Abstract:

PBCCD response surface methodology was applied to optimize the 6 major compounds of the εpolylysineproducing fermentation medium(M3G)for Streptomyces sp.FEEL1. PB experiment showed  yeast extract, K2HPO4 and MgSO4 played important roles for εPL production. Combining with the results of the steep ascent test and the central composite design, the optimum concentrations of factors were determined as follows: glucose 50 g/L, yeast extract 7.54 g/L, (NH4)2SO4 5 g/L, KH2PO4 1 g/L, K2HPO4 2.48 g/L, MgSO4 2 g/L, ZnSO4 0.03 g/L,FeSO4 0.03 g/L. Under such condition, the concentration of εPL in shake flask increased to 1.62 g/L. On the basis of above result, singlefactor experiment was employed to optimize the trace elements ZnSO4 and FeSO4. ZnSO4 showed no influence on the production of εPL while 0.06 g/L of FeSO4 could increase the production of εPL to 1.73 g/L, which was 57.2% higher than that in M3G medium. The εPL yield reached to 876 g/L in 5L fermenter by controlling pH, which was increased by 41.1 % compared to that in M3G medium.

Key words: εpolylysine(εPL), culture medium, response surface methodology, optimization

摘要：

对Streptomyces sp. FEEL1产ε聚赖氨酸的发酵培养基(M3G)中的6种主要成分进行了PBCCD的响应面优化。PB实验表明,酵母粉、KH2PO4和MgSO4对εPL产量影响显著,结合最陡爬坡试验和中心组合实验构建出各因素的最佳浓度:葡萄糖50 g/L,酵母粉7.54 g/L,(NH4)2SO4 5 g/L,KH2PO4  1 g/L,K2HPO4  248 g/L,MgSO4  2 g/L,ZnSO4  0.03 g/L,FeSO4 0.03 g/L,该条件下εPL摇瓶产量能达1.62 g/L。在此基础上对微量元素ZnSO4,FeSO4进行了单因素实验的优化,发现ZnSO4对εPL产量几乎没有影响,而0.06 g/L的FeSO4则可以进一步使εPL产量提高至1.73 g/L,较M3G培养基提高了57.2%。在5 L发酵罐中进行控制pH的分批发酵,εPL产量达到8.76 g/L,较其在M3G培养基提高了41.1%。

关键词: ε聚赖氨酸(εPL);培养基;响应面分析;优化