Facile biosynthesis of taxadiene by a newly constructed Escherichia coli strain fusing enzymes taxadiene synthase and geranylgeranyl pyrophosphate synthase

Taxadiene has received extensive attention as the hydrocarbon backbone of a well-known anti-cancer drug, Paclitaxel. In this study, a de novo pathway for taxadiene biosynthesis from cheap carbon sources was newly constructed using Escherichia coli BL21 (DE3) as a chassis cell. The total biosynthesis pathway of taxadiene was divided into upstream and downstream modules for respective optimization. To facilitate the cyclization of the diterpene substrate geranylgeranyl pyrophosphate, two of the key downstream module enzymes, taxadiene synthase and geranylgeranyl pyrophosphate synthase, were genetically expressed in the form of fusion protein. After a series of optimization, the best recombinant strain, designated as E. coli strain ECU5008, achieved a titer of 93.5 mg/L taxadiene in shake flask cultivation. In addition, a commercially available macroporous adsorption resin was employed for the extraction and purification of taxadiene, in which each gram of resin Hz-816 could adsorb about 13.2 mg of taxadiene from the methanol extract of the cultured E. coli cells. The application of macroporous adsorption resin effecctively improved the isolation yield of taxadiene from fermentation broth. Availability data and materials: All data generated or analyzed during this study are included in this article and its Supplementary information file.