Shen Yuping, Zhou Ziwei, He Xi, Yin Leyi, He Chunlan, Zhang Zujiao
College of Chemistry and Bioengineering, Hunan University of Science and Engineering, Yongzhou 425199, Hunan, China.
Hunan Engineering Research Center for Research and Development of Plant Resources in Nanling Area, Yongzhou 425199, Hunan, China.
Sheng Wu Gong Cheng Xue Bao. 2023 Aug 25;39(8):3379-3393. doi: 10.13345/j.cjb.230136.
Tyrosol is a natural polyphenolic product that is widely used in chemical, pharmaceutical and food industries. Currently, the synthesis of tyrosol by suffers from issues such as low cell density and poor yield. Therefore, the phenylpyruvate decarboxylase mutant ARO10 obtained in our previous study was fused with an alcohol dehydrogenase from different microorganisms for fusion expression, and the optimal ARO-L-YahK produced 1.09 g/L tyrosol in shake flasks. In order to further improve tyrosol production, , a key gene in the competing pathway of 4-hydroxyphenylacetic acid, was knocked out, and the resulted strain produced 1.26 g/L tyrosol with an increase of 21.15% compared to that of the control. To overcome the low cell density in tyrosol fermentation, the quorum-sensing circuit was used to dynamically regulate the tyrosol synthesis pathway, so as to alleviate the toxic effect of tyrosol on chassis cells and relieve the growth inhibition. Using this strategy, the yield of tyrosol was increased to 1.74 g/L, a 33.82% increase. In a 2 L fermenter, the production of tyrosol in the engineered strain TRFQ5 dynamically regulated by quorum-sensing reached 4.22 g/L with an of 42.88. Compared with those in the engineered strain TRF5 statically regulated by induced expression, the yield was increased by 38.58% and the was enhanced by 43.62%. The combination of blocking the competing pathway using gene knockout technology, and reducing the inhibitory effect of tyrosol toxicity on chassis cells through quorum-sensing dynamic regulation increased the production of tyrosol. This study may facilitate the biosynthesis of other chemicals with high toxicity.
酪醇是一种天然多酚类产物，广泛应用于化工、制药和食品工业。目前，通过[具体方式]合成酪醇存在细胞密度低和产量低等问题。因此，将我们之前研究中获得的苯丙酮酸脱羧酶突变体ARO10与来自不同微生物的乙醇脱氢酶进行融合表达，最优的ARO-L-YahK在摇瓶中产生了1.09 g/L的酪醇。为了进一步提高酪醇产量，敲除了4-羟基苯乙酸竞争途径中的关键基因[具体基因名称]，所得菌株产生了1.26 g/L的酪醇，与对照相比增加了21.15%。为了克服酪醇发酵中细胞密度低的问题，采用群体感应电路动态调节酪醇合成途径，以减轻酪醇对底盘细胞的毒性作用并缓解生长抑制。使用该策略，酪醇产量提高到1.74 g/L，增加了33.82%。在2 L发酵罐中，通过群体感应动态调节的工程菌株TRFQ5中酪醇产量达到4.22 g/L，产率为42.88%。与通过诱导表达静态调节的工程菌株TRF5相比，产量提高了38.58%，产率提高了43.62%。利用基因敲除技术阻断竞争途径，并通过群体感应动态调节降低酪醇毒性对底盘细胞的抑制作用，提高了酪醇产量。本研究可能有助于其他高毒性化学品的生物合成。
