A novel halo-alkali-tolerant and thermo-tolerant chitinase from Pseudoalteromonas sp. DC14 isolated from the Caspian Sea

Abstract

A novel halo-alkali and thermo-tolerant chitinase was obtained from an isolated strain found in the Caspian Sea. The effects of media composition and various fermentation conditions for the optimization of chitinase production were studied one factor at a time and by response surface methodology. The novel strain, which is designated as strain DC14 and phylogenetically related to the genus Pseudoalteromonas, produced chitinase after 72 h under the following optimal conditions: glucose 1 % (w/v), ammonium sulphate 0.2 % (w/v), chitin 1.07 % (w/v), pH 8, NaCl 10 % (w/v), inoculums size 2.5 % (v/v), temperature 30 °C, CaCl2 3 mM and MgCl2 4 mM. Using the statistical optimization method, chitinase production was found to increase from 2.30 to 21.90 U/dl. The enzyme showed maximum activity at 40 °C, pH 9 and 10 % NaCl. It was stable in a wide range of temperature from 15 to 65 °C, pH from pH 7 to 11 and NaCl concentration from 0 to 15 % (w/v). The molecular weight of the enzyme was estimated by SDS-PAGE to be about 65 kDa. With regard to the halo-alkali and thermo-stable properties of this enzyme, it has potential industrial activity.