Screening and Identification of a Cold-adapted Chitinolytic Bacterium Strain and Optimization of Its Chitinase Fermentation Conditions

Objective:Screening a cold-adapted chitinolytic bacterium strain,identification and optimization of its chitinase fermentation conditions. Methods:Using colloidal chitin as the sole carbon source,the cold-adapted chitinase-producing bacteria were screened from samples collected in Bohai bay in Dalian city of Liaoning Province,China.It was identified by morphological identification and molecular biological identification. The optimal fermentation conditions of cold-adapted chitinase-producing bacteria by single-factor experiments were determined.Results:The strain was identified as Photobacterium sp.And the optimization results were as follows:colloidal chitin 12.0 g/L,yeast extract 6.0 g/L,fermentation temperature 15 ℃,pH7.0,shaking speed 220 r/min,liquid volume 75 mL/250 mL,inoculums dose 1%,and fermentation time 96 h,respectively. Under these conditions,the maximum activity of cold-adapted chitinase was 4.566 U/mL,and it was increased by 389.91% compared with to that before optimization.Conclusion:It provides a referencefor the study of enzymatic properties and the application of low temperature chitinase in industry.