Exploiting full bioconversion capacities of the microorganisms
entails considering cell robustness as a key aspect in the development
of any co-fermentation process. The impact of the C-source
shifts on the cellular robustness at the single-cell level during a
co-fermentation process has been overlooked so far. The present
study has extended the role of mixed carbon source strategies
beyond the control of the hierarchical carbon utilization, evaluating
for the first time the impacts of C-source shifts on the cellular
responses during a co-fermentation process. Such integrated
knowledge enabled not only to avoid the underlined
carboxylic-acid stress physiological response but also to boost
the metabolic activity of P. taetrolens cells, leading to an overproduction
of lactobionic acid from cheese whey by combining a
C-source limiting bioprocessing approach while supporting higher
cellular robustness (Figs. 4 and S2).