State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Microb Cell Fact. 2022 May 7;21(1):76. doi: 10.1186/s12934-022-01807-3.
Ergothioneine (ERG) is a potent histidine-derived antioxidant that confers health-promoting effects. Only certain bacteria and fungi can biosynthesize ERG, but the ERG productivity in natural producers is low. ERG overproduction through genetic engineering represents an efficient and cost-effective manufacturing strategy.
Here, we showed that Trichoderma reesei can synthesize ERG during conidiogenesis and hyphal growth. Co-expression of two ERG biosynthesis genes (tregt1 and tregt2) from T. reesei enabled E. coli to generate 70.59 mg/L ERG at the shaking flask level after 48 h of whole-cell biocatalysis, whereas minor amounts of ERG were synthesized by the recombinant E. coli strain bearing only the tregt1 gene. By fed-batch fermentation, the extracellular ERG production reached 4.34 g/L after 143 h of cultivation in a 2-L jar fermenter, which is the highest level of ERG production reported thus far. Similarly, ERG synthesis also occurred in the E. coli strain engineered with the two well-characterized genes from N. crassa and the ERG productivity was up to 4.22 g/L after 143 h of cultivation under the above-mentioned conditions.
Our results showed that the overproduction of ERG in E. coli could be achieved through two-enzymatic steps, demonstrating high efficiency of the fungal ERG biosynthetic pathway. Meanwhile, this work offers a more promising approach for the industrial production of ERG.
ergothioneine（ERG）是一种有效的组氨酸衍生抗氧化剂，具有促进健康的作用。只有某些细菌和真菌能够生物合成 ERG，但天然生产者的 ERG 生产力较低。通过基因工程进行 ERG 过量生产代表了一种高效且具有成本效益的制造策略。
在这里，我们表明，里氏木霉在分生孢子发生和菌丝生长过程中可以合成 ERG。来自里氏木霉的两个 ERG 生物合成基因（tregt1 和 tregt2）的共表达使 E. coli 在全细胞生物催化 48 小时后能够在摇瓶水平上产生 70.59mg/L 的 ERG，而仅携带 tregt1 基因的重组 E. coli 菌株则合成了少量的 ERG。通过分批补料发酵，在 2-L 罐发酵罐中培养 143 小时后，细胞外 ERG 的产量达到 4.34g/L，这是迄今为止报道的 ERG 产量的最高水平。同样，在上述条件下培养 143 小时后，工程化的 E. coli 菌株中也合成了 ERG，其产量高达 4.22g/L。
我们的结果表明，通过两步酶促反应可以在 E. coli 中实现 ERG 的过量生产，这证明了真菌 ERG 生物合成途径的高效率。同时，这项工作为 ERG 的工业生产提供了更有前途的方法。
