产低温几丁质酶菌株的筛选、鉴定与产酶条件优化

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

目的:筛选产低温几丁质酶菌株,并对其进行鉴定及发酵条件优化。方法:本实验以渤海海域海泥为样品,以胶体几丁质为唯一碳源,通过平板筛选法筛选产低温几丁质酶细菌,对其进行形态学鉴定和分子生物学鉴定,并对其发酵产酶条件进行了单因素优化。结果:菌株鉴定结果为发光杆菌(Photobacterium sp.),单因素优化结果为:胶体几丁质12.0 g/L、酵母膏6.0 g/L、发酵温度15℃、初始pH7.0、转速为220 r/min、装液量75 mL/250 mL、接种量1%、发酵时间96 h,酶活力达4.566 U/mL,比优化前提高389.91%。结论:为下一步酶学性质研究及低温几丁质酶在工业中的应用提供参考。

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.