Proposal Number: 1132442
Global climate change has stimulated efforts towards a reduction of net carbon dioxide (CO2) emissions. One approach to reduce net CO2 emission is to recycle the CO2 as a feedstock for producing fuels or chemicals using photosynthesis. In any scalable process, continuous production of biofuel under natural light conditions with a dinural (light/dark) cycle is critical to maximize production and minimize costs. The proposed research aims to genetically modify photosynthetic bacteria (cyanobacteria) to convert both CO2 and glucose into isobutyraldehyde, which can be converted to butanol, a potential liquid transportation fuel. Under light conditions, model cyanobacteria will be metabolically engineered to produce isobutyraldehyde from CO2. Systems biology approaches will be used to further engineer the cyanbacteria from an obligate photoautotroph into a heterotroph to produce isobutyraldehyde from glucose under dark conditions as well.
The overall goals of this proposed research are to construct a platform to produce isobutyraldehyde in a cyanobacterium without light, gain understanding of the complex behavior of obligate photoautotrophs, and engineer their biological systems through rational design enabled by metabolic engineering and synthetic biology. The research plan has three components: 1) Heterologous expression of glucose transporter and 2-ketoglutarate dehydrogenase in the cyanobacterium Synechococcus elongatus; 2) Improvement of heterotrophic growth and production using evolutionary and genomic approaches; and 3) Characterization the engineered strains. The research outcomes have the potential to elucidate the critical mechanisms that cause obligate photoautotrophy in photosynthetic bacteria.
The proposed education activities will train undergraduate and graduate students in metabolic engineering and synthetic biology through team and peer mentorship approaches. The proposed outreach activities will be designed to stimulate interest of K-12 students in bioenergy topics using existing programs at University of California at Davis (UCD), including the Teen Biotech Challenge (TBC) program, and American Chemical Society (ACS) project SEED summer research program, and the UCD Young Scholars program.