Scale‐down studies for the scale‐up of a recombinant Corynebacterium glutamicum fed‐batch fermentation: loss of homogeneity leads to lower levels of cadaverine production

Abstract

BACKGROUND: The loss of efficiency and performance of bioprocesses on scale-up is well known, but not fully understood. This work addresses this problem, by studying the effect of some fermentation gradients (pH, glucose and oxygen) that occur at the larger scale in a bench-scale two-compartment reactor [plug flow reactor (PFR) + stirred tank reactor (STR)] using the cadaverine-producing recombinant Corynebacterium glutamicum DM1945 act3 Ptuf-ldcC_OPT. The new scale-down strategy developed here studied the effect of increasing the magnitude of fermentation gradients by considering not only the average cell residence time in the PFR ( PFR ), but also the mean frequency at which the bacterial cells entered the PFR (f m ) section of the two-compartment reactor.RESULTS: On implementing this strategy the cadaverine production decreased on average by 26%, 49% and 59% when the PFR was increased from 1 to 2 min and then 5 min respectively compared to the control fermentation. The carbon dioxide productivity was highest (3.1-fold that of the control) at a PFR of 5 min, but no losses were observed in biomass production. However, the population of viable but non-culturable cells increased as the magnitude of fermentation gradients was increased. The new scale-down approach was also shown to have a bigger impact on fermentation performance than the traditional one.CONCLUSION: This study demonstrated that C. glutamicum DM1945 act3 Ptuf-ldcC_OPT physiological response was a function of the magnitude of fermentation gradients simulated. The adaptations of a bacterial cell within a heterogeneous environment ultimately result in losses in fermentation productivity as observed here.

Impedance flow cytometry for viability analysis of Corynebacterium glutamicum

“…2c, d). This observation might indicate that cultures under these conditions contained viable but not culturable cells (Oliver, 2005), as it has been reported for C. glutamicum cadaverine-production strains (Olughu et al, 2020).…”

“…The copyright holder for this preprint this version posted September 23, 2021. ; https://doi.org/10.1101/2021.09.23.461525 doi: bioRxiv preprint 2005), as it has been reported for C. glutamicum cadaverine-production strains (Olughu et al, 2020).…”

Engineered chromosome-based T7 RNA polymerase in Escherichia coli W3110 for orthogonal T7 promoter circuit as a cell factory

“…Furthermore, the high orthogonality of T7 system was reported as an energy-intensive process [35], leading to less energy in folding the recombinant protein [43]. The in vivo production of DAP by W3110::pI harboring pSU-T7-CadA produced higher DAP without induction, primarily due to the cellular energy was more concentrated for lysine and DAP transportation as well as PLP regeneration [44][45].…”

Does the BioBLU 0.3f single-use scale to the BioFlo® 320 reuseable bioreactor on a matched volumetric oxygen mass transfer coefficient?

“…The use of scale-down models (SDM) in bioprocess development is an essential tool for troubleshooting problems of the large-scale (Enfors et al 2001 ). For example, in fermentation, a validated high throughput scale-down bioreactor confers the advantage of rapid testing of hypothesis and cost-savings during development to mention but a few (Olughu et al 2020 ). Thus, process development teams typically spend considerable time and effort to develop reliable SDM.…”