通过筛选分离获得一株产κ-卡拉胶酶活力较高的菌株NJ-02，通过生理生化实验，16S rRNA基因序列测定和系统发育树分析，鉴定其为农杆菌属Pedobacter sp.。通过设计单因素和响应面实验，确定该菌株的最佳产酶发酵条件。通过单因素实验得其最佳发酵产酶条件为：碳源为κ-卡拉胶（2.00 g/L）、氮源为酵母浸提物（4.00 g/L）、pH 7.00、接种量5%、培养温度30 ℃、摇床转速150 r/min。通过液体培养基单因素研究，确定了三个影响产κ-卡拉胶酶的关键因素，分别是碳源、氮源和初始pH。根据Box-Behnken中心组合方法采用三因素三水平响应值设计实验优化，得到最佳的培养基配方为：卡拉胶浓度2.15 g/L、酵母浸提物4.32 g/L、pH 7.10。结论：优化后酶活最高可达19.01 U/mL，较优化前提高了1.20倍，NJ-02最佳发酵条件的建立，为获得大量的κ-卡拉胶酶进行更深入的研究提供了实验基础和理论依据。

A strain NJ-02 with high κ-carrageenan producing activity was acquired through screening and separation, and identified as Pedobacter sp. by physiology biochemistry experiment, 16S rRNA sequences determination and phylogenetic tree analysis. The optimal fermentation conditions were studied based on the single-factor and response surface experiment. The optimal conditions were obtained by single-factor experiment as follows: κ-carrageenan as carbon source (2.00 g/L), yeast extraction as nitrogen source (4.00 g/L), pH 7.00, inoculation amount 5%, temperature 30℃, and table speed 150 r/min. According to the single factor experiments, the carbon resource, nitrogen source, and pH were determined to be three key factors influencing κ-carrageenan enzyme production in fluid fermentation. A regression model for the yield of κ-carrageenan enzyme was established using a Box-Behnken design involving the above three factors with three levels. The best fermentation medium was found as follows: κ-carrageenan 2.15 g/L, yeast extraction 4.32 g/L, and pH 7.10. Under these conditions, the enzyme activity was 19.01 U/mL, which was 1.20 times as that of the original conditions. It provided the experimental foundation and theoretical basis for large quantity of κ-carrageenan and further study.

国家自然科学基金青年科学基金项目（31601410）