Pseudomonas putida KT2440 endures temporary oxygen limitations

Abstract

The obligate aerobic nature of Pseudomonas putida, one of the most prominent whole-cell biocatalysts emerging for industrial bioprocesses, questions its ability to be cultivated in large-scale bioreactors, which exhibit zones of low dissolved oxygen tension. P. putida KT2440 was repeatedly subjected to temporary oxygen limitations in scale-down approaches to assess the effect on growth and an exemplary production of rhamnolipids. At those conditions, the growth and production of P. putida KT2440 were decelerated compared to well-aerated reference cultivations, but remarkably, final biomass and rhamnolipid titers were similar. The robust growth behavior was confirmed across different cultivation systems, media compositions, and laboratories, even when P. putida KT2440 was repeatedly exposed to dual carbon and oxygen starvation. Quantification of the nucleotides ATP, ADP, and AMP revealed a decrease of intracellular ATP concentrations with increasing duration of oxygen starvation, which can, however, be restored when re-supplied with oxygen.Only small changes in the proteome were detected when cells encountered oscillations in dissolved oxygen tensions. Concluding, P. putida KT2440 appears to be able to cope with repeated oxygen limitations as they occur in large-scale bioreactors, affirming its outstanding suitability as a whole-cell biocatalyst for industrialscale bioprocesses.

Novel multiphase loop reactor with improved aeration enables foam-free rhamnolipid production by Pseudomonas putida

“…P. putida KT2440 SK4 with attTn7::Pffg-rhlAB [23,24], is a RL-producing whole-cell biocatalyst, which tolerates temporary oxygen depletion [22]. Its chassis strain, P. putida KT2440 [26][27][28], is classified as host-vector system with safety level 1 (HV1).…”

“…Additionally, cell retention, commonly applied for in situ liquid-liquid extraction with an external loop to prevent the organisms from excessive anaerobic residence times, is not required [21]. Regarding anaerobe residence times in the MPLR, we previously showed that a short-term oxygen limitation, the obligate aerobe organism P. putida might be exposed to in the MPLR, only influences the productivity due to moderately slower growth and production while the final biomass and product titers remain unaltered [22].…”

Nitrogen metabolism in Pseudomonas putida: functional analysis using random barcode transposon sequencing

“…P. putida KT2440 is a known obligate aerobe, and cannot use alternative terminal electron acceptors during oxidative phosphorylation (30). Because of this, oxidized nitrogen species can only be used as nitrogen sources.…”

Small RNAs in the Antarctic bacterium Pseudomonas extremaustralis responsive to oxygen availability and oxidative stress

“…In P. aeruginosa, a bacterium with clinical importance, the regulatory sRNA PhrS is induced to thrive under anaerobiosis and its transcription is activated by Anr, the oxygen responsive regulator homologue of the FNR protein of E. coli (Hoe et al, 2013). Pseudomonas aeruginosa's sRNAs are the most studied within the genus G omez-Lozano et al, 2014;Miller et al, 2016;Taylor et al, 2017); however, metabolic variability under different oxygen availability conditions can be found among Pseudomonas species (Arai, 2011;Tribelli et al, 2019;Demling et al, 2021).…”

“…coli (Hoe et al ., 2013). Pseudomonas aeruginosa's sRNAs are the most studied within the genus (Sonnleitner et al ., 2011; Gómez‐Lozano et al ., 2014; Miller et al ., 2016; Taylor et al ., 2017); however, metabolic variability under different oxygen availability conditions can be found among Pseudomonas species (Arai, 2011; Tribelli et al ., 2019; Demling et al ., 2021).…”