突变型黄单胞杆菌产黄原胶条件的优化

该文对从甘蓝腐烂根部的土壤中分离选育的黄单胞杆菌C2发酵产黄原胶的条件进行了优化。通过单因素试验对培养基（碳源、氮源及碳氮源的浓度）和发酵条件（接种量、发酵时间、温度、pH、装液量）进行优化；为提高黄原胶的胶体性能，在培养中添加不同量的游离丙酮酸。结果表明，液态发酵生产黄原胶的最佳碳源、氮源分别为蔗糖55 g/L，鱼粉10 g/L。黄单胞杆菌C2菌株在接种量为4%，pH值为7，于28 ℃、130 r/min条件下发酵60 h时，黄原胶产量达到34 g/kg。添加游离丙酮酸2 g/L时发酵液黏度为16.0 Pa·s，此时胶体性能最好。

Optimization of fermentation conditions of xanthan gum-producing Xanthomonas campestris mutants

The fermentation conditions of xanthan gum producing Xanthomonas campestris C2 that screened from rotted roots of cabbage were optimized. The medium composition (carbon source, nitrogen source and their concentration) and fermentation conditions (inoculum, fermentation time, temperature, pH and medium volume) were optimized by single factor experiment. To improve the colloidal properties of xanthan gum, different amount of free pyruvic acid was added into the medium, and the results showed that the optimal liquid fermentation medium composition was sucrose 55 g/L and fishmeal 10 g/L. When the X. campestris C2 was inoculated under the condition of inoculum 4%, pH 7, temperature 28 ℃, rotation speed 130 r/min and fermentation time 60 h, the production of xanthan gum was 34 g/kg. When adding free pyruvic acid 2 g/L in the medium, the fermentation viscosity was 16.0 Pa·s, and colloid performance was the optimal.