Coculture fermentation processes in wheat sourdough simulation media with LMG 23699 and IMDO 010110 reflect their competitiveness and desirable traits for sourdough and sourdough bread production.

Mixed-strain starter cultures can be used to steer sourdough production and yield sourdoughs containing different volatile organic compounds (VOCs), such as esters with fruity notes. The present study aimed to characterize the fermentation dynamics, including ester production capacity, and investigate the involvement of the latter during potential interactions between a novel lactic acid bacteria (LAB)-yeast consortium composed of LMG 23699 and IMDO 010110. Therefore, mono- and co-culture fermentation processes were carried out in a wheat sourdough simulation medium (WSSM) and a modified WSSM that contained ester precursor molecules (mWSSM). The coculture fermentation (CF) processes carried out in WSSM resulted in a faster pH drop and a higher lactic acid production compared with the monoculture ones, which could be of interest in view of the competitive advantage of the LAB-yeast consortium toward background microorganisms. Moreover, these CF processes resulted in higher carbon dioxide production and different VOC profiles, which could be of interest for the production of sourdough breads with desirable specific volumes and flavorful crumbs. Fermentation processes carried out in mWSSM confirmed ethyl lactate biosynthesis by LMG 23699 and showed a change in the ester profile of the yeast strain. However, the CF processes carried out in this medium showed the vulnerability of the yeast strain toward acidic stress. To conclude, the laboratory fermentation processes of the present study showed the ester production and competitiveness of LMG 23699 and IMDO 010110 as a mixed-strain starter culture for the production of novel sourdoughs and sourdough bread.IMPORTANCEStrains of specific species of yeasts and lactic acid bacteria (LAB) often form a stable consortium during sourdough production. Hence, the intentional use of mixed-strain starter cultures composed of such strains can steer sourdough production to obtain, for instance, sourdoughs containing esters with fruity notes. The present study valorized a novel LAB-yeast consortium composed of LMG 23699 and IMDO 010110 for the production of such sourdoughs. The application of coculture fermentation processes in wheat sourdough simulation media showed their ester biosynthesis potential and competitiveness. These data will allow the valorization of mixed-strain starter cultures composed of the strains examined.