BioChem - DOS

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

Microbial biotechnology

Grunwald, Stephan; Mottet, Alexis; Grousseau, Estelle; Plassmeier, Jens K; Popović , Milan K; Uribelarrea, Jean-Louis; Gorret, Nathalie; Guillouet, Sté phane E; Sinskey, Anthony

<P>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&#x2013;Benson&#x2013;Bassham (CBB) cycle into value-added chemical compounds by non-photosynthetic microorganisms. In this work, organoautotrophic growth of <I>R</I><I>alstonia eutropha</I> 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<SUP>&#x2212;1</SUP> 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 (&mu;<SUB>max</SUB> = 0.18 h<SUP>&#x2212;1</SUP>) and to study the impact of increasing formic acid concentrations on growth yields. High formic acid sensitivity was found in <I>R</I> <I>eutropha</I> since a linear decrease in the biomass yield with increasing residual formic acid concentrations was observed between 0 and 1.5 g l<SUP>&#x2212;1</SUP>.</P>

2015

BlackWell Publishing Ltd

1751-7907

1751-7915

8

1

pp.155-163

10.1111/1751-7915.12149

http://click.ndsl.kr/servlet/OpenAPIDetailView?keyValue=05787966&target=NART&cn=NART71458309