Presentation Information
[4GteX-08]Carboxylic Acid Production in Cyanobacteria: From Laboratory Research to the Foundation of a Bioventure Company
○TAKASHI Osanai1,2,3 (1. Meiji University (Japan), 2. Cyanology Co. Ltd. (Japan), 3. Blue and Green Carbon Consortium (Japan))
Keywords:
carboxylic acids,cyanobacteria,fumarate,metabolic engineering,Synechocystis
[Purpose]Cyanobacteria are oxygenic photosynthetic bacteria capable of converting carbon dioxide into value-added chemicals. Among them, Synechocystis sp. PCC 6803 serves as a model unicellular cyanobacterium because of its fully sequenced genome and high efficiency of homologous recombination–based genetic manipulation. Our research aims to elucidate the metabolic mechanisms underlying carboxylic acid production in Synechocystis and to establish a sustainable production platform for industrial application. Furthermore, we explore how fundamental laboratory findings can be translated into societal implementation through the establishment of a bioventure company.
[Method]Carboxylic acid production from Synechocystis was conducted under both dark anaerobic and light aerobic conditions. Metabolic analysis was performed to quantify extracellular organic acids including acetate, lactate, fumarate, and succinate. Gene disruption and overexpression were performed to identify key metabolic enzymes and regulatory mechanisms involved in organic acid synthesis. Photosynthetic activity and growth parameters were evaluated to determine the physiological impact of genetic modifications.
[Results]Dark, anaerobic incubation enabled Synechocystis cells to excrete multiple carboxylic acids into the cultivation medium. Through genetic manipulation, we further achieved carboxylic acid excretion under light, aerobic conditions. Our analyses revealed that fumarate was excreted by the knockout of fumC encoding a fumarase via unique metabolic routes and enzymes that differ from canonical heterotrophic bacterial pathways. Additional genetic manipulation such as phosphoenolpyruvate carboxylase (PEPC) and a carbon/nitrogen balance sensor PII further increased fumarate production. Importantly, genetic modifications targeting organic acid production significantly influenced photosynthetic activity and cell growth, indicating tight metabolic coupling between carbon fixation, redox balance, and organic acid biosynthesis.
[Consideration]These findings demonstrate that cyanobacterial carboxylic acid production is governed by regulatory and metabolic networks different from those in heterotrophic systems. Engineering strategies must therefore consider not only pathway enhancement but also metabolic network, particularly carbon and nitrogen balance, photosynthetic electron transport and redox homeostasis.
[Conclusion]Our laboratory studies provide mechanistic insights into cyanobacterial carboxylic acid production and establish a foundation for metabolic engineering strategies. Based on these scientific outcomes, we have launched the bioventure company named Cyanology to accelerate industrial research and development utilizing microalgae. This work illustrates how fundamental cyanobacterial research can be translated into sustainable biotechnological innovation and contributes to the development of carbon-neutral bioindustries.
[Method]Carboxylic acid production from Synechocystis was conducted under both dark anaerobic and light aerobic conditions. Metabolic analysis was performed to quantify extracellular organic acids including acetate, lactate, fumarate, and succinate. Gene disruption and overexpression were performed to identify key metabolic enzymes and regulatory mechanisms involved in organic acid synthesis. Photosynthetic activity and growth parameters were evaluated to determine the physiological impact of genetic modifications.
[Results]Dark, anaerobic incubation enabled Synechocystis cells to excrete multiple carboxylic acids into the cultivation medium. Through genetic manipulation, we further achieved carboxylic acid excretion under light, aerobic conditions. Our analyses revealed that fumarate was excreted by the knockout of fumC encoding a fumarase via unique metabolic routes and enzymes that differ from canonical heterotrophic bacterial pathways. Additional genetic manipulation such as phosphoenolpyruvate carboxylase (PEPC) and a carbon/nitrogen balance sensor PII further increased fumarate production. Importantly, genetic modifications targeting organic acid production significantly influenced photosynthetic activity and cell growth, indicating tight metabolic coupling between carbon fixation, redox balance, and organic acid biosynthesis.
[Consideration]These findings demonstrate that cyanobacterial carboxylic acid production is governed by regulatory and metabolic networks different from those in heterotrophic systems. Engineering strategies must therefore consider not only pathway enhancement but also metabolic network, particularly carbon and nitrogen balance, photosynthetic electron transport and redox homeostasis.
[Conclusion]Our laboratory studies provide mechanistic insights into cyanobacterial carboxylic acid production and establish a foundation for metabolic engineering strategies. Based on these scientific outcomes, we have launched the bioventure company named Cyanology to accelerate industrial research and development utilizing microalgae. This work illustrates how fundamental cyanobacterial research can be translated into sustainable biotechnological innovation and contributes to the development of carbon-neutral bioindustries.
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