利迪链霉菌A02产纳他霉素补料分批发酵参数的优化

Parameter Optimization for Fed Batch Fermentation of Streptomyces lydicus A02 to Produce Natamycin

为建立利迪链霉菌（Streptomyces lydicus）A02生产纳他霉素的高产发酵工艺，对其补料分批发酵的主要参数进行了优化。利用pH值实时监控自动补料摇床辅助优化，筛选出利迪链霉菌A02产纳他霉素的适宜pH值范围，以此为控制点进行30L自动发酵罐补料分批发酵实验，通过分析软件发酵之星（Biostar）5．0检测分析主要发酵参数动态趋势曲线与纳他霉素产量的相关性。结果显示，菌株A02最适于纳他霉素生物合成的发酵过程多参数优化组合为：培养温度30℃，pH值控制在6．25-6．29范围内。溶氧（DO）为20％。30％，摄氧率（OUR）和CO2释放率（CER）分别为25～15mmol／（L-h）和20-12mmol／（L·h），氨基氮含量0．20～0．23g／L。还原糖保持1．5％左右，至88h后自然下降，至112h为0．32％；此时纳他霉素质量浓度达最高值，发酵上清液中为2．02g／L，发酵液中为6．98g／L，较不控制pH值的对照分别提高28．66％和69．83％，为较好的发酵终点。通过优化调控主要发酵参数有效提高了利迪链霉菌A02生产纳他霉素的发酵水平。

In order to improve the fermentation process of natamycin by Streptomyces lydicus A02, the main parameters for the fed batch fermentation are optimized. The range of suitable pH values is screened by an assisted optimization using a shaker with the function of automatic feeding to regulate pH values. Then the experiments in 30 L fermentor are carried out by controlling pH values within the suitable range as the main regulation point. The relationship between the natamycin yields and the fermentation parameters is obtained through the software Biostar 5.0. It is shown that the optimized parameter combination for the fed batch fermentation of natamyein by S. lydicus A02 is as follows： The culture temperature is 30℃, the pH value is 6.25-6.29, the DO is 20%-30%, the OUR is 25-15 mmol/（L, h）, the CER is 20-12 mmol/（L＂ h）, the amino-N is 0.20-0.23 g/L, and the reducing sugar remains at about 1.5% in 88 h then drops gradually to 0.32% at 112 h, the end of fermentation, when the natamycin yield is up to 2.02 g/L in the supematant and 6.98 g/L in the total fermented broth. It can be concluded that the fermentation level of natamycin by S. lydicus A02 could be increased effectively by the optimization of the main fermentation parameters.