The eight mature spontaneous sourdoughs were subjected to analyses in triplicate using M17 (30 °C, 48 h), mostly for coccus-shaped lactic acid bacteria, and SDB, mMRS and MRS5 (30 °C, 48 h), mostly for dominant lactobacilli and Weissella. Slanetz & Bartley agar (spread plate method, 37 °C, 24–48 h) was used for enterococci, Baird-Parker agar (spread plate method, 30 °C, 48 h) for staphylococci and micrococci, VRBGA for total coliforms, and WA and SDA (30 °C, 48 h) for yeasts. For all media, colonies of bacteria and yeasts with different morphologies were picked and isolated from the penultimate dilution, with the exception of the subdominant culturable lactobacilli, which was isolated from 140 mm diameter plates and considering several decimal dilutions. Isolated colonies were cultivated in broth media and then restreaked onto agar medium (MRS for all lactic acid bacteria and SDA for yeasts) until they were purified. Bacterial and yeast isolates were identified by partial sequencing of the 16S rRNA and 26S rRNA genes, respectively [8 (link), 9 (link)]. The identified strains comprising the sourdough biobank were further used upon selection to reconstruct the de novo synthetic microbial communities.
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