ERC Researchers Increase Production of an Important Chemical Compound

Achievement date: 
2014
Outcome/accomplishment: 

Researchers at the Center for Biorenewable Chemicals (CBiRC), an NSF-funded Engineering Research Center (ERC) headquartered at Iowa State University, have improved substantially the production of the pyrone triacetic acid lactone (TAL) in the yeast Saccharomyces cerevisiae.

Impact/benefits: 

TAL titer (a way of expressing concentration) has been increased by 25-fold and yield (g TAL/g glucose) by 48-fold.  These advances demonstrate a successful route for obtaining commercially viable levels of pyrones. Similar approaches will prove useful for the high-level synthesis of related products.

Explanation/Background: 

To engineer the strains for increased synthesis, information from both the technical literature and an OptKnock computational strategy were used to predict beneficial genetic changes to tune the metabolic pathways in the yeast host. Of 14 single-gene knockouts tested, 11 increased TAL levels (on a per cell basis) by approximately two-fold or more, and combinations of gene knockouts increased pyrone production further. Combining the promising strains and 2-pyrone synthase (2-PS) variants resulted in the highest titers of TAL.

Collaboration between two research thrusts was instrumental in obtaining the improvements. The TAL-containing culture broth has been transferred to a third research thrust for further conversion via chemical catalysis.