## 2 Materials and Methods
### Fermentation Process Monitoring  
Microbiological analyses were conducted on 10 g aliquots of each dough at 0, 3, 6, 9, and 12 h from the start of fermentation. Each sample was collected under sterile conditions  
Figure 1: Experimental design of dough production. Abbreviations: C1, control trial inoculated with _Leuconstoc mesenteroides_; C2, control trial inoculated with _Saccharomyces cerevisiae_; B1, trial co-inoculated with _L. mesenteroides_ and _Papilitrena terrestris_; B2, trial co-inoculated with _S. cerevisiae_ and _P. terrestris_; B3, trial co-inoculated with _L. mesenteroides_, _P. terrestris_, and _S. cerevisiae_.  
and suspended in 90 mL of [PERSON]'s solution (Sigma-Aldrich, Milan, Italy). The samples were then homogenized at maximum speed (10 strokes/s) for 2 min using a BagMixer(r) 400 stomacher (Interscience, Saint Nom, France).  
Cell suspensions were subsequently prepared for the plate counts by performing decimal serial dilutions in sterile glass tubes, which were then inoculated into Petri plates as follows: (i) plate count agar (PCA) was used to enumerate total mesophilic microorganisms (TMM) and incubated aerobically at 30 \({}^{\circ}\)C for 72 h; (ii) modified de Man, Rogosa, and Sharpe (mMRS) agar to enumerate lactic acid bacteria (LAB) rods, incubated anaerobically at 30 \({}^{\circ}\)C for 48 h [21]; (iii) M17 agar to detect LAB cocci, incubated anaerobically at 30 \({}^{\circ}\)C for 48 h; (iv) sourdough bacteria (SDB) agar to count sourdough LAB, incubated anaerobically at 30 \({}^{\circ}\)C for 48 h. For the yeast analysis, both _Saccharomyces_ and non-_Saccharomyces_ yeasts were counted by plating on Wallerstein Laboratory (WL) nutrient agar incubated aerobically at 28 \({}^{\circ}\)C for 72 h; this medium allowed for the differentiation and classification of the yeasts into the two aforementioned groups, as reported by [PERSON] et al. [19]. Anaerobic conditions were created using hermetically sealed jars (Oxoid, Milan, Italy) and the AnaerobicGN AN25 system (Oxoid, Milan, Italy). The media (mMRS, M17, and SDB) used to count the three types of LAB were added with cicloheximide (10 mg/mL) in order to inhibit yeast and mold growth, while WL agar was added with chloramphenicol (0.1 mg/mL) to avoid bacterial growth. Microbiological analyses were performed in triplicate and the final results were expressed as Log colony forming units (CFU)/g. All media and reagents were purchased from Condalab (Torrejon de Ardoz, Spain). The chemical monitoring of the doughs was realized through the measurements of pH and total tittable acidity (TTA). pH was measured by directly immersing a pH meter model HI98165 (Hanna Instruments, Ronchi di Villafranca Padovana, Italy) into 10 g of dough collected aseptically. TTA (expressed as mL of NaOH of 0.1 N/10 g of dough) was determined in the same samples used to measure pH, which were added with sterile distilled water, transferred into stomacher bags, and homogenized for 2 min at the highest speed. Both pH and TTA measurements were performed in triplicate at 0, 3, 6, 9, and 12 h after the inocula.  
Furthermore, both dough volume increase and CO\({}_{2}\) production were monitored throughout the fermentation process. Dough volume increase [22] was measured every 3 h up to the 12 th hour by measuring the height of the dough placed in sterile polypropylene containers (MedicalMarket, Rome, Italy) at 30 \({}^{\circ}\)C. The amount of CO\({}_{2}\) produced was indirectly evaluated by recording weight loss at different intervals using the same containers with perforated lids to allow CO\({}_{2}\) to escape during fermentation [23].