The diversity and function of sourdough starter microbiomes

Humans have relied on sourdough starter microbial communities to make leavened bread for thousands of years, but only a small fraction of global sourdough biodiversity has been characterized. Working with a citizen-scientist network of bread bakers, we determined the microbial diversity of 500 sourdough starters from four continents. In sharp contrast with widespread assumptions, we found little evidence for biogeographic patterns in starter communities. Strong co-occurrence patterns observed in situ and recreated in vitro demonstrate that microbial interactions shape sourdough community structure. Variation in dough rise rates and aromas were largely explained by acetic acid bacteria, a mostly overlooked group of sourdough microbes. Our study reveals the full extent of microbial diversity in an ancient fermented food across diverse cultural and geographic backgrounds.

数千年来，人类一直依靠酸面团发酵剂（sourdough starter）中的微生物群落制作发酵面包，但目前仅对全球范围内极小一部分酸面团生物多样性完成了定性表征。本研究与一个由面包烘焙师组成的公民科学网络合作，对来自四大洲的500份酸面团发酵剂的微生物多样性进行了测定。与学界普遍持有的假设形成鲜明对比的是，本研究几乎未发现酸面团发酵剂群落存在生物地理分布模式的证据。在原位环境中观测到并可在体外人工培养条件下复现的显著共现模式表明，微生物相互作用塑造了酸面团群落的结构。面团发酵速率与风味香气的差异，在很大程度上可由醋酸菌（acetic acid bacteria）这一长期以来被忽视的酸面团微生物类群来解释。本研究揭示了这一古老发酵食品在多元文化与地理背景下所蕴含的全部微生物多样性全貌。