Tuesday, April 30, 2013
Exhibit Hall
Isoprene is a valuable platform chemical with applications not only in the production of rubber but also in the manufacture of medicines, fragrances, pesticides, and aviation fuel. Currently, the industrial production of isoprene relies solely on petrochemical sources through chemical synthesis routes. Due to the steady decline of fossil resources, it is desirable to seek bio-based methods to produce isoprene from renewable carbohydrates. In this study, Escherichia coli was engineered to produce isoprene from galactose. The native galactose catabolic pathway was blocked and redirected to an oxidative route. The advantage of this oxidative pathway is that it directly produces glyceraldehyde 3-phosphate (G3P) and pyruvate, the main substrates of the methylerythritol pathway (MEP). To increase the G3P and pyruvate pools, the galactose dehydrogenase (gld) from Pseudomonas syringae and the native galactonate dehydratase (dgoD), 2-dehydro-3-deoxygalactonate kinase (dgoK), and 2-keto-3-deoxygalactonate 6-phosphate aldolase (dgoA) were overexpressed in Escherichia coli. Next, the 1-deoxy-D-xylulose 5-phosphate (dxs), isopentenyl diphosphate isomerase (idi) and isoprene synthase (ispS) from Populas nigra were also cloned to enhance the production of isoprene. Preliminary experiments showed a ~60% increase in yield of isoprene from galactose via the oxidative pathway compared to the native glycolytic route.
This work was supported by Priority Research Centers Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2012-0006693).