Biotech Updates

Researchers Engineer Arabidopsis In Hopes of Modifying Lignin Molecules

March 1, 2017
https://biotechnologyforbiofuels.biomedcentral.com/articles/10.1186/s13068-017-0725-0

Monolignol-like molecules can be integrated into lignin along with conventional monolignol units, resulting in hydrolyzable lignin, an easily removable form suitable for biofuel production. Disinapoyl esters (DSEs) were found to be promising lignin modifying units in this system. Researchers from Purdue University manipulated the metabolic flux in Arabidopsis thaliana to increase the amounts of DSEs by overexpressing sinapoylglucose:sinapoylglucose sinapoyltransferase (SST), which produces two main DSEs, 1,2-disinapoylglucose, and 3,4-disinapoyl-fructopyranose.

The team were successful in overproducing DSEs by introducing an SST-overexpression construct into the sinapoylglucose accumulator1 (sng1-6) mutant (SST-OE sng1-6), which lacks enzymes that would compete for the SST substrate, sinapoyglucose. Introduction of cinnamyl alcohol dehydrogenase-c (cad-c) and cad-d mutations into the SST-OE sng1-6 line further increased DSEs. However, while the team successfully upregulated the accumulation of the DSEs, the team did not find any evidence of the integration of these DSEs into the cell wall.

These results suggest that although metabolic engineering is possible, a deeper understanding of sequestration and transport mechanisms will be necessary for successful lignin engineering using this approach.