Screening, identification and enzymatic properties of chitosanase-producing strain

Abstract:

[Objective] By screening of chitosanase strains in mud samples from the Fujian coastal intertidal with screening medium, studied the characteristics of the strains for enzyme production. [Methods] Through morphological observation, combined with 26S rDNA sequences were classified and identified, DNS method was use for the determination of enzyme activity. [Results] The conclusion showed a 99% similarity between the chitosanase strain KQ-1002 and Penicillium oxalicum. The strain was tentatively identified as a species of Penicillium fungus. The optimal fermentation temperature was 30 °C, the optimum carbon source was the 1.0% soluble chitosan, the optimal nitrogen source was 1.87% (NH4)2SO4, and the optimum pH was 6.0. Cultured for 72 h under liquid fermentation on the strains, the chitosanase-producing activity reached the maximum, and the maximum of enzyme production had been optimized to 18 U/mL. The molecular masses of purified enzymes was 40 kD which analyzed by SDS-PAGE. Enzymatic reactions’ optimum pH was 5.0, the optimum temperature was 55 °C, and Km was 1.293 g/L. When ion concentration reached 1.0×10?3 mol/L, metal ions of Cu2+, Hg2+, Ag+ would strongly inhibit the enzyme’ activity. There was a different degradation of chitosanase on various substrates and deacetylation of chitosan. [Conclusion] Through screening, the chitosanase activity of chitosanase-producing fungal strains KQ-1002 which had been optimized boosted by approximately 7 times, and it is a chitosanase-producing strains of research and potential applications.