Improve the Biosynthesis of Baicalein and Scutellarein via Manufacturing Self-Assembly Enzyme Reactor In Vivo

Abstract

Baicalein and scutellarein are bioactive flavonoids isolated from the traditional Chinese medicine Scutellaria baicalensis Georgi; however, there is a lack of effective strategies for producing baicalein and scutellarein. In this study, we developed a sequential self-assembly enzyme reactor involving two enzymes in the baicalein pathway with a pair of protein−peptide interactions in E. coli. These domains enabled us to optimize the stoichiometry of two baicalein biosynthetic enzymes recruited to be an enzymes complex. This strategy reduces the accumulation of intermediates and removes the pathway bottleneck. With this strategy, we successfully promoted the titer of baicalein by 6.6fold (from 21.6 to 143.5 mg/L) and that of scutellarein by 1.4-fold (from 84.3 to 120.4 mg/L) in a flask fermentation, respectively. Furthermore, we first achieved the de novo biosynthesis of baicalein directly from glucose, and the strain was capable of producing 214.1 mg/L baicalein by fed-batch fermentation. This work provides novel insights for future optimization and large-scale fermentation of baicalein and scutellarein.

Metabolic engineering of Yarrowia lipolytica for scutellarin production

“…The fed-batch fermentation of scutellarin in YL25 finally reached to 346 mg/L, which was 3.2-fold higher than that produced in S. cerevisiae [ 14 ]. Although the titers in shake flasks and fermenters for E. coli system were similar with our results, there were many expensive inducers and precursors used in E. coli production system, such as IPTG, tyrosine, and sodium malonate [ 66 , 67 ]. In addition, we also noticed that the percentage of apigenin-7-O-glucuronide increased from 3.46% in flask to 18% in the fermenter.…”

Rational engineering in Escherichia coli for high‐titer production of baicalein based on genome‐scale target identification

“…Thus, we control the glucose at 1−5 g/L to keep the strain at a high growth rate. As shown in Figure 5c, the titer of baicalein increased rapidly within 13−29 h, and the maximum titer reached 367.8 mg/L, which was 35.4% higher than the highest titer we previously reported (276.1 mg/L) (Ji et al, 2021). This is the maximum titer of baicalein reported to date.…”

Specific Flavonoids and Their Biosynthetic Pathway in Scutellaria baicalensis

“…Baicalein from the roots of S. baicalensis was reported to be an effective inhibitor of the COVID-19 virus ( Su et al, 2020 ; Liu et al, 2021 ). So far, the complete biosynthetic pathway of baicalein has been elucidated, and the production of baicalein directly from glucose by Escherichia coli -fed batch fermentation can reach 214.1 mg/L ( Ji et al, 2021 ). These studies provide a model for discovering and utilizing medicinal plants for development of therapies.…”