食品科学 ›› 2022, Vol. 43 ›› Issue (24): 110-116.doi: 10.7506/spkx1002-6630-20220602-016

• 生物工程 • 上一篇    

不同通路配置对大肠杆菌合成2’-岩藻糖基乳糖的影响

梁山泉,张登娅,杨绍青,何滋,刘丹,江正强   

  1. (中国农业大学食品科学与营养工程学院,中国轻工业食品生物工程重点实验室,北京 100083)
  • 发布日期:2022-12-28
  • 基金资助:
    国家自然科学基金面上项目(32172159)

Effect of Pathway Configurations on the Synthesis of 2’-Fucosyllactose in Escherichia coli

LIANG Shanquan, ZHANG Dengya, YANG Shaoqing, HE Zi, LIU Dan, JIANG Zhengqiang   

  1. (Key Laboratory of Food Bioengineering, China National Light Industry, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China)
  • Published:2022-12-28

摘要: 在大肠杆菌BL21 Star (DE3)中建立了2’-岩藻糖基乳糖(2’-fucosyllactose,2’-FL)的从头合成途径,通过CRISPR/Cas9系统敲除了β-半乳糖糖苷酶基因lacZ M15序列和尿苷二磷酸-葡萄糖脂质载体转移酶基因wcaJ,探究了操纵子、假操纵子和单顺反子3 种不同通路配置对重组大肠杆菌合成2’-FL的影响。结果表明:从头合成途径的基因在大肠杆菌BL21 Star (DE3)过表达后摇瓶发酵产生的2’-FL质量浓度为0.34 g/L。敲除lacZ M15和wcaJ后,重组菌产生的2’-FL质量浓度增加到了1.26 g/L。在操纵子形式下,重组菌BS-7摇瓶发酵产生的2’-FL质量浓度最高,达1.92 g/L。BS-7在10 L发酵罐中分批补料发酵37 h后产生的2’-FL质量浓度达到14.04 g/L,2’-FL产率为0.59 g/(L·h),乳糖转化率为63%。因此,大肠杆菌合成2’-FL过程中,较低的基因表达强度更有助于提高其产量,同时可提高底物的转化效率。

关键词: 2’-岩藻糖基乳糖;CRISPR/Cas9;通路配置;大肠杆菌;生物合成

Abstract: The de novo synthesis pathway of 2’-fucosyllactose (2’-FL) was established in Escherichia coli BL21 Star (DE3) in this study. The β-galactosidase gene lacZ M15 and the uridine diphosphate (UDP)-glucose lipid carrier transferase gene wcaJ were knocked out using the CRISPR/Cas9 gene editing system. The effects of three different pathway configurations, viz., operon, pseudo-operon, and monocistronic on the synthesis of 2’-FL were explored. The results showed that the concentration of 2’-FL produced in shake flasks was 0.34 g/L after overexpression of the de novo synthesis pathway related genes in E. coli BL21 Star (DE3). The concentration of 2’-FL was increased to 1.26 g/L by deleting the lacZ M15 and wcaJ genes. The highest concentration of 2’-FL of 1.92 g/L was observed in strain BS-7 when regulated by the operon expression. Fed-batch fermentation of strain BS-7 accumulated 14.04 g/L 2’-FL with a productivity of 0.59 g/(L·h) and a lactose conversion rate of 63%, respectively. This study suggested that lower gene expression levels not only increased 2’-FL production, but also could improve the conversion efficiency of substrate in engineered E. coli.

Key words: 2’-fucosyllactose; CRISPR/Cas9; pathway configurations; Escherichia coli; biosynthesis

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