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Refactoring Ehrlich Pathway for High-Yield 2-Phenylethanol Production in Yarrowia lipolytica.
ACS Synthetic Biology ( IF 3.7 ) Pub Date : 2020-03-12 , DOI: 10.1021/acssynbio.9b00468
Yang Gu 1, 2 , Jingbo Ma 1 , Yonglian Zhu 2 , Peng Xu 1
Affiliation  

Efficient microbial synthesis of chemicals requires the coordinated supply of precursors and cofactors to maintain cell growth and product formation. Substrates with different entry points into the metabolic network have different energetic and redox statuses. Generally, substrate cofeeding could bypass the lengthy and highly regulated native metabolism and facilitates high carbon conversion rate. Aiming to efficiently synthesize the high-value rose-smell 2-phenylethanol (2-PE) in Y. lipolytica, we analyzed the stoichiometric constraints of the Ehrlich pathway and identified that the selectivity of the Ehrlich pathway and the availability of 2-oxoglutarate are the rate-limiting factors. Stepwise refactoring of the Ehrlich pathway led us to identify the optimal catalytic modules consisting of l-phenylalanine permease, ketoacid aminotransferase, phenylpyruvate decarboxylase, phenylacetaldehyde reductase, and alcohol dehydrogenase. On the other hand, mitochondrial compartmentalization of 2-oxoglutarate inherently creates a bottleneck for efficient assimilation of l-phenylalanine, which limits 2-PE production. To improve 2-oxoglutarate (aKG) trafficking across the mitochondria membrane, we constructed a cytosolic aKG source pathway by coupling a bacterial aconitase with a native isocitrate dehydrogenase (ylIDP2). Additionally, we also engineered dicarboxylic acid transporters to further improve the 2-oxoglutarate availability. Furthermore, by blocking the precursor-competing pathways and mitigating fatty acid synthesis, the engineered strain produced 2669.54 mg/L of 2-PE in shake flasks, a 4.16-fold increase over the starting strain. The carbon conversion yield reaches 0.702 g/g from l-phenylalanine, 95.0% of the theoretical maximal. The reported work expands our ability to harness the Ehrlich pathway for production of high-value aromatics in oleaginous yeast species.

中文翻译:


重构解脂耶氏酵母高产 2-苯乙醇的艾利希途径。



化学物质的高效微生物合成需要协调供应前体和辅因子以维持细胞生长和产物形成。进入代谢网络的不同入口点的底物具有不同的能量和氧化还原状态。一般来说,底物共饲可以绕过漫长且高度调控的天然代谢,并促进高碳转化率。为了在解脂耶氏酵母中高效合成高价值的玫瑰香味2-苯基乙醇(2-PE),我们分析了艾利希途径的化学计量限制,并确定了艾利希途径的选择性和2-酮戊二酸的可用性速率限制因素。艾利希途径的逐步重构使我们确定了由l-苯丙氨酸通透酶、酮酸转氨酶、苯丙酮酸脱羧酶、苯乙醛还原酶和乙醇脱氢酶组成的最佳催化模块。另一方面,2-酮戊二酸的线粒体区室化本质上为 L-苯丙氨酸的有效同化造成了瓶颈,从而限制了 2-PE 的生产。为了改善 2-酮戊二酸 (aKG) 穿过线粒体膜的运输,我们通过将细菌乌头酸酶与天然异柠檬酸脱氢酶 (ylIDP2) 偶联,构建了胞质 aKG 源途径。此外,我们还设计了二羧酸转运蛋白以进一步提高 2-酮戊二酸的可用性。此外,通过阻断前体竞争途径并减少脂肪酸合成,工程菌株在摇瓶中产生了 2669.54 mg/L 的 2-PE,比起始菌株增加了 4.16 倍。 L-苯丙氨酸的碳转化率达到0.702 g/g,是理论最大值的95.0%。 所报告的工作扩展了我们利用艾利希途径在产油酵母物种中生产高价值芳香烃的能力。
更新日期:2020-03-12
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