Rerouting Carbon Flux To Enhance Photosynthetic Productivity

Journal Article · Fri Mar 23 00:00:00 EDT 2012 · Applied and Environmental Microbiology

DOI:https://doi.org/10.1128/AEM.07901-11· OSTI ID:1211476

Ducat, DC; Avelar-Rivas, JA; Way, JC; Silver, PA

The bioindustrial production of fuels, chemicals, and therapeutics typically relies upon carbohydrate inputs derived from agricultural plants, resulting in the entanglement of food and chemical commodity markets. We demonstrate the efficient production of sucrose from a cyanobacterial species, Synechococcus elongatus, heterologously expressing a symporter of protons and sucrose (cscB). cscB-expressing cyanobacteria export sucrose irreversibly to concentrations of >10 mM without culture toxicity. Moreover, sucrose-exporting cyanobacteria exhibit increased biomass production rates relative to wild-type strains, accompanied by enhanced photosystem II activity, carbon fixation, and chlorophyll content. The genetic modification of sucrose biosynthesis pathways to minimize competing glucose-or sucrose-consuming reactions can further improve sucrose production, allowing the export of sucrose at rates of up to 36.1 mg liter(-1) h illumination(-1). This rate of production exceeds that of previous reports of targeted, photobiological production from microbes. Engineered S. elongatus produces sucrose in sufficient quantities (up to similar to 80% of total biomass) such that it may be a viable alternative to sugar synthesis from terrestrial plants, including sugarcane.

• Sponsoring Organization: USDOE Advanced Research Projects Agency - Energy (ARPA-E)
• OSTI ID: 1211476
• Journal Information: Applied and Environmental Microbiology, Vol. 78, Issue 8; ISSN 0099-2240
• Country of Publication: United States
• Language: English