Improvement of thailanstatins production through metabolic engineering

Thailanstatin A and thailanstatin D are potent antiproliferative natural products discovered by our group from the fermentation broth of Burkholderia thailandensis MSMB43 through a genome-guided approach. Large-scale production of thailanstatin A and thailanstatin D for animal studies, however, has not been possible due to their low titer in fermentation broth and extremely low yield after multiple steps of purification. To address this technical obstacle, we metabolically engineered the thailanstatin biosynthetic pathway through targeted-gene deletion. Deletion of tstP, which encodes a dioxygenase involved in converting thailanstatin A to another compound, resulted in 58% increase of thailanstatin A and 132% increase of thailanstatin D. Deletion of tstR, which encodes a cytochrome P450 involved in converting thailanstatin D to thailanstatin A, resulted in more than 7 fold increase of thailanstatin D. Further metabolic engineering and fermentation optimization to drastically increase the production of those promising experimental therapeutic compounds are in progress.