Sourdough study shows how microbes live together ^{CEFR B2}

New research from Tufts University used microbes isolated from real sourdough starters to ask whether simple pairwise interactions can predict which species coexist in multispecies communities. Published in Ecology, the study combined laboratory measurements with modelling to test this question directly.

The team grew microbes alone and in pairs, used those growth measures to build a model, and then tested its predictions with larger lab communities of up to nine species. The model generally performed well: it predicted which microbes would coexist and often reproduced their relative abundance in multi‑species mixtures. Only two of the nine species behaved differently from the model’s predictions.

The researchers improved those predictions by adjusting the model to reflect the sourdough life cycle, in which a portion of starter is used for each loaf and the remainder is replenished with flour and water, producing repeated population reductions followed by regrowth. Senior author Lawrence Uricchio noted that when model parameters did not include this cycle they “didn’t do quite as good a job.” Co-leader Kasturi Lele added that some species can outcompete others yet grow very slowly, and the repeated reductions prevent slow growers from reproducing enough to drive others out.

The team says the same ideas may apply to other situations where populations crash and recover, such as antibiotic treatments that reduce gut microbes, sanitation of food‑processing equipment or disinfecting hospital rooms, and disruption of soil microbes by pesticides. Researchers are now developing models that follow microbial evolution, since evolution could shift a starter’s properties or change a person’s gut microbiota over time. Source: Tufts University.