生物技术通报2026，Vol.42Issue(1)：329-337,9.DOI:10.13560/j.cnki.biotech.bull.1985.2025-0794
不同启动子过表达xylR基因提高大肠杆菌的葡萄糖-木糖共利用能力
Overexpression of the xylR Gene Driven by Different Promoters Enhances Glucose-xylose Co-utilization Capability in Escherichia coli
摘要
Abstract
[Objective]To mitigate the Carbon Catabolite Repression(CCR)effect and enhance the co-utilization capacity of glucose and xylose by Escherichia coli(E.coli).[Method]Using the D-lactic acid-producing engineered E.coli strain JH15 as the starting strain,the xylR gene encoding the xylose regulatory factor was overexpressed via the pBR322 plasmid carrying four different promoters(PcysG,PrrsA,PJ23119,and PpflBp6).Four recombinant strains,namely CX-A15,RX-A15,JX-A15,and PX-A15,were constructed.Quantitative real-time polymerase chain reaction(qPCR)analysis and fermentation experiments were further performed to compare the transcription levels of xylose transport and metabolism genes,as well as changes in fermentation performance,among all strains under the carbon source condition of 30 g/L glucose+20 g/L xylose.[Result]After xylR overexpresed,the transcription levels of key xylose metabolism genes(xylA and xylB)and xylose transport-related genes(xylF,xylG,and xylH)increased in all recombinant strains.Compared with the parent strain JH15:1)The xylose consumption rates of CX-A15,RX-A15,JX-A15,and PX-A15 increased by 22%,84%,206%,and 209%,respectively;2)the D-lactic acid production rates increased by 8%,27%,97%,and 98%,respectively.Among the recombinant strains,JX-A15 and PX-A15 completely consumed the carbon source within 48 h and achieved the maximum D-lactic acid yield.Their fermentation cycle was shortened by 43%compared with the 84-h cycle of JH15.[Conclusion]The overexpression of the xylR gene driven by promoters PJ23119 and PpflBp6 can effectively reduce the CCR effect.While ensuring D-lactic acid yield,this strategy significantly improves the co-utilization of glucose and xylose by the D-lactic acid-producing engineered bacteria,enhances production intensity,and shortens the fermentation cycle.It provides technical support for promoting industrial fermentation using low-cost raw materials such as lignocellulose.关键词
大肠杆菌/混合糖/木糖/D-乳酸/启动子Key words
Escherichia coli/mixed sugars/xylose/D-lactic acid/promoter引用本文复制引用
李正,邱炜玥,孙瑞雪,赵筱..不同启动子过表达xylR基因提高大肠杆菌的葡萄糖-木糖共利用能力[J].生物技术通报,2026,42(1):329-337,9.基金项目
国家自然科学基金青年项目(31501677),教育部工业发酵省部共建协同创新中心2023年开放基金(4303-00149) （31501677）
