一株嗜热链球菌产多糖条件的优化

Culture condition optimization of Streptococcus thermophiles AR333 for exopolysaccharides production

使用单因素和正交试验设计相结合的方法对培养基配方及培养条件进行优化提高嗜热链球菌AR333的胞外多糖(exopolysaccharides,EPS)产量。获得最佳培养基配方为:脱脂乳粉15%(w/v)、半乳糖1%(w/v)、大豆蛋白胨0.5%(w/v)、磷酸氢二钾0.1%(w/v)。最佳培养条件为:接种量3%,40℃,初始p H 6.5,发酵时间16 h。优化后嗜热链球菌AR333的EPS产量可达256.97mg/L,比优化前的产量提高了3.6倍。

The medium composition and fermentation conditions were optimized by using the single factor analysis method and the orthogonal experiment to elevate the exopolysaccharides（ EPS） production of Streptococcus thermophiles AR333.The optimal composition of the medium： dried skim milk 15%,galactose 1%,soy peptone 1% and K2HPO40. 1%. The optimal fermentation conditions were as follows： 40 ℃,inoculum size 3%,initial p H 6. 5 and fermentation time 16 h.The yield of EPS produced by Streptococcus thermophiles AR333 under the optimal conditions reached 256. 97 mg / L,which was 3. 6-fold of that before optimization.