Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China.
Changhai Biological Company, Zhejiang Medicine Co., Ltd., Shaoxing, 312000, China.
Enzyme Microb Technol. 2020 Mar;134:109485. doi: 10.1016/j.enzmictec.2019.109485. Epub 2019 Dec 2.
Increasing the metabolic flux of the mevalonate pathway, reducing the metabolic flux of competing pathway and utilizing the diauxie-inducible system constructed by GAL promoters are strategies commonly used in yeast metabolic engineering for the production of terpenoids. Using these strategies, we constructed a series of yeast strains with a strengthened mevalonate pathway and finally produced 336.5 mg/L nerolidol in a shake flask. The spliced HAC1 mRNA assay indicated that the unfolded protein response (UPR) occurred in the strains that we constructed. UPR strains exhibited the low transcriptional activities of GAL1 promoter. HAC1-overexpressing strain exhibited dramatically enhanced transcriptional activity of GAL1 promoter at 72 h of fermentation in flasks. HAC1 overexpression also increased the nerolidol titer by 47.7 %, reaching 497.0 mg/L and increased cell vitality. RNA-seq showed that the genes whose transcription responded to HAC1-overexpression were involved in the regulation of monocarboxylic acid metabolic processes and cellular amino acid biosynthetic process, indicating that the metabolic regulation may be part of the reason of the improved nerolidol synthesis. Our findings enrich the knowledge of the relationship between the construction of sesquiterpene-producing cell factories and UPR regulation. This study provides an effective strategy for sesquiterpene production in yeast.
在酵母代谢工程中,提高甲羟戊酸途径的代谢通量、降低竞争途径的代谢通量以及利用 GAL 启动子构建的双相诱导系统是生产萜类化合物的常用策略。利用这些策略,我们构建了一系列强化甲羟戊酸途径的酵母菌株,最终在摇瓶中生产出 336.5mg/L 的橙花叔醇。拼接的 HAC1 mRNA 分析表明,我们构建的菌株中发生了未折叠蛋白反应 (UPR)。UPR 菌株的 GAL1 启动子转录活性较低。在摇瓶发酵 72 小时时,HAC1 过表达菌株的 GAL1 启动子转录活性显著增强。HAC1 过表达还将橙花叔醇的产量提高了 47.7%,达到 497.0mg/L,同时提高了细胞活力。RNA-seq 显示,转录响应 HAC1 过表达的基因参与了单羧酸代谢过程和细胞氨基酸生物合成过程的调节,表明代谢调节可能是提高橙花叔醇合成的部分原因。我们的发现丰富了萜烯类化合物生产细胞工厂构建与 UPR 调节之间关系的知识。本研究为酵母中倍半萜类化合物的生产提供了一种有效的策略。