Optimization of the Sistrom Culture Medium for Large-Scale Batch Cultivation of Rhodospirillum rubrum under Semiaerobic Conditions with Maximal Yield of Photosynthetic Membranes

Abstract

has been modified to allow the growth of Rhodospirillum rubrum in large-scale batch cultures under dark, semiaerobic conditions. The simultaneous use of two substrates, NH4-succinate (46 mM) and fructose (0.3%), which are utilized in aerobic and fermentative metabolism, respectively, leads to very high cell densities with a maximal yield of photosynthetic membranes.

Stepwise reduction of the culture redox potential allows the analysis of microaerobic metabolism and photosynthetic membrane synthesis in Rhodospirillum rubrum

“…For systematic analysis of its microaerobic growth behavior, R. rubrum was cultured on M2SF medium at different states of oxygen limitation according to the CRP‐dependent process control strategy described in CRP‐Dependent Process Control Section. The M2SF medium was used as it allows the maximum expression of photosynthetic membranes (PM) in R. rubrum under oxygen‐limited conditions in the dark (Ghosh et al, 1994). During the time period after the CRP step, the growth behavior of the cells was analyzed by calculating the ΔCRP‐dependent extracellular reaction rates of cell growth, PM production, substrate consumption, production of organic acids and hydrogen emission (see Section Microaerobic Behaviour of R. rubrum Batch Cultures ).…”

“…R. rubrum S1 (ATCC 11170) was cultured on the minimal medium M2SF at pH 6.8 and at 30°C in the dark. The M2SF medium was developed on the basis of the M medium introduced by Sistrom (Sistrom, 1960) and contains 40 mmol L −1 succinate and 16.6 mmol L −1 fructose as carbon sources (Ghosh et al, 1994). As pre‐culture a microaerobic shake flask culture in its exponential growth phase was used.…”

“…This procedure is generally restricted to batch cultures as the accumulation of fermentative organic acids is needed to indicate oxygen limitation. Further, data obtained from this cultivation strategy (Ghosh et al, 1994; Grammel et al, 2003) suggest that this approach results in a transient shift between different oxygen‐limited states and thus did not produce one specific and reproducible oxygen‐limited condition. Zeng et al (1994) showed that optimal microaerobic conditions for the production of 2,3 butanediol by Enterobacter aerogenes can be achieved by controlling the respiratory quotient (RQ).…”

“…First, it provides the possibility to easily monitor the growth mode of the cells, since the limitation of oxygen is indicated by the formation of highly pigmented intracytoplasmatic membranes (PM). Second, only R. rubrum allows the production of maximum PM levels under oxygen‐limited conditions, when grown on a medium containing succinate and fructose as carbon sources, in the dark (Ghosh et al, 1994).…”

Model‐based derivation, analysis and control of unstable microaerobic steady‐states—Considering Rhodospirillum rubrum as an example

“…Bacterial Strain, Media and Cultivation Conditions R. rubrum S1 (ATCC 11170) was cultured on the minimal medium M2SF at pH 6.8 and at 30 C in the dark. The M2SF medium was developed on the basis of the M medium introduced by Sistrom [1960] and contains 40 mmol L À1 succinate and 16.6 mmol L À1 fructose as carbon sources [Ghosh et al, 1994]. As pre-culture a microaerobic shake flask culture in its exponential growth phase (OD $2.5) was used.…”