文献类型：期刊文献

英文题名：The "Coexistence" of Ehrlich pathway and de novo pathway improves 2-PE synthesis in Saccharomyces cerevisiae

作者：Yang, Chenghan[1,2];Lv, Qingqing[1,2];Zhang, Li[1,2];Jia, Huining[2];Chen, Hailong[2];Yang, Sainan[1,2];Qiu, Yuxin[2];Hang, Haifeng[1,2];Mohsin, Ali[2];Chu, Ju[1,2];Zhuang, Yingping[1,2];Tian, Xiwei[1]

机构：[1]East China Univ Sci & Technol, Qingdao Innovat Inst, State Key Lab Bioreactor Engn, Shanghai 200237, Peoples R China;[2]East China Univ Sci & Technol, Natl Engn Res Ctr Biotechnol Shanghai, Shanghai 200237, Peoples R China

年份：2025

卷号：516

外文期刊名：CHEMICAL ENGINEERING JOURNAL

收录：;EI(收录号：20252118488905);WOS:【SCI-EXPANDED(收录号:WOS:001501794700002)】；

基金：This work was financially supported by the National Key Research and Development Program, China (2018YFA0900300) , the Taishan Scholars Program of Shandong Province (NO.tsqn202312316) , the Shanghai Pilot Program for Basic Research (22TQ1400100-14) , the Natural Science Foundation of Shanghai (23ZR1416500) , the Frontiers Science Center for Materiobiology and Dynamic Chemistry (JKVJ1231036) . The authors appreciate technical assistance from Shanghai Applied Protein Technology Co. Ltd. (Shanghai, China) .

语种：英文

外文关键词：beta-Phenylethanol; Saccharomyces cerevisiae; Coexisting metabolism; Specific growth rate; Chemostat culture

摘要：beta-Phenylethanol (2-PE) is the second most widely used flavoring agent after vanillin. Saccharomyces cerevisiae possesses the ability to synthesize 2-PE via two distinct pathways: the Ehrlich pathway and the de novo synthesis pathway. While the conversion efficiencies of these pathways have been improved independently through metabolic engineering strategies, the strong inhibitory effect of L-phenylalanine (L-Phe), the substrate of Ehrlich pathway, limits their synergistic potential for enhancing 2-PE production. In this study, we observed that when the specific growth rate exceeded 0.236 h- 1, the strain exhibited a notable increase in flux through the de novo synthesis pathway. Meanwhile, the Ehrlich pathway maintained a high level of activity in the conversion of LPhe to 2-PE. This metabolic state has been defined as the "Coexisting" metabolism. However, enabling the occurrence of Coexisting metabolism at or below the Critical Specific Growth Rate (0.193 h- 1 in this study) is essential to minimize byproduct formation of ethanol. Metabolic flux analysis has indicated that insufficient intracellular NADH levels, along with significant diversion of flux through the L-tyrosine (L-Tyr) biosynthesis pathway, present major challenges. To identify potential regulatory targets, we utilized transcriptional and protein profiles. Furthermore, reverse metabolic engineering has validated TYR1, the first enzyme in the L-Tyr biosynthetic pathway, as a key regulatory node. By downregulating TYR1 and overexpressing IDH1 to enhance intracellular NADH supply, an engineered strain achieved a conversion rate of 115.2 % at mu = 0.193 h- 1 in chemostat cultivation, surpassing the theoretical maximum of the Ehrlich pathway and indicating the emergence of a significant Coexisting metabolic state. In Fed-Batch bioconversion, this strain showed a 33.2 % increase in conversion rate during the rapid synthesis period, and the final titer of 2-PE increased from 11.2 g/L to 12.1 g/L, representing an 8.0 % improvement. In short, this study provided a new, efficient and green approach to 2-PE production.