摘要
alpha;-L-鼠李糖苷酶具有很多潜在的应用价值，而天然的鼠李糖苷酶活力低，并不能大量生产。因此，利用高密度发酵技术，使用重组大肠杆菌对鼠李糖苷酶进行表达，不失为一种有效的方式。
本文对于重组大肠杆菌高密度发酵培养及发酵工艺进行了系统的研究。通过摇床实验，研究了乳糖浓度、诱导后温度、诱导初始OD值、诱导时长对于重组大肠杆菌表达alpha;-鼠李糖苷酶的影响。实验结果如下，当乳糖浓度为0.15mM，诱导后温度为32℃，OD值为1.2，诱导时长为24h时具有最佳酶活。以此条件为基础，通过发酵罐培养进一步研究。
通过对于发酵罐高密度培养，探究重组大肠杆菌的诱导时机，诱导后的比生长速率，研究其对重组大肠杆菌表达鼠李糖苷酶及产生次级代谢产物乙酸的影响。通过实验得出：当OD600为45时进行诱导，诱导前的比生长速率为0.20 h-1，诱导后控制生长比速率为0.20 h-1，拥有最大酶活为28.5U/mL（33h），且有最高的细胞生物量，产生的乙酸也很少，OD为110（30h）。从而提高了alpha;-L-鼠李糖苷酶的生产强度，降低了生产成本。
关键词：重组大肠杆菌 高密度培养 生长比速率 alpha;-鼠李糖苷酶
ABSTRACT
alpha;-L-rhamonsidase has many potential applications,but the traditional fermentation methods can not meet the demand,and it is difficult to achieve high purity.Therefore,it is urgent to study alpha;-L-rhamnosidase with modern biotechnology to increase its production and expression efficiency.
In this paper,the medium-level fermentation technology of recombinant Escherichia coil in high-density fermentation was studied systematically.The effects of lactose concentration,induction temperature,initial OD value and induction time on the expression of alpha;-L-rhamnosidase in recombinant Escherichia coil were as follows:when the concentration of lactose was 0.15mM,the temperature after induction was 32℃,the OD value was 1.2,and the induction time was 24 hours,the enzyme activity was the best.On the basic of this condition,further study was carried out through fermentation tank culture.
The induction timing and specific growth rate of recombinant Escherichia coil were studied by high-density culture in fermentor.The effects of induction on rhamnosidase expression and acetic acid production were also stduied.The results showed that when OD600 was 45,the specific growth rate was 0.20/h after induction,and 28.5U/mL after induction.The maximun enzyme activity was 28.5U/mL,with the highest cell biomass,and little acetic acid was produced.OD was 110.Thus,the production intensity of alpha;-L-rhamnosidase was increased and the production cost was reduced.
以上是毕业论文文献综述，课题毕业论文、任务书、外文翻译、程序设计、图纸设计等资料可联系客服协助查找。
