The drivers for the establishment and composition of the sourdough microbiota, with particular emphasis on lactic acid bacteria, are reviewed and
discussed. More than 60
different species of lactobacilli were identified from sourdoughs, showing the main overlapping between sourdough and human intestine ecosystems. The microbial kinetics during sourdough preparation was described by several stu
dies using various methodological approaches, inclu
ding culture-dependent and -independent (e.g., high throughput sequencing), and metabolite and meta-transcriptome analyses. Although the abundant microbial
diversity harbored by flours, a succession of dominating and sub-dominating populations of lactic acid bacteria suddenly occurred during sourdough propagation, lea
ding to the progressive assembly of the bacterial community. The contribution of all the potential sources (house microbiota, flour, types of flours and ad
ditional ingre
dients) for contaminating lactic acid bacteria was compared with the aim to find overlapping or specific routes that affect the sourdough microbiota. Once established and mature, pros and cons regar
ding the stability of the sourdough lactic acid bacteria biota were also reviewed, showing contra
dictory results, which were mainly dependent on the species/strains.
Probably, the future research efforts should be dedicated to decrease the sources/drivers of noticeable variation rather than to full standardization of the process for sourdough preparation and use.