Metabolic switching of central carbon metabolism in response to nitrate: Application to autofermentative hydrogen production in cyanobacteria

Kelsey McNeely, G. Kenchappa Kumaraswamy, Tiago Guerra, Nicholas Bennette, Gennady Ananyev, G. Charles Dismukes

Research output: Contribution to journalArticle

11 Citations (Scopus)


Nitrate removal from culture media is widely used to enhance autofermentative hydrogen production in cyanobacteria during dark anaerobiosis. Here we have performed a systematic inventory of carbon and nitrogen metabolites, redox pools, and excreted product fluxes which show that addition of nitrate to cultures of Synechococcus sp. PCC 7002 has no influence on glycogen catabolic rate, but shifts the distribution of excreted products from predominantly lactate and H2 to predominantly CO2 and nitrite, while increasing the total consumption of intracellular reducing equivalents (mainly glycogen) by 3-fold. Together with LC-MS derived metabolite pool sizes these data show that glycogen catabolism is redirected from the upper-glycolytic (EMP) pathway to the oxidative pentose phosphate (OPP) pathway upon nitrate addition. This metabolic switch in carbon catabolism is shown to temporally correlate with the pyridine nucleotide redox-poise (NAD(P)H/NAD(P)+) and demonstrates the reductant availability controls H2 evolution in cyanobacteria.

Original languageEnglish
Pages (from-to)83-91
Number of pages9
JournalJournal of Biotechnology
Issue number1
Publication statusPublished - Jul 20 2014



  • Cyanobacteria
  • Fermentation metabolism
  • Glycolysis
  • Hydrogen
  • OPP

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Applied Microbiology and Biotechnology

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