摘要
利用重组毕赤酵母在7 L的发酵罐中进行分批补料高密度发酵,考察不同NH4+质量浓度对毕赤酵母基因工程菌表达华根霉脂肪酶的影响。结果表明,补加(NH4)2SO4溶液维持NH4+质量浓度在7 g/L时华根霉脂肪酶酶活最高,分别是不补加(NH4)2SO4溶液、补加并维持NH4+质量浓度在5 g/L、10 g/L条件下的1.41、1.11、1.08倍,而且在该氮源质量浓度条件下,胞外总蛋白质质量浓度最高,达到5.61 g/L。通过分析不同氮源条件下发酵参数比生长速率、产物比形成速率和底物比消耗速率的差异,发现发酵维持NH4+质量浓度在7 g/L时,产物比形成速率和底物比消耗速率均较高,这与该条件下产酶水平最高相一致。研究结果表明,对毕赤酵母基因工程菌发酵过程中的氮源进行优化,能够明显促进外源蛋白质的表达。
The effect of NH4^＋ concentration on the expression of Rhizopus chinensis lipase by the recombinant Pichia pastoris was studied by high-density fed-batch fermentation in a 7 L bioreactor. The maximum activity was obtained when the concentration of NH4^＋ was maintained at 7 g/L adjusted with （NH4）2SO4 solution,as high as 1.41,1.11,1.08 fold of that of the control （without （NH4）2SO4 solution）, and of the solution with 5 g/L or 10 g/L NH4＋,respectively. The total protein concentration achieved a maximum value of 5.61 g/L under the optimal condition. The specific growth rate ,the specific production rate and the specific consumption rate were also investigated under different NH4^＋ concentrations. A relative high specific production rate and the specific consumption rate were observed at 7 g/L of NH4^＋, which resulted in the highest level of enzyme production under the condition. Our research suggested that the optimization of nitrogen source could enhance the expression ofheterologous protein significantly in P. pastoris.
作者
赵林水
喻晓蔚
徐岩
ZHAO Linshui YU Xiaowei XU Yan(Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China Center for Brewing Science and Enzyme Technology,School of Biotechnology,Jiangnan University,Wuxi 214122, China)
出处
《食品与生物技术学报》
CAS
CSCD
北大核心
2016年第6期591-596,共6页
Journal of Food Science and Biotechnology
基金
国家自然科学基金项目(20802027)
国家863计划项目(2012AA022207)
关键词
华根霉脂肪酶
毕赤酵母
高密度发酵
铵离子浓度
Rhizopus chinensis lipase,Pichia pastoris, high density fermentation,NH4^＋ concentration
