title: Metabolic engineering of cyanobacteria for the photosynthetic production of succinate.
abstract: Succinate is an important commodity chemical currently used in the food, pharmaceutical, and polymer industries. It can also be chemically converted into other major industrial chemicals such as 1,4-butanediol, butadiene, and tetrahydrofuran. Here we metabolically engineered a model cyanobacterium Synechococcus elongatus PCC 7942 to photosynthetically produce succinate. We expressed the genes encoding for α-ketoglutarate decarboxylase and succinate semialdehyde dehydrogenase in S. elongatus PCC 7942, resulting in a strain capable of producing 120mg/L of succinate. However, this recombinant strain exhibited severe growth retardation upon induction of the genes encoding for the succinate producing pathway, potentially due to the depletion of α-ketoglutarate. To replenish α-ketoglutarate, we expressed the genes encoding for phosphoenolpyruvate carboxylase and citrate synthase from Corynebacterium glutamicum into the succinate producing strain. The resulting strain successfully restored the growth phenotype and produced succinate with a titer of 430mg/L in 8 days. These results demonstrated the possibility of photoautotrophic succinate production.
authors.affiliation: Department of Biological Science and Technology, National Chiao Tung University, Hsinchu 30010, Taiwan. Electronic address: ethanilan@nctu.edu.tw.
authors.forename: Ethan I
authors.initials: EI
authors.lastname: Lan
authors.affiliation: Department of Biological Science and Technology, National Chiao Tung University, Hsinchu 30010, Taiwan.
authors.forename: Crystal T
authors.initials: CT
authors.lastname: Wei
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D048230:Corynebacterium glutamicum / Q000201:enzymology; D060847:Metabolic Engineering; D010788:Photosynthesis / Q000235:genetics*; D019802:Succinic Acid / Q000378:metabolism*; D046940:Synechococcus / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D019802:Succinic Acid
keywords: Bio-based production; Carbon dioxide re-utilization; Cyanobacteria; Succinic acid