(119e) Cyanobacterial Glycogen Production and Hydrolysis for Production of Media for Industrial Bioprocessing

Cyanobacteria, a branch of photosynthetic microorganisms, as well as terrestrial plants can convert sunlight and carbon dioxide into stored carbohydrates, such as starch and glycogen. Cyanobacterial glycogen production could offer an alternate source of carbohydrates, as compared to terrestrial plants, for biocatalytic processes to produce value-added chemicals. Cyanobacteria offer the potential for higher annual yield than terrestrial plants, and they need neither fresh water nor arable land to grow robustly. This work demonstrates an increased glycogen accumulation in the cyanobacterium Synechococcus PCC 7002 through metabolic engineering, and the use of a growth-associated screen for glycogen production. Evaluation of these strains grown in wastewater nutrient sources yielded improved glycogen productivity. Further, optimization of cyanobacterial hydrolysate produced from glycogen rich strains of PCC 7002 supported growth of Escherichia coli for production of value-added chemicals. Finally, a techno-economic analysis of proposed industrial processes for producing cyanobacterial hydrolysate has shown that through improvements in biomass titers and separation techniques, such a process could compete with corn-based sugar feedstocks.