Today BiotecEra published an important research article entitled " Elevating 4-hydroxycoumarin production through alleviating thioesterase-mediated salicoyl-CoA degradation" in Metabolic Engineering, the No. 1 journal in the field with an impact factor of 8.142.
The project was sponsored by the National Science Foundation Small Business Technology Transfer (STTR) program and mutually carried out by BiotecEra Inc. and the University of Georgia. The lead authors Ms. Monika mahajani and Dr. Xiaolin Shen made major contributions to this work under the supervision of the Dr. Yuheng Lin. This work identified and solved an important problem existing in the heterologous biosynthesis of acyl-CoA derived natural products. More information is available in the abstract below and the journal website.
“Acyl-CoAs are essential intermediates in the biosynthetic pathways of a number of industrially and pharmaceutically important molecules. When these pathways are reconstituted in a heterologous microbial host for metabolic engineering purposes, the acyl-CoAs may be subject to undesirable hydrolysis by the host's native thioesterases, resulting in a waste of cellular energy and decreased intermediate availability, thus impairing bioconversion efficiency. 4-hydroxycoumarin (4HC) is a direct synthetic precursor to the commonly used oral anticoagulants (e.g. warfarin) and rodenticides. In our previous study, we have established an artificial pathway for 4HC biosynthesis in Escherichia coli, which involves the thioester intermediate salicoyl-CoA. Here, we utilized the 4HC pathway as a demonstration to examine the negative effect of salicoyl-CoA degradaton, identify and inactivate the responsible thioesterase, and eventually improve the 4HC production. We screened a total of 16 E. coli thioesterases and tested their hydrolytic activity towards salicoyl-CoA in vitro. Among all the tested candidate enzymes, YdiI was found to be the dominant contributor to the salicoyl-CoA degradation in E. coli. Remarkably, the ydiIknockout strain carrying the 4HC pathway exhibited an up to 300% increase in 4HC production. An optimized 4HC pathway construct introduced in the ydiI knockout strain led to the accumulation of 935 mg/L of 4HC in shake flasks, which is about 1.5 folds higher than the wild-type strain. This study demonstrates a systematic strategy to alleviate the undesirable hydrolysis of thioester intermediates, allowing production enhancement for other biosynthetic pathways with similar issues.”