发酵菌融合蛋白中鲜味八肽的分离纯化工艺优化

摘要

To increase the yield of enzyme hydrolysis to prepare umami octapeptide LGAGGSLA from fermented bacteria fusion protein,the umami octapeptide engineering bacteria are fermented in large scale and the process of enzyme hydrolysis to prepare the umami octapeptide from fermented bacteria fusion protein is optimized by response surface method.The results show that the fermented fusion protein is consistent with the theoretical prediction.The mathematic model correlates the EK enzyme concentration,hydrolysis time and hydrolysis temperature with the hydrolysis ratio is reliable,it reflects the relationship between the hydrolysis conditions and the hydrolysis ratio well.The optimal process of hydrolyzing the fusion protein to prepare the umami octapeptide is optimized using this model,the results show that the hydrolysis ratio reaches 93.4％ with the EK enzyme concentration of2 μL/mL,the hydrolysis time of 15 h,and the hydrolysis temperature of 24 ℃.After verification with HPLC,the purified umami octapeptide is basically consistent with the chemical synthesized umami octapeptide.The purity of the obtained biological source umami octapeptide peptide is 98％.%为了提高鲜味八肽LGAGGSLA发酵菌融合蛋白的酶切得率,对鲜味八肽LGAGGSLA的工程菌进行了工业化发酵,并对表达的融合蛋白中的鲜味肽的酶切工艺采用响应面法进行优化,结果显示:工业化发酵所得融合蛋白与理论预测结果相符;响应面法优化酶切工艺建立的EK酶浓度、酶切时间、酶切温度与酶切率的相关性模型具有较高的可靠性,能很好地反映酶切率与EK酶浓度、酶切时间及酶切温度的相互关系.利用该模型对酶切工艺进行优化,得出EK酶浓度2μL/mL、酶切时间15 h、酶解温度24℃时,融合蛋白的酶切率最高,酶切率达93.4％.经HPLC验证,分离纯化后的鲜味八肽与人工合成的鲜味八肽对照品的保留时间基本一致,所得生物源鲜味八肽的纯度高达98％.