通过参数相关性分析对发酵控制策略在植酸酶高密度发酵中的作用探讨

为了优化植酸酶高密度发酵条件,有必要获取在发酵过程中由于控制策略引起有关参数的实时变化及其关联性。本研究利用传感器对植酸酶工程菌高密度发酵过程进行数据在线采集,通过改变转速、接种量与补料甘油,探讨三方面控制因素对高密度发酵产酶过程参数具体影响及各参数变化之间的相关性,建立起与转速-细胞密度-溶氧-乳酸相关的发酵罐内外环境氧控制关系,细胞密度-氧气吸收-二氧化碳释放相关的细胞生长氧控制关系,以及细胞密度-二氧化碳释放-pH变化-蛋白表达的细胞诱导表达的关系。基于参数相关性分析并优化发酵控制条件得到:当搅拌转速递增,植酸酶工程菌接种量为10%时,其生长迟滞期最短(20 h)且发酵末期诱导表达植酸酶酶活可达3037.98 U/mL,相较摇瓶优化发酵的酶活提高了176.18%。本文研究结果可为工业植酸酶高效生产提供参考。

Discussion on role of fermentation control strategy in high-density fermentation of phytase by parameter correlation analysis

In order to optimize the high-density fermentation conditions of phytase,it was necessary to obtain the real-time changes and correlations of relevant parameters caused by fermentation control strategies in the fermentation process.In this study,sensors were used to collect data in the high-density fermentation process by phytase engineering strain on-line.By changing the rotation speed,inoculum amount and feeding glycerol,the specific effects of three control factors on the parameters of high-density fermentation and the correlation between the changes of parameters were discussed.And three correlations were established,such as stirring speed-dissolved oxygen-cell density-lactic acid content related to oxygen control of internal and external environment of fermenter,cell density-absorption of oxygen-release of carbonate dioxide related to oxygen control of cell growth,and cell density-release of carbonate dioxide-pH change-expression of protein.Based on parameter correlation analysis,the experimental fermentation control conditions were optimized.The results showed that when the stirring speed increased and the inoculum amount was 10%,the growth lag period was the shortest(20 h)and the phytase enzyme activity could reach 3037.98 U/mL at the end of fermentation.The enzyme activity increased by 176.18%,if compared with that obtained in the optimized shake-flask fermentation.This study provided a reference for high-efficient phytase production in industry.