Microbiota diversity, composition and drivers in waxy proso millet sourdoughs of Niandoubao, a traditional fermented cereal food in northeast China

Abstract

Niandoubao is a famous fermented proso millet food in northeast China. To investigate the composition and drivers of Niandoubao sourdough microbiota, high-throughput sequencing (HTS) combined with culture-dependent method was used to analyze the bacterial and fungal diversity of 28 spontaneous waxy proso millet sourdoughs (WPMSDs). The 537 isolates were identified by plate culture. HTS identified 271 bacterial and 233 fungal species. The 5 genera of Lactobacillales and 6 genera of Saccharomycetales were the dominant fermentation population. Based on beta diversity, the 22 mature sourdoughs were clustered into 5 bacterial clusters or 9 fungal clusters, and each cluster of sourdoughs had unique biomarker. According to ANOSIM and PERMANOVA analyses, microbial interaction exhibited the key driver for community composition (R > 0.91); flour and water played a fundamental role in bacterial composition (R > 0.66); pH, TTA and fermentation time exhibited specific effects on a few species (R < 0.51). Considering the features of growth, antimicrobial and synergistic fermentation, Lactobacillus curvatus, Candida sake and Wickerhamyces anomalus exhibited the best potential as a WPMSD starter. Altogether, the results provide insights into the diversity and drivers of type I WPMSDs microbiota, and important reference for the starter selection and quality improvement of Niandoubao in the future.