K88大肠杆菌菌毛蛋白发酵工艺条件优化研究

分别采用LB培养基、牛肉膏蛋白胨培养基、强化营养培养基、玉米浆培养基对大肠杆菌K88进行发酵培养，选出最适于大肠杆菌K88生长的玉米浆培养基；采用正交实验对玉米浆培养基的C／N、K2HPO4／KH2PO4、Mg^2＋的配比进行优化，筛选最适于大肠杆菌K88生长的营养配比；研究生长曲线、接种量以及菌体和菌毛生产量的相关性，根据实验结果优化发酵培养条件，确定菌种的最佳发酵工艺，以收获最多的K88菌毛蛋白。研究表明，K88大肠杆菌在玉米浆培养基C／N、K2HP04／KH2PO4的配比分别为5／11、1／1，Mg^2＋为0．1g/mL，pH值为7．2，转速为200r／min，接种量为4．5％的条件下发酵26个小时，菌体和菌毛生产量均达到高峰，同时得出菌毛蛋白产生量和菌体量成正相关。

Optimization of Fermentation Conditions of Enterotoxingenic Escherichia coli K88 for the Production of Fimbrial Protein

LB medium,nutrition-strengthened medium and corn steep liquor medium were respectively used to culture enterotoxingenic Escherichia coli K88（E.coli K88） for the production of K88 fimbrial protein.The best result acquired by the use of corn steep liquor medium.Several factors such as the ratio of C/N、K₂HPO₄/KH₂PO₄ and the concentration of Mg²⁺ in corn steep liquor medium were researched for the same purpose.In addition,bacterial inoculum size and the correlation between E.coli K88 biomass and the quantity of K88 fimbrial protein were studied.It was indicated that E. coli K88 cultivation was obtained in corn steep liquor medium with C/N 5/11,K₂HPO₄/KH₂PO₄ 1/land Mg²⁺ 0.1 g/ mL,the highest yield of K88 fimbrial protein was achieved in conditions of pH 7.2,shaking speed of shake flask 200 r/ min and inoculum size 4.5%（v/v） for 26 h.what’ s more,further experiments showed a positive correlation relationship between E.coli K88 biomass and the quantity of K88 fimbrial protein.