Discipline: Biological Sciences
Tania Lee Class-Martinez - University of Puerto Rico, Mayaguez Campus
Co-Author(s): Andrew L. Markley, Ryan L. Clark, and Brian F. Pfleger, University of Wisonsin, Madison
Today one of the biggest contamination problems is the high level of carbon dioxide in the air. In looking for more ecofriendly and cost-effective processes, we proposed the use of Cyanobacteria for the direct photosynthetic production of glucose and L-lysine without using farmland and synthetic fertilizers. The generated glucose could be used in the biofuels development and the outcome L-lysine could be used for animal feed and pharmaceuticals products. In order to increase the glycogen production in cyanobacteria, we used genetic engineering to design two different strains: glgC + FBA FBP and glgC. To test the glycogen production, a new assay for glycogen analysis was developed and both strains were examined. Also, we utilized Acid Hydrolysis and High Performance Liquid Chromatography to determine the percent of glucose by mass. Analogous to glycogen production, two strains were developed for improve the L-lysine production in Cyanobacteria, DHDPS and DHDPS + YbjE. Both strains were grown to determine the best growing conditions. Also, the extracellular L-lysine production was tested growing an E. coli Lysine Auxotroph on the culture media. A new glycogen screen was developed which successfully predicted the highest glycogen production condition. The High Performance Liquid Chromatography analysis showed that the glgC strain induced a 0.1mM IPTG contained 58% more glycogen than the WT PCC 7002 strain. The DHDPS + YbjE strain show the optimal growing condition and the YbjE lysine efflux transporter was confirmed with E. coli Lysine Auxotroph. Eventually, we want to use the new assay to screen other genetic modifications of WT PCC 7002 (e.g combining genes, removing genes or knocking out genes to maximize glycogen production). Also, we want to repeat the E. coli growth curve experiment to determine whether expressing the YbjE lysine efflux transporter alone without DHDPS also results in L-lysine export.
Funder Acknowledgement(s): National Science Fundation; University of Wisonsin, MRSEC
Faculty Advisor: Department of Chemical and Biological Engineering,