Kinetic and stoichiometric characterization of organoautotrophic growth of Ralstonia eutropha on formic acid in fed-batch and continuous cultures

Microb Biotechnol. 2015 Jan;8(1):155-63. doi: 10.1111/1751-7915.12149. Epub 2014 Aug 13.


Formic acid, acting as both carbon and energy source, is a safe alternative to a carbon dioxide, hydrogen and dioxygen mix for studying the conversion of carbon through the Calvin-Benson-Bassham (CBB) cycle into value-added chemical compounds by non-photosynthetic microorganisms. In this work, organoautotrophic growth of Ralstonia eutropha on formic acid was studied using an approach combining stoichiometric modeling and controlled cultures in bioreactors. A strain deleted of its polyhydroxyalkanoate production pathway was used in order to carry out a physiological characterization. The maximal growth yield was determined at 0.16 Cmole Cmole(-1) in a formate-limited continuous culture. The measured yield corresponded to 76% to 85% of the theoretical yield (later confirmed in pH-controlled fed-batch cultures). The stoichiometric study highlighted the imbalance between carbon and energy provided by formic acid and explained the low growth yields measured. Fed-batch cultures were also used to determine the maximum specific growth rate (μmax = 0.18 h(-1) ) and to study the impact of increasing formic acid concentrations on growth yields. High formic acid sensitivity was found in R eutropha since a linear decrease in the biomass yield with increasing residual formic acid concentrations was observed between 0 and 1.5 g l(-1) .

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Autotrophic Processes
  • Bioreactors / microbiology*
  • Cupriavidus necator / chemistry
  • Cupriavidus necator / growth & development*
  • Cupriavidus necator / metabolism*
  • Formates / metabolism*
  • Kinetics
  • Models, Biological
  • Polyhydroxyalkanoates / metabolism


  • Formates
  • Polyhydroxyalkanoates
  • formic acid