产低温几丁质酶菌株的筛选、鉴定与产酶条件优化

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。

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.