. The subunit molecular weight of the enzyme was estimated by SDS-PAGE to be 107000, 89000, 62000, 42000, 24000 and 17000 daltons, respectively.