谷氨酸棒杆菌耐高温驯化及发酵条件研究

Domestication of thermotolerant Corynebacterium glutamicum and study on its fermentation condition

通过逐级传代驯化的方式,逐步提高菌体的耐高温性能。经过多次驯化,获得一株耐高温菌株,并且在发酵过程中最大菌浓、产酸率、糖酸转化率均有提高。在此基础上,又对该菌的发酵条件进行了初步优化。首先对发酵温度进行了优化,发现最适发酵温度为36℃。然后又采用Plackett-Burman实验,找出影响发酵最大的三个因素:玉米浆、葡萄糖和磷酸氢二钾。最后又进行了三因素三水平的响应面实验,得到三个重要影响因素的最佳浓度为葡萄糖161.98g/L,玉米浆3.64g/L,磷酸氢二钾1.51g/L。在此培养条件下,用7L罐发酵,最终产酸达114.2g/L,糖酸转化率达61.4%。

The thermotolerant property of Corynebacterium glutamicum was improved gradually via a passage transfer approach.After many times of domestication,a thermotolerant strain was obtained.And also,the maximum cell concentration,L-glutamic acid productivity,conversion rate had been increased in fermentation course.The fermentation condition of this strain was further studied.Firstly,the fermentation temperature was studied and found the optimal temperature was 36℃.Then,the top three factors were found out by Plackett-Burman experiment,which were corn steep liquor,glucose and K2HPO4.Finally,three factors and three levers of response surface experiment were carried out.The optimal concentrations of the three important factors were obtained,which were glucose 161.98g/L,corn steep liquor 3.64g/L and K2HPO4 1.51g/L.At the optimal conditions,the L-glutamic acid concentration reached 114.2g/L and conversion rate reached 61.4% in 7-L bioreactor.